Some Diseases
 

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[QUOTE][B]Note:[/B] This thread intends to be complete guide for diseases and pathology. Conducive members are requested to post related material under this thread.

Your co-operation will be appreciated.[/QUOTE]


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[B][FONT=Times New Roman]Some Diseases[/FONT][/B]
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[FONT=Tahoma][B]AIDS[/B][/FONT][FONT=Tahoma] [/FONT]

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[I]in full [B]acquired immunodeficiency syndrome[/B][/I]

Fatal transmissible disorder caused by [URL="bword://!!09HMK27M2P,HIV/"][COLOR=windowtext]HIV[/COLOR][/URL].

AIDS, the last stage of HIV infection, is defined by the appearance of potentially lethal opportunistic infections. The first AIDS cases were identified in 1981, HIV was isolated in 1983, and blood tests were developed by 1985. In 2002 approximately 40,000,000 people worldwide were living with HIV, and more than 25,000,000 had died of AIDS. In the U.S. some 2,000,000 people had been infected with HIV, 800,000 had been diagnosed with AIDS, and 450,000 had died. Sub-Saharan Africa remains the focus of infection, but the number of cases in South and Southeast Asia and elsewhere continues to mount at an alarming rate as well. An initial acute illness usually resolves within weeks. Infected persons then generally have few or no symptoms for about 10 years. As the [URL="bword://!!09HMK27M2P,immune%20system/"][COLOR=windowtext]immune system[/COLOR][/URL] deteriorates, they develop diseases such as [I]Pneumocystis carinii[/I] [URL="bword://!!09HMK27M2P,pneumonia/"][COLOR=windowtext]pneumonia[/COLOR][/URL], [URL="bword://!!09HMK27M2P,cytomegalovirus/"][COLOR=windowtext]cytomegalovirus (CMV)[/COLOR][/URL], [URL="bword://!!09HMK27M2P,lymphoma/"][COLOR=windowtext]lymphoma[/COLOR][/URL], or [URL="bword://!!09HMK27M2P,Kaposi%20sarcoma/"][COLOR=windowtext]Kaposi sarcoma[/COLOR][/URL]. [/FONT]
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[FONT=Tahoma][B]hepatitis[/B][/FONT][FONT=Tahoma] [/FONT]

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[URL="bword://!!09HMK27M2P,inflammation/"][COLOR=windowtext]Inflammation[/COLOR][/URL] of the [URL="bword://!!09HMK27M2P,liver/"][COLOR=windowtext]liver[/COLOR][/URL].

There are seven known types of viral hepatitis (A-G). Types A, spread mainly through food contaminated with feces, and B, transmitted sexually or by injection, cause [URL="bword://!!09HMK27M2P,jaundice/"][COLOR=windowtext]jaundice[/COLOR][/URL] and flulike symptoms. The hepatitis C virus spreads mostly by shared needles in intravenous drug use and can cause liver [URL="bword://!!09HMK27M2P,cirrhosis/"][COLOR=windowtext]cirrhosis[/COLOR][/URL] and cancer after a long latent period. Until recently there was no test to detect it in blood, and many people were exposed through blood transfusions. Hepatitis D becomes active only in the presence of type B; it causes severe chronic liver disease. Type E, like Type A, is transmitted by contaminated food or water; its symptoms are more severe than Type A's and can result in death. The hepatitis F virus (HFV), which was first reported in 1994, is spread like Type A and E. The hepatitis G virus (HGV), isolated in 1996, is believed to be responsible for many sexually transmitted and bloodborne cases of hepatitis. Vaccines exist for types A and B (the second also prevents type D). Drug treatment for B and C is not always effective. The other types may not need drug treatment. Chronic active hepatitis causes spidery and striated skin markings, acne, and abnormal hair growth. It results in liver tissue death (necrosis) progressing to cirrhosis. Alcoholic hepatitis, from long-term overconsumption of alcohol, can be reversed and cirrhosis prevented by early treatment including quitting or sharply reducing drinking. Other drugs can also cause noninfectious hepatitis. An autoimmune hepatitis affects mainly young women and is treated with corticosteroids to relieve symptoms. [/FONT]
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[FONT=Tahoma][B]cholera[/B][/FONT][FONT=Tahoma] [/FONT]

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Acute bacterial infection with [I]Vibrio cholerae[/I], causing massive [URL="bword://!!09HMK27M2P,diarrhea/"][COLOR=windowtext]diarrhea[/COLOR][/URL] with severe depletion of body fluids and salts.

(See [URL="bword://!!09HMK27M2P,bacterial%20diseases/"][COLOR=windowtext]bacterial disease[/COLOR][/URL].) Cholera often occurs in epidemics, spreading in contaminated water or food. The bacteria secrete a toxin that causes the diarrhea, which along with vomiting leads to [URL="bword://!!09HMK27M2P,dehydration/"][COLOR=windowtext]dehydration[/COLOR][/URL], with severe muscle cramps and intense thirst. Stupor and coma may precede death by [URL="bword://!!09HMK27M2P,shock/"][COLOR=windowtext]shock[/COLOR][/URL]. With fluid and salt replacement, the disease passes in two to seven days, sooner if antibiotics are taken the first day. Prevention requires good sanitation, especially clean drinking water. [/FONT]
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[FONT=Tahoma][B]hog cholera[/B][/FONT][FONT=Tahoma] [/FONT]

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[I]or [B]swine fever[/B][/I]

Often fatal viral disease of swine in Europe, North America, and Africa, transmitted by vehicles used to carry pigs, people dealing with them, and uncooked garbage in feed.

Fever progresses to symptoms that include appetite loss; affected eyes and digestive tract; respiratory difficulty; rash; and inflamed mouth and throat. The pig moves reluctantly and staggers; later it cannot rise; coma follows. Antiserum is rarely effective. Survivors become chronically ill and can spread the virus. Illness must be reported, infected animals slaughtered, and quarantine instituted. A vaccine can control it. The African strain causes death sooner and has no effective prevention or treatment. [/FONT]
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[FONT=Tahoma][B]Constipation[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Infrequent (and frequently incomplete) bowel movements. The opposite of diarrhea, constipation is commonly caused by irritable bowel syndrome, diverticulosis, and medications (constipation can paradoxically be caused by overuse of laxatives). Colon cancer can narrow the colon and thereby cause constipation. The large bowel (colon) can be visualized by barium enema x-rays, sigmoidoscopy, and colonoscopy. Barring a condition such as cancer, high-fiber diets can frequently relieve the constipation.[/FONT]
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[FONT=Tahoma][B]Contusion[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Times New Roman][SIZE=3]Another name for a bruise. What is a bruise ? A bruise, or contusion, is caused when blood vessels are damaged or broken as the result of a blow to the skin (be it bumping against something or hitting yourself with a hammer). The raised area of a bump or bruise results from blood leaking from these injured blood vessels into the tissues as well as from the body’s response to the injury. A purplish, flat bruise that occurs when blood leaks out into the top layers of skin is referred to as an ecchymosis. [/SIZE][/FONT]
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[FONT=Tahoma][B]Coronary artery bypass graft (CABG)[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Coronary artery disease develops because of hardening of the arteries (atherosclerosis) that supply blood to the heart muscle. Diagnostic tests include EKG, stress test, echocardiography, and coronary angiography. CABG surgery is advised for selected groups of patients with significant narrowings and blockages of the heart arteries (coronary artery disease) to create new routes around narrowed and blocked arteries, permitting increased blood flow to deliver oxygen and nutrients to the heart muscles. The bypass graft for a CABG can be a vein from the leg or an inner chest wall artery. CABG surgery is performed about 350,000 times annually in the United States, making it one of the most commonly performed major operations. [/FONT]
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[FONT=Tahoma][B]Costochondritis[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Costochondritis is the result of inflammation of the cartilage of the chest wall, usually involving that which surrounds the breast bone (sternum). It causes local pain and tenderness of the chest around the sternum. [/FONT]
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[FONT=Tahoma][B]CPR[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Cardiopulmonary resusitation. CPR involves breathing for the victim and applying external chest compression to make the heart pump. In the case of an early heart attack, death can often be avoided if a bystander starts CPR promptly (within 5 minutes of the onset of ventricular fibrillation). When paramedics arrive, medications and/or electrical shock (cardioversion) to the heart can be administered to convert ventricular fibrillation to a normal heart rhythm. Therefore, prompt CPR and rapid paramedic respronse can improve the survival chances from a heart attack. [/FONT]
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[FONT=Tahoma][B]Cracked tooth syndrome[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]A toothache caused by a broken tooth (tooth fracture) without associated cavity or advanced gum disease. Biting on the area of tooth fracture can cause severe sharp pains. These fractures are usually due to chewing or biting hard objects such as hard candies, pencils, nuts, etc. Sometimes, the fracture can be seen by painting a special dye on the cracked tooth. Treatment usually is to protect the tooth with a crown. However, if placing a crown does not relieve pain symptoms, a root canal procedure may be necessary. [/FONT]
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[FONT=Tahoma][B]Cranial arteritis[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]A serious disease characterized by inflammation of the walls of the blood vessels (vasculitis). The vessels affected by inflammation are the arteries (hence the name "arteritis"). The age of affected patients is usually over 50 years of age. Cranial arteritis is also known as temporal arteritis and as giant cell arteritis. It can lead to blindness and/or stroke. The disease is detected by a biopsy of an artery. It is treated with high dose cortisone-related medications.[/FONT]
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[FONT=Tahoma][B]Cranial dystonia[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]A term used to describe dystonia that affects the muscles of the head, face, and neck. Oromandibular dystonia affects the muscles of the jaw, lips, and tongue. The jaw may be pulled either open or shut, and speech and swallowing can be difficult. Spasmodic dysphonia involves the muscles of the throat that control speech. Also called spastic dysphonia or laryngeal dystonia, it causes strained and difficult speaking or breathy and effortful speech. Meige’s syndrome is the combination of blepharospasm and oromandibular dystonia and sometimes spasmodic dysphonia. Spasmodic torticollis can be classified as a type of cranial dystonia.[/FONT]
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[FONT=Tahoma][B]Creutzfeldt-Jakob disease (CJD)[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]A dementing disease of the brain. It is believed due to an unconventional (not a bacteria or virus), transmissible agent called a prion. Symptoms of CJD include forgetfulness, nervousness, jerky trembling hand movements, unsteady gait, muscle spasms, chronic dementia, balance disorder, and loss of facial expression. CJD is classified as a spongiform encephalopathy. Most cases occur randomly (sporadically), but inherited forms exist. There is neither treatment nor cure for CJD. Other names for CJD include Creutzfeldt-Jakob syndrome, Jakob-Creutzfeldt disease, and spastic pseuodoparalysis.[/FONT]
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[FONT=Tahoma][B]Crib death[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]The sudden and unexpected death of a baby with no known illness, typically affecting infants from 2 weeks to 6 months of age while sleeping. Crib death is now called Sudden Infant Death Syndrome (SIDS). Babies at an increased risk for SIDS include those with a brother or sister who died of SIDS; children whose mothers smoked or used heroin, methadone, or cocaine during pregnancy; infants born weighing less than 4.4 pounds (2000 grams); children with an abnormal breathing pattern with long periods without taking a breath (apnea); and babies who sleep on their stomachs. Since babies who sleep on their stomachs are at least 3 times more likely to die of SIDS than babies who sleep on their backs, children’s health authorities such as the American Academy of Pediatrics recommend always placing infants on their backs to sleep. [/FONT]
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[FONT=Tahoma][B]Crohn’s disease[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]A chronic inflammatory disease of the intestine primarily in the small and large intestines but which can occur anywhere in the digestive system between the mouth and the anus. Named after Burrill Crohn who described the disease in 1932. The disease usually affects persons in their teens or early twenties. It tends to be a chronic, recurrent condition with periods of remission and exacerbation. In the early stages, Crohn’s disease causes small scattered shallow crater-like areas (erosions) called apthous ulcers in the inner surface of the bowel. With time, deeper and larger ulcers develop, causing scarring and stiffness of the bowel and the bowel becomes increasingly narrowed, leading to obstruction. Deep ulcers can puncture holes in the bowel wall, leading to infection in the abdominal cavity (peritonitis) and in adjacent organs.When only the large intestine (colon) is involved, the condition is called Crohn’s colitis. When only the small intestine is involved, the condition is called Crohn’s enteritis. When only the end of the small intestine (the terminal ileum) is involved, it is termed terminal ileitis. When both the small intestine and the large intestine are involved, the condition is called Crohn’s enterocolitis (or ileocolitis). Abdominal pain, diarrhea, vomiting, fever, and weight loss can be symptoms. Crohn’s disease can be associated with reddish tender skin nodules, and inflammation of the joints, spine, eyes, and liver. Diagnosis is by barium enema, barium x-ray of the small bowel, and colonoscopy. Treatment includes medications for inflammation, immune suppression, antibiotics, or surgery. (The disease is also called granulomatous enteritis or regional enteritis). [/FONT]
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[FONT=Tahoma][B]Croup[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]An infection of the larynx, trachea, and the bronchial tubes, mainly in children. Caused usually by viruses, less often by bacteria. Symptoms include a cough that sounds like a barking seal and a harsh crowing sound during inhaling. Treatment can include moist air, salt water nose drops, decongestants and cough suppressants, pain medication, fluids, and occasionally antibiotics. The major concern in croup is breathing difficulty as the air passages narrow. Close monitoring of the breathing of a child with croup is important, especially at night. While most children recover from croup without hospitalization, some children can develop life-threatening breathing difficulties. Therefore, close contact with the doctor during this illness is important. [/FONT]
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[FONT=Tahoma][B]Cushing’s syndrome[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]The constellation of symptoms and signs caused by an excess of cortisol hormone. Cushing syndrome is an extremely complex hormonal condition that involves many areas of the body. Common symptoms are thinning of the skin, weakness, weight gain, bruising, hypertension, diabetes, thin weak bones (osteoporosis), facial puffiness, and in women cessation of periods. Ironically, one of the commonest causes of Cushing’s syndrome is the administration of "cortisol-like medications" for the treatment of diverse diseases. All other cases of Cushing’s syndrome are due to excess production of cortisol by the adrenal gland including 1) an abnormal growth of the pituitary gland, which stimulates the adrenal gland, 2) a benign or malignant growth within the adrenal gland itself, which produces cortisol and 3) production within another part of the body (ectopic production) of a hormone that directly or indirectly stimulates the adrenal gland to make cortisol. Neurosurgeon Harvey Cushing (1869-1939) described hyperadrenocorticism (excessive production of cortisol by the adrenal gland) due quite specifically to an ACTH-secreting pituitary adenoma, a benign pituitary tumor that puts out ACTH (AdrenoCorticoTropic Hormone) which, in turn, drives (or overdrives) the adrenal gland to overproduce cortisol. [/FONT]
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[FONT=Tahoma][B]Cuts[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Severed skin. Washing a cut or scrape with soap and water and keeping it clean and dry is all that is required to care for most wounds. Putting alcohol hydrogen peroxide, and iodine into a wound can delay healing and should be avoided. Seek medical care early if you think that you might need stitches. Any delay can increase the rate of wound infection. Any puncture wound through tennis shoes has a high risk of infection and should be seen by your healthcare professional. Any redness, swelling, increased pain, or pus draining from the wound may indicate an infection that requires professional care. [/FONT]
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[FONT=Tahoma][B]Cystic fibrosis (CF)[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]One of the most common serious genetic (inherited) diseases. The CF gene is carried by 1/20 persons (in Caucasian populations) and 1 in 400 couples is at risk for having children with CF. CF is characterized by the production of abnormal secretions leading to mucous build-up. which can impair the pancreas (and, secondarily, the intestine). CF mucous build-up in lungs can impair respiration. Without treatment, CF results in death for 95% of children before age 5. Early diagnosis of CF is of great importance. Early and continuing treatment of CF is valuable. [/FONT]
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[FONT=Tahoma][B]Cystitis, interstitial (IC)[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Disease that involves inflammation or irritation of the bladder wall. This inflammation can lead to scarring and stiffening of the bladder, and even ulcerations and bleeding. Diagnosis is based on symptoms, findings on cystoscopy and biopsy, and eliminating other treatable causes such as infection. Because doctors do not know what causes IC, treatments are aimed at relieving symptoms. Most people are helped for variable periods of time by one or a combination of treatments. [/FONT]
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[FONT=Tahoma][B]Death rate[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]The number of deaths in the population divided by the average population (or the population at midyear) is the crude death rate. In 1994, for example, the crude death rate per 1,000 population was 8.8 in the United States, 7.1 in Australia, etc. A death rate can also be tabulated according to age or cause. [/FONT]
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[FONT=Tahoma][B]Decongestants[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Drugs that shrink the swollen membranes in the nose and make it easier to breath. Decongestants can be taken orally or by nasal spray. Decongestant nasal spray should not be used for more than five days without the doctor"s advice, and if so, usually only when accompanied by a nasal steroid. Many decongestant nasal sprays often cause a rebound effect if taken too long. A rebound effect is the worsening of symptoms when a drug is discontinued. This is a result of a tissue dependence on the medication. Decongestants should not be used by patients with high blood pressure (hypertension) unless under doctor’s supervision. [/FONT]
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[FONT=Tahoma][B]Defect, enzyme[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]An abnormality in the protein (enzyme) important in catalyzing a normal biochemical reaction in the body. Disorders result from a deficiency (or functional abnormality) of an enzyme. Archibald Garrod in 1902 was the first to attribute a disease to an enzyme defect: an inborn error of metabolism. Today, newborns are routinely screened for certain enzyme defects such as phenylketonuria (PKU) and galactosemia, an error in the handling (metabolism) of the sugar galactose. [/FONT]
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[FONT=Tahoma][B]Deficiency dermatitis and diarrhea, zinc[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]A genetic disease called acrodermatitis enteropathica is characterized by the simultaneous occurrence of skin inflammation (dermatitis) and diarrhea. The skin on the cheeks, elbows and knees and tissue about the mouth and anus are inflammed. There is also balding of the scalp, eyebrows and lashes, delayed wound healing and recurrent bacterial and fungal infections due to immune deficiency. The key laboratory finding is an abnormally low blood zinc level reflecting impaired zinc uptake. Oral treatment with zinc is curative. [/FONT]
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[FONT=Tahoma][B]Deficiency, alpha-1 antitrypsin[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]An inherited disease with little or no production of an important protein, alpha-1 antitrypsin. The lack of this protein leads to damage of various organs, mainly the lung and liver. The disease may become apparent at a very early age or in adulthood, as shortness of breath or liver-related symptoms (jaundice, fatigue, fluid in the abdomen, mental changes, or gastrointestinal bleeding). There are several options for treatment of the lung disease, including replacement of the missing protein. Treatment of the liver disease is a well-timed liver transplant.[/FONT]
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[FONT=Tahoma][B]Deficiency, calcium[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]A low blood calcium (hypocalcemia). Hypocalcemia makes the nervous system highly irritable with tetany (spasms of the hands and feet, muscle cramps, abdominal cramps, overly active reflexes, etc.). Chronic calcium deficiency contributes to poor mineralization of bones, soft bones (osteomalacia) and osteoporosis; and, in children, rickets and impaired growth. Food sources of calcium include dairy foods, some leafy green vegetables such as broccoli and collards, canned salmon, clams, oysters, calcium-fortified foods, and tofu. According to the National Academy of Sciences, adequate intake of calcium is 1 gram daily for both men and women. The upper limit for calcium intake is 2.5 grams daily. [/FONT]
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[FONT=Tahoma][B]Deficiency, glucocerebrosidase[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Causes Gaucher’s disease (type 1), a progressive genetic disease, due to an enzyme defect. The enzyme, glucocerebrosidase, is needed to break down the chemical glucocerebroside. The enzyme defect in persons with Gaucher’s disease (GD) leads to the accumulation of glucocerebroside in the spleen, liver, and lymph nodes. The most common early sign is enlargement of the spleen (located in the upper left abdomen). Other signs include low red blood cell counts (anemia), a decrease in blood clotting cells (platelets), increased pigmentation of the skin, and a yellow fatty spot on the white of the eye (a pinguecula). Severe bone involvement can lead to pain and collapse of the bone of the hips, shoulders, and spine. The GD gene is on chromosome 1. The disease is a recessive trait. Both parents carry a GD gene and transmit it for their child with the disease. The parents’ risk of a child with the disease is 1 in 4 with each pregnancy. This type of Gaucher’s disease (noncerebral juvenile Gaucher’s disease) is most common in Ashkenazi Jews (of European origin) and is the most common genetic disease among Jews in the United States. [/FONT]
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[FONT=Tahoma][B]Deficiency, iron[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Deficiency of iron results in anemia because iron is necessary to make hemoglobin, the key molecule in red blood cells responsible for the transport of oxygen. In iron deficiency anemia, the red cells are unusally small (microcytic) and pale (hypochromic). Characteristic features of iron deficiency anemia in children include failure to thrive (grow) and increased infections. The treatment of iron deficiency anemia , whether it be in children or adults, is with iron and iron-containing foods. Food sources of iron include meat, poultry, eggs, vegetables and cereals (especially those fortified with iron). According to the National Academy of Sciences, the Recommended Dietary Allowances of iron are 15 milligrams per day for women and 10 milligrams per day for men. [/FONT]
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[FONT=Tahoma][B]Deficiency, magnesium[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Can occur due to inadequate intake or impaired intestinal absorption of magnesium. Low magnesium (hypomagnesemia) is often associated with low calcium (hypocalcemia) and potassium (hypokalemia) levels. Deficiency of magnesium causes increased irritability of the nervous system with tetany (spasms of the hands and feet, muscular twitching and cramps, spasm of the larynx, etc.). According to the National Academy of Sciences, the Recommended Dietary Allowances of magnesium are 420milligrams per day for men and 320 milligrams per day for women. The upperlimit of magnesium as supplements is 350 milligrams daily, in addition to the magnesium from food and water. [/FONT]
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[FONT=Tahoma][B]Deficiency, selenium[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Deficiency of the essential mineral selenium causes Keshan disease, a fatal form of cardiomyopathy (disease of the heart muscle) first observed in Keshan province in China and since found elsewhere. According to the National Academy of Sciences, the Recommended Dietary Allowances of selenium are 70 milligrams per day for men and 55 milligrams per day for women. Food sources of selenium include seafoods, some meats such as kidney and liver, and some grains and seeds. [/FONT]
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[FONT=Tahoma][B]Dehydration[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Excessive loss of body water. Diseases of the gastrointestinal tract may lead to dehydration. One clue to dehydration is a rapid drop in weight. A loss of over 10% (15 pounds in a person weighing 150 pounds) is considered severe. Symptoms include increasing thirst, dry mouth, weakness or lightheadedness (particularly if worsening on standing), or a darkening/decrease in urination are suggestive. Severe dehydration can lead to changes in the body’s chemistry, kidney failure, and become life-threatening. The best way to treat dehydration is to prevent it from occurring. If one suspects fluid loss is excessive, notify a physician. Intravenous or oral fluid replacement may be needed. [/FONT]
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[FONT=Tahoma][B]Dental braces (orthodontics)[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]The use of devices to move teeth or adjust underlying bone. The ideal age for starting orthodontic treatment is between ages 3 to 12 years. Temporomandibular joint (TMJ) problems can be corrected with splinting or dental braces. Teeth can be moved by removable appliances or by fixed braces. Crowding of teeth can require extraction of teeth. Retainers may be necessary long after dental braces are placed, especially with orthodontic treatment of adults. [/FONT]
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[FONT=Tahoma][B]Dental pain (toothache)[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]The most common cause of a toothache is a dental cavity. The second most common is gum disease. Toothache can be caused by a problem that does not originate from a tooth or the jaw. [/FONT]
[FONT=Tahoma][B]Deoxyribonucleic acid (DNA)[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]The molecule that encodes the genetic information. DNA is a double-stranded molecule that is held together by weak bonds between base pairs of nucleotides to form a double helix. The four nucleotides in DNA contain the bases: adenine (A), guanine (G), cytosine ©, and thymine(T). Base pairs form naturally only between A and T and between G and C so the base sequence of each single strand of DNA can be simply deduced from that of its partner strand. The code is in triplets such as ATG. The base sequence of that triplet in the partner strand is therefore TAC. [/FONT]
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[FONT=Tahoma][B]Depression[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Low spirits; dejection. Symptoms of depression include apathy, anorexia, lack of emotional expression (flat affect), social withdrawal and fatigue. Prevalent types of depression are major depression, dysthymia, and bipolar disorder. Some types of depression run in families. The first step to getting appropriate treatment is a complete physical and psychological evaluation to determine whether one, in fact, has a depressive illness. [/FONT]
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[FONT=Tahoma][B]Depression, bipolar[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Formerly called manic- depressive illness. Not nearly as prevalent as other forms of depressive disorders, bipolar disorder involves cycles of depression and elation or mania. Sometimes the mood switches are dramatic and rapid, but most often they are gradual. When in the depressed cycle, you can have any or all of the symptoms of a depressive disorder. When in the manic cycle, any or all symptoms listed under mania may be experienced. Mania often affects thinking, judgment, and social behavior in ways that cause serious problems and embarrassment. For example, unwise business or financial decisions may be made when an individual is in a manic phase. Bipolar disorder is often a chronic recurring condition. [/FONT]
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[FONT=Tahoma][B]Desensitization, allergy[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Stimulation of the immune system with gradually increasing doses of the substances to which a person is allergic, the aim being to modify or stop the allergy "war" (by reducing the strength of the IgE and its effect on the mast cells). This form of treatment is very effective for allergies to pollen, mites, cats, and especially stinging insects (eg, bees, hornets, yellowjackets, wasps, velvet ants, fire ants). Allergy immunotherapy usually takes 6 months to a year to become effective and shots (injections) are usually required for 3-5 years. [/FONT]
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[FONT=Tahoma][B]Diabetes mellitus[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]A chronic condition associated with abnormally high levels of sugar (glucose) in the blood.. Absence or insufficient production of insulin (which is produced by the pancreas and lowers blood glucose) causes diabetes. The two types of diabetes are referred to as insulin dependent (type I) and non-insulin dependent (type II). Symptoms of diabetes include increased urine output and appetite as well as fatigue. Diabetes mellitus is diagnosed by blood sugar (glucose) testing. The major complications of diabetes mellitus include dangerously elevated blood sugar, abnormally low blood sugar due to diabetes medications, and disease of the blood vessels which can damage the eye, kidneys, nerves, and heart. Treatment depends on the type of the diabetes. [/FONT]
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[FONT=Tahoma][B]Dialysis[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]The process of cleansing the blood by passing it through a special machine. Dialysis is necessary when the kidneys are not able to filter the blood. Dialysis allows patients with kidney failure a chance to live productive lives. There are two types of dialysis: hemodialysis and peritoneal dialysis. Each type of dialysis has advantages and disadvantages. Patients can often choose the type of long term dialysis that best matches their needs. [/FONT]
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[FONT=Tahoma][B]Dialysis, peritoneal[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Technique that uses the patient’s own body tissues inside of the belly (abdominal cavity) to act as a filter. The intestines lie in the abdominal cavity, the space between the abdominal wall and the spine. A plastic tube called a "dialysis catheter" is placed through the abdominal wall into the abdominal cavity. A special fluid is then flushed into the abdominal cavity and washes around the intestines. The intestinal walls act as a filter between this fluid and the blood stream. By using different types of solutions, waste products and excess water can be removed from the body through this process. [/FONT]
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[FONT=Tahoma][B]Diaphragmatic hernia[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Passage of a loop of bowel through the diaphragm muscle. This type of hernia occurs as the bowel from the abdomen "herniates" upward through the diaphragm into the chest (thoracic) cavity. [/FONT]
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[FONT=Tahoma][B]Diarrhea, antibiotic-induced[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]A bacterium called Clostridium difficile (C.difficile), one of the most common causes of infection of the large bowel (colon). Patients taking antibiotics are at particular risk of becoming infected with C. difficile. Antibiotics disrupt the normal bacteria of the bowel, allowing C. difficile bacteria (and other bacteria) to become established and overgrow the colon. Many persons infected with C. difficile bacteria have no symptoms but can become carriers of the bacteria and infect others. In other people, a toxin produced by C. difficile causes diarrhea, abdominal pain, severe inflammation of the colon (colitis), fever, an elevated white blood count, vomiting and dehydration. In severely affected patients, the inner lining of the colon becomes severely inflamed (a condition called pseudomembranous colitis). Rarely, the walls of the colon wear away and holes develop (colon perforation), which can lead to a life-threatening infection of the abdomen. [/FONT]
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[FONT=Tahoma][B]Diffuse idiopathic skeletal hyperostosis (DISH)[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]A form of degenerative arthritis characteristically associated with flowing calcification along the sides of the vertebrae of the spine and commonly with inflammation (tendinitis) and calcification of the tendons at their attachments points to bone. Because areas of the spine and tendons can become inflamed, antiinflammatory medications (NSAIDs), such ibuprofen, can be helpful in both relieving pain and inflammation. Also called Forestier’s disease. [/FONT]
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[FONT=Tahoma][B]Ear cleaning (yourself)[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Never put anything smaller than your elbow in your ear! Wax is not formed in the deep part of the ear canal near the eardrum, but only in the outer part of the canal. So when a patient has wax pushed up against the eardrum, it is often because he has been probing his ear with such things as cotton-tipped swabs (such as Q-Tips), bobby pins, or twisted napkin corners. Such objects only serve as ramrods to push the wax in deeper. Also, the skin of the ear canal and the eardrum is very thin, fragile and easily injured. The ear canal is more prone to infection after it has been whipped clean of the "good" coating type wax. In addition, we have seen many perforated eardrums as a result of these efforts. [/FONT]
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[FONT=Tahoma][B]Ear cleaning (yourself)[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Never put anything smaller than your elbow in your ear! Wax is not formed in the deep part of the ear canal near the eardrum, but only in the outer part of the canal. So when a patient has wax pushed up against the eardrum, it is often because he has been probing his ear with such things as cotton-tipped swabs (such as Q-Tips), bobby pins, or twisted napkin corners. Such objects only serve as ramrods to push the wax in deeper. Also, the skin of the ear canal and the eardrum is very thin, fragile and easily injured. The ear canal is more prone to infection after it has been whipped clean of the "good" coating type wax. In addition, we have seen many perforated eardrums as a result of these efforts. [/FONT]
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[FONT=Tahoma][B]malaria[/B][/FONT][FONT=Tahoma] [/FONT]

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A serious relapsing infection caused by protozoa of the genus [I]Plasmodium[/I] (see [URL="bword://!!09HMK27M2P,plasmodium/"][COLOR=windowtext]plasmodium[/COLOR][/URL]), transmitted by the bite of the [I]Anopheles[/I] [URL="bword://!!09HMK27M2P,mosquito/"][COLOR=windowtext]mosquito[/COLOR][/URL].

Known since before the 5th century BC, it occurs in tropical and subtropical regions near swamps. The roles of the mosquito and the parasite were proved in the early 20th century. Annual cases worldwide are estimated at 250 million and deaths at 2 million. Malaria from different [I]Plasmodium[/I] species differs in severity, mortality, and geographic distribution. The parasites have an extremely complex life cycle; in one stage they develop synchronously inside red blood cells. Their mass fissions at 48-or 72-hour intervals cause attacks lasting 4–10 hours. Shaking and chills are followed by fever of up to 105 °F (40.6 °C), with severe headache and then profuse sweating as temperature returns to normal. Patients often have anemia, spleen enlargement, and general weakness. Complications can be fatal. Malaria is diagnosed by detecting the parasites in blood. [URL="bword://!!09HMK27M2P,quinine/"][COLOR=windowtext]Quinine[/COLOR][/URL] was long used to alleviate the fevers. Synthetic drugs, such as chloroquine, destroy the parasites in blood cells, but many strains are now resistant. Carriers of a gene for a [URL="bword://!!09HMK27M2P,hemoglobinopathy/"][COLOR=windowtext]hemoglobinopathy[/COLOR][/URL] have natural resistance. Malaria prevention requires preventing mosquito bites: eliminating mosquito breeding places and using insecticides or natural predators, window screens, netting, and insect repellent. See also [URL="bword://!!09HMK27M2P,protozoal%20diseases/"][COLOR=windowtext]protozoal disease[/COLOR][/URL]. [/FONT]
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[FONT=Tahoma][B]Jaundice[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Jaundice is a yellowish staining of the skin and white of the eyes (sclerae) with pigment of bile. Jaundice can be an indicator of liver or gallbladder disease or result from red blood cells rupturing (hemolysis). [/FONT]
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[FONT=Tahoma][B]hepatitis[/B][/FONT][FONT=Tahoma] [/FONT]

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[URL="bword://!!09HMK27M2P,inflammation/"][COLOR=windowtext]Inflammation[/COLOR][/URL] of the [URL="bword://!!09HMK27M2P,liver/"][COLOR=windowtext]liver[/COLOR][/URL].

There are seven known types of viral hepatitis (A-G). Types A, spread mainly through food contaminated with feces, and B, transmitted sexually or by injection, cause [URL="bword://!!09HMK27M2P,jaundice/"][COLOR=windowtext]jaundice[/COLOR][/URL] and flulike symptoms. The hepatitis C virus spreads mostly by shared needles in intravenous drug use and can cause liver [URL="bword://!!09HMK27M2P,cirrhosis/"][COLOR=windowtext]cirrhosis[/COLOR][/URL] and cancer after a long latent period. Until recently there was no test to detect it in blood, and many people were exposed through blood transfusions. Hepatitis D becomes active only in the presence of type B; it causes severe chronic liver disease. Type E, like Type A, is transmitted by contaminated food or water; its symptoms are more severe than Type A's and can result in death. The hepatitis F virus (HFV), which was first reported in 1994, is spread like Type A and E. The hepatitis G virus (HGV), isolated in 1996, is believed to be responsible for many sexually transmitted and bloodborne cases of hepatitis. Vaccines exist for types A and B (the second also prevents type D). Drug treatment for B and C is not always effective. The other types may not need drug treatment. Chronic active hepatitis causes spidery and striated skin markings, acne, and abnormal hair growth. It results in liver tissue death (necrosis) progressing to cirrhosis. Alcoholic hepatitis, from long-term overconsumption of alcohol, can be reversed and cirrhosis prevented by early treatment including quitting or sharply reducing drinking. Other drugs can also cause noninfectious hepatitis. An autoimmune hepatitis affects mainly young women and is treated with corticosteroids to relieve symptoms. [/FONT]
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[FONT=Tahoma][B]cancer[/B][/FONT][FONT=Tahoma] [/FONT]

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Uncontrolled multiplication of abnormal cells.

Cancerous cells and tissues have abnormal growth rates, shapes, sizes, and functioning. Cancer may progress in stages from a localized [URL="bword://!!09HMK27M2P,tumour/"][COLOR=windowtext]tumour[/COLOR][/URL] (confined to the site of origin) to direct extension (spread into nearby tissue or lymph nodes) and metastasis (spread to more distant sites via the blood or lymphatic system). This malignant growth pattern distinguishes cancerous tumours from benign ones. Cancer is also classified by grade, the extent to which cell characteristics remain specific to their tissue of origin. Both stage and grade affect the chances of survival. Genetic factors and immune status affect susceptibility. Triggers include hormones, viruses, smoking, diet, and radiation. Cancer can begin in almost any tissue, including blood (see [URL="bword://!!09HMK27M2P,leukemia/"][COLOR=windowtext]leukemia[/COLOR][/URL]) and lymph (see [URL="bword://!!09HMK27M2P,lymphoma/"][COLOR=windowtext]lymphoma[/COLOR][/URL]). When it metastasizes, it remains a cancer of its tissue of origin. Early diagnosis and treatment increase the chance of cure. Treatment may include [URL="bword://!!09HMK27M2P,chemotherapy/"][COLOR=windowtext]chemotherapy[/COLOR][/URL], surgery, and [URL="bword://!!09HMK27M2P,radiation%20therapy/"][COLOR=windowtext]radiation therapy[/COLOR][/URL]. See also [URL="bword://!!09HMK27M2P,bladder%20cancer/"][COLOR=windowtext]bladder cancer[/COLOR][/URL]; [URL="bword://!!09HMK27M2P,breast%20cancer/"][COLOR=windowtext]breast cancer[/COLOR][/URL]; [URL="bword://!!09HMK27M2P,carcinogen/"][COLOR=windowtext]carcinogen[/COLOR][/URL]; [URL="bword://!!09HMK27M2P,colorectal%20cancer/"][COLOR=windowtext]colorectal cancer[/COLOR][/URL]; [URL="bword://!!09HMK27M2P,Kaposi%20sarcoma/"][COLOR=windowtext]Kaposi sarcoma[/COLOR][/URL]; [URL="bword://!!09HMK27M2P,laryngeal%20cancer/"][COLOR=windowtext]laryngeal cancer[/COLOR][/URL]; [URL="bword://!!09HMK27M2P,lung%20cancer/"][COLOR=windowtext]lung cancer[/COLOR][/URL]; [URL="bword://!!09HMK27M2P,ovarian%20cancer/"][COLOR=windowtext]ovarian cancer[/COLOR][/URL]; [URL="bword://!!09HMK27M2P,pancreatic%20cancer/"][COLOR=windowtext]pancreatic cancer[/COLOR][/URL]; [URL="bword://!!09HMK27M2P,prostate%20cancer/"][COLOR=windowtext]prostate cancer[/COLOR][/URL]; [URL="bword://!!09HMK27M2P,skin%20cancer/"][COLOR=windowtext]skin cancer[/COLOR][/URL]; [URL="bword://!!09HMK27M2P,stomach%20cancer/"][COLOR=windowtext]stomach cancer[/COLOR][/URL]; [URL="bword://!!09HMK27M2P,uterine%20cancer/"][COLOR=windowtext]uterine cancer[/COLOR][/URL]. [/FONT]
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[FONT=Tahoma][B]Cancer[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Also called malignancy. Cancer refers to a abnormal growths which have a tendency to grow uncontrolled and metastasize. It can involve any tissue of the body and can have many different forms in each body area. Cancer is a group of more than 100 different diseases. Benign tumors are not cancer; malignant tumors are cancer. Most cancers are named for the type of cell or the organ in which they begin. When cancer spreads (metastasizes), the new tumor has the same name as the original (primary) tumor. Skin cancer is the most common type of cancer for both men and women. The second most common cancer in men is prostate cancer, in women it is breast cancer. Lung cancer is the leading cause of death from cancer for both men and women in the U.S. Cancer is NOT contagious. [/FONT]
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[FONT=Tahoma][B]rabies[/B][/FONT][FONT=Tahoma] [/FONT]

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Acute, usually fatal infectious disease of warm-blooded animals that attacks the central [URL="bword://!!09HMK27M2P,nervous%20system/"][COLOR=windowtext]nervous system[/COLOR][/URL].

It is spread by contact with an infected animal's saliva, usually from a bite. The [URL="bword://!!09HMK27M2P,rhabdovirus/"][COLOR=windowtext]rhabdovirus[/COLOR][/URL] that causes it spreads along nerve tissue from the wound to the brain. Symptoms usually appear four to six weeks later, often beginning with irritability and aggressiveness. Wild animals lose their fear of humans and are easily provoked to bite, as are pets. Depression and paralysis soon follow. Death usually comes three to five days after symptoms begin. In humans, death can result from a seizure in the early phase even before symptoms of central nervous system depression develop. One name for rabies, hydrophobia ("fear of water"), comes from painful throat contraction on trying to swallow. If not treated in time (within a day or two) with a serum containing antibodies and then a series of vaccinations, rabies in humans is almost always fatal. Immediate cleansing of animal bites with soap and water can remove much of the virus. [/FONT]
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[FONT=Tahoma][B]Rabies[/B][/FONT][FONT=Tahoma] [/FONT]

[FONT=Tahoma]Virus disease of warmblooded animals transmitted to people by a bite (or other means). Animals capable of carrying rabies include dogs, bats, cats, racoons and skunks. In Latin, rabies means madness or rage. [/FONT]
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[FONT=Tahoma][B]insomnia[/B][/FONT][FONT=Tahoma] [/FONT]

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Inability to sleep adequately.

The causes may include poor sleeping conditions, circulatory or brain disorders, breathing disorders (e.g., sleep apnea), mental distress (e.g., tension or depression), or physical discomfort. Mild insomnia may be treated by improving sleeping conditions or through traditional remedies such as warm baths, milk, or systematic relaxation. Apnea and its associated insomnia may be treated surgically or mechanically with breathing apparatus. Severe or chronic insomnia may necessitate the temporary use of barbiturates or tranquilizers, but such drugs are often addictive and may be decreasingly effective as the body builds up tolerance. Other methods of treatment include [URL="bword://!!09HMK27M2P,psychotherapy/"][COLOR=windowtext]psychotherapy[/COLOR][/URL] and [URL="bword://!!09HMK27M2P,hypnosis/"][COLOR=windowtext]hypnosis[/COLOR][/URL]. [/FONT]
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[FONT=Tahoma][B]scurvy[/B][/FONT][FONT=Tahoma] [/FONT]

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[I]or [B]vitamin C deficiency[/B][/I]

Nutritional disorder caused by deficiency of [URL="bword://!!09HMK27M2P,vitamin%20C/"][COLOR=windowtext]vitamin C[/COLOR][/URL].

Deficiency interferes with tissue synthesis, causing swollen, bleeding gums; loose teeth; sore, stiff joints and legs; bleeding under the skin and in deep tissues; slow wound healing; and anemia. The scourge of sailors on long sea voyages, scurvy was recognized as diet-related in 1753, when [URL="bword://!!09HMK27M2P,Lind,%20James/"][COLOR=windowtext]James Lind[/COLOR][/URL] showed that drinking citrus juice could cure and prevent it, leading to the concept of deficiency diseases. Full-blown scurvy is now rare, and adequate vitamin C usually cures even severe cases in days. [/FONT]
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[FONT=Tahoma][B]pneumonia[/B][/FONT][FONT=Tahoma] [/FONT]

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[URL="bword://!!09HMK27M2P,inflammation/"][COLOR=windowtext]Inflammation[/COLOR][/URL] and solidification of [URL="bword://!!09HMK27M2P,lung/"][COLOR=windowtext]lung[/COLOR][/URL] tissue caused by infection, foreign particle inhalation, or irradiation but usually by [URL="bword://!!09HMK27M2P,bacteria/"][COLOR=windowtext]bacteria[/COLOR][/URL].

[I]Mycoplasma pneumoniae[/I] is the most common cause in healthy individuals. The bronchi and alveoli may be inflamed. Coughing becomes severe and may bring up flecks of blood. It can be serious but is rarely fatal. [I]Streptococcus pneumoniae[/I] is more common and generally more severe but usually affects only those with low resistance, especially in hospitals. A highly lethal form caused by [I]Klebsiella pneumoniae[/I] is almost always confined to hospitalized patients with low immunity. Other bacterial pneumonias include [I]Pneumocystis carinii[/I] pneumonia (rare except in [URL="bword://!!09HMK27M2P,AIDS/"][COLOR=windowtext]AIDS[/COLOR][/URL]) and [URL="bword://!!09HMK27M2P,Legionnaire%20disease/"][COLOR=windowtext]Legionnaire disease[/COLOR][/URL]. Most respond to [URL="bword://!!09HMK27M2P,antibiotic/"][COLOR=windowtext]antibiotic[/COLOR][/URL] treatment. [URL="bword://!!09HMK27M2P,virus/"][COLOR=windowtext]Virus[/COLOR][/URL]es set the stage for bacterial pneumonia by weakening the individual's immune system more often than they cause pneumonia directly. Fungal pneumonia usually occurs in hospitalized persons with low resistance, but contaminated dusts can cause it in healthy individuals. It can develop rapidly and may be fatal. [URL="bword://!!09HMK27M2P,X%20ray/"][COLOR=windowtext]X-ray[/COLOR][/URL] treatment (see [URL="bword://!!09HMK27M2P,radiation%20therapy/"][COLOR=windowtext]radiation therapy[/COLOR][/URL]) of structures in the chest may cause temporary lung inflammation. [/FONT]
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Stomach cancer
 

[SIZE="3"]Stomach cancer often begins at a site where the stomach lining is inflamed or irritated. However, many experts argue that inflammation is the result of stomach cancer, not its cause.
Some studies have suggested that stomach ulcers can lead to cancer, but other experts believe most people with ulcers and stomach cancer probably had an undetected cancer before the ulcers developed.
Stomach polyps are thought to be forerunners of cancer and are removed as a precaution. Cancer is increasingly likely with certain types of polyp, a polyp larger than ? inch, or when a number of polyps are present.
Medical conditions that may contribute to stomach cancer include:
Two types of anemia (megaloblastic anemia and pernicious anemia).
Partial removal of the stomach (gastrectomy) .
A stomach disorder called atrophic gastritis, or Menetrier's disease.
Environmental Factors
Exposure to certain dusts, molds, fumes, and other environmental agents at home or in the workplace has been linked to a higher than average risk of stomach cancer.
Some experts believe that smoking might increase stomach cancer risk.
Infection
Helicobacter pylori bacteria associated with duodenal ulcers, has been implicated in stomach cancers.
Diet
Some dietary factors are believed to play a role in the development of stomach cancer. If followed over a long period of time, these dietary practices may increase your risk. These include:
A high salt intake.
High intake of preservatives called nitrates, which are found in salted, pickled, or smoked foods.
A low intake of green leafy vegetables and fruit.[/SIZE]

Polio
 

[SIZE="3"][SIZE="5"][I]DEFINITION[/I][/SIZE]
Polio (pronounced POH-lee-oh) is a serious disease caused by a virus called the poliovirus. The full medical name for the disease is poliomyelitis (pronounced POH-lee-oh-mi-uh-LI-tis). In its severest form, polio causes paralysis of the muscles of the legs, arms, and respiratory (breathing) system.
[SIZE="5"]
[I]DESCRIPTION[/I][/SIZE]
The poliovirus causes most of its infections in the summer and fall. At one time, summer epidemics of polio were common and greatly feared.
The poliovirus primarily affects younger children. But it can also infect older children and adults. Poor hygiene and crowded living conditions encourage the spread of the poliovirus.
Paralysis is the most serious symptom of polio. Only about 1 percent to 2 percent of those infected with the virus are paralyzed, however. Risk factors for paralysis include older age, pregnancy, problems with the immune system, a recent tonsillectomy, and a recent episode of very strenuous exercise.

[SIZE="5"][I]Polio: Words to Know[/I][/SIZE]
Brain stem:
A mass of nervous tissue that connects the main part of the brain to the spinal cord.
Epidemic:
The widespread occurrence of a disease over a large geographic area for an extended period of time.
Paralysis:
The inability to move one's muscles.

[SIZE="5"][I]CAUSES[/I][/SIZE]
Poliovirus is transmitted through saliva and feces. It is passed on when people do not wash their hands after eating or using the bathroom. Once a person is infected with the virus, it can remain in the mouth and throat for about three weeks. It then travels to the intestine. It can remain in the intestine for up to eight weeks.
Inside the intestine, the virus multiplies rapidly. It may invade the lymphatic (pronounced lim-FAT-ic) system. The lymphatic system consists of organs and tissues that help protect a person against disease. The virus eventually enters the bloodstream. It can then pass to the central nervous system (the brain and spinal cord). The virus can also pass directly into nerves. It can then travel along a nerve to the brain.

[SIZE="5"][I]SYMPTOMS[/I][/SIZE]
About 90 percent of those infected with poliovirus have mild or no symptoms. These symptoms include a low fever, fatigue, headache, sore throat, and nausea and vomiting. These symptoms usually last two or three days. People with these symptoms are still infectious and can pass the disease on to other people.
Another 10 percent of those infected with the virus experience more serious symptoms, including severe headache and pain and stiffness of the neck and back. The stiffness is caused when the tissues around the spinal cord and brain become inflamed. These symptoms usually disappear after several days. The patient usually experiences complete recovery.

[SIZE="5"][I]THE IRON LUNG[/I][/SIZE]
People with polio often lose the ability to move their legs and/or arms. This disability is a terrible disaster. But it does not necessarily cause death. If polio also causes loss of control over the respiratory muscles, however, death can and often does occur. For polio patients, then, a device to help them breathe is an absolute necessity.
In 1982, the American physiologist Philip Drinker (1893–1977) invented the most famous of all devices for helping polio patients to breathe. The device was called the Drinker tank respirator. It is more commonly known as an iron lung.
The iron lung is an airtight cylindrical steel drum. It encloses the entire body with only the patient's head exposed. Pumps connected to the device lower and raise air pressure within the drum. As the drum contracts and expands, it forces the patient's chest to contract and expand also. The iron lung forces the patient's body to continue breathing.
Many polio patients were kept alive by the iron lung. They had to spend many years enclosed in the lung, with only short periods outside it. With the development of the Salk and Sabin vaccines, polio has nearly become extinct. As a result, the iron lung no longer finds much use in today's hospitals.
About 1 percent of people infected with the poliovirus develop the most serious symptoms of the disease. At first, they experience only mild symptoms. After a few days, however, the symptoms become much worse. They include severe headache and neck and back pain.
The worst effects of polio are caused when the virus invades motor nerves. Motor nerves are nerves that control the movement of muscles. The virus can destroy these nerves. As the nerves die, muscles lose their ability to move. They first become floppy and weak. Eventually they become paralyzed and lose the ability to move at all. After a few days, the muscles actually begin to decrease in size. The person does not lose the sense of touch in the affected areas, however.
The virus can also infect the brain stem. The brain stem is located at the base of the brain. It connects the brain to the spinal cord. A person may have trouble breathing and swallowing. In the severest cases, the heart rate and blood pressure may be disturbed. These changes can lead to the patient's death.
The maximum degree of paralysis usually occurs within a few days. After that time, some healthy nerves may try to take the place of the damaged nerves. This process lasts about six months. After that time, no further improvement is likely.

[SIZE="5[I]"]DIAGNOSIS[/I][/SIZE]
Polio is now a rare disease in the United States. Many doctors have never seen a case of polio. A few symptoms are quite distinctive, however. A fever and paralysis without the loss of feeling is one clue to the presence of polio.
If a doctor suspects polio, the usual follow-up test is a lumbar puncture, or "spinal tap." A lumbar puncture is a procedure in which a sample of spinal fluid is removed with a long, thin needle. The spinal fluid can be examined for an elevated level of white blood cells and the absence of bacteria. These two factors taken together are a strong indication of polio.
The spinal fluid can also be tested for the presence of polio antibodies. Antibodies are chemicals produced by the immune system to fight against specific foreign invaders, such as the poliovirus.

[SIZE="5"][I]TREATMENT[/I][/SIZE]
There is no cure for polio. Patients can be treated to make them more comfortable, however. For example, medications can reduce pain. Hot packs help soothe sore muscles. Artificial ventilation (breathing machines) may be necessary if a person's respiratory system is affected. Walking aids, such as crutches and walkers, may be necessary for someone whose leg muscles are damaged by the disease.
The prognosis for mild and moderate polio is good. Most patients recover completely within a short period of time. Of those who have the severest form of polio, about half will recover completely. A quarter will experience some disability, and another quarter will have permanent and serious disability. About 1 percent of all those who have the most serious form of polio die of the disease.
In recent years, a new medical problem known as postpolio syndrome has been diagnosed. The condition shows up thirty years or more after a person has had a mild or moderate form of the disease. Postpolio syndrome affects about 25 percent of polio patients. The major symptom of postpolio syndrome is a very slow decrease in muscle strength.

[SIZE="5"][I]PREVENTION[/I][/SIZE]
Polio can now be prevented by immunizations. An immunization is an injection that protects a person against some type of infectious disease. Two kinds of polio immunizations are available in the United States. The Salk vaccine contains dead polioviruses. It is injected just under the skin. The dead viruses cause the immune system to start making antibodies against the poliovirus. If a person is infected with the poliovirus later in life, the immune system can protect the body against the disease.
The Sabin vaccine contains polioviruses that are very weak but not dead. They produce the same effect on the immune system as dead viruses. Both vaccines are highly effective in preventing polio. In fact, some public-health experts think the disease may be completely wiped out in the next decade.[/SIZE]

Tuberculosis
 

[SIZE="4"][I]Tuberculosis (TB) describes an infectious disease that has plagued humans since the Neolithic times. Two organisms cause tuberculosis–Mycobacterium tuberculosis and Mycobacterium bovis.

Physicians in ancient Greece called this illness "phthisis" to reflect its wasting character. During the 17th and 18th centuries, TB caused up to 25% of all deaths in Europe. In more recent times, tuberculosis has been called "consumption."

Robert Koch isolated the tubercle bacillus in 1882 and established TB as an infectious disease.


In the 19th century, patients were isolated in sanatoria and given treatments such as injecting air into the chest cavity. Attempts were made to decrease lung size by surgery called thoracoplasty.


During the first half of the 20th century, no effective treatment was available.


Streptomycin, the first antibiotic to fight TB, was introduced in 1946, and isoniazid (Laniazid, Nydrazid) became available in 1952.


M tuberculosis is a rod-shaped, slow-growing bacterium.


M tuberculosis' cell wall has high acid content, which makes it hydrophobic, resistant to oral fluids.


The cell wall absorbs a certain dye and maintains a red color despite attempts at decolorization, hence the name acid-fast bacilli.


M tuberculosis continues to kill millions of people yearly worldwide. In 1995, 3 million deaths from TB occurred.


Up to 8 million new cases of TB develop each year.


More than 90% of these cases occur in developing nations that have poor resources and high numbers of people infected with HIV.
In the United States, incidence of TB began to decline around 1900, because of improved living conditions.


TB cases have increased since 1985, most likely due to the increase in HIV.
Tuberculosis continues to be a major health problem worldwide. In 1997, the World Health Organization (WHO) estimated that 32% of the global population was infected with TB bacteria.


7.9 million new cases of TB developed.


1.87 million people died of this disease.


With the spread of AIDS, tuberculosis continues to lay waste to large populations. The emergence of drug-resistant organisms threatens to make this disease once again incurable.


In 1993, the WHO declared tuberculosis a global emergency.[/I][/SIZE]

Typhoid fever
 

[SIZE="3"]Typhoid fever is an illness caused by the bacterium Salmonella Typhi. Common worldwide, it is transmitted by ingestion of food or water contaminated with feces from an infected person. The bacteria then multiply in the blood stream of the infected person and are absorbed into the digestive tract and eliminated with the waste.


[SIZE="5"]Symptoms[/SIZE]Persons with typhoid fever usually have a sustained fever as high as 103° to 104° F (39° to 40° C). They may also feel weak, or have stomach pains, headache, or loss of appetite. In some cases, patients have a rash of flat, rose-colored spots. The only way to know for sure if an illness is typhoid fever is to have samples of stool or blood tested for the presence of S. Typhi.

Typhoid fever has an insidious onset characterized by fever, headache, constipation, malaise, chills, and myalgia with few clinical features that reliably distinguish it from a variety of other infectious diseases. Diarrhea is uncommon, and vomiting is not usually severe. Confusion, delirium, intestinal perforation, and death may occur in severe cases.

[SIZE="5"]Diagnosis[/SIZE]Diagnosis is made by blood, bone marrow or stool cultures and with the Widal test (demonstration of salmonella antibodies against antigens O-somatic and H-flagellar). In epidemics and less wealthy countries, after excluding malaria, dysentery or pneumonia, a therapeutic trial with chloramphenicol is generally undertaken while awaiting the results of Widal test and blood cultures.

[SIZE="5"]Treatment[/SIZE]Typhoid fever can be fatal. Antibiotics, such as ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, and ciprofloxacin, have been commonly used to treat typhoid fever in developed countries. Prompt treatment of the disease with antibiotics reduces the case-fatality rate to approximately 1%. Usage of Ofloxacin along with Lactobacillus acidophilus is also recommended.

When untreated, typhoid fever persists for three weeks to a month. Death occurs in between 10% and 30% of untreated cases. Vaccines for typhoid fever are available and are advised for persons traveling in regions where the disease is common (especially Asia, Africa and Latin America). Typhim Vi is an intramuscular killed-bacteria vaccination and Vivotif is an oral live bacteria vaccination, both of which protect against typhoid fever. Neither vaccine is 100% effective against typhoid fever and neither protects against unrelated typhus.[/SIZE]

Oral cancer
 

[SIZE="3"]Oral cancer is any cancerous tissue growth located in the mouth. It may arise as a primary lesion originating in any of the oral tissues, by metastasis from a distant site of origin, or by extension from a neighboring anatomic structure, such as the nasal cavity or the maxillary sinus. Oral cancers may originate in any of the tissues of the mouth, and may be of varied histologic types: adenocarcinoma derived from a major or minor salivary gland, lymphoma from tonsillar or other lymphoid tissue, or melanoma from the pigment producing cells of the oral mucosa. Far and away the most common oral cancer is squamous cell carcinoma, originating in the tissues that line the mouth and lips. Oral or mouth cancer most commonly involves the tissue of the lips or the tongue. It may also occur on the floor of the mouth, cheek lining, gingiva (gums), or palate (roof of the mouth). Most oral cancers look very similar under the microscope and are called squamous cell carcinoma. These are malignant and tend to spread rapidly.

[SIZE="5"][B][I]Known risk factors[/I][/B][/SIZE]
In 2006, in the US alone, about 31,000 individuals will be diagnosed with oral cancer. 66% of the time these will be found as late stage three and four disease. Low public awareness of the disease is a significant factor, but these cancers could be found at early highly survivable stages through a simple, painless, 5 minute examination by a trained medical or dental professional.

All cancers are diseases of the DNA in the cancer cells. Oncogenes are activated as a result of mutation of the DNA. The exact cause is often unknown. Risk factors that predispose a person to oral cancer have been identified in epidemiological studies.

Smoking and other tobacco use are associated with 70 percent to 80 percent of oral cancer cases, caused by irritation of the mucous membranes of the mouth from smoke and heat of cigarettes, cigars, and pipes. Tobacco contains over 19 known carcinogens, and the combustion of it, and by products from this process, is the primary mode of involvement. Use of chewing tobacco or snuff causes irritation from direct contact with the mucous membranes.

In many Asian cultures chewing betel, paan and Areca is known to be a strong risk factor for developing oral cancer. In India where such practices are common, oral cancer represents up to 40% of all cancers, compared to just 4% in the UK.

Alcohol use is another high-risk activity associated with oral cancer. There is known to be a strong synergistic effect on oral cancer risk when a person is both a heavy smoker and a drinker. Their risk is greatly increased compared to a heavy smoker, or a heavy drinker alone.

Other risks include chronic irritation (such as that from rough teeth, dentures, or fillings). Some oral cancers begin as leukoplakia a white patch (lesion), red patches, (erythroplakia) or non healing sores that have existed for more than 14 days. In the US oral cancer accounts for about 8 percent of all malignant growths. Men are affected twice as often as women, particularly men older than 40/60.

Human Papilloma Virus, (HPV) particularly versions 16 and 18 ( there are over 100 varieties) is a known risk factor for oral cancer. A fast growing segment of those diagnosed does not present with the historic stereotypical demographics. Historically that has been people over 50, blacks over whites 2 to 1, males over females 3 to 1, and 75% of the time people who have used tobacco products or are heavy users of alcohol. This new and rapidly growing sub population between 20 and 50 years old is predominantly non smoking, white, and females slightly outnumber males. Recent research from Johns Hopkins indicates that HPV is the primary risk factor in this new population of oral cancer victims. HPV16/18 is the same virus responsible for the vast majority of all cervical cancers and is the most common sexually transmitted disease in the US. Oral cancer in this group tends to favor the tonsil and tonsillar pillars, and the oropharnyx.

[SIZE="5"][SIZE="5"][B][I]Symptoms[/I][/B][/SIZE][/SIZE]
Skin lesion, lump, or ulcer:

On the tongue, lip, or other mouth area
Usually small
Most often pale colored, may be dark or discolored
Early sign may be a white patch (leukoplakia) or a red patch (erythroplakia) on the soft tissues of the mouth
May be a deep, hard edged crack in the tissue
Usually painless initially
May develop a burning sensation or pain when the tumor is advanced
Additional symptoms that may be associated with this disease:

Tongue problems
Swallowing difficulty
Mouth sores
Abnormal taste
Pain and paraesthesia are late symptoms.

[SIZE="5"][B][I] Signs and tests[/I][/B][/SIZE]
An examination of the mouth by the health care provider or dentist shows a visible and/or palpable (can be felt) lesion of the lip, tongue, or other mouth area. As the tumor enlarges, it may become an ulcer and bleed. Speech difficulties, chewing problems, or swallowing difficulties may develop, particularly if the cancer is on the tongue.

While a dentist, physician or other medical professional may suspect a particular lesion is malignant, the only definitive method for determining this is through biopsy and microscopic evaluation of the cells in the removed sample. A tissue biopsy, whether of the tongue or other oral tissues, and microscopic examination of the lesion confirm the diagnosis of oral cancer.


[SIZE="5"][B][I]Treatment[/I][/B][/SIZE]
Surgical excision (removal) of the tumor is usually recommended if the tumor is small enough, and if surgery is likely to result in a functionally satisfactory result. Radiation therapy is often used in conjunction with surgery, or as the definitive radical treatment, especially if the tumour is inoperable. Chemotherapy is commonly used for more advanced tumours, often in combination with radiotherapy and surgery. Biological agents, such as Cetuximab have recently been shown to be effective in the treatment of squamous cell head and neck cancers, and are likely to have an increasing role in the future management of this condition.

Owing to the vital nature of the structures in the head and neck area, surgery for larger cancers is technically demanding. Reconstructive surgery may be required to give an acceptable cosmtetic and functional result. Bone grafts and surgical flaps such as the radial forearm flap are used to help rebuild the structures removed during excision of the cancer.

Survival rates for oral cancer depend on the precise site, and the stage of the cancer at diagnosis. Overall, survival is around 50% at five years when all stages of initial diagnosis are considered. Survival rates for stage 1 cancers are 90%, hence the emphasis on early detection to increase survival outcome for patients.

Following treatment, rehabilitation may be necessary to improve movement, chewing, swallowing, and speech. Speech therapists may be involved at this stage.

[SIZE="5"][B][I]
Complications[/I][/B][/SIZE]
Postoperative disfigurement of the face, head and neck
Complications of radiation therapy, including dry mouth and difficulty swallowing
Other metastasis (spread) of the cancer [/SIZE]

Biological Diseases
 

BIOLOGICAL DISEASES MABAS DIVISION XX
ANTRHAX DIRECTIVE

Pg. 1 of 1 21-1007-1



Purpose

Experts have identified dozens of biological diseases and chemical agents that could be used as weapons. The risk of such an attack remains very low. However, the following directive is meant to educate the fire fighter about the dangers of a biological attack involving ANTHRAX.


Anthrax

A deadly infection caused by bacteria spores commonly found in cows and sheep. It is not contagious.


Symptoms


Infection from inhalation resembles common cold, progresses to severe breathing problems and shock after several days. Inhaled anthrax is usually fatal.


Treatment

Antibiotics such as penicillin or ciprofloxacin must be taken immediately.


Vaccine

Yes. Generally given only to active duty military personnel.


Possibilities as a Weapon

Relatively easy to manufacture and store, but difficult to disperse in large quantities. Bright sunlight kills the spores, and thousands must be inhaled for an infection to develop.


Sources: Centers for Disease Control and Prevention, Center for Civilian Biofense Studies, Journal of American Medical Association, Johns Hopkins University
BIOLOGICAL DISEASES MABAS DIVISION XX
BOTULISM DIRECTIVE

Pg. 1 of 1 21-1007-2



Purpose

Experts have identified dozens of biological diseases and chemical agents that could be used as weapons. The risk of such an attack remains very low. However, the following directive is meant to educate the fire fighter about the dangers of a biological attack involving BOTULISM.


Botulism

A muscle-paralyzing disease usually caused by a toxin found in contamination food.


Symptoms

About 18 to 36 hours after exposure, victims develop blurry vision and slurred speech, and paralysis spread through the body. About 8 percent of those infected die.


Treatment

If diagnosed early, an antitoxin can block spread of toxins. Hospital care is essential.


Vaccine

No.


Possibilities as a Weapon

Lethal strains are hard to grow in large quantities and would be difficult to disperse.





Sources: Centers for Disease Control and Prevention, Center for Civilian Biofense Studies, Journal of American Medical Association, Johns Hopkins University
BIOLOGICAL DISEASES MABAS DIVISION XX
CHOLERA DIRECTIVE

Pg. 1 of 1 21-1007-3


Purpose

Experts have identified dozens of biological diseases and chemical agents that could be used as weapons. The risk of such an attack remains very low. However, the following directive is meant to educate the fire fighter about the dangers of a biological attack involving CHOLERA.


CHOLERA

An acute diarrheal illness transmitted through contaminated food and water.


Symptoms

Often mild. About 1 in 20 cases are severe, with diarrhea, vomiting and leg cramps. Fewer than 1 percent of those infected die if treated promptly.


Treatment

Replace lost fluids and salts. Antibiotics are sometimes used.


Vaccine

Yes, but not in U.S.


Possibilities as a Weapon

Likelihood of use as a weapon is very low.



Sources: Centers for Disease Control and Prevention, Center for Civilian Biofense Studies, Journal of American Medical Association, Johns Hopkins University




BIOLOGICAL DISEASES MABAS DIVISION XX
PLAGUE

Pg. 1 of 1 21-1007-4



Purpose

Experts have identified dozens of biological diseases and chemical agents that could be used as weapons. The risk of such an attack remains very low. However, the following directive is meant to educate the fire fighter about the dangers of a biological attack involving PLAGUE.


PLAGUE

Highly contagious disease has killed millions through history but is very rare today.


Symptoms

Fever, chills and a cough with blood appear one to six days after exposure. Is fatal in almost all untreated cases.


Treatment

Antibiotics (for pneumonic plague, the type most likely to be spread in a terrorist attack).


Vaccine

No.


Possibilities as a Weapon

Bacteria is widely available in microbe banks around the world. Could be transmitted by infecting fleas or by aerosol.





Sources: Centers for Disease Control and Prevention, Center for Civilian Biofense Studies, Journal of American Medical Association, Johns Hopkins University
BIOLOGICAL DISEASES MABAS DIVISION XX
SALMONELLOSIS DIRECTIVE

Pg. 1 of 1 21-1007-5



Purpose

Experts have identified dozens of biological diseases and chemical agents that could be used as weapons. The risk of such an attack remains very low. However, the following directive is meant to educate the fire fighter about the dangers of a biological attack involving SALMONELLOSIS


Salmonellosis

Infection caused by bacteria usually spread by eating foods tainted by animal feces..


Symptoms

Diarrhea, fever and abdominal cramps 12 to 72 hours after infection. Very rarely causes death.


Treatment

Often not required unless dehydration is severe. Recovery is usually 5 to 7 days.


Vaccine

No.


Possibilities as a Weapon

Relatively easy to obtain and manufacture.






Sources: Centers for Disease Control and Prevention, Center for Civilian Biofense Studies, Journal of American Medical Association, Johns Hopkins University
BIOLOGICAL DISEASES MABAS DIVISION XX
SMALLPOX DIRECTIVE

Pg. 1 of 1 21-1007-6



Purpose

Experts have identified dozens of biological diseases and chemical agents that could be used as weapons. The risk of such an attack remains very low. However, the following directive is meant to educate the fire fighter about the dangers of a biological attack involving SMALLPOX


Smallpox

Eradicated from people in 1970’s, highly transmissible virus is universally feared as most devastating infectious disease.


Symptoms

About 12 to 14 days after exposure, high fever and headache give way to rash on the mouth and face. It is fatal about 30 percent of the time.


Treatment

There is no proven treatment. Vaccine within four days of exposure can lessen severity.


Vaccine


Yes. Emergency supplies are available.


Possibilities as a Weapon

U.S. and Russia have only known stores but other countries may have samples. Large-scale manufacture is difficult; would be hard to spread through aerosol.



Sources: Centers for Disease Control and Prevention, Center for Civilian Biofense Studies, Journal of American Medical Association, Johns Hopkins University
BIOLOGICAL DISEASES MABAS DIVISION XX
TULAREMIA DIRECTIVE

Pg. 1 of 1 21-1007-7



Purpose

Experts have identified dozens of biological diseases and chemical agents that could be used as weapons. The risk of such an attack remains very low. However, the following directive is meant to educate the fire fighter about the dangers of a biological attack involving TULAREMIA


Tularemia

Hardy, highly infectious organism usually transmitted by rabbits and mice.


Symptoms

Flulike symptoms usually begin within three days of exposure. Affects the lymph glands; can be fatal in up to 60 percent of untreated cases.


Treatment

Antibiotics are usually effective.


Vaccine

Yes, but not FDA approved. Not available to public.


Possibilities as a Weapon

As few as 10 organisms, which can survive for weeks, can cause disease. Has been stockpiled in the past by U.s., Soviet Union and Japan militaries.





Sources: Centers for Disease Control and Prevention, Center for Civilian Biofense Studies, Journal of American Medical Association, Johns Hopkins University
BIOLOGICAL DISEASES MABAS DIVISION XX
Q FEVER DIRECTIVE

Pg. 1 of 1 21-1007-8



Purpose

Experts have identified dozens of biological diseases and chemical agents that could be used as weapons. The risk of such an attack remains very low. However, the following directive is meant to educate the fire fighter about the dangers of a biological attack involving Q FEVER.


Q Fever

Very infectious, airborne agent commonly found in livestock. A single organism can cause disease.


Symptoms

About half of victims show signs, ranging from high fever and headache to pneumonia. Fewer than 2 percent of infected people die.


Treatment

Antibiotics are effective, though most patients recover without treatment.


Vaccine

Yes, but not widely used.


Possibilities as a Weapon

Organism is resistant to heat and drying.





Sources: Centers for Disease Control and Prevention, Center for Civilian Biofense Studies, Journal of American Medical Association, Johns Hopkins University
BIOLOGICAL DISEASES MABAS DIVISION XX
VIRAL HEMORRHAGIC FEVERS DIRECTIVE

Pg. 1 of 1 21-1007-9



Purpose

Experts have identified dozens of biological diseases and chemical agents that could be used as weapons. The risk of such an attack remains very low. However, the following directive is meant to educate the fire fighter about the dangers of a biological attack involving VIRAL HEMORRHAGIC FEVERS.


Viral Hemorrhagic Fevers

Highly contagious fevers such as Ebola and Marburg diseases are usually caught from animals.


Symptoms

Vary greatly, but generally include high fevers and dizziness with signs of bleeding under the skin. Shock follows, and most cases are fatal.


Treatment

Generally none.


Vaccine

No.


Possibilities as a Weapon

Manufacturing, storing and transporting a little-understood virus like Ebola would be very difficult.




Sources: Centers for Disease Control and Prevention, Center for Civilian Biofense Studies, Journal of American Medical Association, Johns Hopkins University
CHEMICAL AGENTS MABAS DIVISION XX
SARIN DIRECTIVE

Pg. 1 of 1 21-1007-10



Purpose

Experts have identified dozens of biological diseases and chemical agents that could be used as weapons. The risk of such an attack remains very low. However, the following directive is meant to educate the fire fighter about the dangers of a chemical attack involving SARIN.


Sarin

A colorless, odorless gas dispersed in a droplet or mist form.


Symptoms

Runny nose, bronchial secretions, tightness in the chest, dimming of vision, drooling, excessive perspiration, nausea, muscle tremors, coma, death.


Treatment

Wash exposed areas with soap and water and get an immediate antidote at a hospital.


Vaccine

Vaccines do not apply to chemicals.


Possibilities as a Weapon

Can be manufactured with fairly simple chemical techniques. The raw materials are inexpensive and generally available.





Sources: Centers for Disease Control and Prevention, Center for Civilian Biofense Studies, Journal of American Medical Association, Johns Hopkins University
CHEMICAL AGENTS MABAS DIVISION XX
VX DIRECTIVE

Pg. 1 of 1 21-1007-11



Purpose

Experts have identified dozens of biological diseases and chemical agents that could be used as weapons. The risk of such an attack remains very low. However, the following directive is meant to educate the fire fighter about the dangers of a chemical attack involving VX.


VX

Looks like motor oil and is 100 times more lethal than SARIN when it enters through skin.


Symptoms

Runny nose, bronchial secretions, tightness in the chest, dimming of vision, drooling, excessive perspiration, nausea, muscle tremors, coma, death.


Treatment

Wash exposed areas with soap and water and get immediate antidote at a hospital.


Vaccine

No. Vaccines do not apply to chemicals.


Possibilities as a Weapon

Can be made with fairly simple chemical techniques. The raw materials are inexpensive and generally available.




Sources: Centers for Disease Control and Prevention, Center for Civilian Biofense Studies, Journal of American Medical Association, Johns Hopkins University
CHEMICAL AGENTS MABAS DIVISION XX
MUSTARD GAS DIRECTIVE

Pg. 1 of 1 21-1012-12



Purpose

Experts have identified dozens of biological diseases and chemical agents that could be used as weapons. The risk of such an attack remains very low. However, the following directive is meant to educate the fire fighter about the dangers of a chemical attack involving MUSTARD GAS.


Mustard Gas

Can be yellow to dark brown and can smell like burning garlic.


Symptoms

Sneezing, coughing, loss of appetite, diarrhea, fever, apathy, blistering.


Treatment

Wash exposed areas with soap and water and get antidote at a hospital.


Vaccine

No. Vaccines do not apply to chemicals.


Possibilities as a Weapon

Has been used frequently as a weapon in past wars.







Sources: Centers for Disease Control and Prevention, Center for Civilian Biofense Studies, Journal of American Medical Association, Johns Hopkins University

infectious disease
 

[B]INFECTIOUS DISESSASE (Defination):[/B]
Any disease caused by invasion by a pathogen which subsequently grows and multiplies in the body.
a disease transmitted only by a specific kind of contact

[B]Concept:[/B]
The history of the human species, it has been said, is the history of infectious disease. Over the centuries, humans have been exposed to a vast amount and array of contagious conditions, including the Black Death and other forms of plague, typhoid fever, cholera, malaria, influenza, and the acquired immunodeficiency syndrome, or AIDS. Only in the past few hundred years have scientists begun to have any sort of accurate idea concerning the origin of such diseases, through the action of microorganisms and other parasites. Such understanding has led to the development of vaccines and methods of inoculation, yet even before they made these great strides in medicine, humans had an unseen protector: their own immune systems.

[B]Infection and Humanity:[/B]There are two basic types of disease: ones that are infectious, or extrinsic, meaning that they are contagious or communicable and can be spread by contact between people, and ones that are intrinsic, or not infectious.a person can get an infection, such as tetanus or salmonella, without necessarily having a disease that can be passed on through contact with others in the same way that colds, malaria, or syphilis is spread.

[B]Immune Machanism:[/B]
The human body has numerous mechanisms for protecting itself from infectious disease, the first line of defense being the skin. Skin shields us all the time from unseen attackers and generally is able to prevent pathogens from entering the body; however, any break in the skin, such as a cut or scrape, provides an opening for microorganisms to invade the body. Germs that normally would be prevented from entering the body are able to invade the bloodstream through such openings. This is why it is so very important, in any situation involving potential contact with infection, to protect the skin.

[B]Transmission of Disease:[/B]
Infectious diseases are transmitted easily from one person to another.Pathogens can be spread by many methods other than direct contact, including through water, food, air, and bodily fluids—blood, semen, saliva, and so on. For instance, any time a person with an infection coughs or sneezes, they may be transmitting illness. This is how diseases such as measles and tuberculosis are passed from person to person. AIDS and various STDs, as well as many other conditions, such as hepatitis, are transferred when one person comes into contact with the bodily fluids of another. This is the case not only with sexual intercourse but also with blood transfusions and any number of other interactions, including possibly drinking after someone.Additionally, diseases may be transferred by vectors—animals (usually insects) that carry microorganisms from one person to another.

[B]Diagnosis and Therapy:[/B]
Diagnosis is initially by medical history and physical examination, and imaging (such as X-rays), but the principal tool in infectious disease is the microbiological culture. In a culture, a growth medium is provided for a particular agent. After inoculation of a specimen of diseased fluid or tissue onto the medium, it is determined whether bacterial growth occurs.
When a culture has proven to be positive, the sensitivity (or, conversely, the antibiotic resistance) of an agent can be determined by exposing it to test doses of antibiotic. This way, the microbiologist determines how sensitive the target bacterium is to a certain antibiotic.

[B]The work of an Infectiologist:[/B]
Doctors who specialise in the medical treatment of infectious disease are called infectiologists or infectious disease specialists. Generally, infections are initially diagnosed by primary care physicians or internal medicine specialists. For example, an "uncomplicated" pneumonia will generally be treated by the internist or the pulmonologist (lung physician).

Childhood Leukaemia
 

[CENTER][B][SIZE="5"]Childhood Leukaemia[/SIZE][/B][/CENTER]


Leukaemia, accounts for about 25 percent of all childhood cancers and affects about 2,200 young people each year. Luckily, the chances for a cure have increased with latest treatments without any fears of remission.

Cancers of the white blood cells also referred to as 'leukocytes or WBCs' starts with chromosomal changes in cells. It alters the way cells work and grow. When a child has leukaemia, large numbers of abnormal white blood cells are produced in the bone marrow. These abnormal white cells crowd the bone marrow and flood the bloodstream, but they cannot perform their proper role of protecting the body against disease because they are defective.

As leukemia progresses, the cancer interferes with the body's production of other types of blood cells, including red blood cells and platelets. This results in Anemia (low numbers of red cells) and bleeding problems, in addition to the increased risk of infection caused by white cell abnormalities.

These cells keep growing when they are supposed to stop. They also grow faster than other cells. Over time, these abnormal cells crowd out the normal white blood cells (WBC), red blood cells (RBC), and platelets.

As a group, leukaemia's account for about 25 percent of all childhood cancers and affect about 2,200 young people each year. Luckily, the chances for a cure are very good with leukaemia. With treatment, most children with leukaemia are free of the disease without it coming back.

In general, leukaemias are classified into 'acute' (rapidly developing) and 'chronic' (slowly developing) forms. About 98% of leukaemias are acute in children. Childhood leukaemia's are also divided into Acute Lymphocytic Leukaemia (ALL) and Acute Myelogenous Leukemia (AML), depending on whether specific WBC's, which are linked to immune defences, are involved.

Approximately 60% of children with leukemia have ALL, and about 38% have AML. Although slow-growing Chronic Myelogenous Leukemia (CML) may also be seen in children, it is very rare, accounting for fewer than 50 cases of childhood leukemia each year.

The ALL form of the disease most commonly occurs in younger children ages two to eight years, with a peak incidence at age four, but it can affect all age groups.

Children who have received prior radiation or chemotherapy for other types of cancer also have a higher risk for leukemia, usually within the first 8 years after treatment.

To limit the risk of prenatal radiation exposure as a trigger for leukemia (especially ALL), women who are pregnant or who suspect that they might be pregnant should always inform their doctors before undergoing tests or medical procedures that involve radiation (such as X-rays).

Regular checkups can spot early symptoms of leukemia in the relatively rare cases where this cancer is linked to an inherited genetic problem, to prior cancer treatment, or to use of immunosuppressive drugs for organ transplants.

Because infection-fighting white blood cells are defective in children with leukemia, these children may experience increased episodes of fevers and infections.

They may also become anaemic because leukaemia affects the bone marrow's production of oxygen-carrying red blood cells. This makes them appear pale, and they may become abnormally tired and short of breath while playing.

Children with leukemia may also bruise and bleed very easily, experience frequent nosebleeds, or bleed for an unusually long time after even a minor cut because leukemia destroys the bone marrow's ability to produce clot-forming platelets.

Other symptoms of leukemia may include:

* Pain in the bones or joints, sometimes causing a limp

* Swollen lymph nodes (sometimes called swollen glands) in the neck, groin, or elsewhere

* An abnormally tired feeling

* Poor appetite

To diagnose leukaemia bone marrow or lymph node samples are examined, Cell evaluations are also under taken including genetic studies to distinguish between specific types as well as certain features of the leukaemia cells. Children will receive anaesthesia or sedative medications for any painful procedures.

Sometimes a bone marrow transplant may be necessary in addition to - or instead of - chemotherapy, depending on the type of leukaemia a child has. During a bone marrow transplant, healthy bone marrow is introduced into a child's body.

Chemotherapy has certain side effects, including hair loss, nausea and vomiting in the short term, and potential health problems down the line. Some forms of childhood leukaemia have a remission rate of up to 90%; all children then require regular maintenance chemotherapy and other treatment to continue to be cancer-free. Overall cure rates differ depending on the specific features of a child's disease. And the majority of children can be cured –meaning that they are in permanent remission – of the disease.

Natural Remedies for Diabetes !!!!!!!
 

[SIZE="3"]What is Diabetes?
Diabetes deals with the body’s response to blood glucose levels in regards to the production or utilization of insulin. The two main types of diabetes you or someone in your family may come in contact with, includes:
Type 1 Diabetes: Through the millions of diabetic patients in the United States, there is an estimated 5-10% that suffer from this form of the disease. While Type 1 can affect people of all ages, mostly children, adolescents and young adults develop this kind of diabetes. It is said that about one in every 500 children and adolescents in the United States already has or will have Type 1 diabetes in the future [1].
Type 2 Diabetes: This type of diabetes is chronic and hinders the way that the body metabolizes glucose (sugar). Through Type 2 diabetes, the body starts to reject the effects of insulin, which is a hormone needed for the regulation of sugar cell absorption. Some Type 2 diabetics might produce some insulin, but not enough to create a normal level of glucose [2]. When this condition is left untreated, life-threatening results may occur.

Symptoms
There are many symptoms associated with diabetes, and depending on the type you suffer from, you may experience one or more of the following:
a) Excessive Thirst and Increased Urination: One of the most telling signs of diabetes is an urgency to keep drinking fluids. As your kidneys work overtime to filter and absorb the amount of sugar that builds up in the body, increased urination occurs. Through all of this, dehydration sets in, leading you into a vicious cycle of quenching your thirst, and the need to release yourself in the process.
b) Flu-Like Symptoms: The fatigue, weakness, and loss of appetite associated with the flu may also present itself with diabetes because your body is unable to utilize sugar in order to gain energy.
c) Weight Loss or Gain: Changes in weight often occur through the presence of diabetes. Weight loss occurs because as you lose sugar through frequent urination, you will also lose calories. The other side of the weight issue is gaining extra pounds because cells become deprived of nutrients, leading to a feeling of constant hunger. As you eat more to compensate, an increase of fatty tissue develops [3].
d) Blurred Vision: The eyes show signs of diabetes as high levels of blood sugar rob eye lenses of much-needed fluid. When ignored, blood vessels become damaged and can lead to dark spots, flashing lights or rings. Serious cases may also lead to blindness.
e) Slow-Healing: High levels of blood sugar can affect the natural healing process and the body’s defense against infections. Diabetes may also cause bladder or vaginal infections in women.
f) Tingling Hands and Feet: Nerve damage may develop as a result of diabetes, which leads to a tingling or loss of sensation in the hands or feet. Sometimes, a burning pain may attack the hands, arms, legs, and feet.
g) Gum Problems: Diabetes may cause gums to become red, swollen, and tender.

Causes of Diabetes
The causes of this condition depend on what type of diabetes you are suffering from. With Type 1 diabetes, the body has little to no insulin because the immune system attacks the cells responsible for producing the hormone. It is believed that heredity; diet and nutrition all contribute to the development of Type 1. With Type 2 diabetes, the pancreas makes some insulin, but either one or two issues arise: the muscles and body tissue may resist the presence of insulin or the pancreas simply doesn’t make enough. Researchers are unaware what makes the cells resistant to insulin, but weight, laziness, and fatty tissues contribute.

Diagnosis
A random blood sugar test and a fasting blood glucose test both determine whether or not a person has Type 1 or Type 2 diabetes. Blood is drawn from the arm to test your glucose levels at any given time (random) or after an overnight fast. In addition to the two blood tests, Type 2 diabetes is also made known through a glucose challenge test (often used for pregnant women) or a glycated hemoglobin (A1C) test.

Risk Factors
While the definite cause regarding Type 1 diabetes is not known, there are some details that increase the risk of developing the disease. This includes having a family member, such as a diabetic parent or sibling. People who are overweight, inactive, or depressed are more likely to suffer from Type 2 diabetes. Individuals over the age of 45 are also likely to develop the disease, but throughout the years, a higher number of children, adolescents and younger adults have been seen. Race also affects your chances of suffering from diabetes, where some ethnic groups are more prone to certain types than others.

Natural Remedies for Diabetes
Natural remedies allow individuals to find gentler, safer, and sometimes more effective treatment options for their condition. Below are a few natural approaches towards treating diabetes:
a) Fenugreek: This herb has been known to cut down sugar levels in urine by half. Making a decoction or taking 1 gram of powdered herb after meals treats mental confusion, weight loss, and excessive thirst.
b) Bilberry: The leaves of this herb are thought to increase the production of insulin when drinking an infusion before meals.
c) Goat’s Rue: The aerial parts of this herb react with the pancreas to encourage production of insulin. Preparing an infusion or tincture before meals can treat the symptoms of diabetes.
d) Mango: Boiling 15 fresh mango leaves in one glass of water will create a natural treatment for diabetes. After mixing the ingredients, leave the combination overnight. At the start of a new day, filter the water and drink first thing in the morning.

Diabetes Prevention
For many, diabetes is highly preventable. It really comes down to incorporating healthy habits and lifestyle changes to avoid the onset of this manageable, yet frustrating disease. Below you will find a few preventive measures to consider:
a) Lose Extra Pounds: Sometimes diabetes prevention is just as easy as keeping your weight to a healthy number. With every pound you lose, your health improves. Try making it a habit to eat better and exercise on a regular basis. When it comes to losing weight, avoiding fad diets is the healthiest approach towards preventing diabetes. Cooking foods with less fat, oil, and butter also help shed extra weight.
b) Fiber: Many reduce their risk of diabetes when they eat fiber-filled foods, which also decrease the chances of developing heart disease. Some of the foods to consider adding to your diet include vegetables, fruits, and other lean food items.
c) Whole Grains: When eating grains, it is the whole variety that contributes to the decrease in developing diabetes. A few eating habits to change include trading white bread for wheat, or consuming whole-grain pastas and cereals.
d) Increase Exercise: When you get the body moving around, not only is weight lost, but also the overall your overall health improves. Physical activity contributes to the lowering of blood sugar levels. Riding a bike, swimming laps, or walking for 30 minutes per day will increase your levels of exercise. [/SIZE]

All about Diseases
 

[SIZE="6"][B][U][CENTER]All about Diseases[/CENTER][/U][/B][/SIZE]

[QUOTE][B]Note:[/B] This thread intends to be complete guide for diseases and pathology. Conducive members are requested to post related material under this thread.

Your co-operation will be appreciated.[/QUOTE]



[B][U]abscess[/U][/B]

abscess, localized inflamation associated with tissue necrosis. Abscesses are characterized by inflamation, which is due to the accumulation of pus in the local tissues, and often painful swelling. They occur in the skin, at the root of a tooth, in the middle ear, on the eyelid, in the mammary glands, in the recto-anal area, and elsewhere in the body. Abscesses may develop in lung tissue, in the lymph nodes, and in bone. A sinus abscess may result in a fistula, and abscess of the appendix in appendicitis. Unless an abscess discharges spontaneously, surgical incision and drainage is required





[B][U]acne[/U][/B]

Common inflammatory disease of the hair follicles and sebaceous glands characterized by blackheads, whiteheads, pustules, nodules and, in the more severe forms, by cysts and scarring. The lesions appear on the face, neck, back, chest, and arms. There are several types of acne, including tropical acne, a condition of light-skinned people who are exposed to unaccustomed heat and humidity, and chloracne, a form resulting from exposure to chlorinated hydrocarbons.

The most common type is acne vulgaris, a form prevalent among adolescents. Although its exact cause is not known, it is undoubtedly related both to genetic predisposition and to the increased hormonal activity that occurs at puberty, which causes an overproduction of sebum, the oily secretion of the sebaceous glands. Exposure to external oils and grease (e.g., oil-based cosmetics or hair products, occupational use of cooking oils) can worsen the condition. There is no connection between diet and acne.

Washing the skin removes surface oils and can prevent acne from spreading. The contents of blackheads and pustular lesions should be evacuated only by a physician under proper aseptic conditions to lessen the possibility of scarring. Application of benzoyl peroxide, retinoic acid, azelaic acid, and antibiotics to the skin can clear many cases; exposure to ultraviolet light may also be used. More severe cases of acne may require oral antibiotic treatment. Treatment of the most resistant cases of acne includes the use of isotretinoin (Accutane), a drug that decreases sebaceous secretions. Isotretinoin is a well-established teratogen (i.e., it causes birth defects) and is not given to women who are pregnant. In the past dermabrasion (scraping off of the top layer of skin) was used to improve the appearance of skin scarred by acne, but such severe effects can now be avoided with proper treatment.





[B][U]acromegaly[/U][/B]

adult endocrine disorder resulting from hypersecretion of growth hormone produced by the pituitary gland. Since the bones cannot increase in length after full growth is attained, there is a disproportionate thickening of bones, predominantly in the skull and small bones of the hands and feet. Fingers and toes become broadened and spadelike, the skull increases in size, and the cheek bones and jaws protrude. Many of the soft tissues, such as the tongue and liver, enlarge. Frequently glucose metabolism is disturbed, leading to diabetes mellitus. Acromegaly is usually caused by a tumor of the pituitary; treatment consists of irradiation or surgical removal of the tumor. Onset of the disease can also occur in children, before the epiphyses of the bones are closed. In such cases the disorder leads to gigantism.





[B][U]actinomycosis[/U][/B]

Chronic suppurative infection that occurs around the face and neck. The disease is characterized by the formation of abscesses, or pus-filled cavities, below the surface of the skin. These abscesses spread rapidly and form channels that discharge a yellow granular pus on the surface of the skin. In humans these granules consist of Actinomyces israelii, a bacterium that used to be considered a fungus. Actinomycosis also sometimes affects the lungs, appendix, or the pelvic region, especially in women with certain kinds of intrauterine devices. Treatment consists of prolonged therapy with massive doses of penicillin and drainage by surgery. Actinomycosis also occurs in horses, cattle, swine, and dogs; it resembles human actinomycosis, but is caused by various other species of Actinomyces.





[B][U]Addison's disease[/U][/B]

It is a progressive disease brought about by atrophy of the outer layer, or cortex, of the adrenal gland; it is also called chronic adrenocortical insufficiency. The deterioration of this tissue causes a decrease in the secretion of steroid hormones, many of which are necessary for the maintenance of life. In many cases the cause of the wasting process is not known; in others the predominant cause is the formation and infiltration of tumors, inflammatory disease, or surgery. Symptoms are increasing weakness, abnormal pigmentation of the skin and mucous membranes, weight loss, low blood pressure, dehydration, and gastrointestinal upsets. Secondary Addison's disease is most commonly caused by acute withdrawal of steroids. Once considered inevitably fatal, Addison's disease can now be treated with injections of adrenocortical hormones.




[B][U]aflatoxins[/U][/B]

a group of secondary metabolites that are cancer-causing byproducts of a mold that grows on nuts and grains, particularly peanuts. Although aflatoxin is most commonly produced when the potentially affected foods are improperly stored, recent studies have documented its production in the field, particularly if severe climatic changes occur or if the plants are attacked by insects. Most industrialized nations strictly regulate the aflatoxin level in human food. However, many of these products are used in animal feed, and if an animal consumes infected food, the aflatoxin passes to people in contaminated milk and meat products. Aflatoxin is a carcinogenic for certain animals, particularly cattle. Among humans, it is associated with liver cancer, particularly in Third World nations where malnutrition and other health problems are also prevalent.





[B][U]agranulocytosis[/U][/B]

It is a disease in which the production of granulated white blood cells by the bone marrow is impaired. Although the disease may occur spontaneously it is usually induced by exposure to antithyroid drugs, sulfonamides, phenothiazines, chemotherapy, and radiation therapies. Granulocytes protect the body against infectious agents; their depletion results in severe respiratory infections, ulceration of the mouth and colon, high fever, and prostration. These symptoms may occur suddenly or over a period of days or weeks. Penicillin is usually the drug of choice to combat the bacterial invasion. Treatment may require bone marrow transplants to start the production of healthy white blood cells. The fatality rate is high (approaching 80%) in untreated cases, and deaths are common even with antibiotic treatment.





[B][U][COLOR="blue"]AIDS[/COLOR][/U][/B]

AIDS or acquired immunodeficiency syndrome,fatal disease caused by a rapidly mutating retrovirus that attacks the immune system and leaves the victim vulnerable to infections, malignancies, and neurological disorders. It was first recognized as a disease in 1981. The virus was isolated in 1983 and was ultimately named the human immunodeficiency virus (HIV). There are two forms of the HIV virus, HIV-1 and HIV-2. The majority of cases worldwide are caused by HIV-1. In 1999 an international team of genetic scientists reported that HIV-1 can be traced to a closely related strain of virus, called simian immunodeficiency virus (SIV), that infects a subspecies of chimpanzee (Pan troglodytes troglodytes) in W central Africa. Chimpanzees are hunted for meat in this region, and it is believed the virus may have passed from the blood of chimpanzees into humans through superficial wounds, probably in the early 1930s.




[B]Action of the Virus[/B]

In a process still imperfectly understood, HIV infects the CD4 cells (also called T4 or T-helper cells) of the body's immune system, cells that are necessary to activate B-lymphocytes and induce the production of antibodies. Although the body fights back, producing billions of lymphocytes daily to fight the billions of copies of the virus, the immune system is eventually overwhelmed, and the body is left vulnerable to opportunistic infections and cancers.


[B]Signs and Symptoms[/B]

Some people develop flulike symptoms shortly after infection, but many have no symptoms. It may be a few months or many years before serious symptoms develop in adults; symptoms usually develop within the first two years of life in infants infected in the womb or at birth. Before serious symptoms occur, an infected person may experience fever, weight loss, diarrhea, fatigue, skin rashes, shingles (see herpes zoster), thrush, or memory problems. Infants may fail to develop normally.

The definition of AIDS has been refined as more knowledge has become available. In general it refers to that period in the infection when the CD4 count goes below 200 (from a normal count of 1,000) or when the characteristic opportunistic infections and cancers appear. The conditions associated with AIDS include malignancies such as Kaposi's sarcoma, non-Hodgkin's lymphoma, primary lymphoma of the brain, and invasive carcinoma of the cervix. Opportunistic infections characteristic of or more virulent in AIDS include Pneumocystis carinii pneumonia, herpes simplex, cytomegalovirus, and diarrheal diseases caused by cryptosporidium or isospora. In addition, hepatitis C is prevalent in intravenous drug users and hemophiliacs with AIDS, and an estimated 4 to 5 million people who have tuberculosis are coinfected with HIV, each disease hastening the progression of the other. Children may experience more serious forms of common childhood ailments such as tonsillitis and conjunctivitis. These infections conspire to cause a wide range of symptoms (coughing, diarrhea, fever and night sweats, and headaches) and may lead to extreme weight loss, blindness, hallucinations, and dementia before death occurs.








[B][U]alcoholism[/U][/B]

alcoholism, disease characterized by impaired control over the consumption of alcoholic beverages. Alcoholism is a serious problem worldwide; in the United States the wide availability of alcoholic beverages makes alcohol the most accessible drug, and alcoholism is the most prevalent of the nation's addictions.

The understanding of alcoholism, and hence its definition, continues to change. Many terms, often with hazy differences in meaning, have been used to describe different stages and manifestations of the disease. In 1992 the National Council on Alcoholism and Drug Dependence and the American Society of Addiction Medicine published a definition reflecting the current understanding of the disease: “Alcoholism is a primary, chronic disease with genetic, psychosocial, and environmental factors influencing its development and manifestations. The disease is often progressive and fatal. It is characterized by impaired control over drinking, preoccupation with the drug alcohol, use of alcohol despite adverse consequences, and distortions in thinking, most notably denial. Each of these symptoms may be continuous or periodic.” This definition recognizes alcoholism as a disease, i.e., as an involuntary disability. It accepts a genetic vulnerability in some people and identifies the phenomenon of denial as both a psychological defense mechanism and a physiological outcome of alcohol's effect on the memory.





[B][U]allergy[/U][/B]

allergy, hypersensitive reaction of the body tissues of certain individuals to certain substances that, in similar amounts and circumstances, are innocuous to other persons. Allergens, or allergy-causing substances, can be airborne substances (e.g., pollens, dust, smoke), infectious agents (bacteria, fungi, parasites), foods (strawberries, chocolate, eggs), contactants (poison ivy, chemicals, dyes), or physical agents (light, heat, cold). It is believed that a person who is hereditarily predisposed toward allergy produces, when sensitized, special weak types of antibodies, called reagins, that give little immune protection but cause local tissue damage during the antibody-antigen reaction. Allergens can affect the respiratory system, the reaction manifesting itself as asthma or hay fever, or they can affect the skin, causing wheals and rashes. Allergens may also act on the gastrointestinal tract, causing nausea and vomiting. Allergic reactions to substances injected into the bloodstream can cause violent and sometimes fatal reactions. The best treatment of allergic reactions is prevention, i.e., elimination of the offending substances from the sensitive person's environment. If this is not possible, desensitization (i.e., deliberate production of the allergic reaction by injecting the allergen, after which the sufferer is no longer susceptible) is sometimes helpful. Antihistamine drugs may give temporary relief




[B][U]Alzheimer's disease[/U][/B]

Degenerative disease of nerve cells in the cerebral cortex that leads to atrophy of the brain and senile dementia. The disease is characterized by abnormal accumulation of plaques and by neurofibrillary tangles (malformed nerve cells), changes in brain tissue first described by Alois Alzheimer in 1906. The plaques result from the release and accumulation of excessive amounts of beta-amyloid proteins, normal proteins whose function in the body is not known. The neurofibrillary tangles prevent transportation of synthesized products within the cell body to organelles and target sites. The plaques and neurofibrillary tangles prevent proper transmission of electrochemical signals necessary for information processing and retrieval. The plaques also suffocate neurons by inhibiting proper blood supplies from reaching them.

Alzheimer's disease usually affects people over age 65, although it can appear in people as young as 40, especially in some familial forms of the disease. A condition called mild cognitive impairment, in which a person experiences an inability to form memories for events that occurred a few minutes ago, typically is the first sign of the disease. Although other conditions may cause mild cognitive impairment, if no identifiable cause is present, it leads to Alzheimer's in some 80% of the cases. As the disease progresses, a variety of symptoms may become apparent, including loss of memory, anxiety, confusion, irritability, and restlessness, as well as disorientation, impaired judgment and concentration, and more severe emotional and behavioral disorders.

The cause of Alzheimer's is unknown. Mutations in a gene on chromosome 21, which is also associated with Down syndrome, and another gene on chromosome 14 have been found in early-onset cases. Late-onset cases, which are the vast majority, may be caused by a combination of genetic and environmental factors. In 1999 scientists discovered an enzyme, named beta-secretase, that begins a toxic process in the brain leading to Alzheimer's disease.

There is as yet no known cure. Genetic screening for families with a history of early Alzheimer's is sometimes advised. Treatment includes relieving the patient's symptoms and alleviating stress on caregivers through support groups and counseling services. Donepezil (Aricept), rivastigmine (Exelon), and other acetylcholinesterase inhibitors provide temporary improvement for some patients with mild to moderate Alzheimer's. Memantine (Namenda), which appears to protect against damage from the effects of excess glutamate, slows the progression of the disease in some patients in the late stage of Alzheimer's.






[B][U]amenorrhea[/U][/B]

The cessation of menstruation. Primary amenorrhea is a delay in or a failure to start menstruation; secondary amenorrhea is an unexpected stop to the menstrual cycle. It is caused by dysfunctioning of the pituitary gland, ovaries, uterus, and hypothalamus, by surgical removal of the ovaries or uterus, by medication, or by emotional trauma. The result is an inadequate amount of body fat, calories, and protein to sustain menstruation. Female athletes have a higher than average rate of menstrual dysfunction, particularly amenorrhea, but the long-term effects of the exercise-related disorders are not known. It is also common among anorexics. The lack of estrogen, however, may contribute to the development of osteoporosis. Hormonal deficiencies over prolonged periods of time, particularly in combination with poor diets, may cause luteal phase deficiency and hypoestrogenic amenorrhea, which may last a long time. Methods of treatment include oral contraceptives or estrogen-progestin therapy.





[B][U]amyotrophic lateral sclerosis[/U][/B]

It is also known as motor neuron disease,sometimes called Lou Gehrig's disease, degenerative disease that affects motor neurons in the brain and spinal cord, preventing them from sending impulses to the muscles. The muscles atrophy quickly, causing weakness, paralysis, and eventual death, usually when the muscles that control respiration fail. The intellect, eye motion, and bladder control are not affected. ALS sometimes originates in the brain, causing initial symptoms such as difficulty in swallowing or talking; in other cases it originates in the spinal cord, causing initial symptoms such as weakness in the extremities. About 10% of ALS cases are hereditary. ALS usually develops after age 40; more men are affected than women.

There appear to be several causes of ALS. In 1991 a research team led by Teepu Siddique and Robert H. Brown, Jr. located the gene for familial ALS on chromosome 21. A later discovery pinpointed a mutation in the gene that codes for an enzyme, superoxide dismutase (SOD), as responsible for a percentage of familial cases. These defects do not appear to be present in the more common nonfamilial, or “sporadic,” form of the disease. In addition to genetic factors, scientists have studied the buildup of the chemical glutamate that occurs in ALS patients. Glutamate normally acts as a neurotransmitter in the brain, with excess amounts being absorbed by the cells. In ALS patients the reabsorption process fails, and the buildup of glutamate selectively destroys motor neurons. Other possible causes of ALS include defects in the gene that makes the neurofilament proteins that support nerve cell axons, and antibodies that interfere with calcium channels in the cells and cause a toxic buildup of calcium in the neurons.

There is no cure for ALS. Devices such as wheelchairs and speech synthesizers can help patients maintain independence. Research into treatment has concentrated on neurotrophic factors (proteins that assist nerve growth and health) and glutamate blockers. Rilutek (formerly Riluzole), the first drug approved by the Food and Drug Administration for treatment of ALS (1995), adds a few months to the life expectancy of most patients but does not relieve symptoms. Another drug, myotrophin, seemed somewhat promising in early studies (1996), but its effectiveness was not confirmed and it has not been approved. Baseball star Lou Gehrig died of ALS in 1941, bringing it national attention.





[B][U]anaphylaxis[/U][/B]

The hypersensitive state that may develop after introduction of a foreign protein or other antigen into the body tissues. When an anaphylactic state exists, a second dose of the same protein (commonly an antibiotic such as penicillin, or certain insect venoms) will cause a violent allergic reaction. Anaphylaxis results from the production of specific antibodies in the tissues in very high concentration; the violent reaction is produced by the neutralization of antigens by the antibodies. The histamines released during the reaction are thought to cause the most damage, i.e., severe vasodilation and loss of capillary fluid, resulting in circulatory collapse. Other symptoms include urticaria or edema, choking, coughing, shock, and loss of consciousness. Death may occur within 5 to 10 min if no medical help is available. Anaphylaxis differs from immunity; in immunity, antibodies circulate in the blood and neutralize antigens without producing a violent reaction.




[B][U]anemia[/U][/B]

It is a condition in which the concentration of hemoglobin in the circulating blood is below normal. Such a condition is caused by a deficient number of erythrocytes (red blood cells), an abnormally low level of hemoglobin in the individual cells, or both these conditions simultaneously. Regardless of the cause, all types of anemia cause similar signs and symptoms because of the blood's reduced capacity to carry oxygen. These symptoms include pallor of the skin and mucous membranes, weakness, dizziness, easy fatigability, and drowsiness. Severe cases show difficulty in breathing, heart abnormalities, and digestive complaints.

One of the most common anemias, iron-deficiency anemia, is caused by insufficient iron, an element essential for the formation of hemoglobin in the erythrocytes. In most adults (except pregnant women) the cause is chronic blood loss rather than insufficient iron in the diet, and, therefore, the treatment includes locating the source of abnormal bleeding in addition to the administration of iron.

Pernicious anemia causes an increased production of erythrocytes that are structurally abnormal and have attenuated life spans. This condition rarely occurs before age 35 and is inherited, being more prevalent among persons of Scandinavian, Irish, and English extraction. It is caused by the inability of the body to absorb vitamin B12 (which is essential for the maturation of erythrocytes).

There are several conditions that cause the destruction of erythrocytes, thereby producing anemia. Allergic-type reactions to bacterial toxins and various chemical agents, among them sulfonamides and benzene, can cause hemolysis, which requires emergency treatment. In addition, there are unusual situations in which the body produces antibodies against its own erythrocytes; the mechanism triggering such reactions remains obscure.

There are several inherited anemias that are more common among dark-skinned people. Sickle cell disease is inherited as a recessive trait almost exclusively among blacks; the condition is characterized by a chemical abnormality of the hemoglobin molecule that causes the erythrocytes to be misshapen. In 1957 Vernon Ingram determined the amino acid sequence of hemoglobin, and found the beta-globins (which is one of the two polypeptide chain types) that are found in the tetrameric (four-chain) hemoglobin protein. In sickle cell disease a single mutation produces the amino acid valine instead of glutamic acid in one of the protein chain types that make up the hemoglobin molecule.

In thalassemia major (Cooley's anemia), which is the most serious of the hereditary anemias among people of Mediterranean, Middle Eastern, and S Chinese ancestry, the erythrocytes are abnormally shaped. Symptoms include enlarged liver and spleen and jaundice. Thalassemia major usually causes death before adulthood is reached.

Any disease or injury to the bone marrow can cause anemia, since that tissue is the site of erythrocyte synthesis. Bone marrow destruction can also be caused by irradiation, disease, or various chemical agents. In cases of renal dysfunction, the severity of the associated anemia correlates highly with the extent of the dysfunction; it is treated with genetically engineered erythropoietin.






[B][U]aneurysm[/U][/B]

The localized dilatation of a blood vessel, particularly an artery, or the heart. Dilatation of an artery, and therefore weakness of that portion of the arterial wall, may be rarely congenital, or it may be caused by syphilis, hypertension (high blood pressure), arteriosclerosis, bacterial and fungal infections, or penetrating injury as from a bullet or knife. An aneurysm may be asymptomatic or it may cause varying symptoms, depending upon its location and size and on whether the expanding mass is pressing on adjacent nerves or vital organs. The weakened arterial walls of an aneurysm are always in danger of sudden rupture, with resulting hemorrhage and death.

Aneurysms occur most commonly in the large arteries; the aorta, the largest vessel in the body, is the one most often affected. Ventricular aneurysms of the heart often occur after myocardial infarctions. Aneurysms also occur in the arteries within the skull and in other areas of the body.

Aneurysms can be detected by echocardiogram, spin echo magnetic resonance imaging scans, coronary arteriograms, and biplane ventriculograms. Treatment, where feasible, may involve surgery to remove the aneurysm or the insertion of coiled wire to close it off. Coiled wire can only be used on aneurysms that are connected to the blood vessel by a narrowed neck. The coiling fills the aneurysm, obstructing the flow of blood into the dilatation, and blood clots form around the wire, preventing the aneurysm from bursting. Surgical excision of the dilated saclike portion of the affected artery sometimes requires the replacement of that portion by a synthetic graft, a section of vessel (made of polymer fiber) that is similar in size.






[B][U]angina pectoris[/U][/B]

It is a condition characterized by chest pain that occurs when the muscles of the heart receive an insufficient supply of oxygen. This results when the arteries that supply the heart muscle with oxygenated blood are narrowed by arteriosclerosis. In rare cases angina results from spasms of the coronary arteries. Angina is a primary symptom of coronary artery disease.

The pain is usually experienced under or to the left of the sternum (breastbone) and radiates to the left shoulder and down the upper arm; less frequently, it spreads to the right shoulder. The attack usually subsides without residual discomfort and, when precipitated by physical exertion, is quickly halted when the subject rests. Often the attacks are separated by weeks, months, even years in which symptoms subside. Symptoms usually begin after the age of 50, more often in men than women, and frequently follow physical exertion, excitement, eating, smoking, or exposure to cold. Associated symptoms are faintness and difficulty in breathing.

Nitrates (e.g., amyl nitrite or nitroglycerin), drugs that dilate the blood vessels of the heart, are traditionally used in treatment. Newer drug treatments include beta-blockers and calcium-channel blockers. Significant narrowing of the coronary arteries may require surgical treatment, such as a coronary artery bypass, a procedure that splices healthy blood vessels taken from elsewhere in the body to the affected coronary arteries in such a way that the clogged areas are bypassed. In angioplasty, a balloon-tipped catheter is inserted through the skin into a blood vessel and maneuvered to the clogged artery. There it is threaded into the blockage and inflated, compressing the plaque against the arterial walls. New techniques use atherotomes to mechanically cut the plaque or cold lasers to remove plaque with bursts of ultraviolet light.






[B][U]anthrax[/U][/B]

An acute infectious disease of animals that can be secondarily transmitted to humans. It is caused by a bacterium (Bacillus anthracis) that primarily affects sheep, horses, hogs, cattle, and goats and is almost always fatal in animals. The bacillus produces toxins that kill cells and cause fluid to accumulate in the body's tissues.

Anthrax spores, which can survive for decades, are found in the soil, and animals typically contract the disease while grazing. Transmission to humans normally occurs through contact with infected animals but can also occur through eating meat from an infected animal or breathing air laden with the spores of the bacilli. The disease is almost entirely occupational, i.e., restricted to individuals who handle hides of animals (e.g., farmers, butchers, and veterinarians) or sort wool.

In the cutaneous, or skin, form of the disease, which is not usually fatal to humans, the bacillus enters the skin through a scratch, cut, or sore. Pustules occur on the hands, face, and neck; if the disease is not treated with antibiotics, the bacteria can migrate to the blood vessels, causing septicemia (blood poisoning) and death. Gastrointestinal anthrax is more likely to be fatal. Nausea, vomiting, and fever can be followed by abdominal bleeding, tissue death, and septicemia. Pulmonary, or inhalation, anthrax begins with flulike symptoms and ultimately causes lesions in the lungs and brain. It is rarer, but is usually fatal if not treated early. Because of this, individuals without symptoms who have been exposed to inhaled anthrax are treated with antibiotics for 60 days.

Anthrax is a well-known, ancient disease; the fifth plague visited upon the Egyptians in Genesis (see plagues of Egypt) resembles the disease. Pure cultures of the anthrax bacillus were obtained in 1876 by Robert Koch, who demonstrated the relationship of the microbe to the disease. Confirmation of the bacillus as the cause of anthrax was provided by Louis Pasteur, who also developed a method of vaccinating sheep and cattle against the disease. Anthrax is now uncommon in the United States because of widespread vaccination of animals and disinfection of animal products such as hides and wool.

Anthrax spores have been used experimentally by various nations as a biological warfare agent, but effective delivery of anthrax to a population is difficult, and such use is now banned by international convention. Because anthrax has been tested as a biological weapon, the United States has developed a vaccine for military use, but it requires several injections and annual boosters. An accidental release of anthrax from a military laboratory near Sverdlovsk (now Yekaterinburg) in the Soviet Union resulted in 68 deaths from pulmonary anthrax in 1979. In 2001 a number of people in the United States were exposed to spores that were sent through the mails and contracted anthrax; several persons died. Although these bioterror attacks occurred shortly after the terrorist attacks on the World Trade Center and the Pentagon, it did not appear to be linked to them.






[B][U]arrhythmia[/U][/B]

Disturbance in the rate or rhythm of the heartbeat. Various arrhythmias can be symptoms of serious heart disorders; however, they are usually of no medical significance except in the presence of additional symptoms. The heart's rhythm is controlled by an electrical impulse that is generated from a clump of tissue on the right atrium called the sinoatrial node, often referred to as the heart's natural pacemaker. It travels to a second clump of tissue called the atrioventricular node and then to the ventricles.

Bradycardia, or slow heartbeat, is often present in athletes. It may, however, indicate conduction problems, especially in older people. In one type of bradycardia, called sinoatrial or atrioventricular block, or heart block, rhythm can be maintained by implanted electrodes that act as artificial pacemakers.

Tachycardia, or heartbeat faster than 100 beats per minute in the adult, can be precipitated by drugs, caffeine, anemia, shock, and emotional upset. It may also be a sign of overactivity of the thyroid gland or underlying disease. Flutters, and the even faster fibrillations, are rapid, uncoordinated contractions of the atrial or ventricular muscles that usually accompany heart disorders. Atrial fibrillation may be idiopathic, the result of rheumatic mitral valve disease (see rheumatic fever) in young people or hypertensive heart disease (see hypertension) and arteriosclerotic heart diseases (see arteriosclerosis) in older people. It may result in a rapid pulse rate and may be associated with thrombus formation in the atria and a risk of embolization to the brain (stroke) or other organs. Atrial fibrillation is often treated with digitalis and other drugs that regulate heart rhythm or heart rate. Ventricular fibrillation is a sign of the terminal stage of heart failure and is usually fatal unless defibrillation is achieved by immediate direct-current defibrillation. Some tachycardias can be managed by the implantation in the upper chest of small defibrillators that sense dangerous fibrillations and administer an electric shock to the heart to restore normal rhythm.





[B][U]arteriosclerosis[/U][/B]

The general term for a condition characterized by thickening, hardening, and loss of elasticity of the walls of the blood vessels. These changes are frequently accompanied by accumulations inside the vessel walls of lipids, e.g., cholesterol; this condition is frequently referred to as atherosclerosis. Initially lesions are formed on the arterial walls, which results in blistering and the accumulation of low-density cholesterol. This produces higher blood pressure, which facilitates the imbedding of cholesterol and calcium in the vessel walls. The fatty material accumulates calcium and produces hard plaques, thus hardening the walls of the vessels. As the vessel walls thicken, the passageways through the vessels narrow, decreasing the blood supply to the affected region. Constriction of the coronary arteries may affect the heart. If the leg vessels are affected, there may be pain with walking and an onset of gangrene. When there is total clotting of a vessel (thrombosis) the result may be a heart attack (if it occurs in the coronary arteries) or stroke (if in cerebral arteries).

Arteriosclerosis risk factors include hypertension, elevated levels of fats in the blood, cigarette smoking, diabetes mellitus, and obesity. Genetic risks are related to the ability of the body to process (uptake and metabolize) low-density lipids that contain cholesterol. Reduction of body cholesterol to normal levels through cholesterol-lowering drugs and a restricted-fat diet is usually prescribed. The latter generally entails substitution of vegetable fats for animal fats, but an exception may be “trans fat,” artificially hydrogenated vegetable oils found in margarine and vegetable shortening, which studies have linked to increased risk of coronary disease. Treatment of hypertension, stress management, and cessation of smoking are also important. Increasing consumption of antioxidants and folic acid may be protective. Surgical treatment that bypasses clogged areas or procedures such as angioplasty are sometimes necessary; gene therapy that forces the growth of new blood vessels bypassing an area has also been used. Exercise often can increase utilization of excess low-density lipids. Although the relationship between blood cholesterol levels and arteriosclerosis is not fully understood, the utilization of low-density lipids appears to be a primary indicator of the risk of arteriosclerosis.




[B][U]arthritis[/U][/B]

arthritis, painful inflammation of a joint or joints of the body, usually producing heat and redness. There are many kinds of arthritis. In its various forms, arthritis disables more people than any other chronic disorder. The condition can be brought about by nerve impairment, increased or decreased function of the endocrine glands, or degeneration due to age. Less frequently, it is caused by infection (tuberculosis, gonorrhea, Lyme disease, rheumatic fever).

Rheumatoid arthritis, an autoimmune disease of unknown cause, is the most crippling form. Women are much more susceptible to it than men. Although rheumatoid arthritis usually appears between the ages of 25 and 50, it also occurs in children. Osteoarthritis, the most common type, occurs usually in people over 50. It tends to be more severe when the joints have been strained by obesity or overwork. Gout, the third most common form of arthritis, affects men almost exclusively.

Symptomatic treatment for arthritis includes use of heat, physical therapy, and nonsteroidal anti-inflammatory drugs such as a cox-2 inhibitor (Celebrex), aspirin, ibuprofen, and naproxen. Remission of symptoms can sometimes be achieved with methotrexate, gold salts, penicillamine, and short-term cortisone, but they often have undesirable side effects. Orthopedic surgery, including artificial joint implantation, may be done in severe cases.






[B][U]asphyxia[/U][/B]

Deficiency of oxygen and excess of carbon dioxide in the blood and body tissues. Asphyxia, often referred to as suffocation, usually results from an interruption of breathing due to mechanical blockage of the breathing passages, paralysis of the respiratory muscles following electric shock, inundation of the lungs as may occur with pneumonia or drowning, or substitution of carbon monoxide for oxygen in the red blood cells. Symptoms of asphyxia vary but may include light-headedness, nausea, and gasping, followed by unconsciousness and death. An area quickly affected is the cerebral cortex, the brain center for speech and other conscious behavior; it can be irreparably damaged by as little as five minutes of oxygen deprivation. Damage to the medulla may result in interference with the heartbeat or other involuntary processes. Artificial respiration is the most practical first-aid procedure for asphyxia. Trained personnel can provide oxygen and employ techniques to maintain the heart rate and respiration.




[B][U][COLOR="blue"]asthma[/COLOR][/U][/B]

A chronic inflammatory respiratory disease characterized by periodic attacks of wheezing, shortness of breath, and a tight feeling in the chest. A cough producing sticky mucus is symptomatic. The symptoms often appear to be caused by the body's reaction to a trigger such as an allergen (commonly pollen, house dust, animal dander) certain drugs, an irritant (such as cigarette smoke or workplace chemicals), exercise, or emotional stress. These triggers can cause the asthmatic's lungs to release chemicals that create inflammation of the bronchial lining, constriction, and bronchial spasms. If the effect on the bronchi becomes severe enough to impede exhalation, carbon dioxide can build up in the lungs and lead to unconsciousness and death. Following a steady 30-year decline, asthma deaths in the United States, especially among poor, inner-city blacks and among the elderly, began to rise from the late 1970s through the early 1990s. At the same time, the incidence of asthma also increased, both nationally and worldwide.

There is no cure for asthma. Although the disease may go through a period of quiescence, it appears that childhood asthmatics do not outgrow the disease as previously believed. Treatment includes inhaled or oral steroids or bronchodilators (albuterol, theophylline), breathing exercises, and, if possible, the identification and avoidance of triggers.





[B][U]astigmatism[/U][/B]

It is a type of faulty vision caused by a nonuniform curvature in the refractive surfaces—usually the cornea, less frequently the lens—of the eye. As a result, light rays do not all come to a single focal point on the retina. Instead, some focus on the retina while others focus in front of or behind it. The condition may be congenital, or it may result from disease or injury; it can occur in addition to nearsightedness or farsightedness. The spherical lenses used to correct nearsightedness and farsightedness must be specially adapted to correct the out-of-focus plane of vision of the astigmatic eye. When the patient observes a pattern of straight lines placed at various angles, those running in one direction appear sharp while those in other directions (particularly at right angles to the sharp lines) appear blurred. A special cylindrical lens is placed in the out-of-focus axis to correct the condition. In many cases contact lenses are the most effective means of correcting astigmatism.





[B][U]ataxia[/U][/B]

Lack of coordination of the voluntary muscles resulting in irregular movements of the body. Ataxia can be brought on by an injury, infection, or degenerative disease of the central nervous system, e.g., syphilis, encephalitis, brain tumor, or multiple sclerosis. The term also designates a specific type of cerebral palsy.






[B][U]athlete's heart[/U][/B]

athlete's heart, common term for an enlarged heart associated with repeated strenuous exercise. As a result of the increased workload required of it, the heart will increase physiologically by enlarging chambers and muscle mass, or hypertrophy by enlarging the size of the chambers and increasing the volume of blood pumped per stroke. Consequently, the heart has to contract less frequently and at rest will beat as few as 40 times per minute as compared with an average number of 70 beats in a normal heart. The condition is not pathological, and there is generally no danger of cardiac disability arising from it.





[B][U]atrophy[/U][/B]

atrophy may be defined as diminution in the size of a cell, tissue, or organ from its fully developed normal size. Temporary atrophy may occur in muscles that are not used, as when a limb is encased in a plaster cast. Interference with cellular nutrition, as through starvation; diseases affecting the nerve supply of tissues, e.g., poliomyelitis and muscular dystrophy; and prolonged disuse may cause a permanent wasting away of tissue. Atrophy may also follow hypertrophy.




[B][U]autism[/U][/B]

Developmental disability resulting from a neurological disorder that affects the normal functioning of the brain. It is characterized by the abnormal development of communication skills, social skills, and reasoning. Males are affected four times as often as females. Children may appear generally normal until around the age of 24 to 30 months, although studies have identified signs of autism in children under a year of age.

Symptoms, which vary widely in severity, include impairment in social interaction, fixation on inanimate objects, inability to communicate normally, and resistance to changes in daily routine. Characteristic traits include lack of eye contact, repetition of words or phrases, unmotivated tantrums, inability to express needs verbally, and insensitivity to pain. Behaviors may change over time. Autistic children often have other disorders of brain function; about two thirds are mentally retarded; over one quarter develop seizures.

The cause of autism remains unclear, but a psychological one has been ruled out. Neurological studies indicate a primary brain dysfunction, perhaps related to abnormalities that appear to occur in the way the autistic child's brain develops. A genetic component is suggested by a pattern of autism in some families, and the condition also appears to be more common in children born to older fathers. Treatment in which autistic children are intensively and repetitively taught skills and behaviors from a young age appears to help some children with the disorder.






[B][U]autoimmune disease[/U][/B]

Any of a number of abnormal conditions caused when the body produces antibodies to its own substances. In rheumatoid arthritis, a group of antibody molecules called collectively RF, or rheumatoid factor, is complexed to the individual's own gamma globulin blood proteins; the circulating complex apparently causes tissue inflammation and muscle and bone deformities. In Hashimoto's thyroiditis, an inflammatory disease of the thyroid gland, antibodies are produced against the thyroid protein thyroglobulin. In some blood disorders, antibodies may be produced against the body's own red and white blood cells. Myasthenia gravis, a disease characterized by weakened muscles, is thought to have an autoimmune origin. In systemic lupus erythematosus it has been shown that individuals have antibodies to certain of their own body substances that for some reason are acting as antigens; these substances include the individual's own nucleic acids and cell organelles such as ribosomes and mitochondria. Lupus can cause dysfunction of many organs, including the heart, kidneys, and joints. Because lupus and certain diseases of probable autoimmune origin, e.g., scleroderma and dermatomyositis, affect collagen (connective tissue) throughout the body and blood vessels, they are referred to as collagen-vascular diseases. In rheumatic fever, the individual produces antibodies to antigens of streptococcal bacteria; it is believed that the streptococcal antigens are structurally similar to antigens of the heart and that antistreptococcal antibodies, combining with antigenic sites on the heart, damage the muscle and heart valves. Diseases of the immune system are currently treated by a variety of nonspecific immunosuppressive drugs and steroids.

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[B][U]babesiosis[/U][/B]

A tick-borne disease caused by a protozoan of the genus Babesia. Babesiosis most commonly affects domestic and wild animals and can be a serious problem in cattle. In most cases the protozoal species is specific to a single host. The organisms enter the blood via a tick bite, then infect the red blood cells where they reproduce by cell division.

Human babesiosis, sometimes called Nantucket fever, was first diagnosed after an outbreak on Nantucket Island, off the coast of Massachusetts, in the 1970s. The causative organism, Babesia microti, is related to the one that causes malaria, and is transmitted by the deer tick that also hosts the organisms that cause Lyme disease and human erhlichiosis. The main symptoms are fever and chills; treatment is with a combination of antimalarial drugs.







[B][U][COLOR="blue"]baldness[/COLOR][/U][/B]

baldness, thinning or loss of hair as a result of illness, functional disorder, or hereditary disposition; also known as alopecia. Male pattern baldness, a genetic trait, is the most common cause of baldness among white males. It is carried by females, but they are rarely susceptible inasmuch as it develops under the influence of testosterone, a male sex hormone; women, however, may experience an overall thinning of the hair. Hair loss begins at the forehead and crown and is slowly progressive. Male pattern baldness may be cosmetically disguised by hair-follicle transplants. Drug treatments with minoxidil (Rogaine) or finasteride (Propecia) have been used with limited effectiveness.

Diseases characterized by high fever (e.g., scarlet and typhoid fevers), malnutrition, chemotherapy, and glandular disorders can all cause balding. Treatment of the disease or dysfunction will usually halt the loss of hair, and if the scalp and hair follicles are not severely damaged, hair will usually regrow spontaneously. Scalp infection, oiliness or dirtiness of the scalp and hair, and excessive teasing and lacquering of hair are also conducive to baldness. Alopecia areata is a disease of unknown origin characterized by noninflamed bald patches in the scalp hair and beard. It is recurrent but is usually of short duration.







[B][U]beriberi[/U][/B]

deficiency disease occurring when the human body has insufficient amounts of thiamine (vitamin B1). The deficiency may result from improper diet (e.g., ingestion of highly refined grains instead of the whole kernels), from poor absorption of thiamine (as in chronic diarrhea), from conditions which increase the vitamin requirements of the body (e.g., hyperthyroidism, pregnancy, fever), or from poor utilization (as in liver disease). In some instances (e.g., alcoholism) the deficiency arises from a combination of several or of all of these factors. Since thiamine is essential for the proper metabolism of carbohydrate and fat and for the normal functioning of enzymes and nervous tissue, the symptoms of the disorder are primarily those of neurological and gastrointestinal disturbances. In severe cases the heart becomes affected, and the nervous disorder may lead to paralysis and death. The disorder is rarely found in the West, occurring only among alcoholics and other groups who exist on grossly inadequate diets. It is a common malady in parts of Asia where the diet consists mainly of polished white rice. The usual treatment is administering dosages of thiamine.







[B][U][COLOR="blue"]birth defects[/COLOR][/U][/B]

birth defects, abnormalities in physical or mental structure or function that are present at birth. They range from minor to seriously deforming or life-threatening. A major defect of some type occurs in approximately 3% of all births. Defects may be genetic in origin, as in Down syndrome, Tay-Sachs disease, sickle cell disease, and hemophilia, or may be the result of infections, such as rubella and sexually transmitted diseases. Other teratogenic (malformation-causing) agents include drugs or hormones taken by the mother (e.g., thalidomide and DES) and maternal illnesses (e.g., diabetes). The mother's nutrition, drinking (see fetal alcohol syndrome), smoking, and drug abuse, as well as exposure to toxic chemicals and radiation, can also affect the developing fetus. Smoking, drugs, toxic chemicals, and the like can also damage the father's sperm, which may pass on the defect to the embryo in fertilization. The incidence of some disorders is elevated when the mother or father is older, which increases the likelihood of age-related gene mutations. Certain birth defects can now be detected prenatally through amniocentesis and chorionic villus sampling. Surgical procedures to correct certain disorders before birth are still considered experimental.







[B][U]birthmark[/U][/B]

birthmark, pigmented maldevelopment of the skin that varies in size, either present at birth or developing later. Birthmarks may appear as moles (melanocytic nevi) that vary in color from light brown to blue, and are either flat or raised above the surface of the skin. They are usually benign, but do rarely develop into malignant melanoma, a form of skin cancer. The so-called port-wine stains and strawberry marks involve vascular tissue. The flat port-wine stains can be made lighter with the use of laser therapy. The strawberry marks generally disappear a few years after birth.





[B][U]blackhead[/U][/B]

blackhead, yellowish or blackish plug of material accumulated in the duct of a sebaceous gland. The material consists of keratin (horny cells of the epidermis) and modified sebum (oily secretions of the sebaceous gland). Blackheads are the primary lesions in acne. Treatment is the same as for acne, with frequent cleansing of the skin followed by the application of astringent solutions. Plugs should be extracted only by a physician, since damage to the surrounding tissues occasioned by squeezing often leads to scarring.





[B][U][COLOR="blue"]blindness[/COLOR][/U][/B]

blindness, partial or complete loss of sight. Blindness may be caused by injury, by lesions of the brain or optic nerve, by disease of the cornea or retina, by pathological changes originating in systemic disorders (e.g., diabetes) and by cataract, glaucoma, or retinal detachment. Blindness caused by infectious diseases, such as trachoma, and by dietary deficiencies is common in underdeveloped countries where medical care is inadequate. River blindness, caused by a parasitic worm transmitted by black flies, results in severe itching and disfiguring lesions. Infection of the eye area can destroy vision. An estimated 18 million people in Africa, Latin America, South America, and Yemen are infected with the parasite; 1 million of those infected are expected to become blind or severely impaired. Until recently, pesticides have been used to eradicate the flies. Two new drugs, ivermectin and amocarzine, have proved effective when used together. Most infectious diseases of the eye can be prevented or cured.

A major cause of congenital blindness in the United States, ophthalmia neonatorum, which is caused by gonorrhea organisms in the maternal birth canal, is now prevented by placing silver nitrate solution in all newborn infants' eyes. Retinitis pigmentosis, a hereditary and degenerative eye disease, affects 100,000 people in the United States. An early sign is night blindness which progresses to total blindness. Color blindness, an hereditary problem, is an inability to distinguish colors, most commonly red and green. Snow blindness is a temporary condition resulting from a burn of the cornea caused by the reflection of sunlight on snow. Night blindness results from a deficiency of vitamin A.





[B][U]blister[/U][/B]

blister, puffy swelling of the outer skin (epidermis) caused by burn, friction, or irritants like poison ivy. A response of the body to protect deeper tissue, blisters generally contain serum, the liquid component of blood. The so-called blood blister, however, forms over ruptured capillaries and therefore contains whole blood.







[B][U]blue baby[/U][/B]

blue baby, infant born with a congenital heart defect that causes a bluish coloration of the skin as a result of cyanosis (deoxygenated blood). The color is most noticeable around the lips and at the tips of the fingers and toes. The cyanotic condition occurs when a large portion of the venous blood bypasses the lungs. Normally, deoxygenated blood from the veins is pumped from the right side of the heart to the lungs, where it is oxygenated. In some blue babies, the pulmonary artery is too narrow to allow sufficient blood to pass into the lungs for oxygenation. Surgical correction of the defect is usually required and is usually successful. An incompatibility of fetal and maternal blood types may also cause a bluish coloration in newborn infants, a condition that results when red blood cells in the infant's blood are destroyed by antibodies in the mother's blood. Sophisticated knowledge of blood types has made this condition increasingly rare.








[B][U]boil[/U][/B]

boil or furuncle may be defined as tender, painful inflammatory nodule in the skin, which becomes pustular but with a hard center. It may be caused by any of various microbes, the most usual being Staphylococcus aureus. If proper care and precautions are not taken it may spread to many sites (a condition called furunculosis). Several adjoining furuncles that coalesce are known as a carbuncle. The point of entry is usually a hair follicle or a sebaceous gland duct. Boils may occur anywhere in the skin but are most common at places where the skin is constantly exposed or chafed—neck, face, ear, armpit, breast, and extremities. The treatment of small boils consists of scrupulous cleanliness, protection from irritation, and applications of antibiotic ointments and moist heat. Large boils, especially those on the nose, upper lip, or near the eyes (where there is the greatest danger of their causing meningitis or blood poisoning), must be treated professionally with antibiotics. Such lesions should be incised and drained by a physician rather than allowed to discharge spontaneously.






[B][U]botulism[/U][/B]

acute poisoning resulting from ingestion of food containing toxins produced by the bacillus Clostridium botulinum. The bacterium can grow only in an anaerobic atmosphere, such as that found in canned foods. Consequently, botulism is almost always caused by preserved foods that have been improperly processed, usually a product canned imperfectly at home. The toxins are destroyed by boiling canned food for 30 min at 176°F (80°C). Once the toxins (which are impervious to destruction by the enzymes of the gastrointestinal tract) have entered the body, they interfere with the transmission of nerve impulses, causing disturbances in vision, speech, and swallowing, and ultimately paralysis of the respiratory muscles, leading to suffocation. Symptoms of the disease appear about 18 to 36 hr after ingestion of toxins. Botulinus antiserum is given to persons who have been exposed to contaminated food before they develop symptoms of the disease and is given to diagnosed cases of the disease as soon as possible. Developments in early detection have reduced the mortality rate from 65% to 10%.






[B][U]bowlegs[/U][/B]

It is outward curvature of the leg bone (tibia) or thighbone (femur) causing the knees to separate when the feet are placed together. When the condition is severe enough to be considered a deformity, the cause is usually a disorder that occurs early in life such as rickets, flat feet, a congenital disease, or an injury. Bowlegs can be corrected mechanically by braces, shoe wedges, or other orthopedic devices. In some cases the bone is straightened surgically.






[B][U]bronchitis[/U][/B]

inflammation of the mucous membrane of the bronchial tubes. It can be caused by viral or bacterial infections or by allergic reactions to irritants such as tobacco smoke. The disease is characterized by low-grade fever, chest pains, hoarseness, and productive cough. Acute bronchitis is rarely serious in otherwise healthy adults, but it can be dangerous in infants, children, or adults who suffer from underlying respiratory disease, especially emphysema. It may subside or, particularly with continued exposure to irritants, may persist and progress to chronic bronchitis or pneumonia. The more prolonged chronic bronchitis is frequently secondary to a serious underlying disorder. Chronic bronchitis affected 71,099 persons in the United States in 1986. Cigarette smoking is the risk factor most often associated with chronic bronchitis. Bronchial inflammation can be severe; cough and bronchial spasms are treated with antihistamines, cough suppressants, and bronchodilators. Antibiotics are used if there is evidence of bacterial invasion.








[B][U]brucellosis[/U][/B]

brucellosis or Bang's disease,infectious disease of farm animals that is sometimes transmitted to humans. In humans the disease is also known as undulant fever, Mediterranean fever, or Malta fever. In susceptible animals, primarily cattle, swine, and goats, brucellosis causes infertility and death. The symptoms are spontaneous abortion and inability to conceive in females and inflammation of sex organs in male animals. Animal brucellosis is transmitted by contact or by such mechanical vectors as contaminated food, water, and excrement. The disease is caused by three species of Brucella bacteria, and the causative organism is present in aborted fetuses and uterine secretions; antibodies to the bacteria are present in the blood or milk, an important diagnostic factor. Measures for prevention and control of brucellosis include vaccination of calves, blood tests of adults, and slaughtering of infected animals. Human brucellosis is an occupational disease among farmers, slaughterhouse workers, and others who come in direct contact with infected animals or their products (raw meat or unpasteurized dairy products). The most prominent symptoms are weakness and intermittent fever. The disease persists for months if left untreated but is seldom fatal in humans. There is no effective vaccine for human brucellosis, and antibiotics are the usual treatment.









[B][U]bunion[/U][/B]

bunion, swelling or thickening around the first joint of the big toe. The toe is forced inward and compresses the other toes. The fluid-filled sac, or bursa, in the toe joint becomes inflamed (a condition called bursitis), which may lead to pain, deformity, and an inability to wear ordinary shoes. Bunions may arise from years of wearing ill-fitting shoes. However, congenital bone deformities are usually indicated when they occur on both feet. Proper foot care, especially in selecting shoes, is the most important aspect of treatment and prevention. The toes can often be straightened by pads or splints, and orthopedic shoes are generally prescribed. Serious cases may require surgery.







[B][U]burn[/U][/B]

burn, injury resulting from exposure to heat, electricity, radiation, or caustic chemicals. Three degrees of burn are commonly recognized. In first-degree burns the outer layer of skin, called epidermis, becomes red, sensitive to the touch, and often swollen. Medical attention is not required but application of an ointment may relieve the pain. Second-degree burns are characterized by the variable destruction of epidermis and the formation of blisters; nerve endings may be exposed. The more serious cases should be seen by a physician and care should be taken to avoid infection. Local therapy includes application of a chemical such as silver nitrate to produce a soft crust, reduce the threat of infection, and relieve the pain. Third-degree burns involve destruction of the entire thickness of skin and the underlying connective tissue. In the more severe cases underlying bones are also charred. The surface area involved is more significant than the depth of the burn. Shock must be prevented or counteracted; blood transfusion may be required to replace lost body fluids. Invasion of various bacteria must be prevented or cured by administering antibiotics and other drugs. Morphine may be employed to ease pain. Long-term treatment may include transplantation of natural or artificial skin grafts.







[B][U]bursitis[/U][/B]

acute or chronic inflammation of a bursa, or fluid sac, located close to a joint. In response to irritation or injury the bursa may become inflamed, causing pain, restricting motion, and producing more fluid than can be absorbed readily. An attack of bursitis usually causes great pain and tenderness in the affected area. Common areas of involvement include the shoulder and big toe. Depending on the cause and the degree of involvement, bursitis is treated with nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics, corticosteroids, and immobility until the pain subsides. Superficial bursas, not necessary to the function of a joint, or bursas that have become calcified, may be excised.

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[B][U][COLOR="blue"][SIZE="3"]cancer[/SIZE][/COLOR][/U][/B]

cancer, in medicine, common term for neoplasms, or tumors, that are malignant. Like benign tumors, malignant tumors do not respond to body mechanisms that limit cell growth. Unlike benign tumors, malignant tumors consist of undifferentiated, or unspecialized, cells that show an atypical cell structure and do not function like the normal cells from the organ from which they derive. Cancer cells, unlike normal cells, lack contact inhibition; cancer cells growing in laboratory tissue culture do not stop growing when they touch each other on a glass or other solid surface but grow in masses several layers deep.

Loss of contact inhibition accounts for two other characteristics of cancer cells: invasiveness of surrounding tissues, and metastasis, or spreading via the lymph system or blood to other tissues and organs. Whereas normal cells have a limited lifespan controlled by the telomere gene, which signals the end of the cell line, cancer cells contain telomerase, an enzyme that alters the telomere gene and allows the cell to continue to divide. Cancer tissue, growing without limits, competes with normal tissue for nutrients, eventually killing normal cells by nutritional deprivation. Cancerous tissue can also cause secondary effects, in which the expanding malignant growth puts pressure on surrounding tissue or organs or the cancer cells metastasize and invade other organs.

Virtually all organs and tissues are susceptible to cancer. Cancers are usually named for their site of origin. Cancer cells that spread to other organs are similar to those of the original tumor, therefore these secondary (metastatic) cancers are still named for their primary site even though they may have invaded a different organ. For example, lung cancer that has spread to the brain is called metastatic lung cancer, rather than brain cancer. Carcinoma in situ refers to a cancer that has not spread.

Cancer is the second leading cause of death in the United States. Lung cancer is the leading cause of cancer death in adults; leukemia is the most common cancer in children. Other common types of cancer include breast cancer (in women), prostate cancer (in men), and colon cancer (see also Hodgkin's disease). The incidence of particular cancers varies around the world and sometimes according to ethnic group. For instance, African Americans have comparatively higher cancer rates and cancer mortality rates. It is unclear whether this is due to differences in exposure or to biological susceptibility. The number of diagnosed cases of cancer rose steadily in the United States for decades, but in 1998 it was announced that the number of new cases had begun to decline.



[B]Causes of Cancer[/B]

Cancer results from mutations of certain genes that allow the cells to begin their uncontrolled growth. These mutations are either inherited or acquired. Acquired mutations are caused by repeated insults from triggers (e.g., cigarette smoke or ultraviolet rays) referred to as carcinogens. There is usually a latency period of years or decades between exposure to a carcinogen and the appearance of cancer. This, combined with the individual nature of susceptibility to cancer, makes it very difficult to establish a cause for many cancers.

The most significant avoidable carcinogens are the chemical components of tobacco smoke (see smoking). Dietary components, like excessive consumption of alcohol or of foods high in fat and low in fiber rather than fruits and vegetables that contain antioxidants and necessary micronutrients, have also been linked with various cancers. Some cancers may be triggered by hormone imbalances. For example, some daughters of mothers who had been given DES (diethylstilbestrol) during pregnancy to prevent miscarriage developed vaginal adenocarcinomas as young women. Aflatoxins are natural mold byproducts that can cause cancer of the liver.

Certain carcinogens present occupational hazards. For example, in the asbestos industry, workers have a high probability of developing lung and colon cancer or a particularly virulent cancer of the mesothelium (the lining of the chest and abdomen). Benzene and vinyl chloride are other known industrial carcinogens.

X rays and radioactive elements are also carcinogenic; the high incidence of leukemia and other cancers in Japanese survivors of the atomic bombing of Hiroshima and Nagasaki and the increased incidence of thyroid cancer after the Chernobyl nuclear disaster give evidence of this. Exposure to the ultraviolet radiation of sunlight is the leading cause of skin cancer.

Many other substances have been identified as carcinogenic to a greater or lesser extent, including chemicals in pesticides that leave residues on foods. The Delaney clause, an amendment (1958) to the U.S. Food, Drug, and Cosmetic Act that prohibits even minuscule amounts of carcinogens in the food supply, has provided the impetus for the investigation of many such chemicals but has also been a source of controversy between industry and environmentalists.

In the early 20th cent., the American virologist Peyton Rous showed that certain sarcomas affecting fowl could be transmitted by injection of an agent invisible under the microscope and later indentified as an RNA-containing virus. Other research uncovered oncogenic, or tumor-causing, viruses, first in experimental animals and then in humans. The Epstein-Barr virus, a member of the herpesvirus group, has been linked with a number of human cancers, including the lymphomas that often occur in immunosuppressed people, such as people with AIDS. Several human papillomaviruses (HPV) have also been shown to initiate cancers. For example, some types of HPV cause genital warts known as condylomata acuminata, which can lead to invasive cancer of the cervix, vulva, vagina, or penis, and another human papillomavirus has been associated with some forms of Kaposi's sarcoma. In addition, hepatitis B has been shown to increase the risk of liver cancer. Bacteria have also been associated with cancer. For example, the Helicobacter pylori bacterium that causes many ulcers is also associated with an increased risk of stomach cancer.



[B]Cancer Susceptibility[/B]

Risk to humans from carcinogens depends upon the dose and a person's biologic susceptibility. Factors influencing a person's biological susceptibility to cancer include age, sex, immune status, nutritional status, genetics, and ethnicity. Only 5% of all cancers in the United States are thought to be explained by inherited genetic mutations. Known genes associated with hereditary cancer include the aberrant BRCA1 and BRCA2 genes that increase breast cancer risk and the HNPCC gene that is linked with colon cancer. In hereditary forms, it is often the normal gene of the allele that is injured or destroyed, leaving the abnormal inherited gene in control. Nonhereditary cancers sometimes involve the same gene mutations that hereditary forms have.




[B]Tumor Development[/B]

Most bodily insults by carcinogens come to nothing because DNA has built-in repair mechanisms, but repeated insults can eventually result in mutations or altered gene expression in key genes called oncogenes and tumor-suppressor genes. Oncogenes produce growth factors, substances that signal a cell to grow and divide into daughter cells; tumor-suppressor genes (such as the p16, p53, and BRCA1 genes) normally produce a negative growth factor that tells a cell when to stop dividing. The abnormally inactivated tumor-suppressor gene or the abnormally activated oncogene is inherited by each of the cell's daughter cells, and a tumor develops. In many cases tumors remain small and in one place (in situ) for years, but some develop their own blood vessels (a process known as angiogenesis) and begin to grow and spread.





[B]Symptoms[/B]

The classic symptoms of cancer are rapid weight loss; a change in a wart or mole; a sore that does not heal; difficulty swallowing; chronic hoarseness, blood in phlegm, urine, or stool (a consequence of angiogenesis); chronic abdominal pain; a change in size or shape of the testes; a change in bowel habits; a lump in the breast; and unusual vaginal bleeding. Many of these and other symptoms are often nonspecific, e.g., weakness, loss of appetite, and weight loss, and thus are not obvious in the early stages. Sometimes the side effects of tumor growth are more severe than the actual effects of the malignancy; for example, some tumors secrete materials such as serotonin and histamine that can cause drastic vascular changes. Conversely, cancers that destroy tissue may also have serious effects, e.g., malignant destruction of bone tissue may raise the blood level of calcium.






[B]Prevention and Detection[/B]

As more has been learned about cancer, emphasis on prevention and early detection has increased. Cessation of smoking and other tobacco use is the most important controllable means of prevention; smoking causes about 30% of the cancer deaths in the United States. A diet low in fat and high in fiber, including a variety of fruits and vegetables (especially those high in antioxidants), is also recommended. Effective protection against the rays of the sun is recommended to avoid skin cancer. Another preventive approach is vaccination against cancer-causing viruses, such as the hepatitis B virus.

Cancers caught early, before metastasis, have the best cure rates. A number of screening tools are now available to allow early detection and treatment. Among these are monthly breast self-examinations and regular mammography and Pap tests for women, regular self-examination of the testes for young men, and, for older men, regular examination of the prostate gland with blood tests for prostate-specific antigen (PSA) tumor marker (a substance in the body that heralds an increased cancer risk). Sigmoidoscopy plus physical examination and laboratory tests for carcinoembryonic antigen (CEA) are recommended for detection of colon cancer. Self-examination of the skin is important for the early detection of skin cancers. Suspicion of a tumor may be confirmed by X-ray study, endoscopy (see endoscope), blood tests for various tumor markers, and biopsy from which the cells are examined by a pathologist for malignancy.






[B]Treatment[/B]

Developments in the treatment of cancer have led to greatly improved survival and quality of life for cancer patients in the past three decades. Traditionally, cancer has been treated by surgery, chemotherapy, and radiation therapy. In recent years immunotherapy has been added to that list. New drugs and techniques are constantly being researched and developed, such as antiangiogenic agents (e.g., angiostatin and endostatin), genetically engineered monoclonal antibodies, retinoid agents, and vaccine agents (stimulating the immune system).

For most kinds of cancer, surgery remains the primary treatment. It is most effective if the cancer is caught while still localized. Some cancers that spread to the lymph system are sometimes treated by extensive surgical removal of tissue, but the trend is toward more conservative procedures. Cryosurgery, the use of extreme cold, and electrodessication, the use of extreme heat, are also being used to kill cancerous tissue and the surrounding blood supply. If the cancer has metastasized, surgery is often replaced by or followed by radiation therapy (which is a localized therapy) and chemotherapy (which is a system-wide therapy).

For some cancers, radiation therapy—either from an external beam or from implanted radioactive pellets—is the primary treatment. The usual forms are X rays and gamma rays. Use of radioactive elements specific for particular target organs, such as radioactive iodine specific for the thyroid gland, is effective in treating malignancies of those organs.

Cytotoxic chemotherapy is used as a primary treatment for some cancers, such as lymphomas and leukemias or as an addition to surgery or radiation therapy. Cytotoxic drugs (drugs that are toxic to cells) are aimed at rapidly proliferating cells and interfere with nucleic acid and protein synthesis in the cancer cell, but they are often toxic to normal rapidly proliferating cells, such as bone marrow and hair cells. Often a combination of cytotoxic drugs is used. Drugs that reduce side effects may be added to the treatment, such as antinausea agents.

Hormonal chemotherapy is based upon the fact that the growth of some malignant tumors (specifically those of the reproductive organs) is influenced by reproductive hormones. Tamoxifen is a naturally occurring estrogen inhibitor used to prevent breast cancer recurrences. Flutamide is sometimes used in prostate cancer to inhibit androgen uptake. Sex-hormone related drugs such as DES and tamoxifen, which may be carcinogenic under some conditions, have proven to be protective under others.

More specifically targeted drug therapies have begun to be explored as a better understanding of the molecular biology of individual cancers has been developed. Such drugs are designed to kill only cancer cells while having fewer side effects. Gleevec (STI-571), which is used to treat chronic myelogenous leukemia and some other cancers, inhibits certain kinase receptors that become hyperactive in cancer cells, resulting in the cells' rapid reproduction.

Immunotherapy (sometimes called biological therapy) uses substances that help the body mobilize its immune defenses. Some attack the tumor itself, while others bolster the body's ability to withstand conventional chemotherapy treatment. Other new or experimental therapies include drugs that inhibit angiogenesis and photodynamic therapy, in which a patient is given a drug to make the tumor light-sensitive, after which the tumor is exposed to bright laser light. The best choice of treatment will increasingly be influenced by the growing field of molecular pathology, in which characteristics of individual cancers (e.g., virulence or resistance to a particular treatment) can be revealed by analysis of their genetic characteristics rather than by the microscope.

Besides treatment of the cancer itself, progress has been made in the management of the chronic pain that often accompanies cancer and in the education of patients and physicians in such techniques as biofeedback, acupuncture, and meditation and the appropriate use of narcotics and other medications. Because of improvements in early detection and treatment, many more people are now living with cancer. Over half of all people with cancer now survive for five or more years.

[B][U]candidiasis[/U][/B]

infection of the mucous membranes caused by the fungus Candida albicans. Other terms for candidiasis are yeast infection, moniliasis (after a former name of the fungal genus), and thrush, the latter term usually being reserved for infection of the mucous membrane of the mouth. The fungus is a normal inhabitant of the mouth and vagina, and its growth is usually kept in check by certain bacteria that also live in these areas. When the balance of these organisms is disturbed by antibiotic treatment, by hormonal imbalances, or by a weakening of the body's resistance to disease (as occurs in AIDS), the fungus can begin to proliferate. Candidiasis of the penis (usually traceable to a female with the infection) is called balanitis. Candidal infections are treated with antifungal drugs such as nystatin and miconazole.






[B][U]canker[/U][/B]

canker, small sore on the inside of the mouth. A canker appears as a shallow, whitish ulcer surrounded by a thin, red area. It is tender, sometimes painful, and may occur singly or as one of a group of sores. Cankers develop on the inner surfaces of the lips or cheeks, on the gums, under the tongue, or on the roof of the mouth. The cause is unknown, but cankers have been associated with friction, injury, allergy, and viral infection. They generally heal by themselves in a few days but can be recurrent.





[B][U]carbuncle[/U][/B]

carbuncle, acute inflammatory nodule of the skin caused by bacterial invasion into the hair follicles or sebaceous gland ducts. It is actually a boil, but one that has more than one focus of infection, i.e., involves several follicles or ducts. Carbuncles occur more often in men because of their more extensive body hair growth. The infection is treated by applying antibiotics systemically and directly to the lesion and by incision and drainage at the proper time.






[B][U]cataract[/U][/B]

cataract, in medicine, opacity of the lens of the eye, which impairs vision. In the young, cataracts are generally congenital or hereditary; later they are usually the result of degenerative changes brought on by aging or systemic disease (diabetes). Cataracts brought on by aging are most common; most individuals over 60 exhibit some degree of lens opacity. Injury, extreme heat, ultraviolet light, X rays, nuclear radiation, inflammatory disease, and toxic substances also cause cataracts. There is growing concern that further disintegration of the ozone layer will increase the incidence of cataracts. Advanced cataracts are usually treated by surgical removal of the lens and implantation of an artificial lens. After cataract surgery, which is the most common surgical procedure in the United States, most patients do not require thick glasses or contact lenses.














[B][U]cerebral palsy[/U][/B]

disability caused by brain damage before or during birth or in the first years, resulting in a loss of voluntary muscular control and coordination. Although the exact cause is unknown, apparent predisposing factors include disease (e.g., rubella, genital herpes simplex), very low infant birthweight (less than 3.3 lb [1.5 kg]), and injury or physical abuse. Maternal smoking, alcohol consumption, and ingestion of certain drugs can also contribute. Most cases are associated with prenatal problems; about 10% of the cases are thought to be due to oxygen deficiency during the birth process. The severity of the affliction is dependent on the extent of the brain damage. Those with mild cases may have only a few affected muscles, while severe cases can result in total loss of coordination or paralysis.

There are many different forms of the disability, each caused by damage to a different area of the brain. The spastic type, accounting for over half of the cases, results from damage to the motor areas of the cerebral cortex and causes the affected muscles to be contracted and overresponsive to stimuli. Athetoid cerebral palsy, caused by damage to the basal ganglia, results in continual, involuntary writhing movements. Choreic cerebral palsy is characterized by jerking, flailing movements. Ataxic cerebral palsy, involving the cerebellum, causes either an impaired sense of balance or a lack of coordinated movements. In addition to these types, which may occur singly or together, emotional, visual, and hearing impairments and convulsive seizures may be present. Some of those affected have a degree of mental retardation, but in many the intellect is unimpaired.

There is no cure for the disorder. Treatment usually includes physical, occupational, and speech therapy, and sometimes includes biofeedback and muscle relaxants. Sometimes appliances such as braces and surgery are helpful. Measures that appear to help decrease the incidence of cerebral palsy include maternal immunization against rubella, maternal abstention from smoking and alcohol consumption, magnesium sulfate given in premature labor, treatment for Rh incompatibility , and treatment of hyperbilirubinemia (jaundice) in the newborn.












[B][U]Chagas' disease[/U][/B]

Chagas' disease, disease of South and Central America caused by the parasite Trypanosoma cruzi. It usually affects children and young adults and is transmitted by the feces of infected insects, typically the assassin bug. Most of those infected have mild symptoms, such as fever and swelling and redness around the eyes, but from 10% to 30% develop chronic disease that may result in serious or fatal inflammation of the brain and heart tissues. There is no vaccine and no satisfactory treatment. The incidence of Chagas' disease in the United States has increased since the 1970s, possibly because of increased immigration from Mexico and Central America, where the incidence is very high. In immunosuppressed patients (see AIDS) Chagas' disease can form a mass in the cranial cavity that mimics a tumor, presumably because the lymphocytes that guard against the parasite are the same that are depleted by the AIDS virus.










[COLOR="blue"][B][U]chicken pox[/U][/B][/COLOR]

infectious disease usually occurring in childhood. It is believed to be caused by the same herpesvirus that produces shingles. Chicken pox is highly communicable and is characterized by an easily recognizable rash consisting of blisterlike lesions that appear two to three weeks after infection. Usually there are also low fever and headache. When the lesions have crusted over, the disease is believed to be no longer communicable; however, most patients simultaneously exhibit lesions at different stages of eruption. Chicken pox is usually a mild disease requiring little treatment other than medication to relieve the troublesome itching, but care must be taken that the rash does not become secondarily infected by bacteria. Pneumonia and encephalitis are rare complications. A vaccine for chicken pox was approved for use in the United States in 1995. The drug acyclovir may be used to treat the disease, particularly in older patients.












[B][U]chlamydia[/U][/B]

genus of microorganisms that cause a variety of diseases in humans and other animals. Psittacosis, or parrot fever, caused by the species Chlamydia psittaci, is transmitted to people by birds, particularly parrots, parakeets, and lovebirds. In birds the disease takes the form of an intestinal infection, but in people it runs the course of a viral pneumonia. Different forms of Chlamydia trachomatis cause trachoma, an infection of the mucous membrane of the eyelids, and the sexually transmitted disease lymphogranuloma venereum. This same species also causes the sexually transmitted disease called chlamydia, the most common such disease in the United States. In women, chlamydia is a common cause of pelvic inflammatory disease, which can result in infertility and an increased risk of tubal pregnancy. Men are the primary carriers, but painful urination and discharge often prompt men to get treatment before the testes can be infected and male infertility can result. Chlamydial infections can be treated with antibiotics such as tetracycline.











[COLOR="blue"][B][U]cholera[/U][/B][/COLOR]

Asiatic cholera,acute infectious disease caused by strains of the bacterium Vibrio cholerae that have been infected by bacteriophages. The bacteria, which are found in fecal-contaminated food and water and in raw or undercooked seafood, produce a toxin that affects the intestines causing diarrhea, vomiting, and severe fluid and electrolyte loss. This overwhelming dehydration is the outstanding characteristic of the disease and is the main cause of death. Cholera has a short incubation period (two or three days) and runs a quick course. In untreated cases the death rate is high, averaging 50%, and as high as 90% in epidemics, but with effective treatment the death rate is less than 1%. The intravenous and oral replacement of body fluids and essential electrolytes and the restoration of kidney function are more important in therapy than the administration of antibacterial drugs. In regions of Asia, Africa, and South America where public sanitation is poor the disease is still endemic or epidemic; vaccination is recommended for people living in those areas. A theory of evolutionary biologists holds that the cystic fibrosis gene, a common but lethal recessive gene carried by approximately one in twenty Caucasians, affords those carriers partial protection against cholera.












[B][U]chorea[/U][/B]

chorea OR St. Vitus's dance,acute disturbance of the central nervous system characterized by involuntary muscular movements of the face and extremities. The disease, known also as Sydenham's chorea (not to be confused with Huntington's disease, a hereditary disease of adults that is sometimes called Huntington's chorea), is usually, but not always, a complication of rheumatic fever. Sydenham's chorea, a disease of children, especially females, usually appears between the ages of 7 and 14. Facial grimacing and jerking movements persist for 6 to 10 weeks and sometimes recur after months or even years. Eventually the symptoms disappear. Although there is no specific treatment, sedatives and tranquilizers are helpful in suppressing the involuntary movements. Technically, it is sometimes called chorea minor or juvenile chorea to distinguish it from several less common choreas, chorea also being a general term for continuous, involuntary jerking movements.
















[COLOR="blue"][B][U]chronic fatigue syndrome[/U][/B][/COLOR]

chronic fatigue syndrome (CFS), collection of persistent, debilitating symptoms, the most notable of which is severe, lasting fatigue. In other countries it is known variously as myalgic encephalomyelitis, chronic fatigue and immune dysfunction syndrome, and postviral fatigue syndrome. It was first recognized as a syndrome in the 1860s by Dr. George Beard, who called it neurasthenia. He believed it to be a neurosis with a fatigue component. Definitions and theories of its cause have changed over the years; many cases have been misdiagnosed as imaginary because doctors could find no cause. In the mid-1980s it came to the public's attention, as affluent women in their thirties began to seek treatment. (For unknown reasons, more women than men seek treatment for the disease.)



[B]Symptoms and Identification[/B]

As currently defined, chronic fatigue syndrome is the presence of severe, disabling fatigue lasting for six or more consecutive months. The fatigue is persistent or relapsing, and is new (i.e., not lifelong), not relieved by rest, not the result of ongoing exertion, and interferes with normal work, social, educational, or personal activities. Diagnosis also requires at least four of the following symptoms, each persistent or recurring and not present before the fatigue: impairment of short-term memory or concentration, sore throat, tender lymph nodes in the neck or axillary region, muscle pain, joint pain, headaches peculiar to the syndrome, unrefreshing sleep, and malaise of more than one day's duration following exertion. Chronic fatigue that does not meet all these criteria is termed “idiopathic fatigue.”

The course of the disease varies. Many people first experience symptoms after a cold or bout of the flu. Most people reach a plateau early on; the symptoms come and go with varying severity afterward. Some experience complete remission; others have their symptoms indefinitely.

There are no specific diagnostic tests. Diagnosis must first rule out known causes of fatigue such as hypothyroidism, cancer, multiple sclerosis, and major depression with psychotic or melancholic features (e.g., schizophrenia, bipolar disorder). Chronic fatigue syndrome and nonpsychotic, nonmelancholic depression, however, are not mutually exclusive. Substance abuse and side effects of prescribed medications must also be eliminated as possible causes.







[B]Cause and Treatment[/B]

There is no known single cause of CFS. Some authorities believe it is a condition shared by many different underlying diseases rather than an entity unto itself; others believe it is caused by a defect of the immune system. Hormonal deficits, low blood pressure, and viral infections have been studied as possible causes or contributors. The postulated causal link with Epstein-Barr virus hypothesized in the mid-1980s has been discounted.

There is no definitive treatment for CFS, although success has been reported anecdotally with antidepressants, antianxiety medications, antivirals, and immune boosters. Symptomatic treatment for the muscle and joint pains is helpful in some cases. Counseling and peer support groups help some patients cope with the frustrating nature of the disease.














[B][U]cirrhosis[/U][/B]

degeneration of tissue in an organ resulting in fibrosis, with nodule and scar formation. The term is most often used in relation to the liver, because that organ is most often involved in cirrhosis. Cirrhosis of the liver interferes with the liver's metabolism of nutrients, detoxification of the blood, bile production, and other normal functions. its damage is irreversible.

The most prevalent form of cirrhosis of the liver, portal cirrhosis, appears most often in middle-aged males with a history of chronic alcoholism and is caused in part by protein deficiency (specifically choline), a type of malnutrition common in alcoholics. Protein deprivation is also responsible for kwashiorkor, a nutritional deficiency with symptoms resembling those of cirrhosis of the liver. A major cause of cirrhosis worldwide is infection by the hepatitis B virus. Biliary cirrhosis is a type caused by disruption of bile flow and is more common in women. Other causes include schistosomiasis and hemochromatosis, a hereditary iron storage disease.

Failure of liver function results in ascites (fluid accumulation in the abdominal cavity), increased albumin and blood protein, gastrointestinal disturbances, bleeding, emaciation, portal hypertension, enlargement of the liver and spleen, jaundice, edema, and obstruction of the venous circulation with distention of the veins. It is not uncommon for greatly distended veins in the esophagus to rupture and cause massive hemorrhage. Treatment is first aimed at any reversible underlying disease. Supportive measures include avoidance of alcohol, a diet with adequate protein, vitamin supplements, transfusions to replace any blood loss, and removal of accumulated fluid. Beta-blockers, such as propranolol, have been shown to be effective in reducing the rate of gastrointestinal bleeding, one of the most lethal complications of cirrhosis.









[B][U]cleft palate[/U][/B]

cleft palate, incomplete fusion of bones of the palate. The cleft may be confined to the soft palate at the back of the mouth; it may include the hard palate, or roof of the mouth; or it may extend through the gum and lip, producing a gap in the teeth and a cleft lip, which is cosmetically difficult to repair but is not disabling. The condition appears to be hereditary but not under the control of a single pair of genes. A cleft palate causes separation between the oral and nasal cavities. An infant cannot develop proper suction for drinking, and there is the danger of milk entering the nasal cavity and being aspirated into the lungs. Formula must be carefully placed at the back of the tongue for normal swallowing to take place. Ear infection may result from food or fluid passing from the nasal cavity to the middle ear by way of the Eustachian tubes. Proper speech articulation is difficult unless the cleft is surgically closed, with a prosthesis. The proper time for such an operation is in dispute; some authorities prefer early closure, before the cleft interferes with development of normal speech habits, while others prefer to wait for several years until facial growth has been completed. Dental, orthodontic, psychiatric, and speech therapy may be required.










[B][U]clubfoot[/U][/B]

deformity in which the foot is twisted out of position. Maldevelopment is usually congenital, although it can result from injury or disease (e.g., poliomyelitis) after birth. It can affect one or both feet. Often the foot is twisted downward, with the heel and toe turning inward, causing only part of the foot—the heel, the toes, or the outer margin—to touch the ground; walking is difficult or impossible. Correction can be made in infancy by manipulation, braces, and casts; in severe cases only surgery can correct the condition.









[B][U]coccidioidomycosis[/U][/B]

It is a systemic fungus disease endemic to arid regions of the Americas, contracted by inhaling dust containing spores of the fungus Coccidioides immitis. From the respiratory tract, it can spread to the skin, bones, and central nervous system. Manifestions of the disease range from complete absence of symptoms to systemic infection and death. In 60% of the cases no clinical evidence of the disease is present and the only recognizable sign is a positive skin test; in 15% symptoms resembling those of influenza occur; and in 25% more serious signs such as swelling of the knees, weakness, pleural pain, and prostration occur. Diagnosis is made upon positive cultural identification of the fungus. Treatment is with the antifungal amphotericin B and bed rest. The soil that supports Coccidioides spores is indigenous to dry, hot geographical areas; the SW United States, Argentina, and Paraguay are areas of high incidence of infection. Cases in the San Joaquin Valley in California, where the disease is called valley fever, increased tenfold between 1991 and 1995.










[B][U]cold, common[/U][/B]

cold, common, acute viral infection of the mucous membranes of the nose and throat, often involving the sinuses. The typical sore throat, sneezing, and fatigue may be accompanied by body aches, headache, low fever, and chills. The congested and discharging mucous membrane may become a fertile ground for a secondary bacterial invasion that can spread to the larynx, bronchi, lungs, or ears. Uncomplicated infections usually last from three to ten days.

The cold is the most common human ailment. Most adult Americans suffer from one to four colds per year, but children ages one to five—who are the most susceptible—typically may contract as many as eight. Colds are spread by respiratory droplets or by contaminated hands or objects. Although the incidence of colds is higher in winter, exposure to chilling or dampness is considered to be of little significance.

Any one of up to 200 viruses (such as the rhinoviruses, coronaviruses, or respiratory syncytial virus [RSV]) can cause colds, to which it seems almost no one is immune. Infection with a viral strain confers only temporary immunity to that strain. Colds in infants and young children caused by RSV can progress to pneumonia and other complications, especially in those under a year old who were born prematurely or have chronic lung disease; RSV causes an estimated 4,500 deaths yearly in these groups in the United States.

There is no treatment for the common cold other than that aimed at relieving symptoms and keeping the body well-rested, -fed, and -hydrated. Because of the growing problem of drug resistance, doctors are being discouraged from prescribing antibiotics (which do not affect viruses) for colds unless secondary bacterial infection makes them necessary. There is no convincing evidence that vitamin C megadoses can prevent the common cold.

Researchers have reported reduction or prevention of cold symptoms in human tests of an experimental drug against rhinoviruses, which cause nearly half of all colds. The drug acts by imitating a molecule in the body called ICAM-1, to which the rhinovirus attaches to produce colds. As rhinoviruses attach to the decoy molecules instead, the likelihood or severity of infection is decreased.











[B][U]colic[/U][/B]

colic, intense pain caused by spasmodic contractions of one of the hollow organs, e.g., the stomach, intestine, gall bladder, ureter, or oviduct. The cause of colic is irritation and/or obstruction, and the irritant and/or obstruction may be a stone (as in the gall bladder or ureter), an irritant food or gas (in the stomach and intestines), appendicitis, or implantation of an embryo in an oviduct. Intestinal colic in infancy is sometimes attributed to gas formed by excessive swallowing of air or inadequate digestion of milk. Treatment of colic is relative to the cause.










[B][U]colitis[/U][/B]

colitis, inflammation of the colon, or large intestine. The term “colitis” may be used to refer to any of a number of disorders involving the colon. Symptoms include diarrhea (often with blood and mucus), abdominal pain, and fever.

Ulcerative colitis is a serious chronic inflammation and ulceration of the lining of the colon and rectum. Another form of colitis, called Crohn's disease, has similar signs and includes thickening of the intestinal wall. The disease typically occurs in the small intestine near the point where it joins the colon, but the colon and other parts of the gastrointestinal tract may be affected as well. The term “inflammatory bowel disease” has been used to refer to both ulcerative colitis and Crohn's disease, the causes of which are unknown. A less severe disorder, known as irritable bowel syndrome, or IBS, was formerly called mucous colitis.

Colitis is sometimes caused by infections with viruses, parasites, or bacteria. For example, two distinct types of dysentery are caused by amebas and bacteria. Infectious forms of colitis are often the result of poor hygienic practices. Prolonged use of antibiotics can also cause colitis, either by direct irritation of the colon or by killing bacteria that normally live in the intestine, allowing the toxin-producing bacterium Clostridium difficile to proliferate. Colitis is also sometimes caused by diverticulitis.











[COLOR="blue"][B][U]colon cancer[/U][/B][/COLOR]

colon cancer, cancer of any part of the colon (often called the large intestine). Colon cancer is the second most common cancer diagnosed in the United States. Epidemiological evidence has shown that a diet high in fat and low in fruits, vegetables, and fiber contributes to the development of the disease. Smoking is also a factor in some types of colon cancer. Statistically, a family history of colon cancer or cancer of the female reproductive organs, a history of colon polyps, or a history of ulcerative colitis puts one at a greater risk of developing colon cancer. Colon cancer is most common in people over age 50.

Several genes that signal a hereditary predisposition to colon cancer have been identified. For example, mutations in either of two genes, MSH2 and MLH1, can predispose a person to hereditary nonpolyposis colorectal cancer (HNPCC). People in HNPCC families can undergo blood tests that can tell them whether they have an affected gene. With the information obtained from such screening, an appropriate course of preventive measures and follow-up tests can be initiated (see genetic screening).


[B]Diagnosis[/B]

A sudden change in bowel habits or blood in the feces (often detectable only in a laboratory) may be the first symptoms of colon cancer. In the early stages of the disease there may be no obvious symptoms. Diagnosis is made by physical examination of the rectum and a laboratory examination of blood for carcinoembryonic antigen (CEA), a tumor marker produced by colon cancers. These may be followed by an endoscopic examination of the colon with a sigmoidoscope (to examine the rectum and the adjoining sigmoid colon) or colonoscope (to examine the entire colon). A biopsy of any suspicious tissue is then examined in a laboratory to determine if cancerous changes are present. If cancer is found, the patient is evaluated to determine the extent of the primary tumor and whether the disease has spread throughout the body.




[B]Treatment[/B]

Treatment depends upon the stage of the cancer. The initial treatment is usually local excision of the tumor or excision of a larger part of the colon followed by the joining of the two adjacent ends, a procedure referred to as end-to-end anastomosis. In some cases a colostomy (an opening that allows waste to be expelled through an opening in the abdomen rather than through the anus) is created either temporarily, to allow healing, or permanently, if significant portions of the colon have had to be removed. If the disease is advanced, radiation therapy, chemotherapy, or biological therapies (therapies that stimulate the body's own immune defenses against the disease) may be used in addition to surgery.














[B][U][COLOR="blue"]color blindness[/COLOR][/U][/B]

color blindness, visual defect resulting in the inability to distinguish colors. About 8% of men and 0.5% of women experience some difficulty in color perception. Color blindness is usually an inherited sex-linked characteristic, transmitted through, but recessive in, females. Acquired color blindness results from certain degenerative diseases of the eyes. Most of those with defective color vision are only partially color-blind to red and green, i.e., they have a limited ability to distinguish reddish and greenish shades. Those who are completely color-blind to red and green see both colors as a shade of yellow. Completely color-blind individuals can recognize only black, white, and shades of gray. Color blindness is usually not related to visual acuity; it is significant, therefore, only when persons who suffer from it seek employment in occupations where color recognition is important, such as airline pilots, railroad engineers, and others who must recognize red and green traffic signals. Tests for color blindness include identifying partially concealed figures or patterns from a mass of colored dots and matching skeins of wool or enameled chips of various colors.













[B][U][COLOR="blue"]communicable diseases[/COLOR][/U][/B]

communicable diseases, illnesses caused by microorganisms and transmitted from an infected person or animal to another person or animal. Some diseases are passed on by direct or indirect contact with infected persons or with their excretions. Most diseases are spread through contact or close proximity because the causative bacteria or viruses are airborne; i.e., they can be expelled from the nose and mouth of the infected person and inhaled by anyone in the vicinity. Such diseases include diphtheria, scarlet fever, measles, mumps, whooping cough, influenza, and smallpox. Some infectious diseases can be spread only indirectly, usually through contaminated food or water, e.g., typhoid, cholera, dysentery. Still other infections are introduced into the body by animal or insect carriers, e.g., rabies, malaria, encephalitis, Rocky Mountain spotted fever. The human disease carriers, i.e., the healthy persons who may be immune to the organisms they harbor, are also a source of transmission. Some infective organisms require specific circumstances for their transmission, e.g., sexual contact in syphilis and gonorrhea, injury in the presence of infected soil or dirt in tetanus, infected tranfusion blood or medical instruments in serum hepatitis and sometimes in malaria. In the case of AIDS, while a number of different circumstances will transmit the disease, each requires the introduction of a contaminant into the bloodstream. A disease such as tuberculosis may be transmitted in several ways—by contact (human or animal), through food or eating utensils, and by the air. Control of communicable disease depends upon recognition of the many ways transmission takes place. It must include isolation or even quarantine of persons with certain diseases. Proper antisepsis should be observed in illness and in health. Immunologic measures should be utilized fully. Some sexually transmitted infections are associated with cancer (cervical or penile). Education of the population in rules of public health is of great importance both in the matter of personal responsibility (disposal of secretions, preventing contact with the blood of others, proper handling and preparation of food, personal hygiene) and community responsibility (safe water and food supply, sterile blood supply, garbage and waste disposal). Animal and insect carriers must be controlled, and the activities of human carriers must be limited.












[B][U]compulsive gambling[/U][/B]

compulsive gambling or pathological gambling,a psychological disorder characterized by a persistent inability to resist the impulse to gamble. The disorder is progressive and typically results in difficulties in one's personal, social, and work life; it may lead to bankruptcy or criminal activity to obtain money. The prevalence of compulsive gambling in the United States has increased with that of gambling itself, and it has been estimated that up to 3% of the adult population may gamble pathologically.

Most gamblers are able to stay within reasonable limits in the amounts they gamble. Compulsive gamblers tend to lose control of the amounts they risk and cannot stop gambling even when they continue to lose. Although money is important to them, they often say they are looking for “action,” an excited or euphoric state comparable to the “high”of drug abuse. They often use gambling as a way of escaping from problems in daily life or from feelings of depression or anxiety. Eventually, compulsive gamblers may engage in forgery, theft, or other crimes to provide money for continued gambling or to alleviate a desperate financial situation resulting from gambling losses.

Compulsive gambling is a highly treatable disorder. For many, psychotherapy and active participation in Gamblers Anonymous, a support group with local chapters patterned on Alcoholics Anonymous, have proven effective.










[B][U]congenital heart disease[/U][/B]

congenital heart disease, any defect in the heart present at birth. There is evidence that some congenital heart defects are inherited, but the cause of most cases is unknown. One known cause is infection of the mother with the rubella (German measles) virus during the first trimester of pregnancy. Among the most common congenital heart disorders are malformations in the valves and the persistence of structures that are normally closed off at birth, i.e., the ductus arteriosis (the fetal blood vessel that shunts blood from the pulmonary vein to the aorta, bypassing the heart) and the foramen ovale (the opening between the left and right atria of the fetal heart). If the malformation is severe, it will produce various symptoms of insufficient heart function, such as cyanosis (a bluish tinge to the skin), dyspnea (difficulty in breathing), fatigue, and abnormal heartbeat; valvular deformities predispose the patient to bacterial infection of the endocardium. Less severe malformations may not produce noticeable symptoms until later in life, and some may not require any medical attention. Many congenital heart defects that are debilitating can be corrected surgically. Other congenital anomalies, such as Down syndrome, are present in about 20% of cases of congenital heart disease.












[B][U]congestive heart failure[/U][/B]

congestive heart failure, inability of the heart to expel sufficient blood to keep pace with the metabolic demands of the body. In the healthy individual the heart can tolerate large increases of workload for a considerable length of time. Cardiac failure results from conditions, e.g., coronary artery disease, hypertensive heart disease (see hypertension), valvular insufficiency, and rheumatic heart disease, that interfere with the nutrition and oxygenation of the heart muscle itself. Congestive heart failure develops in 50% to 60% of patients with such disorders, and it can be either acute or chronic. If the heart has time to compensate, the heart muscle may become hypertrophic (enlarged); this is caused by structural changes that impede blood flow and impair the ability of the heart to relax. Eventually the great demand for oxygen by the heart muscle cells cannot be met, and cell death results. Either the left or right ventricle alone may fail first, although combined failure is most common and almost always eventually occurs. Left ventricular failure is marked by shortness of breath (dyspnea), often accompanied by cough; pulmonary congestion and edema are evident. Failure of the right ventricle produces systemic edema, reflecting hepatic and visceral engorgement. Diagnosis is often confirmed by echocardiography. Treatment of cardiac failure usually includes dietary changes, restrictions on physical activity, rest, oxygenation, measures to improve myocardial contractility, and correction of arrhythmias. Restriction on sodium intake and the administration of diuretics (the dosages of which depend on the patient's weight) are used to remove excess sodium and water from the body. Digitalis is often prescribed to increase the speed and force of cardiac contractions, and ACE inhibitors are used to decrease peripheral vascular resistance, making heart pumping easier and more effective.














[B][U]conjunctivitis[/U][/B]

It is an inflammation or infection of the mucosal membrane that covers the eyeball and lines the eyelid, usually acute, caused by a virus or, less often, by a bacillus, an allergic reaction, or an irritating chemical. Commonly called pinkeye, mild conjunctivitis usually causes redness, discharge, and itching of the membrane. Conjunctivitis may also be associated with upper respiratory infection or with childhood diseases such as measles. Bacterial forms of the disorder, whether chronic or acute, are treated successfully with antibiotics, and although viral conjunctivitis will clear up on its own in 8 to 10 days, antibiotic eyedrops or ointments are often prescribed for most cases of the disease in order to prevent bacterial conjunctivitis. Trachoma, though rare in the United States, is a severe conjunctivitis that can cause loss of vision. Another severe form of conjunctivitis is caused by the gonococcus bacterium and is usually associated with a genital infection. Conjunctivitis in newborn infants, called ophthalmia neonatorum, was a problem at one time; however, routine instillation of silver nitrate solution into the eyes of newborn infants has materially reduced the incidence of blindness.












[B][U]constipation[/U][/B]

constipation, infrequent or difficult passage of feces. Constipation may be caused by the lack of adequate roughage or fluid in the diet, prolonged physical inactivity, certain drugs, or emotional disturbance. Sudden unexplained changes in bowel habits can be a symptom of a serious disorder (such as lower intestinal obstruction by a growth) and should receive medical attention. Most cases of constipation can be relieved by following a diet that includes adequate roughage and fluid and by establishing regular habits of evacuation. The continued use of laxatives is inadvisable. Daily bowel movements are not essential; many persons suffer from the harm caused by constant use of laxatives and enemas in an effort to establish the desired regularity.














[B][U]convulsion[/U][/B]

convulsion, sudden, violent, involuntary contraction of the muscles of the body, often accompanied by loss of consciousness. It is not known what causes the abnormal impulses from the brain that result in convulsive seizures, since the disturbance may arise in normal brain tissue as well as in diseased or injured tissue. Convulsions may occur in such conditions as epilepsy, poisoning, high fever (especially in young children), disturbances of calcium or phosphorus metabolism, alkalosis, diabetes, oxygen insufficiency, and a low blood-sugar content, as well as in local irritation or injury of the brain. Persons undergoing convulsions should be guarded against self-injury. Otherwise, treatment must be directed to the underlying cause.










[B][U]corns and calluses[/U][/B]

corns and calluses, thickenings of the outer layer of skin where there is irritation or constant pressure. Corns are cone-shaped with their points protruding into the dermis, or inner layer of skin. They usually have hard, shiny surfaces surrounded by red, painful areas. Soft-surfaced corns sometimes develop between overlapping toes where there is an accumulation of moisture. Treatment of corns is directed at the relief of irritation or pressure, e.g., wearing properly fitted shoes; they can also be softened by pastes and ointments or removed by a physician. Calluses typically involve only the outermost layers of skin and are not usually painful; they tend to disappear once the source of irritation has been removed.








[B][U]coronary artery disease[/U][/B]

coronary artery disease, condition that results when the coronary arteries are narrowed or occluded, most commonly by atherosclerotic deposits of fibrous and fatty tissue. Coronary artery disease is the most common underlying cause of cardiovascular disability and death. Men are affected about four times as frequently as women; before the age of 40 the ratio is eight to one. Other predisposing factors are lack of blood supply; spasms in the coronary vessels, which cause and/or are caused by hypertension; diabetes; high cholesterol levels; adverse physical reactions to mental stress; and heavy cigarette smoking. The primary symptom is angina pectoris, a pain that radiates in the upper left quadrant of the body due to the lack of oxygen reaching the heart. A myocardial infarction (heart attack) is precipitated when the interior passage of an artery, usually already narrowed by atherosclerosis (see arteriosclerosis), is completely blocked by thrombosis (blood clot) or arterial plaque.

Nitroglycerin, beta-blockers, and calcium-channel blockers are often used for control of angina. Aspirin, with its ability to inhibit blood clots, cholesterol-lowering drugs (e.g., simvastatin), and estrogen replacement in postmenopausal women all appear to have a protective effect against eventual heart attack. If the buildup of plaque has progressed, an invasive or surgical procedure is often necessary, although a combination of a strict low-fat diet, stress management, and exercise has been found to reverse the disease. The most common procedure is angioplasty with a balloon catheter. The use of the balloon catheter often can be complicated by cracks or weakening of the walls of the vessels and may lead to rapid reclogging of the vessel. Another procedure is coronary artery bypass surgery, which splices veins or internal mammary arteries to the affected coronary artery in order to bypass the atherosclerotic blockage and supply blood to the heart muscle. A cold laser may be used to remove atherosclerotic plaques with bursts of ultraviolet light. It does little damage to the arteries and leaves the walls of the vessels smooth, without the burning and scarring created by hot lasers. Mechanical cutting devices, called atherotomes, are sometimes to ream atherosclerotic plaque material from the vessel in a procedure called atherectomy.












[COLOR="blue"][B][U]cough[/U][/B][/COLOR]

cough, sudden, forceful expiration of air from the lungs caused by an involuntary contraction of the muscles controlling the process of breathing. The cough is a response to some irritating condition such as inflammation or the presence of mucus (sputum) in the respiratory tract, as in infectious disease, or to heavy dust or industrial or tobacco smoke. Coughing may also be a reflex action to factors outside the respiratory tract; diseases that are not respiratory in nature (e.g., congestive heart failure or mitral valve disease) often bring on coughing. If there is mucus or a foreign substance in the respiratory tract, the cough should not be hindered since by this action the offending matter is expelled from the body. If, however, the cough becomes exhausting, sedation is indicated.











[COLOR="blue"][B][U]coma[/U][/B][/COLOR]

coma, in medicine, deep state of unconsciousness from which a person cannot be aroused even by painful stimuli. The patient cannot speak and does not respond to command. Coma is the result of damage to the brain stem and cerebrum that may be caused by severe head or brain injury, cardiac arrest, stroke, diabetes, drug overdose, shock, or hemorrhage. It occurs just before death in many diseases. There are various depths of coma; the nature of the injury determines the level of supportive treatment necessary. Survival and prognosis depend upon the cause, extent of damage, and duration of the coma.

The term persistent vegetative state. was coined in 1972 to describe an unconscious state in which sleep and wake cycles remain and eyes may open, but there is no thinking, feeling, or awareness of one's surroundings (although one may react reflexive to certain stimulations). The brain stem is usually relatively intact but the cerebral cortex is severely impaired. It is this state that sometimes results from resuscitation and life support of people who otherwise would have died; partial emergence from such a state sometimes occurs with a year or two, but not after that.










[B][U]cramp[/U][/B]

cramp, painful uncontrollable contraction of a muscle or group of muscles. The type that results from cold, strain, or disturbance of circulation (as experienced by swimmers) is eased by massage and the application of heat. Cramp in the abdominal or skeletal muscles brought on by hard physical exertion in extremely high temperatures (e.g., in miners, stokers, or firemen) because of loss of salt from the body during profuse perspiration can last for hours or days if untreated. Such cramps are considered to be a type of heat exhaustion. A cool atmosphere and the replacement of salt and water orally or intravenously is required, and application of heat is not recommended. Heat cramps in persons who do heavy labor can be prevented by the addition of salt to drinking water or by taking salt tablets. Contraction of muscles in a hollow organ is known as colic. A stitch in the side is due to a cramp in the muscles between the ribs.











[B][U]cretinism[/U][/B]

The condition produced in infants and children due to lack of thyroid hormone. It usually results from a congenital defect (e.g., absence of the thyroid, presence of only a rudimentary gland, inability of the gland to produce thyroxine). However, it can develop later if there is a lack of iodine in the diet, or if the thyroid is diseased or surgically removed. Cretinism causes very serious retardation of physical and mental development; if the condition is left untreated, growth is stunted and the physical stature attained is that of a dwarf. In addition, the skin is thick, flabby, and waxy in color, the nose is flattened, the abdomen protrudes, and there is a general slowness of movement and speech. If discovered early enough and treated with thyroid extract and sufficient iodine intake throughout life, growth may become normal and mental facility greatly improved. If the condition commences after adulthood is reached it is called myxedema.











[B][U]croup[/U][/B]

An acute obstructive laryngitis in young children, usually between the ages of three and six. The manifestations are a high-pitched cough and difficulty in breathing, owing to a spasm or swelling of the larynx. The cause can be an acute infection (especially by the influenza virus or diphtheria bacterium), an allergy, a tumor of the larynx, or obstruction by a swallowed object. Treatment depends on the cause; e.g., antibiotics are used in the case of bacterial infections, epinephrine and similar drugs in the case of allergy. The inhalation of steam from a vaporizer or hot-water faucet relieves breathing difficulties in most cases. In severe cases oxygen may be administered, or it may be necessary to cut an opening in the trachea to prevent suffocation.











[B][U]cryptosporidium[/U][/B]

A genus of protozoans having at least four species; they are waterborne parasites that cause the disease cryptosporidiosis. One of the species appears to be responsible for most of the illnesses. Symptoms of the disease are vomiting, diarrhea, abdominal cramps, and fever usually lasting one to two weeks. In immunosuppressed individuals, such as people with AIDS, the disease can be fatal. Nitazoxanide is an effective treatment in some immunosuppressed individuals.

The usual sources of cryptosporidial contamination of drinking water are human sewage (e.g., sewage system overflows) and runoff carrying animal waste (e.g., from dairy farms). Although coagulation-sedimentation and filtration reduce the levels of cryptosporidium in water supplies, they do not eliminate it. Chlorination has no effect on the organism, which protects itself in the form of an oocyst, a tiny encapsulated egglike structure, when not in the intestine of an animal or human, but ozone disinfection has been more successful. Cryptosporidiosis affected more that 400,000 people and caused over 60 deaths in Milwaukee in 1993 when the parasites contaminated the public water system. Smaller outbreaks have occurred in other states.












[B][U]cyanosis[/U][/B]

It is a bluish coloration of the skin, mucous membranes, and nailbeds, resulting from a lack of oxygenated hemoglobin in the blood. It is a symptom of many disorders, including various pulmonary and heart diseases and many congenital heart defects. Cyanosis that is caused by slowed circulation through peripheral blood vessels results in a bluish tinge only on the cool portions of the body (fingertips, nose, ears). In such cases the capillary blood gives up more than normal amounts of oxygen. Although this type of cyanosis can be caused by reduced cardiac output (e.g., in congestive heart failure), the most common causes are nervous tension and exposure to cold. Another type of cyanosis results from poisoning, either by nitrates in contaminated food or water or by certain chemicals and drugs.









[B][U]cyst[/U][/B]

cyst, abnormal sac in the body, filled with a fluid or semisolid and enclosed in a membrane. Cysts can be congenital but are usually acquired, the most common locations being the skin and the ovaries. Sebaceous cysts of the skin, known as blackheads or whiteheads, occur when dirt or other material blocks the oil glands of the skin, preventing secretions from escaping. Retention cysts develop in glandular organs when ducts are blocked, commonly in kidney tubules, mammary glands, and sweat glands. Most cysts can be aspirated for treatment and/or cytology (diagnostic purposes); often cysts require surgical removal.










[B][U]cystic fibrosis[/U][/B]

inherited disorder of the exocrine glands, affecting children and young people; median survival is 25 years in females and 30 years in males. It is caused by a genetic abnormality in the CF transmembrane conductance regulator (CFTR) gene that results in the disruption of chloride transfer across cell membranes. As a consequence, chloride ions build up in the cells of the lungs and other organs. Water stays inside the cells to dilute the chloride rather than being drawn out of the cells by normal chloride movement and the normal secretions of the organs thicken. Mucus in the exocrine glands becomes thick and sticky and eventually blocks the ducts of these glands (especially in the pancreas, lungs, and liver), forming cysts. The disease also causes the sweat glands to secrete excessive salt, causing heat prostration in hot weather. Symptoms, which vary according to the severity of the condition and the glands involved, include a distended abdomen; diarrhea; bulky, foul-smelling stools; and malnutrition. Medical problems include nasal polyps and sinus disease, repeated respiratory infections, infertility, liver disease, and diabetes. Diagnosis is confirmed by a sweat test or measurement of transmembrane potential.

Treatment consists of dietary adjustment (low fat–high calorie) and the administration of vitamins, pancreatin, and antibiotics to ward off secondary infections. Special measures are necessary to decrease the viscosity of pulmonary secretions; aerosol application of recombinant human DNase, an enzyme that digests the sticky extracellular DNA that helps form these viscous secretions, was approved in 1993. In some cases lung transplantation (see transplantation, medical) is helpful. The identification of the abnormal gene (1989) paved the way for gene therapy aimed at altering the genetic structure by transferring to the patient cells with normal CFTR genes.

Identification of the genes has also made tests for genetic screening and diagnosis possible. Evolutionary biologists have suggested that the gene, which must be inherited from both parents to cause the disorder, affords carriers some protection against cholera, a disease that kills through profound loss of fluids.













[B][U]cystitis[/U][/B]

common acute or chronic inflammation of the urinary bladder. The disease occurs primarily in young women and frequently results from bacterial invasion of the urethra from the adjacent rectum, most commonly with normally occurring intestinal bacteria such as E. coli. It is also common in menopausal women; in them, the bacteria is transmitted from a vagina left more susceptible to bacterial overgrowth by changes in estrogen levels. In men cystitis rarely occurs without some other urinary tract disorder, such as kidney stones or, especially in older men, an enlarged prostate gland. Other predisposing factors are pregnancy, diabetes, and various systemic disorders.

Usual symptoms are frequent urination with burning pain, blood in the urine, and pain in the pubic area; chills and fever, back pain, and nausea may indicate kidney involvement. Treatment is with antibiotics and can also include the relief of any obstructions.

[B]Interstitial cystitis.[/B] is an inflammation of the bladder wall of unknown cause. It has the same symptoms as cystitis plus severe pelvic pain and frequency of urination (sometimes more than 60 times daily) that interferes with sleep, work, and daily life. No bacteria are present in the urine and it does not respond to antibiotics. It is diagnosed by the presence of lesions seen on the bladder wall during cystoscopy. Ninety percent of those affected are women. Diagnostic criteria were standardized only in 1988; it was often treated as a psychological disorder prior to that time. Treatment includes direct instillation of dimethyl sulfoxide (DMSO) into the bladder for relief of pain and inflammation, tricyclic antidepressants for pain relief, and a low-acid diet.










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[SIZE="6"][CENTER][B]D[/B][/CENTER][/SIZE]


[B][U]dandruff[/U][/B]

dandruff, excessive flaking of skin from the scalp, apparent as dry or greasy diffuse scaling with variable itching. It is the sign of a skin disease, such as seborrhea or a fungal infection. Treatment requires the use of shampoos containing pyrithione zinc, selenium sulfide, sulfur and salicylic acid, or tar shampoo used daily until the dandruff is under control.






[B][U][COLOR="blue"]deafness[/COLOR][/U][/B]

deafness, partial or total lack of hearing. It may be present at birth (congenital) or may be acquired at any age thereafter. A person who cannot detect sound at an amplitude of 20 decibels in a frequency range of from 800 to 1,800 vibrations per second is said to be hard of hearing. The ear normally perceives sounds in the range of 20 to 20,000 vibrations per second. There are two principal kinds of deafness, conductive deafness and sensorineural deafness. In some cases of deafness both the conductive and the nerve mechanisms are disturbed.



[B]Conductive Deafness[/B]

Conductive problems are those that disrupt the conduction of sound through the outer and middle ear (see ear), affecting hearing before the sound reaches the cochlea and the nerve receptors of the inner ear. Disturbances of the conductive mechanism are often temporary or curable. Most such cases are caused by otitis media, an infection that spreads to the middle ear from the upper respiratory tract; the condition usually responds to antibiotic therapy, but serious cases may require drainage of collected fluids through an incision in the eardrum (tympanum) or insertion of a tiny drainage tube. Foreign bodies or impacted wax can cause hearing loss and must be removed by a physician. In adults a predominant cause of conductive deafness is otosclerosis, a chronic hereditary condition in which spongy bone formation results in fixation of the stapes (the bone that connects the middle ear to the inner ear) and restricts its vibration. Important advances in surgical techniques have led to successful treatment of otosclerosis by replacing the stapes with a combination of grafted tissue, plastic, and wire appliances. Deafness can also be caused by perforation or rupture of the eardrum by a sudden loud noise, by physical puncture, or as a result of an infectious disease. In some such cases the eardrum can be repaired by grafting. Today there are many advanced medical techniques for treating infection of the mastoid and congenital malformations of the outer and middle ear that, if neglected, might result in deafness.




[B]Sensorineural Deafness[/B]

Sensorineural deafness results from damage to the neural receptors of the inner ear (the hair cells, organ of Corti), the nerve pathways to the brain (notably the auditory nerve), or the area of the brain that receives sound information. Deafness of this type is usually permanent. It can be congenital or accompany other birth-related problems such as erythroblastosis fetalis (Rh incompatibility) or anoxia (lack of oxygen during delivery). Before vaccines were available, German measles (rubella) and common measles (rubeola) were leading causes; maternal cytomegalovirus and genital herpes simplex continue to be threats.

Tumors, injury, stroke, toxic substances (e.g., mercury), and certain over-the-counter and prescription drugs (e.g., streptomycin) are additional factors that can affect auditory pathways and the brain and lead to sensorineural deafness. Continued exposure to loud noise, as in certain industries or from loud music, can result in damage to the inner ear, causing irreversible hearing loss. Presbycusis, or changes in hearing, especially of high frequencies, in adults has long been accepted as inevitable, but study of cultures where the phenomenon does not exist is bringing this into question. The hearing of patients with sensorineural deafness can sometimes be improved if the patient discontinues harmful medications or avoids exposure to loud noise, e.g., by wearing protective earplugs. In some cases, limited hearing has been restored by cochlear implants, tiny devices implanted into the inner ear that translate sound waves into electrical impulses that are then transmitted to the auditory nerve.








[B][U][COLOR="blue"]death[/COLOR][/U][/B]

death, cessation of all life (metabolic) processes. Death may involve the organism as a whole (somatic death) or may be confined to cells and tissues within the organism. Causes of death in human beings include injury, acute or chronic disease, and neoplasia (cancer). The physiological death of cells that are normally replaced throughout life is called necrobiosis; the death of cells caused by external changes, such as an abnormal lack of blood supply, is called necrosis.

[B]Somatic death[/B] is characterized by the discontinuance of cardiac activity and respiration, and eventually leads to the death of all body cells from lack of oxygen, although for approximately six minutes after somatic death—a period referred to as clinical death—a person whose vital organs have not been damaged may be revived. However, achievements of modern biomedical technology have enabled the physician to artificially maintain critical functions for indefinite periods.

Somatic death is followed by a number of irreversible changes that are of legal importance, especially in estimating the time of death. These include rigor mortis, livor mortis (discoloration of the body due to settling of blood), algor mortis (cooling of the body), autolysis (breakdown of tissue by enzymes liberated by that tissue after death), and putrefaction (invasion of the body by organisms from the gastrointestinal tract).

[B]Brain death[/B],. which is now a legal condition in most states for declared death, requires that the following be absent for at least 12 hours: behavioral or reflex motor functions above the neck, including pupillary reflexes to testing jaw reflex, gag reflex, response to noxious stimuli, and any spontaneous respiratory movement. Purely spinal reflexes can remain. If the patient has agreed to be an organ donor, the observation period can be shortened to 6 hours.

As a result of recent refinements in organ transplantation (see transplantation, medical) techniques, the need has arisen to more precisely define medical death. The current definition is that of a 1981 U.S. presidential commission, which recommended that death be defined as “irreversible cessation of all functions of the entire brain, including the brain stem,” the brain stem being that part of the brain that controls breathing and other basic body functions. Some feel, however, that people in persistent vegetative states, i.e., people who have brain-stem function but have lost higher brain functions (vision, abstract thought, personality), should be considered dead and allowed, through living wills or relatives, to donate organs.







[B][U]decompression sickness[/U][/B]

decompression sickness, physiological disorder caused by a rapid decrease in atmospheric pressure, resulting in the release of nitrogen bubbles into the body tissues. It is also known as caisson disease, altitude sickness, and the bends. It is an occupational hazard of persons who work under greatly increased atmospheric pressure below the surface of the earth (e.g., divers and laborers who work under compressed air) when their return to normal atmospheric pressure is made too quickly. When the body is subjected to high atmospheric pressure the respiratory gases are compressed and larger amounts are dissolved in the body tissues. During ascent from depths greater than 30 ft (9.1 m), these gases escape as the external pressure decreases. Airplane pilots who go rapidly from normal atmospheric pressure to high altitudes (low atmospheric pressure) in unpressurized aircraft or in aircraft with faulty pressurizing apparatus also encounter the disorder. The decrease in air pressure releases body nitrogen in the form of gas bubbles that block the small veins and arteries and collect in the tissues, cutting off the oxygen supply and causing nausea, vomiting, dizziness, pain in the joints and abdomen, paralysis, and other neurological symptoms. In severe cases there may be shock, total collapse, and, if treatment is not prompt, death. Persons who work under increased atmospheric pressure must make the ascent to normal atmospheric pressure gradually, often through pressurized chambers, a procedure that allows the nitrogen to be released slowly from the blood and expired from the lungs. Inhalation of pure oxygen aids in clearing nitrogen from the body. Those who suffer symptoms of decompression sickness at high altitudes (commonly called aeroembolism) experience relief on returning to an atmospheric pressure normal to them; this and oxygen inhalation will usually effect recovery.









[B][U]delirium tremens[/U][/B]

hallucinatory episodes that may occur during withdrawal from chronic alcoholism, popularly known as the DTs. An episode of delirium tremens is usually preceded by disturbed sleep and irritability, and generally takes several days to develop. The patient may experience sweating and increases in heart rate and body temperature, as well as hallucinations, tremors, and convulsions. In severe cases, delirium tremens may lead to hypothermia, cardiovascular collapse, and death. Delirium tremens can be treated, and even prevented, by the injection of fairly large doses of glucose, thiamine (vitamin B1), and insulin, and the continued administration of fluids (sodium chloride and sodium lactate) and the B vitamins. The condition is related to the abrupt drop in blood alcohol level after drinking ceases. Tranquilizers, sedatives, and anticonvulsants are also used in treatment.








[B][U][COLOR="blue"]dengue fever[/COLOR][/U][/B]

An acute infectious disease caused by four closely related viruses and transmitted by the bite of the Aedes mosquito; it is also known as breakbone fever and bone-crusher disease. The disease occurs in both epidemic and sporadic form in warm climates (S United States, South America, the Mediterranean countries, India, the Philippines, and Indonesia). The classic symptoms, following an incubation period of five to eight days, are high fever, chills, severe headache, pain in the joints, pain behind the eyes, rash, sweating, and prostration, but infected persons may experience milder symptoms. Symptoms subside in two to four days, but after a remission lasting from a few hours to two days there is another rise in temperature, and a generalized rash appears. Convalescence is sometimes prolonged, with weakness and low blood pressure.

[B]Dengue hemorrhagic fever,. [/B]a severe form of the disease, can cause hemorrhage, shock, and encephalitis. It occurs when a person who has acquired immunity to one of the viruses that cause dengue fever is infected by a different dengue virus. It is a leading cause of death among children in Southeast Asia and in recent years has become increasingly prevalent in tropical America. There is no specific treatment for dengue fever except good nursing care. Both diseases can be controlled by eradicating the mosquitoes and destroying their breeding places.







[B][U]dermatitis[/U][/B]

nonspecific irritation of the skin. The causative agent may be a bacterium, fungus, or parasite; it can also be a foreign substance, known as an allergen. Contact dermatitis is an allergic reaction to a substance that comes in contact with the skin, such as soap. Atopic dermatitis, also known as eczema, is a chronic, itching inflammation that tends to run in families susceptible to asthma and hay fever. Stasis dermatitis, or eczema of the legs, is caused by poor circulation and is found in older persons suffering from vascular disorders. When dermatitis is chronic it tends to cause thickening, pigmentation, and scaling, and when acute, a red, itching area of blisters and oozing.








[B][U]diagnosis[/U][/B]

diagnosis, determination of the nature of a disease or ailment. A clinical diagnosis is based on the medical history and physical examination of the patient: it may be confirmed with X-Rays, CAT Scans (Computerized Axial Tomography), MRI (Magnetic Resonance Imaging), and other laboratory tests. Diagnosis by physical examination includes ascertaining temperature, pulse, and blood pressure and involves the use of palpation, to detect enlarged organs and other abnormalities; tapping, to delineate some of the internal organs; and listening, to interpret sounds from organs such as the heart and lungs. Instruments that facilitate physical examination include the sphygmomanometer for blood pressure; the stethoscope for listening to the heart and lungs; the ophthalmoscope to examine the inner eye; and the laryngoscope and bronchoscope to view the larynx, windpipe, and other air passages. Recent innovations in electronics have made it possible for any of these devices to be fitted with video cameras and lights, so that the interior of the body can be viewed on video monitors and recorded on videotape for future reference. In diagnostic tests, the blood, urine, tissues, and other excretions and secretions of the body are examined for evidence of chemical imbalance, cellular change, and the presence of pathogenic organisms. Exploratory surgery and the insertion of visual equipment through a small incision (e.g., laparoscopy and arthroscopy) may be used to assist in diagnosis.













[B][U][COLOR="blue"]diabetes[/COLOR][/U][/B]

diabetes or diabetes mellitus, chronic disorder of glucose (sugar) metabolism caused by inadequate production or use of insulin, a hormone produced in specialized cells (beta cells in the islets of Langerhans) in the pancreas that allows the body to use and store glucose. It is a leading cause of death in the United States and is especially prevalent among African Americans. The treatment of diabetes was revolutionized when F. G. Banting and C. H. Best isolated insulin in 1921.





[B]The Disorder[/B]

The lack of insulin results in an inability to metabolize glucose, and the capacity to store glycogen (a form of glucose) in the liver and the active transport of glucose across cell membranes are impaired. The symptoms are elevated sugar levels in the urine and blood, increased urination, thirst, hunger, weakness, weight loss, and itching. Prolonged hyperglycemia (excess blood glucose) leads to increased protein and fat catabolism, a condition that can cause premature vascular degeneration and atherosclerosis (see arteriosclerosis). Uncontrolled diabetes leads to diabetic acidosis, in which ketones build up in the blood. Patients have sweet-smelling breath, and may suffer confusion, unconsciousness, and death. There are two distinct types of diabetes mellitus: insulin-dependent and noninsulin-dependent.

[COLOR="blue"]Insulin-dependent Diabetes[/COLOR]

Insulin-dependent diabetes (Type I), also called juvenile-onset diabetes, is the more serious form of the disease; about 10% of diabetics have this form. It is caused by destruction of pancreatic cells that make insulin and usually develops before age 30. Type I diabetics have a genetic predisposition to the disease. There is some evidence that it is triggered by a virus that changes the pancreatic cells in a way that prompts the immune system to attack them. The symptoms are the same as in the non-insulin-dependent variant, but they develop more rapidly and with more severity. Treatment includes a diet limited in carbohydrates and saturated fat, exercise to burn glucose, and regular insulin injections, sometimes administered via a portable insulin pump. Transplantation of islet cells has also proved somewhat successful since 1999, after new transplant procedures were developed, but the number of pancreases available for extraction of the islet cells is far smaller than the number of Type I diabetics. Patients receiving a transplant must take immunosuppressive drugs to prevent rejection of the cells, and many ultimately need to resume insulin injections, but despite that transplants provide real benefits for some whose diabetes has become difficult to control.

[COLOR="blue"]Noninsulin-dependent diabetes[/COLOR]

Noninsulin-dependent diabetes (Type 2), also called adult-onset diabetes, results from the inability of the cells in the body to respond to insulin. About 90% of diabetics have this form, which is more prevalent in minorities and usually occurs after age 40. Although the cause is not completely understood, there is a genetic factor and 90% of those affected are obese. As in Type I diabetes, treatment includes exercise and weight loss and a diet low in total carbohydrates and saturated fat. Some individuals require insulin injections; many rely on oral drugs, such as sulphonylureas, metformin, acarbose, or a dipeptidyl peptidase–IV (DPP-IV) inhibitor.





[B]Complications[/B]

Diabetes affects the way the body handles fats, leading to fat accumulation in the arteries and potential damage to the kidneys, eyes, heart, and brain, and statins (cholesterol-lowering drugs) may be prescribed to prevent heart disease. It is the leading cause of kidney disease. Many patients require dialysis or kidney transplants (see transplantation, medical). Most cases of acquired blindness in the United States are caused by diabetes. Diabetes can also affect the nerves, causing numbness or pain in the face and extremities. A complication of insulin therapy is insulin shock, a hypoglycemic condition that results from an oversupply of insulin in relation to the glucose level in the blood












[B][U]diathermy[/U][/B]

therapeutic measure used in medicine to generate heat in the body tissues. Electrodes and other instruments are used to transmit electric current to surface structures, thereby increasing the local blood circulation and facilitating and accelerating the process of absorption and repair. Diathermy is used for arthritis, bursitis, and other disorders of the tendons and muscles, as well as for certain other conditions requiring tissue repair. Because of the high-frequency current used in shortwave diathermy, care must be taken to avoid burning the patient's skin or injuring the deeper tissues.







[B][U]diarrhea[/U][/B]

frequent discharge of watery feces from the intestines, sometimes containing blood and mucus. It can be caused by excessive indulgence in alcohol or other liquids or foods that prove irritating to the stomach or intestine, by allergy to certain food products, by poisoning with heavy metals, by chemicals such as are found in cathartics, by hyperactivity of the nervous system, and by infection with a virus (intestinal grippe) or with bacteria or their toxins. Diarrhea is a concomitant of many infectious diseases, especially typhoid fever, bacillary or amebic dysentery, and cholera. Persistent diarrhea may result in severe dehydration and shock. It is therefore necessary to replace the fluid lost by the body. Treatment is with a bland diet and drugs that will decrease the activity of the intestines, as well as with specific measures directed at the underlying cause. The elderly are at especially high risk for diarrheal deaths caused by viruses. Ulcerative colitis is an inflamatory and ulcerative disease of the colon, properly described as “irritable bowl,” and characterized by bloody diarrhea. Crohn's disease affects the distal ileum and colon, but may occur in any part of the gastrointestinal tract, from the mouth to the anus and perianal area. The symptoms are chronic diarrhea associated with abdominal pain, fever, anorexia, weight loss, and a mass or fullness in the right lower quadrant (of the abdomen).













[B][U]diphtheria[/U][/B]

It is an acute contagious disease caused by Corynebacterium diphtheriae (Klebs-Loffler bacillus) bacteria that have been infected by a bacteriophage. It begins as a soreness of the throat with fever. The bacteria lodge in the mucous membranes of the throat, producing virulent toxins that destroy the tissue. The resultant formation of a tough gray membrane is one of the most dangerous aspects of diphtheria, since it can spread to the larynx and cause suffocation. Deaths from diphtheria often result from inflammation of the heart. Diphtheria usually occurs in children of preschool age. Treatment with antitoxin is begun as early as possible. Penicillin or erythromycin is also given, particularly to guard against complicating factors such as pneumonia or streptococcal infection. Diphtheria was once a common and dreaded disease with a high mortality rate; it is now rare in countries where infants are vaccinated (see vaccination). Underimmunization, however, can lead to epidemics such as the one in Russia during 1994–95.











[B][U]dislocation[/U][/B]

dislocation, displacement of a body part, usually a bone. When a bone is dislocated, the ends of opposing bones are usually forced out of connection with one another. In the process, bruising of tissues and tearing of ligaments may occur. The condition may be congenital, but usually it is the result of injury. In some persons recurrent dislocation, usually of the jaw or of the knee, is brought on by only slight provocation. Manipulation, bandages, splints, and other appliances are used to reposition the dislocated part. Occasionally corrective surgery may be required.







[B][U]diverticulosis[/U][/B]

diverticulosis, a disorder characterized by the presence of diverticula, which are small, usually multiple saclike protrusions through the wall of the colon (large intestine). Diverticula usually do not cause symptoms unless they become inflamed, in which case the condition is called diverticulitis.. Symptoms of diverticulitis vary and may include abdominal pain, fever, bleeding, and diarrhea or constipation. Treatment includes bed rest, antibiotics, and a soft diet.

Diverticulosis becomes more common as people grow older, and it is estimated that more than 50% of people in Western countries acquire the condition by age 80. Many physicians believe that lack of fiber or bulk in the diet is a contributing factor in diverticulosis.








[B][U]Down syndrome[/U][/B]

Down syndrome, congenital disorder characterized by mild to severe mental retardation, slow physical development, and characteristic physical features. Down syndrome affects about 1 in every 730 live births and occurs in all populations equally. It was first described in 1866 by an English physician, J. Langdon Down. In 1959 a French physician, Jerome Lejeune, discovered that the syndrome was caused by an extra chromosome. It was later discovered that this extra chromosome appears as a third chromosome attached to the 21st of the 23 pairs of chromosomes normally present in the human genome. This third chromosome gives rise to the alternate name trisomy 21.

The extra genetic material is responsible for the physical characteristics of the syndrome: low muscle tone, flattish facial features, an upward slant to the eyes and epicanthal folds (which were the basis for the former name, mongolism), a single crease across the palm, hyperflexibility of the joints, and a displastic middle phalanx on the fifth finger. People with Down syndrome have an increased incidence of infection, childhood leukemia, congenital heart defects, and respiratory problems, but modern medical treatment has improved the life expectancy from 9 (in 1910) to 55 (in 1995).

Mental retardation varies widely, from minimal to severe. The great majority of those who have the disorder attend public schools and as adults can live independently or in group homes. After age 35 individuals with the syndrome develop the neurological changes of Alzheimer's disease, and many develop the dementia that accompanies them.

Eighty percent of children with Down syndrome are born to women under 35 years of age, but the incidence of Down syndrome births does increase with age. Approximately 5% of cases are transmitted by the sperm. Amniocentesis or chorionic villus sampling can be used to detect the disorder in the fetus. Children born to women with Down syndrome have a 50% chance of having the disorder.











[B][U]drug poisoning[/U][/B]

drug poisoning, toxic effects caused by an administered drug. Worldwide more than 9 million natural and synthetic chemicals have been identified; fewer than 3000 cause more than 95% of acidental and deliberate poisonings. Reaction to a drug caused by an allergic sensitivity is not considered drug poisoning. Virtually all drugs, especially in large doses or when taken over long periods of time, can initiate a toxic condition. Certain drugs used in combination, such as alcohol and barbiturates, result in an intensified alteration of physiological state that is frequently dangerous. Drugs that affect the nervous system often cause adverse reactions in high concentrations. Alcohol and other nervous system depressants, such as barbiturates and narcotics, taken in sufficiently large doses, can result in coma and convulsions. Excessively high doses of stimulants such as amphetamines result in blurred vision, spasms, heart irregularities, and respiratory failure. In addition, continued use of both stimulants and depressants can lead to addiction and tolerance for toxic doses. Overdosage of an analgesic like aspirin can result in acid-base disturbances, spontaneous bleeding, and convulsions. Virtually all drugs produce some side effects. For example, side reactions with barbiturates may include respiratory depression and skin rashes. Other drugs cause adverse reactions when taken over long periods of time. The antibiotic streptomycin taken over long periods can result in deafness, and continued use of aspirin and other salicylates can result in kidney damage and anemia. Some drugs only have toxic effects on sensitive individuals. Hallucinogenic drugs such as LSD can result in hyperexcitability, coma, and prolonged psychotic states and can cause major personality changes in some users. In susceptible persons even moderate doses of phenothiazine tranquilizers, which are used to calm psychotic patients, can cause such toxic effects as low blood pressure, uncontrollable muscle movements, and various pigmentation and blood cell disorders .









[B][U][COLOR="blue"]drug addiction and drug abuse[/COLOR][/U][/B]

drug addiction and drug abuse, chronic or habitual use of any chemical substance to alter states of body or mind for other than medically warranted purposes. Traditional definitions of addiction, with their criteria of physical dependence and withdrawal (and often an underlying tenor of depravity and sin) have been modified with increased understanding; with the introduction of new drugs, such as cocaine, that are psychologically or neuropsychologically addicting; and with the realization that its stereotypical application to opiate-drug users was invalid because many of them remain occasional users with no physical dependence. Addiction is more often now defined by the continuing, compulsive nature of the drug use despite physical and/or psychological harm to the user and society and includes both licit and illicit drugs, and the term “substance abuse” is now frequently used because of the broad range of substances (including alcohol and inhalants) that can fit the addictive profile. Psychological dependence is the subjective feeling that the user needs the drug to maintain a feeling of well-being; physical dependence is characterized by tolerance (the need for increasingly larger doses in order to achieve the initial effect) and withdrawal symptoms when the user is abstinent.

Definitions of drug abuse and addiction are subjective and infused with the political and moral values of the society or culture. For example, the stimulant caffeine in coffee and tea is a drug used by millions of people, but because of its relatively mild stimulatory effects and because caffeine does not generally trigger antisocial behavior in users, the drinking of coffee and tea, despite the fact that caffeine is physically addictive, is not generally considered drug abuse. Even narcotics addiction is seen only as drug abuse in certain social contexts. In India opium has been used for centuries without becoming unduly corrosive to the social fabric.

The United States has the highest substance abuse rate of any industrialized nation. Government statistics (1997) show that 36% of the United States population has tried marijuana, cocaine, or other illicit drugs. By comparison, 71% of the population has smoked cigarettes and 82% has tried alcoholic beverages. Marijuana is the most commonly used illicit drug.



[B]Types of Abused Substances[/B]

There are many levels of substance abuse and many kinds of drugs, some of them readily accepted by society.


[COLOR="blue"]Legal Substances[/COLOR]

Legal substances, approved by law for sale over the counter or by doctor's prescription, include caffeine, alcoholic beverages (see alcoholism), nicotine (see smoking), and inhalants (nail polish, glue, inhalers, gasoline). Prescription drugs such as tranquilizers, amphetamines, benzodiazepines, barbiturates, steroids, and analgesics can be knowingly or unknowingly overprescribed or otherwise used improperly. In many cases, new drugs prescribed in good conscience by physicians turn out to be a problem later. For example, diazepam (Valium) was widely prescribed in the 1960s and 70s before its potential for serious addiction was realized. In the 1990s, sales of fluoxetine (Prozac) helped create a $3 billion antidepressant market in the United States, leading many people to criticize what they saw as the creation of a legal drug culture that discouraged people from learning other ways to deal with their problems. At the same time, readily available but largely unregulated herbal medicines have grown in popularity; many of these are psychoactive to some degree, raising questions of quality and safety. Prescription drugs are regulated by the Food and Drug Administration and the Drug Enforcement Administration.

[COLOR="blue"]Illegal Substances[/COLOR]

Prescription drugs are considered illegal when diverted from proper use. Some people shop until they find a doctor who freely writes prescriptions; supplies are sometimes stolen from laboratories, clinics, or hospitals. Morphine, a strictly controlled opiate, and synthetic opiates, such as fentanyl, are most often abused by people in the medical professions, who have easier access to these drugs. Other illegal substances include cocaine and crack, marijuana and hashish, heroin, hallucinogenic drugs such as LSD, PCP (phencycline or “angel dust”), “designer drugs” such as MDMA (Ecstasy), and “party drugs” such as GHB (gamma hydroxybutyrate).



[B]Motivations for Drug Use[/B]

People take drugs for many reasons: peer pressure, relief of stress, increased energy, to relax, to relieve pain, to escape reality, to feel more self-esteem, and for recreation. They may take stimulants to keep alert, or cocaine for the feeling of excitement it produces. Athletes and bodybuilders may take anabolic steroids to increase muscle mass.



[B]Effects of Substance Abuse[/B]

The effects of substance abuse can be felt on many levels: on the individual, on friends and family, and on society.

[COLOR="blue"]On the Individual[/COLOR]

People who use drugs experience a wide array of physical effects other than those expected. The excitement of a cocaine high, for instance, is followed by a “crash”: a period of anxiety, fatigue, depression, and an acute desire for more cocaine to alleviate the feelings of the crash. Marijuana and alcohol interfere with motor control and are factors in many automobile accidents. Users of marijuana and hallucinogenic drugs may experience flashbacks, unwanted recurrences of the drug's effects weeks or months after use. Sudden abstinence from certain drugs results in withdrawal symptoms. For example, heroin withdrawal can cause vomiting, muscle cramps, convulsions, and delirium. With the continued use of a physically addictive drug, tolerance develops; i.e., constantly increasing amounts of the drug are needed to duplicate the initial effect. Sharing hypodermic needles used to inject some drugs dramatically increases the risk of contracting AIDS and some types of hepatitis. In addition, increased sexual activity among drug users, both in prostitution and from the disinhibiting effect of some drugs, also puts them at a higher risk of AIDS and other sexually transmitted diseases. Because the purity and dosage of illegal drugs are uncontrolled, drug overdose is a constant risk. There are over 10,000 deaths directly attributable to drug use in the United States every year; the substances most frequently involved are cocaine, heroin, and morphine, often combined with alcohol or other drugs. Many drug users engage in criminal activity, such as burglary and prostitution, to raise the money to buy drugs, and some drugs, especially alcohol, are associated with violent behavior.

[COLOR="blue"]Effects on the Family[/COLOR]

The user's preoccupation with the substance, plus its effects on mood and performance, can lead to marital problems and poor work performance or dismissal. Drug use can disrupt family life and create destructive patterns of codependency, that is, the spouse or whole family, out of love or fear of consequences, inadvertently enables the user to continue using drugs by covering up, supplying money, or denying there is a problem. Pregnant drug users, because of the drugs themselves or poor self-care in general, bear a much higher rate of low birth-weight babies than the average. Many drugs (e.g., crack and heroin) cross the placental barrier, resulting in addicted babies who go through withdrawal soon after birth, and fetal alcohol syndrome can affect children of mothers who consume alcohol during pregnancy. Pregnant women who acquire the AIDS virus through intravenous drug use pass the virus to their infant.

[COLOR="blue"]Effects on Society[/COLOR]

Drug abuse affects society in many ways. In the workplace it is costly in terms of lost work time and inefficiency. Drug users are more likely than nonusers to have occupational accidents, endangering themselves and those around them. Over half of the highway deaths in the United States involve alcohol. Drug-related crime can disrupt neighborhoods due to violence among drug dealers, threats to residents, and the crimes of the addicts themselves. In some neighborhoods, younger children are recruited as lookouts and helpers because of the lighter sentences given to juvenile offenders, and guns have become commonplace among children and adolescents. The great majority of homeless people have either a drug or alcohol problem or a mental illness—many have all three.

The federal government budgeted $17.9 billion on drug control in 1999 for interdiction, prosecution, international law enforcement, prisons, treatment, prevention, and related items. In 1998, drug-related health care costs in the United States came to more than $9.9 billion.





[B][U]drug resistance[/U][/B]

drug resistance, condition in which infecting bacteria can resist the destructive effects of drugs such as antibiotics and sulfa drugs. Drug resistance has become a serious public health problem, since many disease-causing bacteria are no longer susceptible to previously effective drug therapies. For nearly 50 years after the first antibiotic, penicillin, became available in the 1940s, people took antibiotics' effectiveness against bacterial infections for granted. By the 1960s some doctors were predicting the end of infectious diseases. By the 1990s, however, a “post-antibiotic era,” characterized by the proliferation of untreatable bacterial strains, was considered inevitable, and the rate at which bacteria were becoming resistant to antibiotics was catching up with the rate at which new antibiotics were being produced.

The number of drug-resistant bacterial strains has increased in part because of the indiscriminate use of antibiotics, which have sometimes been overprescribed. Such misuse speeds the process by destroying bacteria that would compete with resistant strains. In addition, patients sometimes stop treatment when they start to feel better, leaving a residual population of bacteria that is likely to be more resistant to drug treatment. Another source of resistance is the routine use of antibiotics in animal feed to enhance growth, a practice that has led to resistant strains of Escherichia coli and Salmonella that have been passed on to consumers. The presence of drugs in the water supply, due at least in part to human and animal excretion and the disposal of unused drugs, is also believed to contribute to drug resistance in bacteria.

Resistance is due to random genetic mutations in the bacterial cell that alter its sensitivity to a single drug or to chemically similar drugs through a variety of mechanisms. Many bacteria can transfer their resistance to other bacteria of the same or different species. Resistance has occurred in common infectious bacteria such as pneumococcus (a cause of pneumonia, meningitis, and childhood ear infections) and enterococcus (a cause of wound infections). It has also occurred in such diseases as malaria and tuberculosis. Concerns are increasing as strains develop resistance to multiple drugs, including even the most powerful antibiotics (e.g., vancomycin). Although drug companies are again concentrating on antibiotic research, no new products are expected until the turn of the century, and many infectious-disease experts are urging that doctors consider the public health risk before prescribing antibiotics and that the government regulate the use of antibiotics in agriculture.









[B][U]dwarfism[/U][/B]

dwarfism, condition in which an animal or plant is less than normal in size and lacks the capacity for normal growth. Dwarfism is deliberately produced and perpetuated in certain species (e.g., in breeding miniature dogs and cultivating dwarf plants). Among humans, dwarfism usually results from a combination of genetic factors and endocrine malfunction. It can also be caused, however, by acquired conditions, such as kidney disease. Pituitary dwarfism is caused by an insufficiency of the pituitary growth hormone (hypopituitary dwarfism). Typically, the pituitary dwarf stops growing in early childhood but retains normal body proportion, mental capacity, and sexual development. Pharmaceutical companies are cloning human growth hormone to stimulate growth in children afflicted with hypopituitary glands. This type of dwarf, who is completely normal except for size, is commonly called a midget. Cretinism is a type of dwarfism accompanied by mental retardation and distortion of the body, resulting from an insufficiency of thyroid hormone. Unlike cretinism and pituitary dwarfism (which are thought to be caused by a combination of heredity and endocrine malfunction), achondroplastic dwarfism is the result of a completely hereditary, dominant genetic trait. Typically, the growth of the limbs is stunted, but the size of the trunk and mental capacity are normal. Humans who range in height from 2 to 4 ft (5.08–10.16 cm) are generally classified as dwarfs. However, small size that is an inherited characteristic of race (such as among African Pygmies) is not considered to be dwarfism since the individuals in such groups are physiologically normal.






[B][U]dyslexia[/U][/B]

in psychology, a developmental disability in reading or spelling, generally becoming evident in early schooling. To a dyslexic, letters and words may appear reversed, e.g., d seen as b or was seen as saw. Many dyslexics never learn to read or write effectively, although they tend to show above average intelligence in other areas. With the aid of computerized brain scans such as positron emission tomography (PET), recent studies have offered strong evidence that dyslexia is located in the brain. Damage to the brain can cause a reading disability similar to dyslexia, known as acquired dyslexia or alexia.








[B][U]dysentery[/U][/B]

inflammation of the intestine characterized by the frequent passage of feces, usually with blood and mucus. The two most common causes of dysentery are infection with a bacillus, of the Shigella group, and infestation by an ameba, Entamoeba histolytica. Both bacillary and amebic dysentery are spread by fecal contamination of food and water and are most common where sanitation is poor. They are primarily diseases of the tropics, but may occur in any climate.



[B]Bacillary Dysentery[/B]

It is estimated that in some parts of the tropics 80% of the children acquire bacillary dysentery before the age of five; the mortality rate is high among infants and the aged if the infection is not treated, preferably with a broad-spectrum antibiotic. In adults bacillary dysentery usually subsides spontaneously, but treatment is desirable to prevent recurrence.


[B]Amebic Dysentery[/B]

Amebic dysentery is prevalent in regions where human excrement is used as fertilizer; in some such regions over half the population probably harbors the amebic cyst. The cyst is the inactive, resistant stage in which the ameba is transmitted from one host to another; the active form is that which causes damage. Both cysts and active amebas are excreted in the feces of an infected person, but only the cysts are hardy enough to survive outside the body. A person recovering from the infection, or one with an inactive case, passes mostly cysts; such a person is a more likely source of contamination than one with an active case. When cysts are ingested with contaminated food or water they are transformed in the intestine into active amebas. If these remain within the lumen of the intestine they are relatively innocuous, but if they invade the intestinal wall they cause ulceration, dysentery, and usually pain. In severe cases the resulting dehydration may lead to prostration.

Amebic dysentery may occur in acute or chronic form. In prolonged infections the amebas may invade the blood vessels of the intestine and be carried to other parts of the body, where they cause amebic abcesses. Abcesses of the liver and brain are especially dangerous; destruction of liver tissue is the most frequent complication of amebic dysentery. Infection by amebas, whether of the intestine alone or of other parts of the body, is called amebiasis. Infections are diagnosed by finding cysts or active amebas in the feces. However, the disease is easily misdiagnosed for several reasons. Entamoeba histolytica may be harbored without causing symptoms (although it may be passed on and cause the disease in others); it is easily confused with harmless amebas of the human intestine, especially Entamoeba coli; it commonly coexists with bacteria that may in some cases be the cause of the symptoms.

A combination of drugs is generally used to treat amebic dysentery: an amebicide (metronidazole or tinidazole) to eliminate the organism from the intestinal tract, an antibiotic to eradicate associated bacterial infection, and a drug to combat infection of the liver and other tissues. Preventive measures include the protection of water supplies from contamination and the washing of hands by food handlers.










[COLOR="Magenta"]__________________[/COLOR]

[B][CENTER][SIZE="6"]E[/SIZE][/CENTER][/B]



[B][U]eating disorders[/U][/B]

eating disorders, in psychology, disorders in eating patterns that comprise four categories: anorexia nervosa, bulimia, rumination disorder, and pica. Anorexia nervosa is characterized by self-starvation to avoid obesity. People with this disorder believe they are overweight, even when their bodies become grotesquely distorted by malnourishment. Bulimia is characterized by massive food binges followed by self-induced vomiting or use of diuretics and laxatives to avoid weight gain. Some anorexic patients combine bulimic purges with their starvation routine. These disorders generally afflict women—particularly in adolescence and young adulthood—and are much less common among men. Some researchers believe that anorexia and bulimia are caused by chemical imbalances in the brain; one study has linked bulimia to deprivation of tryptophan, an amino acid used by the body to make the neurotransmitter serotonin. Others contend that these disorders are rooted in societal ideals that value slenderness. Rumination disorder generally occurs during infancy, and involves repeated regurgitation accompanied by low body weight. Infants suffering from rumination disorder may re-ingest the regurgitated food. Pica, also found primarily among infants, is characterized by eating various non-nutritive substances like plaster, paint, or leaves. Obesity is not generally considered an eating disorder, since its causes tend to be physiological.








[B][U]Ebola virus[/U][/B]

a member of a family (Filovirus) of viruses that cause hemorrhagic fevers. The virus, named for the region in Congo (Kinshasa) where it was first identified in 1976, emerged from the rain forest, where it survives in as yet unconfirmed hosts, possibly several species of fruit bats. The virus can be fatal to chimpanzees and gorillas as well as humans.

Three strains of the virus, which are found in Africa, cause hemorrhagic fever; the fourth, found in the W Pacific, does not. Once a person is infected with the virus, the disease has an incubation period of 2–21 days; however, some infected persons are asymptomatic. Initial symptoms are sudden malaise, headache, and muscle pain, progressing to high fever, vomiting, severe hemorrhaging (internally and out of the eyes and mouth) and in 50%–90% of patients, death, usually within days. The likelihood of death is governed by the virulence of the particular Ebola strain involved. Ebola virus is transmitted in body fluids and secretions; there is no evidence of transmission by casual contact. There is no vaccine and no cure.

Outbreaks of Ebola virus in humans occurred in both Congo-Kinshasa (then Zaïre) and Sudan in 1976 and 1979; other outbreaks have occurred since in Gabon, Uganda, and both Congos. Outbreaks have been exacerbated by underequipped hospitals that reused syringes and lacked proper protective clothing for personnel. In 1989 a similar virus was found in monkeys imported to the United States.









[B][U]eclampsia[/U][/B]

It is a term applied to toxic complications that can occur late in pregnancy. Toxemia of pregnancy occurs in 10% to 20% of pregnant women; symptoms include headache, vertigo, visual disturbances, vomiting, hypertension, and edema. The four categories of hypertension during pregnancy are pre-eclampsia, eclampsia, chronic hypertension, and transient hypertension. Pre-eclampsia, which occurs late in pregnancy, is characterized by decreased cardiac output and increased blood vessel resistance. It may be prevented with calcium supplements and low-dose aspirin, and a cesarian section is often safer than natural childbirth. Only 5% of of women with pre-eclampsia progress to eclampsia, which is accompanied by convulsions and coma. To avoid renal and cardiovascular damage of the mother and to prevent fetal damage, the condition is treated by termination of pregnancy.








[B][U]eczema[/U][/B]

An acute or chronic skin disease characterized by redness, itching, serum-filled blisters, crusting, and scaling. Predisposing factors are familial history of allergic disorders (hay fever, asthma, or eczema) and sensitivity to contact allergens or certain foods. The condition is often irritated by excessive sweating, exposure to extreme heat or cold, and abnormal dryness or oiliness of the skin. Eczema may occur at any age and in both sexes. It is frequently chronic and difficult to treat, and it tends to disappear and recur. Itching can be extreme and severe, and it can often lead to an emotional disturbance. Treatment usually necessitates the avoidance of all unnecessary skin irritation; creams or lotions containing topical immunomodulators, such as tacrolimus (ProTopic and Eladil), or corticosteroids are sometimes helpful. Care should be taken to avoid secondary infections.








[B][U]edema[/U][/B]

An abnormal accumulation of fluid in the body tissues or in the body cavities causing swelling or distention of the affected parts. Edema of the ankles and lower legs (in ambulatory patients) is characteristic of congestive heart failure, but it can accompany other conditions, including obesity, diseased leg veins, kidney disease, cirrhosis of the liver, anemia, and severe malnutrition. Edema is the result of venous ulceration, which is often caused by an increase in tissue pressure (increased fluid within the tissue) because of increased capillary permeability. A failing heart is often accompanied by edema because the blood backs up into the veins, venules, and capillaries, thereby increasing blood pressure. In severe cases of heart failure, the abdomen may fill with fluid; this condition is called ascities. Appendage edema is often treated by bandaging the area to relieve pressure on the skin and decrease venous pressure. More severe cases may require a surgical procedure that diverts the blood flow to healthy veins. The accumulation of fluid within the lungs is a serious complication of cardiac failure, pneumonia, and other disorders. The collection of fluid in the pleural space (within the two-layered membrane surrounding the lungs) can be the symptom of numerous infectious and circulatory disorders. Lymphatic obstructions may result from various surgical procedures or from certain parasitic infections. These blockages cause increased back pressure in the lymph vessels and interfere with movement of fluid from interstitial tissue into venule ends of capillaries. The resulting collection of water within the skull is a serious and usually incurable condition. Since edema is a symptom, the underlying cause must be treated.








[B][U]ehrlichiosis[/U][/B]

any of several diseases caused by rickettsia of the genus Ehrlichia. Ehrlichiosis is transmitted by ticks. Both human forms tend to develop about nine days after a tick bite. Symptoms include severe headache and chills and low white blood cell and platelet counts. The lack of a rash distinguishes them from Rocky Mountain spotted fever and Lyme disease; lack of upper respiratory and gastrointestinal symptoms distinguishes them from influenza. Many cases are mild, and all are treatable with antibiotics (tetracycline and doxycycline); however, ehrlichiosis can be fatal in some cases when diagnosis and treatment are delayed.

It was known for years that certain species (some believe them to be variant strains of a single species) can cause disease in animals, for example E. canis in dogs and E. phagocytophila in sheep and cattle. In the mid-1980s human ehrlichiosis was first recognized. The causative agent was found to be E. chaffeensis. This form is now known as human monocytic ehrlichiosis. In 1990 another form of the disease, human granulocytic ehrlichiosis, was identified. The Ehrlichia organisms invade various white blood cells. E. chaffeensis invades monocytes; granulocytic Ehrlichia invades granulocytes.







[B][U]elephantiasis[/U][/B]

It may be viewed as an abnormal enlargement of any part of the body due to obstruction of the lymphatic channels in the area (see lymphatic system), usually affecting the arms, legs, or external genitals. In tropical countries the most common cause is filariasis, infestation with certain filaria, small parasitic roundworms of the genera Wuchereria bancrofti or Brugia malayi that are introduced into the body by many species of mosquitoes. The adult worms live in the lymphatic system, causing local inflammation, fibrosis, and obstruction, and resulting in the characteristic enlargement and thickening of the skin. The initial damage done by the worms can be greatly worsened by secondary bacterial and fungal infections.

Recovery from filariasis is possible and surgery sometimes helps, but any elephantiasis that develops during the disease cannot be cured. Ivermectin, an antifilarial drug, has been effective with a single dose. Diethylcarbamazine often kills the adult worms or impairs their reproductive capabilities, and the antibiotic doxycycline, which works by killing symbiotic bacteria that live inside the worms, also eliminates adult worms. Albendazole, in combination with others drugs, is being used in a program of mass drug administration undertaken under the auspices of the World Health Organization in an attempt to eliminate filariasis. Begun in 1999 the program treats an entire population in an attempt to eradicate the worm. Control of mosquitoes also is instrumental in holding down the incidence of the disease. Careful hygiene and other measures that prevent and control subsequent bacterial and fungal infections in limbs or genitals in which the lymphatic system has been damaged can reduce disfigurement and suffering. Blocking of the lymph channels and elephantiasis can also result from lymphogranuloma venereum, a sexually transmitted disease.










[B][U]embolus[/U][/B]

The foreign matter circulating in and obstructing a blood vessel. It may be a portion of a clot that has separated from the wall of a vessel, a bubble of gas or air (known as an air embolus), a globule of fat, a clump of bacterial matter, or a clump of tumor cells. It circulates freely through the vessels until it reaches one so small that it cannot go further. An embolus in one of the vessels leading to the lungs, brain, or heart, if large enough, can be fatal; in an arm or leg it may lead to gangrene and, ultimately, the need for amputation. Emergency surgical removal is usually the treatment of choice for a solid embolus. Otherwise, drugs that dilate the vessels and anticoagulants are indicated.







[COLOR="blue"][B][U]emphysema[/U][/B][/COLOR]

pathological or physiological enlargement or overdistention of the air sacs of the lungs. A major cause of pulmonary insufficiency in chronic cigarette smokers, emphysema is a progressive disease that commonly occurs in conjunction with chronic bronchitis. It is found predominantly in people over age 45, but a genetically based early-onset form also exists. Symptoms are difficulty in breathing, cough with thick sticky sputum, and a bluish tinge of the skin. Progressive disease can result in disability, and in severe cases heart or respiratory failure and death.



[B]Causes[/B]

Cigarette smoking is the cause of most cases of emphysema. Tobacco smoke damages the lungs' alveoli, the tiny air sacs through which inhaled oxygen is transferred to the bloodstream and carbon dioxide is passed back to the lungs to be exhaled. The lungs become less elastic and breathing becomes increasingly difficult. The genetic form of emphysema occurs earlier in life (worsened by, but not dependent upon cigarette smoking). It is caused by a rare genetic deficiency of the protein alpha1-antitrypsin. In the absence of antitrypsin, which normally functions to protect the lungs from damage, the walls of the alveoli are attacked by chemicals released in alveoli in response to tobacco smoke and air pollutants.



[B]Treatment[/B]

Emphysematous lung damage is irreversible. Its progression can be slowed by giving up smoking. Treatment is aimed at increasing the functional capacity of the lungs and may include bronchodilators, administration of supplemental oxygen, or lung transplantation. Surgical removal of affected lung tissue (lung volume reduction surgery), aimed at allowing healthy areas of the lung room to function, is being studied for its effectiveness and safety. The genetic form is treated with supplemental antitrypsin administered by infusion or by a gene therapy technique that uses T cells (special immune cells that identify diseased or deformed cells) to deliver it to the desired cell sites.














[B][U]empyema[/U][/B]

persistent purulent discharge into a cavity such as the pleural space or the gallbladder. Empyema results as a complication of bacterial infections such as pneumonia and lung abscess. It is now relatively rare because of the widespread availability of therapy for the infections that precipitate the disease.









[B][U]encephalitis[/U][/B]

It is a general term used to describe a diffuse inflammation of the brain and spinal cord, usually of viral origin, often transmitted by mosquitoes, in contrast to a bacterial infection of the meninges (membrane surrounding the brain and spinal cord), known as meningitis. Diagnostic symptoms include capillary congestion, small hemorrhages into perivascular spaces, accumulation of plasma cells and lymphocytes, and increased pressure and protein content of cerebrospinal fluid.

Among the several forms of viral brain inflammation are rabies, polio, and two types transmitted by the mosquito: equine encephalitis in its various forms and St. Louis encephalitis. The latter two have appeared in epidemic form in the United States and are characterized by high fever, prolonged coma (which is responsible for the disease being known as a “sleeping sickness”; see also trypanosomiasis), and convulsions sometimes followed by death. Encephalitis that results as a complication of another systemic infection is known as parainfectious encephalitis and can follow such diseases as measles (rubeola), influenza, and scarlet fever. The AIDS virus also infects the brain and produces dementia in a predictably progressive pattern. Although no specific treatment can destroy the virus once the disease has become established, many types of encephalitis can be prevented by immunization.











[B][U]endocarditis[/U][/B]

bacterial or fungal infection of the endocardium (inner lining of the heart) that can be either acute or subacute. In the acute form the symptoms (fever, malaise, fatigue, weight loss, anemia) are directly related to the presence of an active infection that runs its course within a few weeks. Acute endocarditis may follow respiratory infection, surgery, or other trauma; but in some cases the source of infection is unknown. A major cause of endocarditis is the use of contaminated intravenous needles by drug addicts. Bacterial endocarditis is an insidious, often progressive, disease that can lead to kidney failure and congestive heart failure. The causative agent in many cases of subacute disease is Streptococcus viridans. Endocarditis is often a complication of Lyme disease. A previously damaged valve increases the risk of infection tenfold. The most common diseases causing these predisposing valvular deformities are rheumatic fever and congenital heart disease. Thrombi associated with the infection on the valve often dislodge and spread septic emboli throughout the body that may damage the kidney. Primary diagnostic symptoms are fever and a changing heart murmur. Physical diagnosis can be confirmed by the use of echocardiography (ultrasound). Treatment with high doses of antibiotics often kills the bacteria, but the damage to the valve may put an additional strain on the heart that can eventually lead to cardiac failure. However, it is sometimes possible through follow-up corrective surgery to repair or replace valves damaged by endocarditis.











[B][U]endometriosis[/U][/B]

a condition in which small pieces of the endometrium (the lining of the uterus) migrate to other places in the pelvic area. The endometrial fragments may move to the fallopian tubes, ovaries, or other pelvic structures (e.g., the bladder or rectum). The migrated tissue retains its character and changes with the fluctuations of the menstrual cycle, bleeding at the time of menstruation. The blood becomes trapped in cysts that can grow from the size of a pinhead to the size of a grapefruit. Symptoms of endometriosis can be absent or can include painful menstruation, severe abdominal or low back pain, painful intercourse, and rectal bleeding at the time of menstruation. Symptoms often disappear with pregnancy, but 30%–40% of women who have endometriosis are infertile.

The cause of endometriosis is unknown. One hypothesis is that the endometrial fragments move back up through the fallopian tubes rather than leaving the body with the menstrual flow. Diagnosis is by pelvic examination or laparoscopy. Treatment, which depends on the severity of the disease, may include a course of oral contraceptives, or danazol if the patient is trying to conceive. In severe cases surgical removal of the cysts or hysterectomy may be performed.










[B][U]enteritis[/U][/B]

inflammation of the gastrointestinal tract. Acute enteritis is not usually serious except in infants and older people, in whom the accompanying diarrhea can cause dehydration through the loss of fluids. The condition known as regional enteritis (Crohn's disease) is a chronic disease that occurs most frequently in young adults, producing a segmented thickening of the bowel wall and narrowing of the bowel opening (lumen). The lower portion of the small intestine is usually affected, but the infection can extend up to the esophagus and down into the colon. Clinical symptoms include mild, intermittent diarrhea, abdominal pain, weight loss, and fever. In prolonged cases there may be anemia and nutritional deficiency. The term enteritis is sometimes applied to the conditions of gastroenteritis (inflammation of the stomach commonly caused by food poisoning) and ulcerative colitis. Surgery may be necessary to treat severe complications such as abscesses and obstructions.








[B][U]epidemic[/U][/B]

epidemic, outbreak of disease that affects a much greater number of people than is usual for the locality or that spreads to regions where it is ordinarily not present. A disease that tends to be restricted to a particular region (endemic disease) can become epidemic if nonimmune persons are present in large numbers (as in time of war or during pilgrimages), if the infectious agent is more virulent than usual, or if distribution of the disease is more easily effected. Cholera and plague, endemic in parts of Asia, can become epidemic under the above conditions, as can dysentery and many other infections. Epidemics may also be caused by new disease agents in the human population, such as the Ebola virus. A worldwide epidemic is known as a pandemic, e.g., the influenza pandemic of 1918 or the AIDS pandemic beginning in the 1980s. A disease is said to be sporadic when only a few cases occur here and there in a given region. Epidemic disease is controlled by various measures, depending on whether transmission is through respiratory droplets, food and water contaminated with intestinal wastes, insect vectors, or other means. The Centers for Disease Control and Prevention tracks epidemics in the United States.










[B][U]epilepsy[/U][/B]

epilepsy, a chronic disorder of cerebral function characterized by periodic convulsive seizures. There are many conditions that have epileptic seizures. Sudden discharge of excess electrical activity, which can be either generalized (involving many areas of cells in the brain) or focal, also known as partial (involving one area of cells in the brain), initiates the epileptic seizure. Generalized seizures are classified as tonic-clonic (grand mal), in which there is loss of consciousness and involuntary contraction of all the muscles of the body, lasting a few minutes; or absence (petit mal), in which there is clouding of the consciousness for about 1 to 30 sec and no falling, with as many as 100 attacks occurring daily. Partial seizures include Jacksonian epilepsy, characterized by jerking in the hand and face on the side opposite the brain activity; and psychomotor seizures, in which there may be localized convulsion with no loss of consciousness, as well as incoherent speech and various involuntary movements of the body. Often these are accompanied by a warning cluster of signs and symptoms called an aura.

The cause is unknown in over half the cases of epilepsy, especially in those with onset under age 20. Predisposing factors in other cases include familial history, head injury, alcohol withdrawal, infections (such as meningitis), and abnormalities (such as tumors) of the brain.

The recording of brain waves by electroencephalography is an important diagnostic test for epilepsy. Other diagnostic technologies include CAT scan and magnetic resonance imaging (MRI). Standard treatment of epilepsy is with anticonvulsive drugs, such as carbamazepine, phenytoin, and valproate; it requires a careful analysis of seizure motor activity, anatomical cause, precipitating factors, age of onset of the disorder, severity, daily rhythms, and prognosis. Some cases of childhood epilepsy (which is often eventually outgrown) have been successfully treated with surgery or a very high-fat “ketogenic” diet. The diet results in a natural buildup of ketones in the body, which appear to inhibit the seizures. First aid, such as cushioning the head, is used to prevent the person from self-inflicted injuries during seizures. With proper medication, most epileptics live normal lives. Repeated seizures that lead to unconsciousness, however, appear to be associated with damage to the hippocampus in the brain and sudden unexpected death.












[B][U]Epstein-Barr virus[/U][/B]

Epstein-Barr virus (EBV), herpesvirus that is the major cause of infectious mononucleosis and is associated with a number of cancers, particularly lymphomas in immunosuppressed persons, including persons with AIDS. Epstein-Barr is a ubiquitous virus, so common that it has been difficult to determine whether it is the cause of certain diseases or whether it is simply there as an artifact. In Third World nations, most children are infected with EBV; in most industrialized nations, about 50% of the people are infected. Research has found that all of the lymphomas associated with AIDS and most lymphomas in other immunocompromised persons are connected with latent EBV infection. EBV has been found in biopsy tissue of patients with Hodgkin's disease, breast cancer, and some smooth muscle tumors. EBV also was formerly suspected as the cause of chronic fatigue syndrome (originally named chronic EBV syndrome).













[B][U]erysipelas[/U][/B]

An acute infection of the skin characterized by a sharply demarcated, shiny red swelling, accompanied by high fever and a feeling of general illness. The causative agent is the hemolytic streptococcus, which often enters the body through a break in the skin. Erysipelas affects the skin of the face so frequently that when it strikes other parts of the body, it may often be misdiagnosed. Bacteremia (blood poisoning) and pneumonia are the most common complications. Erysipelas is a highly contagious disease that was formerly dangerous to life; however, it can now be quickly controlled by antibiotic therapy.









[B][U]erythema[/U][/B]

more or less diffuse redness of the skin due to concentration of an abnormally large amount of blood within the small vessels of the skin (hyperemia), as in burns. Erythema nodosum is often associated with systemic diseases such as tuberculosis and rheumatic fever. Tender, bright red, slightly elevated nodules develop along the shins. Erythema multiforme can have a number of causes, including viral and bacterial infection, chronic disease of the visceral organs, or allergic reactions to drugs.












[B][U]erythroblastosis fetalis[/U][/B]

hemolytic disease of a newborn infant caused by blood group incompatibility between mother and child. Although the Rh factor is responsible for the most severe cases of erythroblastosis fetalis, the disease may be produced by any of the other blood group antigens, such as those of the AOB system. With an Rh-negative mother and an Rh-positive father, the possibility exists that the fetus will be Rh positive. Microhemorrhages during gestation permit fetal red blood cells to enter the maternal circulation, causing an immunologic reaction that leads to sensitization of the mother against the Rh factor. Maternal antibodies against fetal red blood cell antigens pass through the placenta into the fetus, where an excessive destruction of fetal red blood cells occurs. When such hemolysis begins during pregnancy, stillbirth may result. While there is little danger of damage to the fetus during the first pregnancy, by the second pregnancy sufficient antibodies will have accumulated in the mother's bloodstream to cause increasing danger of hemolytic disease. The formation of maternal anti-Rh antibodies has been largely prevented in the United States by the injection of human immune globulin into the mother within 72 hours after delivery. This globulin contains antibodies against the Rh-positive fetal red blood cells, destroying them before the maternal bloodstream reacts by producing its own anti-Rh antibodies. Thus during the next pregnancy there will be few, if any, antibodies in the maternal bloodstream to destroy the fetal Rh-positive blood cells.

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[B][U]fainting[/U][/B]

temporary loss of consciousness caused by an insufficient supply of oxygen to the brain. It can be concurrent with any serious disease or condition, such as heart failure, hypertension (high blood pressure), arrhythmia, hemorrhage, injury to the brain or other organs, or poisoning. Less serious conditions can also cause fainting, e.g., fatigue, prolonged standing, getting up after long confinement to bed, pain, hunger, dehydration, anemia, or fright or other emotional disturbance. Loss of control of blood pressure can be detected with the tilt test. Such drugs as scopolamine, beta-blockers, and disopyrmide have been successful in restoring the integrity of the vascular system. Person aware of an oncoming fainting spell should sit down and lower their heads between their knees for a moment or two to increase the flow of oxygen to the brain. The already unconscious person should be placed in a supine position, preferably with the feet raised. If unconsciousness persists, cold water on the face or the inhalation of aromatic spirits of ammonia may be tried. Under no circumstances should any liquid or medication be forced down the throat of an unconscious person. Fainting for more than a few minutes requires medical attention. After regaining consciousness, the patient should remain recumbent for at least 10 minutes and arise gradually.








[B][U]farsightedness[/U][/B]

farsightedness or hyperopia,condition in which far objects can be seen easily but there is difficulty in near vision. It is caused by a defect of refraction in which the image is focused behind the retina of the eye rather than upon it, either because the eyeball is too short or because the refractive power of the lens is too weak. Presbyopia, a similarly faulty vision, is attributable to physiological changes in the lens brought on by age. Corrective eyeglasses with convex lenses compensate for the refractive errors.










[B][U]fatigue[/U][/B]

fatigue, in physiology, inability to perform reasonable and necessary physical or mental activity. When the metabolic reserves of the body are exhausted and the waste products increased, as for example after prolonged exertion, the body finds it difficult to continue its function and activity. The accumulation of lactic acid in muscle tissue and the depletion of glycogen (stored glucose) results in muscle fatigue. The contractile properties of muscle are reduced, and continued exertion is impossible unless the muscle is allowed to rest. In the normal body a period of rest permits redistribution of nutritive elements to the muscles and tissues and elimination of accumulated waste products; the body is then ready to resume activity. There are some persons in whom fatigue is a chronic state that does not necessarily result from activity or exertion. In some instances this abnormal fatigue may be associated with systemic disorders such as anemia, a deficiency of protein or oxygen in the blood, addiction to drugs, increased or decreased function of the endocrine glands, or kidney disease in which there is a large accumulation of waste products. If excessive fatigue occurs over a prolonged period, exhaustion (marked loss of vital and nervous power) may result. In most persons with chronic fatigue, however, the condition seems to be associated with bipolar disorder. Thorough medical and psychiatric examination may be required.










[B][U]fetal alcohol syndrome[/U][/B]

fetal alcohol syndrome (FAS), pattern of physical, developmental, and psychological abnormalities seen in babies born to mothers who consumed alcohol during pregnancy. The abnormalities include low birthweight, facial deformities, and mental retardation, and there appears to be an association with impulsive behavior, anxiousness, and an inability on the part of the affected children to understand the consequences of their actions. When some but not all of these abnormalities are present, they are referred to as fetal alcohol effects (FAE). FAE has been observed in children of mothers who drank as little as two drinks per week during pregnancy. FAS affects 1 to 2 babies per 1,000 born worldwide. Many require constant lifelong supervision and end up institutionalized because of dysfunction in the family. FAS was first defined as a syndrome in 1973, although it has been observed for centuries.










[B][U][COLOR="blue"]fever[/COLOR][/U][/B]

fever, elevation of body temperature above the normal level, which in humans is about 98°F (37°C) when measured orally. Fever is considered to be a symptom of a disorder rather than a disease in itself. Under normal conditions the heat that is generated by the burning of food by the body is dissipated through such processes as perspiration and breathing. It is believed that infectious disease, injury to the body tissues, and other conditions that cause fever somehow trigger a disturbance in the functioning of the hypothalamus, the center of temperature control in the body. The rise in temperature is thought to be one of the body's defenses against infection: it may kill bacteria that cause disease or it may increase the rate at which the body's defenses fight infection. The effects of fever on the body are weakness, exhaustion, and sometimes a depletion of body fluids through excessive perspiration. Extremely high fevers may cause convulsive reactions and eventual death. In addition to infectious diseases (such as pneumonia and tonsillitis), disorders of the brain, certain types of cancer, and severe heatstroke may cause fever. There are also cases of fever where the cause cannot be detected. Treatment includes increasing the intake of fluids and administering aspirin and other fever-reducing medications. Aspirin may be dangerous in fevers of children because of Reye's syndrome. However, primary treatment is directed at the underlying cause unless the fever is very high (above 104°F/40°C). Persons with such dangerously high fevers are sometimes sponged with cool water or immersed in cool baths.










[B][U]fistula[/U][/B]

It is an abnormal, usually ulcerous channellike formation between two internal organs or between an internal organ and the skin. It may follow a surgical procedure with improper healing, or it may be caused by injury, abscess, or infection with penetration deep enough to reach another organ or the skin. When open at only one end it is called an incomplete fistula or sinus. The most common sites of fistula are the rectum and the urinary organs, but almost any part of the body may be affected. Rectal fistulas are often associated with colitis, cancer, sexually transmitted diseases, and other disorders. Usually a fistula requires surgery. In horses an abscess on the withers from chafing and infection is termed a fistula.












[B][U]flat foot[/U][/B]

flat foot, condition of the human foot in which the entire sole rests on the ground when the person is standing. When the foot muscles are weakened or the ligaments are strained and stretched, the arch lowers, so that instead of the natural curved contour, there is flattening of the entire sole. Sometimes no discomfort accompanies flat foot. However, fallen arches may cause disalignment of other foot structures so that there is pain not only in the arch area but also in the calf muscles and sometimes as far up as the lower back; the discomfort is increased by prolonged standing. Flat foot may be inherited or may be caused by rickets, obesity, metabolic disorder, debilitating disease, or faulty footwear. Treatment and exercise directed by an orthopedic physician are sometimes advisable. Arch supports or other devices to be worn inside the shoe are often prescribed.











[B][U][COLOR="blue"]food poisoning[/COLOR][/U][/B]

food poisoning, acute illness following the eating of foods contaminated by bacteria, bacterial toxins, natural poisons, or harmful chemical substances. It was once customary to classify all such illnesses as “ptomaine poisoning,” but it was later discovered that ptomaines, the products of decayed protein, do not cause illness. The symptoms, in varying degree and combination, include abdominal pain, vomiting, diarrhea, headache, and prostration; more serious cases can result in permanent disability or death.



[B]Bacterial Food Poisoning[/B]

In general, the bacteria that cause food poisoning do not affect the appearance, aroma, or flavor of food. The most common bacterial causes of food poisoning are Salmonella (see salmonellosis), staphylococcus, Escherichia coli, Listeria monocytogenes, Shigella, and Campylobacter jejuni. The symptoms may be caused by toxins produced by the bacteria. The most serious type of food poisoning caused by bacterial toxins is botulism, which results from toxins made by the bacterium Clostridium botulinum.

Salmonella, most notoriously spread via raw eggs, develops from 6 to 72 hours after exposure. Symptoms include severe diarrhea, fever and chills, vomiting, and abdominal cramps and usually last from three to five days. Staphylococcal food poisoning is actually caused by the potent toxins that they produce. Typical sources are unrefrigerated ham, poultry, potato or egg salad, and custards. Carriers and food handlers with staphylococcal skin infections are mainly responsible for the spread of staphylococcus toxin poisoning. The onset of symptoms from such poisoning (similar to those of Salmonella infection) occurs abruptly one to six hours after ingestion of the polluted food. The illness lasts from 24 to 48 hours; fatalities are rare.

Infection with a particular strain of the usually harmless E. coli began to appear in food poisoning cases from the 1980s on, typically in raw or undercooked ground meat. Onset of symptoms comes one to eight days after eating the contaminated food. Symptoms include bloody diarrhea, nausea, and sporadic vomiting, with or without fever. It can progress to kidney failure and death, especially in children.

Listeriosis, caused by the bacterium Listeria monocytogenes, is spread in soft cheeses, undercooked meats, and prepared foods from delicatessen counters. Its onset is abrupt. Symptoms vary with the person's immune status and may include fever, muscle aches, fatigue, and nausea. The illness is especially serious for the very young or for pregnant women, who may miscarry or transmit blood infections or meningitis to the baby. In adults, the disease can progress to central nervous system complications, endocarditis, or pneumonia, and is an especially serious threat to the elderly.

Shigella is spread by contaminated food or from person to person (principally via a fecal-oral route). New strains of bacteria of the genus Shigella have been associated with food poisoning from ground meat. Symptoms include watery diarrhea, abdominal cramps, and bloody mucus in the stools.

Campylobacter enteritis is caused by either of two species of the Campylobacter bacterium. The bacterium is ubiquitous in uncooked poultry. Symptoms (diarrhea, fever, chills, headache) arise 2 to 11 days after exposure and last one to two weeks. Although usually mild, the infection can cause Guillain-Barré syndrome, a weakness of the peripheral nerves that can lead to paralysis and death.

Treatment for most bacterial food poisoning includes rest, sedation, and replacement of fluid loss if necessary. Antibiotics usually are used only in severe cases. Preventive measures in the home include thorough cooking and prompt refrigeration of meats and eggs, washing and peeling fruits and vegetables (and avoiding uncooked produce entirely if a person has a compromised immune system), washing of cooking surfaces and utensils that may have been contaminated by uncooked foods, and careful handwashing after use of the toilet.

Since the 1970s the number of food poisoning cases in the United States has gradually increased, and beginning in the 1980s more virulent organisms and more serious cases of food poisoning with complications leading to miscarriage, kidney failure, or death were observed. Some experts have attributed this to overprescription of antibiotics and the routine use of antibiotics as growth enhancers and to treat disease in livestock, practices that encourage the development of drug-resistant bacterial variants. An increase in the consumption of uncooked fresh produce has also contributed to the increase in food-borne illnesses. The increase in the number and severity of food poisoning cases have led to concern about food inspection and preparation methods, and to consideration of irradiating high-risk foods to eliminate bacterial contamination. More stringent meat inspection procedures were put in place by the U.S. Dept. of Agriculture in 1996 in response to some of these concerns, and the Food and Drug Administration approved the irradiation of meat. The vast majority of food poisoning cases, however, involve fruits and vegetables, seafood, cheese, and products, such as juices or deli salads, made with them.




[B]Food Poisoning by Natural Poisons and Metal[/B]

Nonbacterial food poisoning may occur after eating foods that contain a naturally occurring or acquired deleterious substance. Ingestion of poisonous mushrooms or toadstools (see mushroom poisoning) may be followed in a matter of several minutes to two hours by severe thirst, abdominal cramps, diarrhea, vomiting, sweating, dizziness, confusion, collapse, coma, and, occasionally, convulsions. Poisoning may occur also after the ingestion of immature or sprouting potatoes because of the presence of solanine, an alkaloid. Mussels and clams that have fed on poisonous plankton also are a cause of food poisoning, since the poisonous substance is not destroyed by cooking. Ergot poisoning, caused by ingestion of rye grain infected with that fungus, causes damage to the blood vessels and gangrene, as well as gastrointestinal and neurologic symptoms.

It is also possible to take into the body poisons such as arsenic, lead, or mercury via foods that have been accidentally contaminated or sprayed with preservatives and not properly cleansed before ingestion. Food stored in containers lined with cadmium has been known to cause poisoning. Typical symptoms of this sort of food poisoning (diarrhea, vomiting) may occur right away; the nervous system and respiratory systems may be affected with continued exposure.










[B][U][COLOR="blue"]fracture[/COLOR][/U][/B]

fracture, breaking of a bone. A simple fracture is one in which there is no contact of the broken bone with the outer air, i.e., the overlying tissues are intact. In a comminuted fracture the bone is splintered. In greenstick fracture (common in children) one side of the bone is fractured and the other side bent. In multiple fracture there is more than one break. A compound fracture is one in which the broken bone is in contact with the air because there is a wound through the skin; the bone may project through the wound. The bones of older people are especially liable to fracture, although no age is exempt. Fractures are caused most often by injury, although certain pathological conditions may predispose a bone to fracture. Osteoporosis, the leaching of calcium from the bone, can cause spontaneous fractures, as can malnutrition and cancer. A person with a fracture should not be moved unless the broken bone has been splinted or otherwise immobilized (see first aid). Proper setting of bones and the application of a cast should be performed by a doctor. X rays aid in the repositioning of the bone as well as in determining the state of healing. Surgery that involves implanting metal pins or screws to join broken bones may be necessary; in certain cases traction devices are used to align bone fragments. Skull and jaw fractures require special treatment.












[B][U]frostbite[/U][/B]

frostbite (chilblains), injury to the tissue caused by exposure to cold, usually affecting the extremities of the body, such as the hands, feet, ears, or nose. Extreme cold causes the small blood vessels in the extremities to constrict. The blood circulates more slowly and stagnation results. Eventually the body fluids may freeze. The condition is aggravated by tight clothing, physical inactivity, and dampness. Severe frostbite that is not treated may result in gangrene; amputation of the affected part may be necessary.








[B][U][COLOR="blue"]fungal infection[/COLOR][/U][/B]

fungal infection, infection caused by a fungus , some affecting animals, others plants.


[B]Fungal Infections of Human and Animals[/B]

Many fungal infections, or mycoses, of humans and animals affect only the outer layers of skin, and although they are sometimes difficult to cure, they are not considered dangerous. Athlete's foot and ringworm are among the common superficial fungal infections. Fungal infections of the mucous membranes are caused primarily by Candida albicans (see candidiasis). It usually affects the mouth and the vaginal and anal regions.

The fungi that affect the deeper layers of skin and internal organs are capable of causing serious, often fatal illness. Sporotrichosis is an infection of farmers, horticulturists, and others who come into contact with plants or mud. The disease affects the skin and lymphatic system and, in rare cases, becomes disseminated. Blastomycosis is caused by a yeastlike fungus that reproduces by budding. The North American variety, caused by Blastomycosis dermatitidis, occurs more often in men and seems to be limited to the central and E United States and Canada. Wartlike lesions appear most often on the skin, sometimes spreading to the bones and other organs. The South American variety of blastomycosis is caused by B. brasiliensis. Chytridiomycosis, caused by Batrachochytrium dendrobatidis, is a deadly fungal skin infection in amphibians, which it kills by damaging to the animals' normally permeable skin, thus disrupting the transport of air and moisture.

Among the fungi that infect the deeper tissues is Coccidioides immitis, which causes coccidioidomycosis, sometimes called valley fever, a lung infection that is prevalent in the SW United States. Cryptococcosis is another fungus disease that may be localized in the lung or disseminated, especially to the central nervous system. It has a worldwide distribution, affecting men twice as often as women. The causative agent (Cryptococcus neoformans) has been isolated in pigeon excretions. Histoplasmosis, which is caused by spores of the fungal genus Histoplasma, is a severe infection that shows varied symptoms. In acute cases ulcers of the pharynx and enlargement of the liver and spleen are present. In other forms tubercularlike lesions of the lung occur. In its benign form no symptoms may be present.

Fungal infections sometimes follow the use of antibiotics, which kill nonpathogenic as well as pathogenic bacteria, thereby providing a free field in the body for fungal invasion. Opportunistic fungal infection occurs when a fungus enters a compromised host, as in the case of such diseases as AIDS. Treatment for fungal infections includes systemic antifungal agents, such as amphotericin B, fluconazole, and itraconazole, and agents usually used topically, such as clotrimazole (Lotrimin) and miconazole (Monistat).




[B]Fungal Infections of Plants[/B]

Serious damage is done to crops each year by fungal infections of plants such as smuts, rusts, ergots, and mildews. Dutch elm disease, a disease that has seriously depleted the number of elm trees in the United States, is caused by the fungus Ceratostomella ulmi. Such diseases are usually fought with fungicides or by developing resistant plants.

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[B][U]galactosemia[/U][/B]

An inherited metabolic disorder caused by an enzyme deficiency and transmitted as a recessive trait; it results in the accumulation of the sugar galactose in the body. The disorder is manifested soon after birth by feeding problems and diarrhea. Galactose is accumulated principally in the liver of the newborn infant, where it may induce cirrhosis, and in the lens of the eye, where cataracts may develop. Low glucose levels cause sufficient hypoglycemia to affect the central nervous system with resulting mental retardation. These ill effects can be prevented by removing milk and all other foods containing galactose and lactose from the diet.







[B][U]gangrene[/U][/B]

gangrene, local death of body tissue. Dry gangrene, the most common form, follows a disturbance of the blood supply to the tissues, e.g., in diabetes, arteriosclerosis, thrombosis, or destruction of tissue by injury. A second type, moist gangrene, results from an invasion of toxin-producing bacteria that destroy tissue. Gangrene usually affects an arm or leg, but it may occur anywhere, e.g., pulmonary gangrene may follow an abscess of the lung. Treatment of gangrene includes rest and the administration of antibiotics if the gangrene is moist and bacterial invasion is present. Excision of the diseased portions of the body may be necessary and, in advanced involvement, amputation of the part. In gas gangrene, which results from the invasion of wounds by anaerobic bacteria, gas forms under the skin and a watery exudate is produced. Emergency treatment with penicillin and antitoxin is needed; without treatment, gas gangrene is invariably fatal.











[B][U]Gaucher's disease[/U][/B]

The rare genetic disease involving a deficiency of an enzyme, glucocerebrosidase, which normally breaks down certain body glycolipids (i.e., lipids (fats) that have a sugar molecule attached). There are three types of the disease. In all three types, the enzyme deficiency results in a buildup of the glycolipid glucocerebroside in the bone marrow, liver, and spleen, resulting in anemia and other blood disorders, bone pain and pathologic fractures, and enlarged liver and spleen. In Type II, the central nervous system is also affected. Patients are severely mentally retarded and have difficulty controlling their muscles. The disease progresses quickly from birth and usually is fatal by the age of two. In Type III disease, the course is chronic and central nervous system involvement begins later on. The symptoms are the same as those of Type II. Type I disease occurs most often in Ashkenazi Jews of Eastern European origin, Type III in people of Swedish origin.

There is no cure for Gaucher's disease, but in 1991 an enzyme replacement drug, Ceridase, was approved and allowed people with Type I disease (the most common) to live nearly normal lives. Ceridase was extracted from human placental tissue in very small amounts and the supply was limited. In 1994, a genetically engineered version of the drug (Cerezyme) was introduced. Both were developed as orphan drugs and were controversial because of their costliness.











[B][U]giardiasis[/U][/B]

An infection of the small intestine by a protozoan, Giardia lamblia. Giardia, which was named after Alfred M. Giard, a French biologist, is spread via the fecal-oral route, most commonly by eating food contaminated by the unwashed hands of an infected person or by drinking groundwater polluted by the feces of infected animals such as dogs and beavers (hence the nickname “beaver fever”). It attaches itself to the walls of the small intestine and there multiplies quickly. About two thirds of infected individuals develop no symptoms. Symptoms, when present, occur one to three days after infection and consist of diarrhea, flatulence, and abdominal cramps, often accompanied by weight loss. In some cases the infection becomes chronic. Giardiasis has traditionally been considered a tropical disease, but it is becoming more common in developed countries, especially among gay men and among groups of very young children in close contact with each other, as in day-care centers before toilet training and proper handwashing techniques have been mastered. Diagnosis is by direct microscopic examination of the stool or by testing for antibodies to the parasite. In most cases no treatment is necessary. The drugs metronidazole, tinidazole, and nitazoxanide are sometimes prescribed.











[B][U]gigantism[/U][/B]

gigantism, condition in which an animal or plant is far greater than normal in size. Plants are often deliberately bred to increase their size. However, among animals, gigantism is usually the result of hereditary and glandular disturbance. Among humans, gigantism is produced by an oversecretion of growth hormones by the acidophilic cells in the anterior lobe of the pituitary, causing excessive growth of all the tissues of the body. The metabolic rate is usually at least 20% above normal, which could be caused by an excess of the growth hormone alone, or oversecretion of the thyroid hormone in addition. Usually hyperglycemia (overactivity of the insulin-producing cells of the pancreas) is present. This condition eventually leads to degeneration of the islet cells, causing diabetes. Because of these metabolic abnormalities, the life expectancy of a giant is considerably less than normal. The treatment for gigantism is usually irradiation of the pituitary. The excessive height of the pituitary giant, which is defined at various levels above 7 ft (213 cm), is caused by excessive growth of the long bones. However, if the pituitary becomes overactive after growth is complete (marked by closure of the epiphyses of the long bones), the condition known as acromegaly results. Giants appear in the legends and folklore of many cultures.












[B][U]gingivitis[/U][/B]

inflammation of the gums. It may be acute, subacute, chronic, or recurrent. The gums usually become red, swollen, and spongy, and bleed easily. Chronic gingivitis is the usual form, resulting from irritating bacteria or debris, food impaction, or poor dental restoration. It can also accompany vitamin C deficiency or metabolic disturbances such as diabetes. If left untreated, it can lead to the more serious pyorrhea, with gum destruction and loosening of teeth. Trench mouth, an ulcerative infection of the gums and mouth, is sometimes referred to as a form of gingivitis.












[B][U]glaucoma[/U][/B]

ocular disorder characterized by pressure within the eyeball caused by an excessive amount of aqueous humor (the fluid substance filling the eyeball). This causes pressure against the optic nerve and compression of the blood vessels of the eye—the resulting impairment of vision ranges from slight abnormalities to total blindness. Chronic open-angle glaucoma is the result of impeded drainage of aqueous humor. In acute angle-closure glaucoma, the anterior chamber of the eye is shallower and the iris may obstruct the meshwork at the entrance of the canal of Schlemm. Although glaucoma is a leading cause of blindness in the United States, with timely treatment blindness is almost always avoided.

Chronic glaucoma begins gradually over a period of months or years, usually in patients over the age of 40. There are no symptoms in the early stages, and the condition can be detected only by measurement of the intraocular pressure. Such an examination is recommended every three years for all persons over the age of 20. As the disease progresses, often the only symptom is a gradual loss of peripheral vision. Chronic glaucoma can usually be controlled with eye drops or pills that increase the outflow or decrease the production of aqueous humor; laser treatment is also effective in the early stages. If treatment is continued throughout life, useful vision will be preserved in most cases; untreated individuals will gradually become blind.

Acute closed-angle glaucoma, which accounts for only 10% of the incidence of the disease, begins abruptly with severe pain and blurred vision. It is a medical emergency that causes permanent blindness in two to five days if left untreated. Surgery is usually necessary.











[B][U]gonorrhea[/U][/B]

common infectious disease caused by a bacterium (Neisseria gonorrhoeae), involving chiefly the mucous membranes of the genitourinary tract. It may occasionally spread to membranes in other parts of the body, especially those of the joints and the eyes. Since the principal mode of transmission is sexual contact, gonorrhea is classified as a sexually transmitted disease. Gonorrheal conjunctivitis was once a prominent cause of blindness in the newborn, the infection being transmitted during delivery. Routine use of silver nitrate solution in the eyes of every infant at birth has largely overcome this problem.

The usual site of infection in women is the cervix. From there it can spread to the uterus and fallopian tubes and cause pelvic inflammatory disease, ectopic pregnancy, or infertility. Other complications, in both sexes, include infection of the joints, heart valves, and brain. Women are often asymptomatic, but may have a vaginal discharge or burning sensation on urination; men may have a discharge from the penis and pain on urination. Examination of the discharge reveals the presence of the bacteria. In most cases, the disease can be cured by adequate treatment with a fluoroquinolone or cephalosporin antibiotic such as ciprofloxacin or ceftriaxone. Failure of treatment is usually due to resistant strains. Prior infection does not confer resistance and reinfection is common.















[B][U]gooseflesh[/U][/B]

gooseflesh, temporary rumpling of the skin into tiny bumps, also called goose bumps and goose pimples, and technically known as cutis ansirina. In response to cold or certain emotional states, such as fear or rage, the smooth muscles of the subsurface layer (dermis) of skin tend to contract, causing the skin to pucker and body hair to stand erect. In furred animals this can serve a dual purpose. Erection of the fur may make an animal seem larger than it actually is and act to frighten away a potential aggressor. Second, the erect fur traps a blanket of air close to the skin thus providing the organism with additional insulation against loss of body heat. In humans, this response would seem to be vestigial.












[B][U]gout[/U][/B]

The condition that manifests itself as recurrent attacks of acute arthritis, which may become chronic and deforming. It results from deposits of uric acid crystals in connective tissue or joints. The presence of increased uric acid (a breakdown product of DNA) in the body distinguishes gout from other forms of arthritis, although hyperuricemia alone, which often occurs in the complete absence of gout, is not thought to be the sole causative factor. About 95% of patients with this disorder are men, usually over 30. Gout is associated with obesity and a hereditary factor in some cases. Diet also has an affect on gout. Consumption of meat and seafood, which are high in purine (from which digestion produces uric acid), increase the risk of gout, and gout is worsened by kidney problems and drinking alcoholic beverages, which slow the excretion of uric acid. Beer, which is higher than other alcoholic beverages in purines, also has been shown to increase the risk of gout.

Gout usually begins with an acute attack of pain, inflammation, extreme tenderness, and redness in the affected joint—often the big toe and sometimes the ankle or knee. After repeated attacks the disease can cause the deposition of sodium urate crystals in the tissues about the joints, causing stiffness and deformity. The aim of treatment is to minimize the formation of uric acid crystals. A high liquid intake that increases daily urine output is usually recommended. An acute attack of gout is usually treated with nonsteroidal anti-inflammatory drugs, such as indomethecine or naproxen, or the corticosteroid prednisone. Colchicine, a preparation of the meadow saffron, used since 1763 for gout, is still used when symptoms are not controlled by other drugs.













[B][U]Gulf War syndrome[/U][/B]

Gulf War syndrome, popular name for a variety of ailments experienced by veterans after the Persian Gulf War. Symptoms reported include nausea, cramps, rashes, short-term memory loss, fatigue, difficulty in breathing, headaches, joint and muscle pain, and birth defects. Ailments have been reported by American, Canadian, Australian, and British veterans alike; in some cases spouses of veterans have reported similar symptoms. The mysterious syndrome has sparked debate between veteran's groups, Senate investigators, and the military over questions of accountability, treatment, and compensation. Hypothesized causes include parasites, biological and chemical warfare agents, prophylactic vaccines and medications given against biological and chemical warfare agents, fumes from oil well fires, and stress. In 1994 an advisory panel organized by the National Institutes of Health reported that the syndrome represented many illnesses and many causes; they deemed biological and chemical warfare agents unlikely as causes. Causes for the illnesses in many subsets of patients have been identified, e.g., some 30 veterans had leishmaniasis, a parasitic disease spread by sand flies, but in many instances the cause has not been identified. In 1999 researchers said that brain scans of some sick veterans revealed signs of damage caused by exposure to toxic chemicals. A study in 2004 suggested that some veterans may have been sensitive enough to otherwise low levels of poison gases to cause symptons associated with the syndrome. Some medical historians have pointed out that syndromes of undiagnosable diseases have occurred after other wars, including World Wars I and II and the American Civil War.

[B][CENTER][SIZE="6"]H[/SIZE][/CENTER][/B]




[B][U]halitosis[/U][/B]

An unpleasant odor carried on the breath. It is usually the result of gum disorder, tooth decay, smoking, indulgence in aromatic foods, or a mild digestive upset. Known commonly as bad breath, halitosis may also be indicative of lung or sinus infection, uremia, or cirrhosis of the liver. The minty odor of acetone on the breath is a symptom of diabetes mellitus. Successful treatment of halitosis consists of eliminating or controlling the underlying cause. Proper diet and dental hygiene are often helpful. Mouthwashes and scented toothpastes mask the condition but do not alleviate it. A physician should be consulted for persistent cases of halitosis.










[B][U]hantavirus[/U][/B]

any of a genus (Hantavirus) of single-stranded RNA viruses that are carried by rodents and transmitted to humans when they inhale vapors from contaminated rodent urine, saliva, or feces. There are many strains of hantavirus. The first to be isolated (1976) was the Hantaan virus (from the Han River in South Korea, which also gives the species its name). Hantaan virus and its related strains, Seoul virus and Puulmala virus, cause Korean hemorrhagic fever (more correctly, “hemorrhagic fever with renal syndrome”), a condition in which the capillaries of the circulatory system begin to leak blood. Although some people with the disease are nearly asymptomatic, in others it can lead to shock, acute kidney failure, and, in 10% of cases, death.

A second disease, hantavirus pulmonary syndrome, was identified in the United States in 1993 and is caused by at least three strains of the virus. It is known to be carried by deer mice, white-footed mice, and cotton rats. This disease is much more deadly, causing flulike symptoms that can lead to fluid accumulation in the lungs and death. One of the pulmonary strains, the Sin Nombre virus (named for a Spanish massacre of Native Americans that occurred in the canyon where it was discovered), was the cause of a 1993 outbreak in the Four Corners area of the SW United States that killed 32 of 53 people known to have been infected. Sporadic occurrences of hantavirus pulmonary syndrome still occur in North America. Outbreaks of a hantavirus strain that apparently can be spread from person to person occurred in South America in 1996 and 1997. There is no vaccination for pulmonary hantavirus. Treatment includes respiratory and hemodynamic support; the antiviral drug ribavirin has been effective in some cases.













[B][U]harelip[/U][/B]

A congenital abnormality in which there is a cleft or split in the upper lip. There may be a single opening in the middle portion of the lip or an opening on each side. The condition frequently occurs along with a cleft palate, an opening in the roof of the mouth. Harelip is usually corrected by plastic surgery soon after birth.










[B][U]hay fever[/U][/B]

A seasonal allergy causing inflammation of the mucous membranes of the nose and eyes. It is characterized by itching about the eyes and nose, sneezing, a profuse watery nasal discharge, and tearing of the eyes. The cause is a sensitivity to one or more species of pollens or fungi. In addition, many patients with hay fever develop other allergic conditions, e.g., asthma and sinusitis. In the spring, hay fever may be caused by tree pollens (oak, elm, maple); in summer, by grass pollens, wheat or corn rusts, or fungus spores; in late summer and fall, by ragweed pollen, which is the most common cause. Temporary relief of symptoms may be obtained from antihistamines and decongestants, such as ephedrine. Physicians may resort to corticosteroids in severe cases. Sometimes desensitization measures are taken, consisting of repeated injections of small amounts of the allergen (pollen) until its presence produces no symptoms; however, the treatment must be continued from year to year, since immunity is not permanent. Some relief can be obtained by removing pollen from the air by air conditioners and filters.











[B][U]heartburn[/U][/B]

The burning sensation beneath the breastbone, also called pyrosis. Heartburn does not indicate heart malfunction but results from nervous tension or overindulgence in food or drink. The sensation is produced by spasmodic constrictions of the esophagus accompanied or occasioned by regurgitation of stomach acids, which spread upward into the throat, and may result in belching or vomiting. Physical activity immediately following ingestion of food may exaggerate symptoms.

The discomfort can usually be relieved by taking alkaline preparations to counteract the excessive acidity (see antacid). Proper dietary habits, e.g., eating slowly, avoiding spicy foods, and a period of physical inactivity after eating, may prevent heartburn. Sometimes the condition is symptomatic of a disease of the digestive system, such as a stomach ulcer or gall bladder disorder.

Chronic heartburn, known as gastroesophageal reflux disease (GERD) increases the risk of esophageal cancer. Persistent recurrence should be called to the attention of a physician, and is often treated with drugs such as the H2-blockers ranitidine (Zantac), famotidine (Pepcid), and cimetidine (Tagamet) and the proton pump inhibitor omeprazole (Prilosec). Surgery in which the upper dome-shaped portion of the stomach is sutured around the lower esophagus to increase the pressure on the esophogeal side of the sphincter and prevent reflux is also used to treat GERD.










[COLOR="blue"][B][U]heart disease[/U][/B][/COLOR]

any of several abnormalities of the heart and its function in maintaining blood circulation. Heart disease is the cause of approximately half the deaths in the United States each year. Among the most common causes of heart disease are degenerative changes in the coronary blood vessels, infectious diseases, and congenital heart disease. Congenital defects result from abnormal development of the fetal heart, commonly in the valves or septa. Such defects can be precipitated by environmental conditions in the uterus, such as the presence of the rubella virus, or they can be inherited. Infectious diseases acquired after birth, such as rheumatic fever, syphilis, and endocarditis, can also damage the valves of the heart. In addition, the heart muscle itself can be affected: hypertensive heart disease (see hypertension) can cause it to enlarge, and it can become inflamed by rheumatic fever. Arteriosclerotic depositions in the coronary arteries result in the narrowing of these vessels, causing insufficient blood flow and oxygen to the heart muscle, a condition known as coronary artery disease. The characteristic radiating chest pain, angina pectoris, is the most prominent symptom of this condition. Coronary arteries already narrowed by arteriosclerosis are made susceptible to blockage by a clot (coronary thrombosis), causing the death of the heart muscle supplied by the affected artery, a life-threatening event called a myocardial infarction, or heart attack. Hypertensive, coronary, congenital, and other forms of cardiovascular disease, either singly or in combination, can lead to a state in which the heart is unable to expel sufficient blood for the metabolic demands of the body, ultimately resulting in congestive heart failure. Disturbances in the normal heartbeat, called arrhythmias, can occur by themselves or in conjunction with other heart problems, for example infarction affecting the area of the heart that controls the heartbeat.













[B][U]heat exhaustion[/U][/B]

The condition caused by overexposure to sunlight or another heat source and resulting in dehydration and salt depletion, also known as heat prostration. The symptoms are severe headaches, weakness, dizziness, blurred vision, and sometimes unconsciousness. However, the body temperature is not elevated as in heatstroke. The condition is usually temporary and rarely fatal. Water, mineral, and ion depletion may be so severe that painful spasms of the muscles, commonly called heat cramps, occur. Treatment includes administering a supplemental solution to replace the water, minerals, and ions that have been depleted from the body.












[B][U]heatstroke[/U][/B]

A profound disturbance of the heat-regulating mechanism of the body, also known as sunstroke. It is characterized by extremely high body temperatures and sometimes by convulsions and coma. The skin is usually hot and dry because the body-cooling process of sweating has ceased. In some cases, however, the skin may feel relatively cool because blood vessels just below the skin have constricted and the overheated blood is not being carried to the surface; an actively exercising person with heatstroke may be sweating freely. Heatstroke is a rare disorder and is more common among elderly and obese people and those with debilitating diseases. Heatstroke, unlike heat exhaustion, is considered a serious threat to life; treatment must be swift to prevent death or serious brain damage from high body temperature. The body should be cooled as quickly as possible by removing the patient to a cool shady place and applying cold water or ice water to the skin.













[B][U]hemolysis[/U][/B]

The destruction of red blood cells in the bloodstream. Although new red blood cells, or erythrocytes, are continuously created and old ones destroyed, an excessive rate of destruction sometimes occurs. The dead cells, in sufficiently large numbers, overwhelm the organ that destroys them, the spleen, so that serum pigments resulting from hemoglobin breakdown appear in the blood serum. Jaundice is caused by overloading the liver with pigment. Large-scale destruction of red blood cells, from any of a variety of causes, results in anemia. Rh disease, or erythroblastosis fetalis, is a hemolytic disease of newborns caused by an immune reaction between fetal red blood cells and maternal antibodies to them. Some hemolytic conditions, e.g., those in which red blood cells are fragile and rupture easily, are treated by removal of the spleen to slow cell breakdown or by administration of steroids. Autoimmune hemolytic conditions result from splenomegaly. The spleen not only sequesters red blood cells, but produces antibodies against the body's red blood cells. This is a potentially lethal condition that occurs more often in women than men.






[B][U]hemophilia[/U][/B]

A genetic disease in which the clotting ability of the blood is impaired and excessive bleeding results. The disease is transmitted through females but almost invariably affects male offspring only. A male born to a carrier mother has a 50% chance of having the disease. A hemophiliac cannot pass the disease to his sons, but all his daughters will be carriers. There are two diseases usually classified as hemophilia: hemophilia A (classical hemophilia, or Factor VIII deficiency) and hemophilia B (Christmas disease, or Factor IX deficiency).











[COLOR="blue"][B][U]hemorrhage[/U][/B][/COLOR]

The escape of blood from the circulation (arteries, veins, capillaries) to the internal or external tissues. The term is usually applied to a loss of blood that is copious enough to threaten health or life. Slow bleeding may lead to anemia, while the sudden loss of a large amount of blood may cause shock. Hemorrhage from a cerebral artery can be fatal because of interference with brain function. Many diseases and disorders (e.g., hemophilia, hemorrhagic fevers, hemorrhoids, peptic ulcer, scurvy, tuberculosis, and typhoid fever) as well as childbirth and many injuries can give rise to hemorrhage. Internal hemorrhage may require surgical intervention.










[COLOR="blue"][B][U]hemorrhagic fever[/U][/B][/COLOR]

any of a group of viral diseases characterized by sudden onset, muscle and joint pain, fever, bleeding, and shock from loss of blood. Bleeding occurs in the form of leakage from capillaries in the internal organs and the skin and mucous membranes. The causative viruses may be transmitted to humans by insects, ticks, or rodents, but in the case of the African hemorrhagic fevers, Ebola and Marburg, the animal carrier is unknown. In addition to Ebola and Marburg, well-known hemorrhagic fevers include hantavirus, Lassa fever, yellow fever, and a severe form of dengue called dengue hemorrhagic fever.


Ebola and Marburg are closely related, newly emergent viruses that have in recent years caused epidemics in central Africa, with very high rates of mortality. Hantavirus occurs in many different parts of the world and is spread to humans from field rodents via microscopic bits of their excretions that get into the air and are inhaled. It was originally known as a disease of Asia and Europe that primarily attacked the kidneys, but a more deadly pulmonary form of hantavirus infection has more recently caused numerous fatalities in the United States, Chile, and other countries. Lassa fever, also spread to humans from rodent excretions, occurs primarily in W Africa. Closely related to the Lassa virus are the Junin and Machupo viruses, which have caused outbreaks of hemorrhagic fever in South America. Yellow fever, transmitted by the bite of a mosquito, still occurs in tropical areas despite largely successful control efforts. Dengue hemorrhagic fever, also spread by mosquitoes, has in recent years caused many fatalities among children in tropical countries.

There is usually no specific treatment to combat the viruses that cause hemorrhagic fevers. An exception is the drug ribavirin, which has been effective in treating Lassa fever. Treatment generally consists of such supportive measures as the replacement of lost blood, the maintainence of fluid balance, and the alleviation of symptoms. Survival depends largely upon the virulence of the virus strain and the quality of treatment.










[B][U]hemorrhoids[/U][/B]

hemorrhoids Or piles,dilatations of the veins about the anus (external hemorrhoids) or those higher up inside it (internal hemorrhoids). They appear as small, rounded, purplish tumors, often complicated by inflammation, clotting, and bleeding. Hemorrhoids are very common phenomena and are brought about by factors that produce venous congestion, such as constipation, diarrhea, or pregnancy. In some instances, the pain from inflamed hemorrhoids can be intense, and the bleeding so profuse as to pose the threat of anemia. Hemorrhoids that are uncomplicated or bleed only slightly at infrequent intervals do not require specific treatment except to improve the condition that may be causing them, such as constipation. Hemorrhoids that are very painful or bleed excessively are treated by warm baths and suppositories and, if necessary, by injection, laser surgery, or traditional surgery.









[COLOR="blue"]to be continued[/COLOR]

[COLOR="blue"][B][U]hepatitis[/U][/B][/COLOR]

It is an inflammation of the liver. There are many types of hepatitis. Causes include viruses, toxic chemicals, alcohol consumption, parasites and bacteria, and certain drugs. Symptoms of hepatitis are nausea, fever, weakness, loss of appetite, sudden distaste for tobacco smoking, and jaundice.

A number of viruses can cause acute viral hepatitis. Five have been identified and named hepatitis A through E. At least 10 other viruses are under study. Hepatitis A,. also called infectious hepatitis, occurs sporadically or in epidemics, the virus being present in feces and transmittable via contaminated food (e.g., food prepared by an infected person with unwashed hands or fresh food washed or grown with contaminated water) or water. A person with active infection can spread it by physical contact. The disease usually resolves on its own. Exposed persons can be protected by injections of gamma globulin. A vaccine was made available in 1995 and is recommended for children at risk for the virus.

[B]Hepatitis B[/B],. also called serum hepatitis, was commonly transmitted through blood transfusions until the 1970s, when screening tests were introduced. Intravenous-drug abusers remain a high-risk group because of the sharing of needles. It is also spread by sexual transmission and from mother to baby at birth. Some infected individuals, particularly children, become chronic carriers of the virus. Hepatitis B can progress to chronic liver disease and is associated with an increased risk of developing liver cancer. A vaccine, available since 1981, is recommended for all infants and others at risk for the virus. Alpha-interferon was approved as a treatment in 1992.

[B]Hepatitis C[/B],. formerly called non-A, non-B hepatitis, is also transmitted by contaminated blood transfusions and by sharing of needles among drug abusers, although in many cases no source can be identified. It is the most common form of chronic liver disease in the United States. Many of those infected have no symptoms but become carriers, and the virus may eventually cause liver damage. Blood banks routinely screen for hepatitis C. Alpha-interferon is used also to treat hepatitis C, in combination with the drug ribavirin.

[B]Hepatitis D[/B],. or delta hepatitis, affects only people with hepatitis B; those infected with both viruses tend to have more severe symptoms. Hepatitis E. is spread by consuming feces-contaminated food or water. It is common in Mexico, Africa, and Asia and is especially serious in pregnant women.

Hepatitis can be incurred as a complication of several other disorders in addition to viral infection, among them amebic dysentery, cirrhosis of the liver, and mononucleosis. Also, alcohol, carbon tetrachloride, some tranquilizers and antibiotics, and many other substances can produce a toxic reaction in the liver, resulting in toxic hepatitis.








[COLOR="blue"][B][U]hernia[/U][/B][/COLOR]

The protrusion of an internal organ or part of an organ through the wall of a body cavity. The hernia is enclosed by a sac formed by the lining of the cavity. It results from a weakness or rupture in the wall, usually where there is already a natural weakness. A hernia may be present at birth or acquired later in life after heavy strain on the musculature. Structurally weak points, e.g., where various blood vessels, nerves, and ducts enter or leave a body cavity, occur in areas such as the lower abdomen, the diaphragm, and the region around the navel. If the protruding structure is caught in the muscular aperture of the wall, the result is a strangulation of the part, or an incarcerated hernia. Prompt medical attention must be received or loss of blood and eventual gangrene may result. A small hernia usually bulges spontaneously under exercise and strain and recedes into the cavity when the subject relaxes. A truss or external pad held against the weak spot may be used to control a hernia. However, surgery is usually recommended, even for a mild hernia, since it may eventually enlarge.












[B][U]herpes simplex[/U][/B]

an acute viral infection of the skin characterized by one or more painful, itching blisters filled with clear fluid. It is caused by either of two herpes simplex viruses: Type 1, herpes labialis, which generally involves the lip (producing what are commonly known as cold sores) or the mouth area (producing canker sores), but can involve the genital area; and Type 2, herpes genitalis, which involves the genitals, but may involve the mouth. It is believed that invasion of Type 1 herpes occurs in most persons during infancy and childhood, either as a systemic or severe local infection. Type 2 herpes, or genital herpes, is a sexually transmitted disease that became epidemic in the United States in the late 1960s. Newborns exposed to active herpes in the mother's birth canal can contract a serious form of the disease. The herpes simplex virus can be spread by an infected but asymptomatic person.

Outbreaks of both types of herpes simplex alternate with periods when the virus lies dormant in the nerve cells. The reappearance of blisters may be triggered by such factors as fever, infectious diseases, exposure to sunlight, menstruation, or pregnancy. The blisters usually last from 10 to 14 days. Treatment for recurrent herpes includes elimination of the precipitating conditions, local antibiotic treatment to prevent bacterial infection, and treatment with antiviral drugs such as acyclovir, although some resistant strains have developed. There is no cure. The herpes simplex virus is also the cause of a form of viral encephalitis.











[B][U]herpesvirus[/U][/B]

any of the family (Herpesviridae) of common DNA-containing viruses, many of which are associated with human disease.









[B][U]herpes zoster[/U][/B]

An infection of a ganglion (nerve center) with severe pain and a blisterlike eruption in the area of the nerve distribution, a condition called shingles. The causative organism is varicella zoster, a common, filtrable virus that is also known to cause chicken pox. Herpes zoster usually affects persons past middle life. It most often involves the area of the upper abdomen and lower chest, but may appear along other nerve pathways including that leading to the eye; serious ocular complications can lead to blindness. The disease can be treated with antivirals, and aspirin and other analgesics are used to relieve pain. Although it is generally nonrecurrent, it can permanently damage nerves and lead to postherpetic neuralgia, whose often severe, persistent pain is more difficult to control.











[COLOR="blue"][B][U]HIV[/U][/B][/COLOR]

HIV (Human Immunodeficiency Virus), either of two closely related retroviruses that invade T-helper lymphocytes and are responsible for AIDS. There are two types of HIV: HIV-1 and HIV-2. HIV-1 is responsible for the vast majority of AIDS in the United States. HIV-2, seen more often in western Africa, has a slower course than HIV-1. There are many strains of both types and the virus mutates rapidly, a trait that has made it especially difficult for researchers to find an effective treatment or vaccine. In many cases, a person's immune system will fight off the invasion of HIV for many years, producing billions of CD4 cells daily, always trying to keep up with the HIV's mutations, before it succumbs and permits the well-known signs of AIDS to develop.

HIV is especially lethal because it attacks the very immune system cells (variously called T4, CD4, or T-helper lymphocytes) that would ordinarily fight off such a viral infection. Receptors on these cells appear to enable the viral RNA to enter the cell. As with all retroviruses, once the RNA is inside the cell, an enzyme called reverse transcriptase allows it to act as the template for its own RNA to DNA transcription. The resultant viral DNA inserts itself into a cell's DNA and is reproduced along with the cell and its daughters.

The exact origin of the virus in humans is unclear. Scientists surmise that it jumped from an animal population, probably African monkeys or chimpanzees, to humans via a bite or meat. The first case documented in humans dates from 1959. The virus was isolated by Luc Montagnier of France's Pasteur Institute in 1983. It went through several name changes before the official name, human immunodeficiency virus, was agreed upon.














[B][U]hives[/U][/B]

hives (urticaria), rash consisting of blotches or localized swellings (wheals) of the skin, caused by an allergic reaction. The swelling is caused by distention of the skin capillaries and escape of serum and white cells into the skin and tissues. Hives are usually extremely itchy, and they may occur in a small area or cover virtually the entire body. The allergic reaction is commonly to a food or a drug, although injections of serum, insect bites, inhalants (pollen), and physical factors (cold, light, heat) may also be causative. Usually crops of hives come and go, remaining at one site for several hours and then reappearing at another; commonly an acute attack subsides spontaneously in a week or two. However, chronic cases of hives may last for long periods of time. Antihistamines and cortisone are considered helpful in relieving the itching and reducing the swelling.











[COLOR="blue"][B][U]Hodgkin's disease[/U][/B][/COLOR]

Hodgkin's disease, a type of cancer of the lymphatic system. First identified in 1832 in England by Thomas Hodgkin, it is a type of malignant lymphoma. Incidence peaks in young adults and the elderly. There is some evidence that it is caused by an infection (the Epstein-Barr virus is sometimes present), and studies of twins suggest a hereditary susceptibility. In addition, exposure to the defoliant, Agent Orange, has been strongly linked to Hodgkin's disease and other lymphomas.

The first sign is often enlarged lymph nodes in the neck or armpit. Lymph node biopsy shows the multinucleated Reed-Sternberg cells peculiar to the disease. It spreads from node to node in an orderly fashion. Symptoms include itching, fever, night sweats, and weight loss. Because it affects the lymphatic system, the body becomes less able to fight off infection as the disease progresses. Radiation therapy and combinations of chemotherapeutic agents are used in treatment. By the 1990s most newly diagnosed cases were curable.












[B][U]hookworm[/U][/B]

any of a number of bloodsucking nematodes in the phylum Nematoda, order Strongiloidae that live as parasites in humans and other mammals and attach themselves to the host's intestines by means of hooks. Hookworm infection in humans is caused by infestation with Ancylostoma duodenale (the European species) or with Necator americanus (the American species). It is found in tropical and subtropical climates, especially where the inhabitants do not wear shoes or stockings and where the soil is contaminated by human excrement. The larva of the hookworm, living in moist soil or mud, easily penetrates the exposed skin, usually the sole of the foot, and is then carried by the blood to the lungs. An early sign of hookworm infestation is a dermatitis at the site of entry, known as ground itch. As the larva passes through the lungs, it causes episodes of coughing with bloody sputum. Raised with the mucus into the mouth, the larva is then swallowed. It may also be swallowed with polluted drinking water or with unclean vegetables eaten raw. By means of its hooks the larva attaches itself to the upper portion of the small intestine, where it nourishes itself on the blood of its host. The larva matures and the female produces eggs, as many as 30,000 per day, that are passed from the intestine with the feces, usually to contaminate the soil still further. The drain on the blood of the host results in anemia. This, together with the resulting abdominal pain and diarrhea, causes general debility. Hookworm is treated with drugs, notably tetrachloroethylene, that loosen and destroy the parasite, as well as with specifics for the anemia and abdominal symptoms. Incidence of this disease, which was once seriously prevalent, has been much reduced by improved sanitation and the wearing of shoes.








[B][U]human papillomavirus[/U][/B]

human papillomavirus (HPV), any of a family of more than 60 viruses that cause various growths, including plantar warts and genital warts, a sexually transmitted disease. Detectable warts can be or removed, usually by chemicals, freezing, or laser, but often recur. Intralesional alpha interferon has been effective in the treatment of genital warts. Genital warts, sometimes called condylomata acuminata, are soft and often occur in clusters. They can occur internally or externally, but even in the absence of warts the virus may be present and transmittable. Problems can result from untreated warts, which can grow quite large, or, in rare cases, from infection of an infant during delivery. In addition, certain strains of HPV are associated with cancer of the cervix, vulva, vagina, and penis. HPV 16 has been shown to be associated with some forms of Kaposi's sarcoma (see AIDS). A vaccine approved by the Food and Drug Administration in 2006 can protect a woman against those strains that cause most cases of cervical cancer and genital warts; HPV vaccination is recommended for girls beginning at 11 to 12 years of age.












[B][U]Huntington's disease[/U][/B]

Huntington's disease, hereditary, acute disturbance of the central nervous system usually beginning in middle age and characterized by involuntary muscular movements and progressive intellectual deterioration; formerly called Huntington's chorea. The disease is sometimes confused with chorea or St. Vitus's dance, which is not hereditary. It attacks the cells of the basal ganglia, clusters of nerve tissue deep within the brain that govern coordination.

The onset is insidious and inexorably progressive; no treatment is known. Psychiatric disturbances range from personality changes involving apathy and irritability to bipolar or schizophreniform illness. Motor manifestations include flicking movements of the extremities, a lilting gait, and motor impersistence (inability to sustain a motor act such as tongue protrusion).

In 1993 the gene responsible for the disease was located; within that gene a small segment of code is, for some reason, copied over and over. Genetic counseling is extremely important, since 50% of the offspring of an affected parent inherit the gene, which inevitably leads to the disease.
















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[B][U]hydrocephalus[/U][/B]

It is also known as water on the brain, developmental (congenital) or acquired condition in which there is an abnormal accumulation of body fluids within the skull. The congenital form may be associated with other abnormalities. The acquired form may follow meningitis or another cerebral inflammation or tumor. The accumulation of fluid causes compression of the brain and enlargement of the skull, sometimes with separation of bone structures. Paralysis and death may result or, at the least, mental retardation. Many forms of therapy, including surgery, have been attempted, but usually without much success in extreme cases.










[B][U]hyperinsulinism[/U][/B]

The presence in the system of an above-normal amount of insulin, the substance secreted by the pancreas and needed by the body to utilize sugar. An increased amount of insulin in the body results in below-normal amounts of sugar in the system, giving rise to such symptoms as headache, dizziness, weakness, and emotional instability. In severe cases there may be convulsions, coma, and death. The cause of oversecretion of insulin may be organic, i.e., a tumor of the pancreas, impaired liver function, or endocrine disorders, or it may be functional, e.g., unusual muscular exertion, pregnancy, or lactation. In diabetics, hyperinsulinism is known as insulin shock and may occur from overdosage with insulin in the course of treatment. Where there is some organic cause for hyperinsulinism, surgery may be required to eliminate it. Functional hyperinsulinism and insulin shock are treated by dietary measures designed to bring the insulin-sugar ratio into better balance.












[B][U]hypertrophy[/U][/B]

The enlargement of a tissue or organ of the body resulting from an increase in the size of its cells. Such growth accompanies an increase in the functioning of the tissue. In normal physiology the growth in size of muscles (e.g., in an athlete as a result of increased exercise) and also the enlargement of a uterus in pregnancy are caused by hypertrophy of muscle cells. In pathology the thickening of the heart muscle from overstrain, as in hypertension (high blood pressure), is the result of hypertrophy. An organ subjected to extra work (e.g., the one kidney left to function after surgical removal of the other) usually compensates by enlarging; in such cases hyperplasia, an increase in the number of cells, generally accompanies hypertrophy.

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[B][U]impetigo[/U][/B]

contagious skin infection affecting mainly infants and children. The causative organisms are either hemolytic streptococci or staphylococci. The eruption consists of small red spots or blisters that rupture, discharge, and become encrusted. The infection is easily spread over the skin by fingernails because of its symptomatic itching; it can also be spread by contaminated linen, clothing, or other objects. Effective treatment with antibiotic ointments usually relieves the infection within 10 days. Systemic treatment with antibiotics is sometimes necessary to prevent the nephritis that occasionally develops.









[B][U]indigestion[/U][/B]

indigestion or dyspepsia,discomfort during or after eating caused by some interference with the normal digestive process. Symptoms include nausea, heartburn, abdominal pain, gas distress, and a feeling of abdominal distention. Common indigestion may be a result of poor eating habits, including eating too much or too rapidly, eating during emotional upsets, and swallowing large amounts of air. Excessive smoking may also be a factor. Certain foods and drinks may contribute to indigestion, including such gas-forming vegetables as beans, cabbage, and onions, as well as foods with a high fat content and carbonated or alcoholic beverages. Constipation may also be a cause. Indigestion may be a symptom of such conditions as ulcers and gall bladder inflammation. Persistent indigestion should be diagnosed by a physician.










[COLOR="blue"][B][U]infarction[/U][/B][/COLOR]

The blockage of blood circulation to a localized area or organ of the body resulting in tissue death. Infarctions commonly occur in the spleen, kidney, lungs, brain, and heart. The acute emergency known as myocardial infarction. or heart attack is usually caused by a blockage in one of the coronary arteries that supply blood to the heart muscle. The blockage typically occurs when a blood clot lodges in an area already narrowed by arteriosclerosis; other causes are vasospasms in the arterial walls or viral infection of the heart. Symptoms include a crushing pain in the chest radiated to either arm (more commonly the left arm), the jaw, and the neck. The pain may be experienced, particularly in women, as pain in the shoulder or stomach, instead of the chest, and in some cases there are no symptoms at all. The seriousness of the infarction is dependent upon the amount of heart muscle affected, how long the area is deprived of blood, and whether it affects the natural pacemaker of the heart, setting off arrhythmias such as ventricular fibrillation. Death of heart muscle tissue and heart failure may result; damage to other vital organs, including the brain, may occur if the heart is unable to pump necessary oxygen and blood to them. Confirmation of myocardial infarction is made by electrocardiography and measurement of elevations of white blood cells and certain enzymes. Treatment of acute myocardial infarction may include first aid in the form of cardiopulmonary resuscitation (CPR), an emergency balloon angioplasty, or the administration of beta-blockers and thrombolytic drugs (clot-dissolving drugs), such as tissue plasminogen activator. The healing of an infarction occurs through replacement of the dead tissue by scar tissue.












[B][U][COLOR="blue"]infection[/COLOR][/U][/B]

The invasion of plant or animal tissues by microorganisms, i.e., bacteria, viruses, viroids, fungi, rickettsias, and protozoans. The invasion of body tissues by parasitic worms and other higher organisms is commonly referred to as infestation.

Invading organisms such as bacteria produce toxins that damage host tissues and interfere with normal metabolism; some toxins are actually enzymes that, by breaking down host tissues, prevent the localization of infections. Other bacterial substances destroy the host's phagocytes. Viruses and retroviruses are parasitic on host cells, causing cellular degeneration, as in rabies, poliomyelitis, and AIDS, or cellular proliferation, as in warts and cold sores. Some viruses have been associated with the development of certain cancers. Substances produced by many invading organisms cause allergic sensitivity in the host; the immune response to virus infection has been implicated in some diseases.


Infections may be spread via respiratory droplets, direct contact, contaminated food, or vectors, such as insects. They can also be transmitted sexually and from mother to fetus. Immunity is the term used to describe the capacity of the host to respond to infection. Drugs that help fight infections include antibiotics and antiviral drugs.














[B][U][COLOR="blue"]infertility[/COLOR][/U][/B]

It can be discribed as inability to conceive or carry a child to delivery. The term is usually limited to situations where the couple has had intercourse regularly for one year without using birth control. The term sterility is restricted to lack of sperm production or inability to ovulate. Approximately 40% of reported cases of infertility are due to problems in the male; another 40% to problems in the female; the remaining 20% are of unknown cause or due to problems in both the male and female.


[B]Causes[/B]

Infertility can be caused by any interruption in the usual process of fertilization, pregnancy, and birth, which includes ejaculation of normal amounts of healthy sperm, passage of the sperm through the cervix and into the fallopian tube of the female, passage of an ovum (egg) down the fallopian tube from an ovary, fertilization in the fallopian tube, implantation of the fertilized egg in a receptive uterus, and the ability to carry the fetus to term. In women, the most common problems are failure to ovulate and blockage of the fallopian tubes. In men, low sperm count is the most common problem.

Underlying problems include disease, such as diabetes or mumps in adult men, hormonal imbalances, endometriosis, pelvic inflammatory disease (often caused by sexually transmitted diseases, e.g., chlamydia), the abuse of alcohol and other drugs, and exposure to workplace hazards or environmental toxins. Uterine irritation or infection that sometimes accompanies IUD use can also reduce fertility. Occasionally there is a chemical or immunological incompatibility between male and female. Psychological factors are difficult to evaluate because of the stressful nature of infertility itself.

The number of couples seeking treatment for infertility has increased as more of them have postponed childbearing to a later age. In women, fertility begins to decline in the mid-twenties, and continues to decline, more and more sharply, until menopause. Male fertility declines gradually until age forty, then declines more quickly.










[B][U]inflammation[/U][/B]

A reaction of the body to injury or to infectious, allergic, or chemical irritation. The symptoms are redness, swelling, heat, and pain resulting from dilation of the blood vessels in the affected part with loss of plasma and leucocytes (white blood cells) into the tissues. White blood cells communicate with each other via cytokines, which are polypeptides released by cells of the immune system that regulate other cells. They are a broad class of soluble compounds that signal one cell type to another, particularly in response to foreign substances. Granulomas are most common in infectious diseases such as tuberculosis, leishmaniasis, and schistosomiasis, in which the body's defenses, unable to destroy the offending organisms, try to enclose them in a mass of inflammatory cells. Certain types of inflammation result in pus formation, as in an abscess. The leukocytes destroy harmful microorganisms and dead cells, preventing the spread of the irritation and permitting the injured tissue to repair itself.












[B][U][COLOR="blue"]influenza[/COLOR][/U][/B]

influenza or flu,acute, highly contagious disease caused by a virus; formerly known as the grippe. There are three types of the virus, designated A, B, and C, but only types A and B cause more serious contagious infections. Influenza is difficult to diagnose in the absence of an epidemic, since it resembles many common respiratory ailments. It can be distinguished from a cold, however, by sudden fever, prostration, weakness, and sometimes severe muscular aches and pains. Stomach and intestinal symptoms, such as nausea and vomiting, are not commonly due to influenza infection, and the term stomach flu is a misnomer. Influenza is usually self-limiting, but complications such as pneumonia and bronchitis can be serious threats to newborns, the elderly, and people with chronic diseases. The viruses are spread by respiratory droplets, and the disease is typically most widespread from the late fall to early spring.

Vaccination is recommended for persons who are likely to be exposed to influenza (such as health-care workers) or who are at risk for complicatons. The antiviral drugs amantadine and rimantadine are effective against most strains of type A influenza, and zanamivir and oseltamivir against types A and B. Given within two days of the first appearance of symptoms, they may reduce the symptoms; they may also be given to prevent influenza infection in persons exposed to the disease. Uncomplicated influenza requires only rest and treatment of symptoms, and the use of antibiotics has greatly reduced fatalities from secondary infections. Return to normal activity should be undertaken slowly, as relapses are easily precipitated.

Serious influenza in humans is caused by strains of several A subtypes (which are designated by the specific combination of the 19 hemagglutinin and 9 neuraminidase proteins, or antigens, found on the virus's surface, e.g., H1N1) and by strains of type B. Type A is also found in swine, horses, whales, seals, and other animals, but wild birds are the only animals to have all A subtypes, and migratory birds can spread a strain of the disease great distances. Some H5 and H7 strains of avian influenza (also called avian flu or bird flu) are especially virulent and can result in financially devastating losses in the poultry industry. As a result, outbreaks of the disease are usually controlled by severe measures, including killing all poultry within a couple miles of the outbreak. Avian and swine influenza occasionally infect humans, but such cases rarely result in human-to-human transmission.

The influenza vaccine confers immunity only to a particular strain, and immunity to one strain or subtype, whether acquired through infection or vaccination, does not prevent susceptibility to another. Because the surface antigens of flu viruses change over time, it is necessary to reformulate the vaccine yearly in an educated guess at what strain will appear. Abrupt major changes in a virus, which can result in increased virulence, also occur. Swine, which can be infected by avian and human influenzas, can facilitate such a development when avian and human strains are both present in an animal, enabling the genetic material of the two to reassort (mix). A major change can similarly occur in a person who is infected by both human and avian viruses.

Epidemics of influenza may be caused by type A or B strains, although type B is more likely to occur sporadically. Pandemics (worldwide epidemics) are caused only by type A. Three such pandemics occurred in the 20th cent., in 1918–19 (the “Spanish flu”), 1957–58 (the “Asian flu”), and 1968–69 (the “Hong Kong flu”). In 1918–19, some 675,000 people died in the United States, and between 50 and 100 million died worldwide. Research suggests that the 1918–19 strain arose when an avian strain acquired the ability to infect humans, and the other two pandemics are known to have been caused by strains produced by the reassorting of human and avian viruses. The avian strain A (H5N1), first known to have been transmitted directly to humans in 1997, began a new outbreak in several E Asian nations in 2003 and has shown increased virulence when transmitted to humans. International health officials are concerned that it could reassort with a human influenza virus, resulting in a new strain that would be both extremely virulent and highly contagious. By early 2006 the A (H5N1) outbreak had spread across Asia to birds and poultry in many European and some Africa nations. Fewer than 300 cases of A (H5N1) influenza have been identified in humans, largely in Asia; roughly 60% of the cases have been fatal.














[B][U]insomnia[/U][/B]

An abnormal wakefulness or inability to sleep. The condition may result from illness or physical discomfort, or it may be caused by stimulants such as coffee or drugs. However, frequently some psychological factor, such as worry or tension, is the cause. Mild insomnia may often be relieved by a soothing activity like reading or listening to soft music. Chronic or severe insomnia requires treatment of the underlying physical or psychological disorder. In a few, very rare cases, individuals in certain families are subject to an incurable inherited insomia caused by prions that form plaques in the thalamus; the disease appears suddenly in adulthood and ultimately is fatal.

Many patients respond to the assurance that their sleeplessness is a result of normal anxieties or a treatable physical disorder. Opportunities to ventilate anxieties often ease distress and helps resume normal sleeping patterns. Elderly persons are encourage to exercise more during the day; instructed relaxation, administration of tryptophan, and intake of warm milk helps some patients sleep. Sedatives and hypnotics drugs may be employed if the sleeplessness is impairing the subject's sense of well being. Those who wake because of pain receive an analgesic at bedtime; for those who experience insomnia accompanied with depression, an antidepressant often suffices.










[B][U]iritis[/U][/B]

The inflammation of the iris, the pigmented portion of the eye surrounding the pupil. The condition is sometimes associated with diabetes, with rheumatic diseases such as rheumatoid arthritis, and with infections such as syphilis. Iritis may cause severe pain, a swollen, discolored iris, abnormal sensitivity to light, and blurred vision. If not quickly treated, it may result in impaired vision or blindness. Iritis is treated with antibiotics or other drugs to eliminate infection, atropine to dilate the pupil and prevent scarring, and sometimes steroids to reduce inflammation.

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[B][U][COLOR="blue"]jaundice[/COLOR][/U][/B]

An abnormal condition in which the body fluids and tissues, particularly the skin and eyes, take on a yellowish color as a result of an excess of bilirubin. During the normal breakdown of old erythrocytes (red blood cells), their hemoglobin is converted into bilirubin. Normally the bilirubin is removed from the bloodstream by the liver and eliminated from the body in the bile, which passes from the liver into the intestines. There are several conditions that may interrupt the elimination of bilirubin from the blood and cause jaundice. Hemolytic jaundice is caused by excessive disintegration of erythrocytes; it occurs in hemolytic and other types of anemia and in some infectious diseases like malaria. Another type of jaundice results from obstruction in or about the liver; usually a stone or stricture of the bile duct blocks the passage of bile from the liver into the intestines. A third type of jaundice occurs when the liver cells are damaged by diseases such as hepatitis or cirrhosis of the liver; the damaged liver is unable to remove bilirubin from the blood. Treatment of jaundice is directed to the underlying cause. Many instances of obstructive jaundice may require surgery.









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[B][U]Kaposi's sarcoma
[/U][/B]
usually fatal cancer that was considered rare until its appearance in AIDS patients. First described by an Austro-Hungarian physician, Moritz Kaposi, in 1872, it appears in three forms and is characterized by vascular skin tumors. Kaposi's sarcoma is endemic in Africa, where it is more aggressive, seen in children and young men, and accounts for 10% of malignancies in Congo (Kinshasa) and Uganda. A mild form of the disease is sometimes seen in elderly men of Mediterranean origin. The development of AIDS-related Kaposi's sarcoma has been linked to a virus of the herpes group. In the early 1980s it was seen in nearly 50% of AIDS patients, but the proportion has decreased since that time. In AIDS, Kaposi's presents as barely raised pink or red papules or plaques that become widely disseminated on the skin and in the gastrointestinal and respiratory tracts, where they may cause extensive bleeding. Treatment includes chemotherapy or surgical excision, cryosurgury (destruction by freezing), or electrodessication (destruction by heat). Local radiation therapy can also be effective. AIDS patients are treated with Vinblastine, an active, but weak, agent, which further lowers immunity.







[B][U]kwashiorkor[/U][/B]

protein deficiency disorder of children. It is prevalent in overpopulated parts of the world where the diet consists mainly of starchy vegetables, particularly in sections of Africa, Central and South America, and S Asia. Such a diet, although adequate in calories, is deficient in certain amino acids, the constituents of proteins vital for growth. The nursing infant gets the required amino acids from the mother's milk. But the weaned child, who receives neither milk nor meat, is likely to develop kwashiorkor. The most striking manifestations of the disease are a swollen and severely bloated abdomen, resulting from decreased albumin in the blood, and various skin changes resulting in a reddish discoloration of the hair and skin in black African children. Other symptoms include severe diarrhea, enlarged fatty liver, atrophy of muscles and glands, mental apathy, and generally retarded development. Kwashiorkor is treated by adding proteins to the diet, usually in the form of dried milk.











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[B][U]laryngitis[/U][/B]

inflammation of the mucous membrane of the voice box, or larynx, usually accompanied by hoarseness, sore throat, and coughing. Acute laryngitis is often a secondary bacterial infection triggered by infecting agents causing such illnesses as colds, measles, whooping cough, or influenza. It may also result from straining the voice, drinking hot liquids, or exposure to irritating gases. In chronic laryngitis, inflammation of the mucous membrane of the larynx persists. When such a condition continues for long periods, the membrane becomes irreversibly thickened and the voice permanently changed. Laryngitis resulting from weakened laryngeal muscles is common in singers, teachers, and others who use the voice professionally.











[B][U][COLOR="blue"]Lassa fever[/COLOR][/U][/B]

a severe viral disease occurring mostly in W Africa, characterized by high fever, muscle aches, mouth ulcers, and bleeding in the skin. The disease was first recognized in Lassa, Nigeria, in 1969. The causative virus belongs to a group called arenaviruses and is harbored by a rat, Mastomys natalensis. The virus is spread to humans via the rat's urine in airborne droplets or contaminated food. The disease can also be caught by medical personnel treating patients in hospitals.

The incubation period of Lassa fever is 3 to 17 days. Following fever and general malaise, later stages of the disease may include abdominal pain, diarrhea, vomiting, and petechiae, tiny purplish spots in the skin caused by leakage of blood from the capillaries. Heart and kidney failure may also occur in severe cases, and mortality is high, ranging from about 15% to, among pregnant women, as much as 60%. Treatment by injection of the antiviral drug ribavirin is often successful if begun early.










[B][U]lead poisoning[/U][/B]

An intoxication of the system by organic compounds containing lead. These enter the body by respiration (of dust, fumes, or sprays) or by ingestion of food or other substances that contain lead. Lead poisoning, formerly a leading occupational hazard in industrialized countries, can be an acute episode but is usually a chronic, cumulative disease brought about by continuous exposure.











[B][U]Legionnaire's disease[/U][/B]

An infectious, sometimes fatal, disease characterized by high fever, dry cough, lung congestion, and subsequent pneumonia. Major organs, such as the heart, may be damaged as the disease progresses. The disease struck over 180 people attending an American Legion convention in Philadelphia in July, 1976—hence the name. The causative bacterium, later identified as Legionella pneumophilia, is inhaled via contaminated water droplets, primarily from air conditioning and ventilation systems. A milder form of the disease has also been identified. Treatment is with the antibiotic erythromycin.

[B][U]leishmaniasis[/U][/B]

any of a group of tropical diseases caused by parasitic protozoans of the genus Leishmania. The parasites live in dogs, foxes, rodents, and humans; they are transmitted by the bites of sand flies. There they infect the very white blood cells that normally would defend the body from such invaders. There are two forms of leishmaniasis. The more serious, called kala-azar or visceral leishmaniasis, affects the internal organs, causing fever, anemia, splenomegaly, and discoloration of the skin. Untreated, it can be fatal. The second, or cutaneous form, leaves deep, disfiguring sores at the site of the bite. Treatment is with amphotericin B and other drugs. Leishmaniasis is rarely seen in the United States, but is prevalent in South Asia, the Middle East, North Africa, and parts of the Mediterranean.













[B][U][COLOR="blue"]leprosy[/COLOR][/U][/B]

leprosy or Hansen's disease is chronic, mildly infectious malady capable of producing, when untreated, various deformities and disfigurements. It is caused by the rod-shaped bacterium Mycobacterium leprae, first described by G. Armauer Hansen, a Norwegian physician, in 1874. The mode of transmission is not fully understood. It is thought to be transmitted by nasal discharges and skin sores, possibly also by contaminated objects and arthropods. Only 5% of those exposed acquire the disease. The onset is intermittent and gradual; symptoms may not appear until years after exposure. It is seldom fatal, but its involvement of the peripheral nerves destroys sensation and makes the patient prone to inadvertent injury.

[B]Types of Leprosy[/B]

There are two forms of leprosy. In the tuberculoid form of the disease the skin lesions appear as light red or purplish spots. Tuberculoid leprosy is the more benign type, even though it is accompanied by nerve involvement, which leads to numbness (usually of the extremities), contractures, and ulceration. In lepromatous leprosy the skin lesions appear as yellow or brown infiltrated nodules (protuberances) that affect the mucous membranes of the eyes, nose, and throat. There is a general thickening of the skin, especially the face and ears. Lepromatous leprosy is the more easily spread of the two.














[B][U][COLOR="blue"]leukemia[/COLOR][/U][/B]

The cancerous disorder of the blood-forming tissues (bone marrow, lymphatics, liver, spleen) characterized by excessive production of immature or mature leukocytes and consequently a crowding-out of red blood cells and platelets. It was first named by Rudolf Virchow in 1887.

[B]Incidence and Cause[/B]

Leukemia is seen in animals, such as cats, guinea pigs, and cattle, as well as in humans. In humans it can occur at any age, but most types are more prevalent in older people. Possible causes include exposure to certain chemicals (e.g., benzene), chromosomal abnormalities such as Down syndrome, exposure to ionizing radiation, certain drugs (e.g., alkylating agents used in cancer treatment), and infection with retroviruses such as HTLV-I, a relative of the AIDS virus. All of these agents are suspected of causing mutations or other disruptions that interfere with the normal regulation of cell growth and division in leukocytes.


[B]Types[/B]

Leukemias are classified as either lymphocytic or myeloid, depending on the type of leukocyte affected. In addition, leukemias are classified as either acute, referring to a rapidly progressing disease that involves immature leukocytes, or chronic, referring to a slower proliferation involving mature white cells. In acute leukemias, immature nonfunctioning leukocytes called blast cells proliferate.

The myeloid leukemias affect white blood cells (myelocytes) that give rise to granulocytes (phagocytic white blood cells that mount an inflammatory immune response). They include chronic myeloid leukemia (CML) and acute myeloid leukemia (AML), also called acute nonlymphocytic leukemia (ANLL). The lymphocytic leukemias affect the white blood cells that give rise to various types of lymphocytes. They include acute lymphocytic leukemia (ALL); chronic lymphocytic leukemia (CLL), also called chronic granulocytic leukemia; and hairy cell leukemia (HCL), a chronic leukemia named for the cells' tiny hairlike projections. The lymphocytic leukemias are sometimes referred to as B cell leukemias or T cell leukemias depending upon whether they arise in antibody-producing B cells (HCL, CLL, and some cases of ALL) or in the T cell lymphocytes involved in cell-mediated immunity (some cases of ALL). (See immunity for a further explanation of the cells of the immune system.) Each of these types may be further classified into subtypes. Most childhood leukemias are of the acute lymphocytic type; acute myeloid leukemia is the most common type of adult leukemia.



[B]Symptoms[/B]

Many of the symptoms of acute leukemia can be attributed to anemia, which results from the attrition of red blood cells as they are crowded out by the leukemic cells. Frequent infections result from a dearth of functioning white blood cells. Bone tenderness may also be present. Hemorrhaging may develop because blood-clotting elements are scarce. Blasts may congregate in the lymph nodes, spleen, and liver, causing enlargement and pain, or they may invade the central nervous system, causing dizziness, headache, or fever. If untreated, death can supervene rapidly in acute leukemia.

Patients with chronic leukemias often have no symptoms and may be hard to diagnose, but less virulent versions of the symptoms seen in the acute leukemias may be present. Death from chronic leukemia is usually from infection.













[B][U][COLOR="blue"]lung cancer[/COLOR][/U][/B]

cancerthat originates in the tissues of the lungs. Lung cancer is the leading cause of cancer death in the United States in both men and women. Like other cancers, lung cancer occurs after repeated insults to the genetic material of the cell. By far the most common source of these insults is tobacco smoke, which is responsible for about 85% of U.S. lung cancer deaths (see smoking). The incidence of lung cancer in other countries follows their smoking patterns. Some other carcinogens known to cause lung cancer are found in the workplace. These include bischloromethyl ether and chloromethyl ether in chemical workers, arsenic in copper smelting, and asbestos in shipbuilders and other asbestos workers. Radon poses a risk to uranium and fluorspar miners and may pose a risk in some private residences as well. African Americans have a higher incidence of lung cancer than European Americans, even after adjusting for smoking.


[B]Types of Lung Cancer[/B]

Lung cancers are classified according to the type of cell present in the tumor. The majority are referred to as non–small cell carcinomas. These include squamous cell or epidermoid carcinomas (the most common type worldwide), adenocarcinomas, and large cell carcinomas. Small cell carcinoma (which includes the subtypes oat cell and intermediate) comprises approximately 20% to 25% of lung cancers; it often has metastasized by the time it is detected. Lung cancer most commonly spreads to the brain, bone, liver, or bone marrow.
[B]
Symptoms[/B]

The primary symptoms of lung cancer are cough, shortness of breath, hoarseness, blood in the sputum, and pain. In some types, the cancer cells themselves produce hormones or other substances that can create an imbalance and result in various symptoms. Metastatic lung cancer also can cause symptoms that result from its effect on the organ to which the cancer has spread.











[B][U]lupus[/U][/B]

noninfectious chronic disease in which antibodies in an individual's immune system attack the body's own substances. In lupus, medically known as lupus erythematosus, antibodies are produced against the individual's own cells, causing tissue inflammation and cell damage. Because the vascular and connective tissue of any body organ may be affected, various symptoms may result. Generalized symptoms include fever, weakness, weight loss, anemia, enlargement of the spleen, and a characteristic butterfly-shaped skin rash on the face. Heart, joint, and kidney disease are common (see nephritis). It is believed that the disease may be triggered by certain drugs or foreign proteins, exposure to ultraviolet radiation, or extreme stress. The disease, which may range from mild to fatal, occurs commonly in young women. It is treated with immunosuppressive drugs and steroids.












[B][U]lymphoma[/U][/B]

a cancer of the tissue of the lymphatic system. There are two categories of lymphomas. One type is termed Hodgkin's disease, the other, non-Hodgkin's lymphoma.

[B]lymphoma, non-Hodgkin's[/B]

any cancer of the lymphoid tissue (see lymphatic system) in which the Reed-Sternberg cells characteristic of Hodgkin's disease (the other category of lymphoma) are not present. There are about 10 different types of non-Hodgkin's lymphomas, some slower- or faster-growing than others. Non-Hodgkin's lymphoma can affect children as well as adults. In most cases the cause is unknown, but an increased incidence has been observed in people who have been exposed to Agent Orange, and some forms of the disease are frequently seen in people with AIDS, many of these in association with latent Epstein-Barr virus infection.


[B]Symptoms[/B]

The first symptom of non-Hodgkin's lymphoma is often a painless swelling of a lymph node in the neck, the groin, or under the arm. Other symptoms include fever, night sweats, itching, and unexplained weight loss. Diagnosis is made by laboratory study of tissue obtained by taking a biopsy of the suspicious lymph node or nodes.

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[B][U]macular degeneration[/U][/B]

eye disorder causing loss of central vision. The affected area, the macula, lies at the back of the retina and is the part that produces the sharpest vision. The most serious visual impairment occurs when abnormal blood vessels form and leak serous fluid or bleed into the tissue of the macula, ultimately producing scar tissue. Peripheral (side) vision is unaffected. Onset may be acute with hemorrhage but usually is gradually progressive. Although some vision is retained, the ability to read, recognize faces, and drive a motor vehicle is greatly reduced. The condition is painless.

Macular degeneration is a major cause of vision impairment among elderly people. Although its underlying cause is unknown, it sometimes appears to run in families. Serious macular degeneraton, if diagnosed early, may have its progress stemmed by laser or photodynamic (cold laser and drug) treatment that closes leaking vessels. Antiangiogenic drugs, which inhibit the formation of new blood vessels, can be injected into the eye to stop degeneration and in some cases even improve vision. Sudden change in vision in someone over age 50 thus requires immediate medical attention.













[B][U][COLOR="blue"]malaria[/COLOR][/U][/B]

An infectious parasitic disease that can be either acute or chronic and is frequently recurrent. Malaria is common in Africa, Central and South America, the Mediterranean countries, Asia, and many of the Pacific islands. In the United States it was found in the South and less frequently in the northern and western parts of the country.

The primary causative organism, Plasmodium falciparum, requires both the Anopheles mosquito and humans to complete its life cycle: sexual reproduction of the protozoan occurs in the mosquito; an immature form is then transmitted to the human via the bite of the mosquito. In a person the parasite goes to the liver, replicates, and moves into the bloodstream, where it attacks red blood cells for their hemoglobin. Some of the plasmodia become sexually mature and are transmitted back to another biting mosquito. Three other Plasmodium species also infect humans.


[B]Symptoms[/B]

At the onset of malaria, bouts of chills (ague) and fever lasting several hours and occurring every three or four days are the usual symptoms. If the disease is not treated, the spleen and the liver become enlarged, anemia develops, and jaundice appears. Death may occur from general debility, anemia, or clogging of the vessels of cerebral tissues by affected red blood cells. Cerebral malaria is most commonly seen in infants, pregnant women, and nonimmune travelers to endemic areas.


[B]Immune Response[/B]

. falciparum creates protein knobs on the surfaces of the red blood cells it attacks. These knobs attach the cell to the lining of the blood vessel, preventing its removal to the spleen for destruction. The parasite slows detection by the immune system by changing the makeup of the knobs periodically, substituting or rearranging its 150 “var” (variability) genes, a strategy unique to malaria. A pattern of remission and relapse results as the immune system learns each new “code” only to have it again changed. Patients with malaria gradually do develop immunity that modifies the course of the disease, but this immunity has a degree of strain specificity.



[B]Treatment and Control[/B]

The bark of the cinchona and its product, quinine, have been used in the treatment of malaria for centuries. After World War II, they were largely replaced by the synthetic analog chloroquine. The use of chloroquine, in addition to the use of DDT for mosquito control, was expected to eradicate the disease, but a World Health Organization campaign (1955–69) to eradicate the disease globally (by controlling mosquitoes long enough to allow the human population to become disease free) proved unsuccessful. Despite that, spraying successfully eradicated the disease in some areas (Sardinia, Japan, and Taiwan).

In the 1960s several strains of the malarial parasite developed resistance to chloroquine. This, plus the growing immunity of mosquitoes to insecticides, has caused malaria to become one the of world's leading re-emerging infectious diseases, infecting an estimated 300 million people a year and killing more than a million. Mefloquine may be used in areas where the disease has become highly resistant to chloroquine, but some strains are now resistant to it and other drugs. Artemisinin (derived from sweet wormwood) in combination with other drugs is now in many cases the preferred treat for resistant strains. Amodiaquine in combination with sulfadoxine and pyrimethamine has also been shown to be effective, and malarone (atovaquone and proguanil) also is used for resistant strains. Vaccines against malaria are still experimental. Spraying is still used to control malaria-transmitting mosquitoes, but fish that feed on mosquito larva also have been employed.











[B][U]malnutrition[/U][/B]

insufficiency of one or more nutritional elements necessary for health and well-being. Primary malnutrition is caused by the lack of essential foodstuffs—usually vitamins, minerals, or proteins—in the diet. In some areas of the world a poor economy or such regional conditions as drought or overpopulation cause a scarcity of certain foodstuffs, and a certain portion of the population is malnourished because essential nutrients are not available. However, even when food is plentiful, malnutrition can result from poor eating habits. Secondary malnutrition is caused by failure of absorption or utilization of nutrients (as in disease of the gastrointestinal tract, thyroid, kidney, liver, or pancreas), by increased nutritional requirements (growth, injuries, burns, surgical procedures, pregnancy, lactation, fever), or by excessive excretion (diarrhea).












[B][U]measles[/U][/B]

highly contagious disease of young children, caused by a filterable virus and spread by droplet spray from the nose, mouth, and throat of individuals in the infective stage. This period begins 2 to 4 days before the appearance of the rash and lasts from 2 to 5 days thereafter. The first symptoms of measles, after an incubation period of 7 to 14 days, are fever, nasal discharge, and redness of the eyes. Characteristic white spots appear in the mouth, followed by a rash on the face that spreads to the rest of the body. The symptoms disappear in 4 to 7 days. One attack of measles confers lifelong immunity. However, it renders the patient susceptible to other more serious infections such as bronchial pneumonia and encephalitis. The measles virus has also been associated with subacute sclerosing panencephalitis (SSPE), which causes chronic brain disease in children and adolescents. After the attack of measles, it can cause intellectual deterioration, convulsive seizures, and motor abnormalities and is usually fatal. Common measles in pregnant women can be a threat to the unborn child, and vaccination of women well before pregnancy is recommended.












[B][U][COLOR="blue"]meningitis[/COLOR][/U][/B]

meningitis or or cerebrospinal meningitis is defined as an acute inflammation of the meninges, the membranes that cover and protect the brain and spinal cord. It can be caused by bacteria, viruses, fungi, or other organisms, usually introduced via the bloodstream from infections elsewhere in the body.

[B]Viral meningitis[/B]

sometimes referred to as nonbacterial or aseptic meningitis, is milder and more common than bacterial forms. It can be caused by any of a number of viruses, including enteroviruses, the mumps virus, herpesviruses, HIV, and several mosquito-borne viruses (Bunyavirus and flavivirus) usually associated with encephalitis. Viral meningitis is usually seen only in individual cases rather than in outbreaks. Those not vector-borne are usually spread from person to person by the fecal-oral route. Symptoms include headache, fever, stiff neck, and tiredness, sometimes accompanied by a rash. There is no specific treatment.

[B]Bacterial meningitis[/B]

A variety of organisms can cause bacterial meningitis, a serious form that can be fatal, especially in children. Symptoms include high fever, headache, chills, vomiting, stiff neck or back, and confusion, sometimes accompanied by a purplish rash. Serious cases can quickly lead to delirium, coma, or convulsions. It is spread by oral or nasal secretions.

The leading cause of bacterial meningitis is the ill-named bacterium Haemophilus influenzae b (Hib), originally thought to be an influenza virus. It commonly affects infants and children. The second most common bacterial cause of meningitis is Neisseria meningitidis (meningococcus). Meningococcal meningitis affects people of all ages and tends to occur in epidemics, especially among those who live in crowded conditions. An outbreak in the slums of Brazil in 1974–75 killed 11,000 people and left over 75,000 with permanent neurological complications. In 1996, an epidemic centered in the Sahel region of W Africa killed 16,000. In the United States it is seen most often in children and teens.

Strepococcus pneumoniae, also referred to as pneumococcus, is another cause of serious meningitis cases. It is the most common cause of meningitis in adults. It often accompanies pneumococcus infections in other parts of the body, such as the ear or sinuses. Other bacterial causes of meningitis include tuberculosis, leptospirosis, and Lyme disease.

Bacterial meningitis calls for emergency medical care and the administration of antibiotics. Close contacts of patients with bacterial meningitis may receive prophylactic antibiotics, such as rifampin. Definitive diagnosis can be made by laboratory tests of cerebrospinal fluid obtained by a lumbar puncture (spinal tap). Twenty to thirty percent of children who survive bacterial meningitis sustain permanent neurological damage such as deafness, mental retardation, or convulsions. Since the late 1980s, routine vaccination of young children against Hib has virtually eliminated Hib disease in the United States. Routine vaccination against meningococcal meningitis is recommended for pre-adolescents, and vaccination is also recommended for persons in the military or traveling to parts of Africa where the disease is endemic. The meningococcal vaccine does not provide protection against all meningococcus strains.


[B]Fungal meningitis[/B]

Fungal meningitis has been on the rise in the United States due to opportunistic infection with Cryptococcus neoformans in people weakened by AIDS. In these patients, it is often fatal. It can be treated with the antifungals amphotericin B and fluconazole. Other causes include coccidioidomycosis and histoplasmosis.













[B][U]mercury poisoning[/U][/B]

tissue damage resulting from exposure to more than trace amounts of the element mercury or its compounds. Elemental mercury (the silver liquid familiar from thermometers) is the most common occupational source. Exposure typically comes from inhaling mercury vapors. Inorganic salts of mercury (e.g., mercurous chloride, or calomel) are used in some products to inhibit the growth of fungi and bacteria. Organic mercury compounds, especially methylmercury, are more toxic than other forms because they easily cross cell membranes. They are most often ingested in contaminated fish.

Mercury poisoning can cause severe neurological and kidney damage. Acute exposure can affect the respiratory and gastrointestinal systems. Organic mercury can cross the blood-brain barrier and cause irreversible nervous system and brain damage, e.g., loss of motor control, numbness in limbs, blindness, and inability to speak. Some studies have connected maternal mercury exposure to fetal damage. Mercury poisoning can be confirmed by urine tests. Chelation therapy is used for poisoning with elemental mercury and mercury salts; there is no treatment for organic mercury poisoning.

Mercury has become an environmental pollutant in areas where eroding mercury-bearing rock or agricultural and industrial wastes containing the metal escape or are discharged into waterways. Mercury also is released into the atmosphere when coal is burned. Elemental mercury and mercury salts, although fairly inert when deposited on the bottom of waterways, are converted into organic mercury, typically methylmercury, by microorganisms. This compound then enters the food chain where it is biomagnified up to 100,000 times in predacious fish. Consumption of toxic fish and of game birds and mammals that feed on fish is the main risk to humans. Minamata disease was named after the occurrence, in the 1950s and 1960s in Minamata, Japan, of many cases of severe mercury poisoning. It was found that a chemicals factory was discharging mercury-containing wastes into the local waters, contaminating fish that residents caught for food.















[COLOR="blue"]to be continued[/COLOR]

Interesting!!!

so many diseases... can some one tell me how many are cureable ones in above mention diseases?

[B][U]migraine[/U][/B]

headache characterized by recurrent attacks of severe pain, usually on one side of the head. It may be preceded by flashes or spots before the eyes or a ringing in the ears, and accompanied by double vision, nausea, vomiting, or dizziness. The attacks vary in frequency from daily occurrences to one every few years.

Migraine affects women three times as often as men and is frequently inherited. Many disturbances, such as allergy, temporary swelling of the brain, and endocrine disturbances, have been suspected of causing some varieties of the disorder. Although the exact cause is unknown, evidence suggests a genetically transmitted functional disturbance of cranial circulation. The pain is believed to be associated with constriction followed by dilation of blood vessels leading to and within the brain.

Untreated attacks may last for many hours. Mild attacks are often relieved by common sedatives such as aspirin or codeine. Severe attacks may be treated with any of a variety of drugs, including a group called triptans, by injection or in the form of pills or nasal sprays. Certain beta-blockers, antiepileptic drugs, or tricyclic antidepressants may reduce the recurrence of migraines in some patients. Biofeedback is used in training people to recognize the warning symptoms and to practice control over the vascular dilation that initiates attacks.










[B][U]infectious mononucleosis[/U][/B]

An acute infectious disease of older children and young adults, occurring sporadically or in epidemic form, also known as mono, glandular fever, and kissing disease. The causative organism is a herpesvirus known as Epstein-Barr virus. The disease occurs most often in patients between the ages of 15 and 35. The virus is present in the saliva; it is usually spread by sharing a glass or kissing. Symptoms usually take 30 to 50 days to develop.

Diagnosis of mononucleosis follows the exhibition of a large number of abnormal white blood cells (lymphocytes) on microscopic blood examination. These blood cells have a single nucleus that give the disease its name. Symptoms are varied but include enlarged lymph nodes, sore throat, fever, enlarged spleen in about half the cases, and excessive fatigue. Occasional rashes and throat and mouth infections occur. Liver inflammation is common. Fatalities are very rare and, when they do occur, usually result from splenic rupture. General therapeutic measures include bed rest and treatment of symptoms.













[B][U][COLOR="blue"]motion sickness[/COLOR][/U][/B]

waves of nausea and vomiting experienced by some people, resulting from the sudden changes in movement of a vehicle. The ailment is also known as seasickness, car sickness, train sickness, airsickness, and swing sickness. The principal cause of the disturbance is the effect of motion on the semicircular canals of the inner ear, although other factors such as inadequate ventilation and fumes or noxious odors may contribute. Drugs are available that, when taken beforehand, prevent the occurrence of motion sickness.









[B][U]multiple chemical sensitivity[/U][/B]

multiple chemical sensitivity (MCS) is an adverse physical reaction to certain chemicals in susceptible persons. When exposed to the chemicals, people with MCS react with symptoms such as nausea, headache, dizziness, fatigue, impaired memory, rash, and respiratory difficulty. A wide range of household and industrial chemicals, including cleaning products, tobacco smoke, perfumes, inks, and pesticides, have been implicated as triggers for MCS.

Many researchers do not regard multiple chemical sensitivity as a medically valid syndrome, believing that the depression that frequently accompanies it is an indication that the symptoms are psychological in origin. Others note that descriptions of the syndrome are largely anecdotal and not proven scientifically, or that the imprecisely defined syndrome is easily abused as a diagnosis, pointing to what they feel is an exaggerated number of worker's compensation cases involving MCS. Nevertheless, many sufferers do seem to improve when they eliminate contact with the chemicals known to trigger their condition; in extreme cases this may mean confinement to specially treated living quarters.










[B][U]multiple sclerosis[/U][/B]

multiple sclerosis (MS), chronic, slowly progressive autoimmune disease in which the body's immune system attacks the protective myelin sheaths that surround the nerve cells of the brain and spinal cord (a process called demyelination), resulting in damaged areas that are unable to transmit nerve impulses. The disease also gradually damages the nerves themselves. There are elevated numbers of lymphocytes in the cerebral spinal fluid and of T cells in the blood.

The onset of MS is usually at age 20 to 40 years, and its many symptoms affect almost every system of the body. There may be visual difficulties, emotional disturbances, speech disorders, convulsions, paralysis or numbness of various regions of the body, bladder disturbances, and muscular weakness. The course of the disease varies greatly from person to person. In some patients, the symptoms remit and return, sometimes at frequent intervals and sometimes after several years. In others the disease progresses steadily.

There is a genetic predisposition to MS, and environmental factors also seem to play some role. The disease is more common in temperate climates (1:2,000) than in the tropics (1:10,000).

There is no cure for MS, but a number of drugs—the first of which became available in the 1990s—can slow its underlying progress and reduce the frequency of attacks. These are Avonex, Rebif, and Betaseron, forms of beta interferon (a synthetic version of a natural substance produced by the immune system); Copaxone (glatiramer acetate); and Tysabri (natalizumab).









[B][U]mumps[/U][/B]

mumps (epidemic parotitis) is an acute contagious viral disease, manifesting itself chiefly in pain and swelling of the salivary glands, especially those at the angle of the jaw. Other symptoms are fever, a general feeling of illness, and pain on chewing or swallowing. Mumps most often affects children between the ages of 5 and 15, the incubation period being 14 to 21 days; the acute phase rarely lasts more than 3 days. The disease is usually more severe in adults, the most common complications being pain and swelling of the testes (in 20% of adult male patients) and swelling of the meninges that cover the brain and spinal cord (in about 30% of cases). Sterility resulting from involvement of the testes and fatalities from the meningoencephalitis occur in a small minority of male cases. Other possible complications include pancreatitis and involvement of the heart or thyroid. The ovaries are sometimes affected in females. Treatment consists mainly of bed rest, intake of fluids, and the administration of analgesics. A live virus vaccine has been developed that can be given to susceptible children at 15 months.











[B][U][COLOR="blue"]muscular dystrophy[/COLOR][/U][/B]

any of several inherited diseases characterized by progressive wasting of the skeletal muscles. There are five main forms of the disease. They are classified according to the age at onset of symptoms, the pattern of inheritance, and the part of the body primarily affected.


[B]Types of Muscular Dystrophy[/B]

The most common form of muscular dystrophy, Duchenne, was first described by the French physician Guillaume Benjamin Amand Duchenne in 1861. Most cases are caused by a recessive sex-linked gene located on the X chromosome and carried only by females. Each son of a carrier has a 50% chance of inheriting the gene and developing the disease. Each daughter has a 50% chance of inheriting the gene and becoming a carrier. In small number of “sporadic” cases there is no family history. The disease begins with leg weakness before age 3 and progresses rapidly, with death often occurring before age 30, often because of involvement of lung or heart muscle. Research has shown that the abnormal gene fails to produce an essential skeletal muscle protein called dystrophin. Becker's muscular dystrophy is similar to the Duchenne form, but appears somewhat later in life and progresses more slowly.

Fascioscapulohumeral muscular dystrophy primarily involves facial and shoulder muscles and affects both sexes. Symptoms can begin from adolescence to around age 40. It is caused by an autosomal dominant trait (at least one parent will have the disease). Progression is usually slow and severe disability is unusual.

Myotonic muscular dystrophy is another autosomally dominant disease affecting both sexes. It appears to be caused by the repetition of a section of DNA on chromosome 4. In a surprising development, researchers found that the number of repetitions on the chromosome increase and the disease becomes more severe with each generation. It is characterized by an inability of the muscles to relax properly after contraction and primarily affects the muscles of the hands and feet. It usually begins in adulthood and is often accompanied by cataracts, baldness, and abnormal endocrine function.

The limb-girdle form of the disease first affects the muscles of the hip and shoulder areas. Symptoms usually become apparent in late adolescence or early adulthood. Caused by an autosomal recessive trait (carried by a gene passed on by both asymptomatic parents), it can affect males and females alike. This form usually progresses slowly.


[B]Treatment[/B]

There is no known treatment or cure for muscular dystrophy. Supportive measures and exercises can improve the quality of life and preserve mobility for as long as possible. Scientists have begun to identify the genetic abnormalities responsible for multiple dystrophy and hope that further understanding will lead to treatment. Genetic screening is recommended for all family members who might be carriers. Prenatal tests such as chorionic villus sampling and amniocentesis can detect some forms of muscular dystrophy early in a pregnancy.









[B][U]myasthenia gravis[/U][/B]

A chronic disorder of the muscles characterized by weakness and a tendency to tire easily. It is caused by an autoimmune attack on the acetylcholine receptor of the post synaptic neuromuscular junction. The initiating event leading to antibody production is unknown. The disease is most common between the ages of 20 and 40 and more frequent in women. The muscles of the neck, throat, lips, tongue, face, and eyes are primarily involved. Exertion quickly brings on difficulty in swallowing, chewing, and talking. The eyelids may droop, and there are visual disorders. Myasthenia gravis is transmitted passively to fetuses from infected mothers, a syndrome call neonatal myasthenia. Congenital myasthenia is a rare autosomal recessive disorder of neuromuscular transmission beginning in childhood, usually with ophthalmoplegia. Life-threatening myasthenic crisis, in which the diaphragm is affected and the patient has respiratory failure, occurs in 10% of the patients. Treatment of the disease includes the use of cholinesterase inhibitors, thymectomy, corticosteroids, and immunosuppressive agents and plasmapheresis (see apheresis). Prolonged rest is likely to restore some of the muscle function; restricted activity at all times and complete rest during periods of aggravation of the illness are necessary.












[B][U]myxedema[/U][/B]

Condition associated with severe hypothyroidism and lack of thyroid hormone in the adult. In the child it is known as cretinism. Symptoms include a dry swelling of the skin, slowed speech and mental awareness, deepened voice, intolerance to cold, fatigue and weakness, and nonspecific degeneration of the heart. Most cases result from atrophy of the thyroid from unknown causes, although surgical removal or irradiation of the gland also precipitates the disorder. Myxedema is treated by administering synthetic preparations of thyroxine (thryoid hormone), liothyronine (triiiodothyronine), a combination of the two synthetic hormones, and desicated animal thyroid.









@ Mahin

Thanx for appreciation. Well, Every disease can be proved harmful. By reading all of them, you will know about all scenario.

Take care,

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[B][U]narcolepsy[/U][/B]

a sleep disorder characterized by excessive daytime sleepiness and recurring unwanted episodes of sleep (“sleep attacks”). People with narcolepsy may abruptly fall asleep at almost any time, including while talking, eating, or even walking. The attacks may range from embarrassing or inconvenient to severely disabling, interfering with a person's daily life. An estimated 125,000–250,000 people in the United States have narcolepsy; it occurs about equally in males and females.

Most people with narcolepsy also experience cataplexy, sudden muscular weakness without loss of consciousness, which usually accompanies laughter or anger. Other symptoms, occurring just after falling asleep or upon awakening, include sleep paralysis (a feeling that one cannot move) and vivid hallucinations.

The cause of narcolepsy is not known with certainty, and there is no cure. Treatment, including regular planned naps and the use of stimulant drugs (e.g., amphetamines) plus antidepressants for cataplexy, can help to control its symptoms.









[B][U]nausea[/U][/B]

sensation of discomfort, or queasiness, in the stomach. It may be caused by irritation of the stomach by food or drugs, unpleasant odors, overeating, fright, or psychological stress. It is usually relieved by vomiting. Nausea is frequently present during the early months of pregnancy, and it is a concomitant of motion sickness. However, nausea may also be the symptom of a serious illness; thus persistent nausea should receive medical attention.











[B][U]nearsightedness[/U][/B]

nearsightedness or myopia is the defect of vision in which far objects appear blurred but near objects are seen clearly. Because the eyeball is too long or the refractive power of the eye's lens is too strong, the image is focused in front of the retina rather than upon it. Corrective eyeglasses with concave lenses compensate for the refractive error and help to focus the image on the retina. Hard corneal contact lenses or soft hydrophilic contact lenses are another option, usually offering better acuity and peripheral vision than do eyeglasses. (Contact lenses may be troublesome for people who tend to get eye infections or have hand tremors, however.) Nearsightedness can also be corrected by using laser cornea surgery and a device called a microkeratome to flatten the eye, or by surgically implanting a corrective lens behind the iris.











[B][U]neoplasm[/U][/B]

neoplasm or tumor is a tissue composed of cells that grow in an abnormal way. Normal tissue is growth-limited, i.e., cell reproduction is equal to cell death. Feedback controls limit cell division after a certain number of cells have developed, allowing for tissue repair but not expansion. Tumor cells are less responsive to these restraints and can proliferate to the point where they disrupt tissue architecture, distort the flow of nutrients, and otherwise do damage.

Tumors may be benign or malignant. Benign tumors remain localized as a discrete mass. They may differ appreciably from normal tissue in structure and excessive growth of cells, but are rarely fatal. However, even benign tumors may grow large enough to interfere with normal function. Some benign uterine tumors, which can weigh as much as 50 lb (22.7 kg), displace adjacent organs, causing digestive and reproductive disorders. Benign tumors are usually treated by complete surgical removal. Cells of malignant tumors, i.e., cancers, have characteristics that differ from normal cells in other ways beside cell proliferation. For example, they may be deficient in some specialized functions of the tissues where they originate. Malignant cells are invasive, i.e., they infiltrate surrounding normal tissue; later, malignant cells metastasize, i.e., spread via blood and the lymph system to other sites.

Both benign and malignant tumors are classified according to the type of tissue in which they are found. For example, fibromas are neoplasms of fibrous connective tissue, and melanomas are abnormal growths of pigment (melanin) cells. Malignant tumors originating from epithelial tissue, e.g., in skin, bronchi, and stomach, are termed carcinomas. Malignancies of epithelial glandular tissue such as are found in the breast, prostate, and colon, are known as adenocarcinomas. Malignant growths of connective tissue, e.g., muscle, cartilage, lymph tissue, and bone, are called sarcomas. Lymphomas and leukemias are malignancies arising among the white blood cells. A system has been devised to classify malignant tissue according to the degree of malignancy, from grade 1, barely malignant, to grade 4, highly malignant. In practice it is not always possible to determine the degree of malignancy, and it may be difficult even to determine whether particular tumor tissue is benign or malignant.












[B][U]nephritis[/U][/B]

The inflammation of the kidney. The earliest finding is within the renal capillaries (glomeruli); interstitial edema is typically followed by interstitial infiltration of lymphocytes, plasma cells, eosinophils, and a small number of polymorphonuclear leukocytes. The disease is thought to be immunological, but immunoglobulins and drug antigens have been found in only a few cases. The damage is usually reversible when the cause is recognized and removed, but severe cases can progress to fibrosis and renal failure. The disease can take several forms. Pyelonephritis is usually associated with a bacterial infection transmitted from the bladder or blood; it affects the renal pelvis and is treated with antibiotics. Glomerulonephritis, or Bright's disease, causes degenerative changes in the glomeruli and is believed to be an allergic response to infection elsewhere in the body. Symptoms include headache, mild fever, puffiness of the eyes and face, high blood pressure, and discoloration of the urine. Treatment includes bed rest and limiting the intake of water, sodium, and proteins, and, if necessary, dialysis; antibiotics are given to halt infections (e.g., streptococcal) invasion. The disease occurs more frequently among the young. About 95% of patients recover from the acute phase of the disease; however, if glomerulonephritis becomes chronic, renal damage results after many years, causing kidney failure..













[B][U]nephrosis[/U][/B]

kidney disease characterized by lesions of the epithelial lining of the renal tubules, resulting in marked disturbance in the filtration function and the consequent appearance of large amounts of protein (albumin) in the urine (see urinary system). The nephrotic syndrome can result from a number of conditions including streptococcal infection in children leading to chronic glomerulonephritis, reaction to toxins, diabetes, collagen disease, and other end-stage kidney diseases. The major symptom is massive edema. Corticosteroid therapy has been successful in treating certain forms of the disease.











[B][U]neuralgia[/U][/B]

An acute paroxysmal pain along a peripheral sensory nerve. Unlike neuritis, there is no inflammation or degeneration of nerve tissue. Neuralgia occurs commonly in the area of the facial, or trigeminal, nerve and brings attacks of excruciating pain at varying intervals. Often no cause can be found for trigeminal neuralgia, and in severe cases deadening of the nerve with novocaine or alcohol, or even surgical interruption of the nerve, is necessary to bring relief. Neuralgia can be caused by such disturbances as diabetes, infections, diseases of the nervous system, anemia, and extreme cold. The pain may occur for many months after an attack of shingles (see herpes zoster), and it is one of the symptoms of syphilitic involvement of the central nervous system. In many cases, pain can be relieved by hot applications, drugs, and various kinds of physiotherapy.











[B][U]neuritis[/U][/B]

The inflammation of a peripheral nerve, often accompanied by degenerative changes in nervous tissue. The cause can be mechanical (injury, pressure), vascular (occlusion of a vessel or hemorrhage into nerve tissue), infectious (invasion by microorganisms), toxic (metallic or chemical poisoning, alcoholism), or metabolic (vitamin deficiencies, pernicious anemia). Symptoms of neuritis that arise from involvement of sensory nerves are tingling, burning, pin-and-needle sensations, or even loss of sensation. If motor nerves are involved, symptoms may range from a slight loss of muscle tone to paralysis. Since neuritis is regarded as a condition that results from a number of disorders, rather than a disease in itself, treatment is directed first at the underlying cause.








[COLOR="blue"][B][U]night blindness[/U][/B][/COLOR]

An inability to see normally in subdued light. It is usually a result of vitamin A deficiency. The rod cells, one of two light-sensitive areas of the retina of the eye, are impaired in their capacity to produce a chemical compound called rhodopsin, or visual purple, that is necessary for the perception of objects in dim light. Consequently, the visual threshold, or the minimum intensity of light necessary for sight, is greatly increased. Folk medicine has long recognized the role of the ingestion of liver in alleviating the condition, but it was not until the first quarter of the 20th cent. that vitamin A was identified as the crucial element. Treatment of night blindness consists of the oral or intravenous administration of vitamin A.












[B][U][COLOR="blue"]nosebleed[/COLOR][/U][/B]

nasal hemorrhage occurring as the result of local injury or disturbance. Most nosebleeds are not serious and occur when one of the small veins of the septum (the partition between the nostrils) ruptures. These will usually stop without treatment or when pressure is applied to the nose. A nosebleed may also occur in association with infections, heart failure, hypertension (high blood pressure), arteriosclerosis, scurvy, leukemia, hemophilia, and other disorders. Persistent nosebleeds should be brought to the attention of a physician, who can stop the bleeding with vasoconstrictors and topical anesthetics.

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[B][U][COLOR="blue"]obesity[/COLOR][/U][/B]

A condition resulting from excessive storage of fat in the body. Obesity has been defined as a weight more than 20% above what is considered normal according to standard age, height, and weight tables, or by a complex formula known as the body mass index. It has been estimated that 30% to 35% of Americans are overweight or obese.


[B]Health and Social Implications[/B]

Obesity is a major public health concern because it predisposes the individual to many disorders, such as noninsulin-dependent diabetes, hypertension, stroke, and coronary artery disease, and has been associated with an increased incidence of certain cancers, notably cancers of the colon, rectum, prostate, breast, uterus, and cervix. In contemporary American society, obesity also carries with it a sometimes devastating social stigma. Obese people are often ostracized, and discrimination against them, especially in hiring and promotion, is common.


[B]Causes of Obesity[/B]

Obesity research has yielded a complicated picture of the underlying causes of the condition. The simple cause is ingestion of more calories than are required for energy, the excess being stored in the body as fat. Inactivity and insufficient exercise can be contributing factors; the less active the person, the fewer calories are needed to maintain normal body weight. Overeating may result from unhealthful patterns of eating established by the family and cultural environment, perhaps exacerbated by psychological distress, an emotional dependence on food, or the omnipresence of high-calorie foods.

In some cases, obesity can come from an eating disorder. It has been shown, for example, that binging for some people releases natural opiates in the brain, providing a sense of well-being and physical pleasure. Other studies have found a strong relationship between obesity in women and childhood sexual abuse.

Some weight-loss experts see obesity as based upon genetics and physiology rather than as a behavioral or psychological problem. For example, rat studies have shown that fat cells secrete a hormone that helps the rat's brain assess the amount of body fat present. The brain tries to keep the amount of that hormone (which also appears to act on the brain area that regulates appetite and metabolic rate) at a set level, resulting in the so-called set point—a weight that the body comes back to, even after resolute dieting. The gene that encodes this hormone, called the obese or ob gene, has been isolated in both rats and humans. In addition, a gene that influences obesity and the onset of diabetes has been identified. It has been estimated that from 8 to 30 different genes may influence obesity.



[B]Treatment[/B]

Radical treatments for weight loss have included wiring shut the jaw, stapling the stomach, and intestinal bypass operations circumventing a large area of the small intestine, limiting the area where food is absorbed. The “diet pills” of the 1960s, essentially amphetamines such as Dexedrine, are now seldom prescribed for weight loss. Fenfluramine and dexfenfluramine, drugs formerly used to achieve short-term weight loss, were withdrawn from the market following concerns that they could cause heart valve damage. Drugs available by the late 1990s included sibutramine (Meridia), which is an appetite suppressant, and orlistat (Xenical), which acts to block absorption of dietary fat in the intestine. In 2007 an over-the-counter version of orlistat was approved by the Food and Drug Administration.

Although the study of obesity is yielding many possibilities for treatment, the main focus remains diet (especially a diet limiting fat calories) and exercise, often coupled with emotional and behavioral support. The long-term weight-loss success of most attempts at dieting, however, is notoriously low. Groups such as Overeaters Anonymous, modeled after Alcoholics Anonymous, give support to people with weight problems and eating disorders.
















[B][U][COLOR="blue"]occupational disease[/COLOR][/U][/B]

An illness incurred because of the conditions or environment of employment. Unlike with accidents, some time usually elapses between exposure to the cause and development of symptoms. In some instances, symptoms may not become evident for 20 years or more.


[B]Sources of Occupational Disease[/B]

Among the environmental causes of occupational disease are subjection to extremes of temperature (leading to heatstroke or frostbite), unusual dampness (causing diseases of the respiratory tract, skin, or muscles and joints) or changes in atmospheric pressure (causing decompression sickness, or the bends), excessive noise (see noise pollution), and exposure to infrared or ultraviolet radiation or to radioactive substances. The widespread use of X rays, radium, and materials essential to the production of nuclear power has led to an especial awareness of the dangers of radiation sickness; careful checking of equipment and the proper protection of all personnel are now mandatory.

In addition there are hundreds of industries in which metal dusts, chemical substances, and unusual exposure to infective substances constitute occupational hazards. The most common of the dust- and fiber-inspired disorders are the lung diseases caused by silica, beryllium, bauxite, and iron ore to which miners, granite workers, and many others are exposed and those caused by asbestos.

Fumes, smoke, and toxic liquids from a great number of chemicals are other occupational dangers. Carbon monoxide, carbon tetrachloride, chlorine, creosote, cyanides, dinitrobenzene, mercury, lead, phosphorus, and nitrous chloride are but a few of the substances that on entering through the skin, respiratory tract, or digestive tract cause serious and often fatal illness.

Occupational hazards also are presented by infective sources. Persons who come into contact with infected animals in a living or deceased state are in danger of acquiring such diseases as anthrax and tularemia. Doctors, nurses, and other hospital personnel are prime targets for the tuberculosis bacillus and for many other infectious organisms.


[B]Worker Protection[/B]

Recognition of the effects of working under deleterious conditions and with harmful substances has resulted in efforts to protect workers from exposure to them. Legislation to prevent or limit the occurrence of occupational disease dates from the Factory Act in England in 1802. Prevention of unhealthy or unsafe working conditions and oversight of healthy and safe workplaces are the responsibility in the United States of the federal Occupational Safety and Health Administration (OSHA) and Environmental Protection Agency, as well as many state agencies. Many occupational abuses have been redressed by litigation and legislation in the United States, and workers' compensation takes care, by a system of insurance, of those who suffer from occupational diseases.

















[B][U]osteomyelitis[/U][/B]

An infection of the bone and bone marrow. Direct infection of bone usually occurs through open fractures, penetrating wounds, or surgical operations. Infecting microorganisms may also reach the bone via the bloodstream, the most common means of bone infection in children. Osteomyelitis is characterized by pain, high fever, and formation of an abscess at the site of infection. Infection may be caused by a variety of microorganisms, including staphylococci, streptococci, and other pathogenic bacteria. Unless treated vigorously with antibiotics and sometimes surgery, bone destruction may result.












[B][U]osteoporosis[/U][/B]

A disorder in which the normal replenishment of old bone tissue is severely disrupted, resulting in weakened bones and increased risk of fracture; osteopenia results when bone-mass loss is significant but not as severe as in osteoporosis. Although osteoporosis can occur in anyone, it is most common in thin white women after menopause.

Bone mass is typically at its greatest during a person's mid-twenties; after that point there is a gradual reduction in bone mass as bone is not replenished as quickly as it is resorbed. In postmenopausal women the production of estrogen, a hormone that helps maintain the levels of calcium and other minerals necessary for normal bone regeneration, drops off dramatically, resulting in an accelerated loss of bone mass of up to 3% per year over a period of five to seven years. Smoking, excessive alcohol consumption, and a sedentary lifestyle increase the risk of bone-mass loss; a diet high in protein and sodium also speed calcium loss. The disorder also has a genetic component. A vitamin D receptor gene that affects calcium uptake and bone density has been identified, and the different forms of this gene appear to correlate with differences in levels of bone density among osteoporosis patients.

Osteoporosis has no early symptoms and is usually not diagnosed until a fracture occurs, typically in the hip, spine, or wrist. A diagnostic bone density test is thus recommended as a preventive measure for women at high risk. Treatment can slow the process or prevent further bone loss. Estrogen replacement therapy for postmenopausal women is effective but has potential side effects. Calcitonin, a thyroid hormone, is administered in some cases. Nonhormonal drugs for the treatment of osteoporosis include alendronate (Fosamax) and risedronate (Actonel), bisphosphonates that decrease bone resorption, and raloxifene (Evista), a selective estrogen receptor modulator that can increase bone mineral density. Teriparatide (Forteo), which consists of the biologically active region of human parathyroid hormone, stimulates the activity of osteoblasts, the specialized cells that form new bone. Dietary and supplemental calcium and vitamin D are usually recommended for people at risk, but a seven-year study of more than 36,000 women over 50 that was released in 2006 found that supplements conferred little benefit. Exercise, including weight training, has been found to strengthen bones directly and to improve muscle strength and balance and thus minimize the chance of falls.

[B][U][CENTER][SIZE="6"]P[/SIZE][/CENTER][/U][/B]



[B][U]pain[/U][/B]

An unpleasant or hurtful sensation resulting from stimulation of nerve endings. The stimulus is carried by nerve fibers to the spinal cord and then to the brain, where the nerve impulse is interpreted as pain. The excessive stimulation of nerve endings during pain is attributed to tissue damage, and in this sense pain has protective value, serving as a danger signal of disease and often facilitating diagnosis. Unlike other sensory experiences, e.g., response to touch or cold, pain may be modified by sedatives and nonsteroidal anti-inflammatory drugs or, if unusually severe, by opioid narcotics. Recently, patient-controlled analgesic techniques have been introduced, in which patients have the option of injecting small quantities of narcotic type analgesics to control their own pain. Microprocessor-controlled injections may be made through intravenous catheters, or through a catheter into the epidural (covering of the spinal cord) area. If such treatments do not suffice and if the cause of the pain cannot be removed or treated, severing a nerve in the pain pathway may bring relief.

Pain is occasionally felt not only at the site of stimulation but in other parts of the body supplied by nerves in the same sensory path; for example, the pain of angina pectoris or coronary thrombosis may extend to the left arm. This phenomenon is known as referred pain. Subjective or hysterical pain originates in the sensory centers of the brain without stimulation of the nerves at the site of the pain.

Progress has been made in the management of chronic pain and in the education of patients and physicians in such techniques as biofeedback, acupuncture, and meditation and the appropriate use of narcotics and other medications. Using advanced medical-imaging technology, researchers have now located multiple pain centers in the cerebral cortex of the brain, offering promise of possible improvements in measuring and managing pain.









[B][U]palpitation[/U][/B]

An abnormal heartbeat that is often associated with a sensation of fluttering or thumping. The normal heartbeat is not noticeable to the individual. Palpitation may be a symptom of organic heart disease or of other body disorders such as an overactive thyroid gland or anemia. In healthy persons palpitation can be brought on by undue exertion, shock, excitement, or stimulants.









[B][U]paraplegia[/U][/B]

It means paralysis of the lower part of the body, commonly affecting both legs and often internal organs below the waist. When both legs and arms are affected, the condition is called quadriplegia. Paraplegia and quadriplegia are caused by an injury or disease that damages the spinal cord, and consequently always affects both sides of the body. The extent of the paralysis depends on the level of the spinal cord at which the damage occurs. For example, damage to the lowest area of the cord may result only in paralysis of the legs, whereas damage farther up on the cord causes possible loss of control over the muscles of the bladder and rectum as well or, if occurring even higher, may result in paralysis of all four limbs and loss of control over the muscles involved in breathing.

Most frequently the cause is an injury that either completely severs the spinal cord or damages some of the nervous tissue in the cord. Such damage could result from broken vertebrae that press against the cord. Diseases that cause paraplegia or quadriplegia include spinal tuberculosis, syphilis, spinal tumors, multiple sclerosis, and poliomyelitis. Sometimes when the disease is treated and cured, the paralysis disappears, but usually the nerve damage is irreparable and paralysis is permanent. Treatment of paraplegia and quadriplegia is aimed at helping to compensate for the paralysis by means of mechanical devices and through psychological and physical therapy.











[COLOR="blue"][B][U]paralysis[/U][/B][/COLOR]

paralysis or palsy may be viewed as complete loss or impairment of the ability to use voluntary muscles, usually as the result of a disorder of the nervous system. The nervous tissue that is injured may be in the brain, the spinal cord, or in the muscles themselves. Accordingly there may be general paralysis, involvement of only one side (hemiplegia), paralysis on both sides at one level (paraplegia or quadriplegia), or localized paralysis in a small group of nerves or muscles.

The cause of paralysis may be any injury that tears or compresses the nerves; it may be hemorrhage, tumor, infection, or substances toxic to nerve tissue. One of the most frequent causes of paralysis is stroke, in which hemorrhage, thrombosis, or obstruction of a cerebral vessel interferes with nerve function. Another disorder in which a resting tremor is one of the main symptoms, accompanied by slowness and poverty of movement, muscular rigidity, and postural instability is Parkinson's disease. Cerebral palsy is due to an injury to the brain motor tissue before or during birth. However, this disorder is nonprogressive. Partial or complete paralysis often accompanies multiple sclerosis.












[B][U]parvovirus[/U][/B]

any of several small DNA viruses that cause several diseases in animals, including humans. In humans, parvoviruses cause fifth disease, or erythema infectiosum, an acute disease usually affecting young children. Symptoms include a rash that spreads from the cheeks (hence the common name slap-cheek disease) to the extremities, low fever, fatigue, and, in adults, mild to severe joint pain and swelling. Treatment consists of bed rest, fluids, and acetaminophen for the fever. Parvoviruses have also been associated with aplastic anemia, arthritis, and spontaneous abortion in humans.

Dogs, wolves, and coyotes can become infected with canine parvovirus. Puppies are most susceptible to the virus, which causes diarrhea, vomiting, and fever. There was an outbreak of canine parvovirus in the United States in 1978, and it has become more common worldwide since then. Feline distemper, also called feline panleukopenia, an often fatal disease of cats, raccoons, and minks caused by a parvovirus, is characterized by fever, dehydration, loss of appetite, and a reduction in white blood cells. Annual vaccination against parvoviruses is routine in cats and dogs.












[B][U]Parkinson's disease[/U][/B]

Parkinson's disease or Parkinsonism,degenerative brain disorder first described by the English surgeon James Parkinson in 1817. When there is no known cause, the disease usually appears after age 40 and is referred to as Parkinson's disease. Parkinsonism usually refers to similar symptoms resulting from head injury, encephalitis, syphilis, carbon monoxide poisoning, cerebral arteriosclerosis, or use of MPTP (a synthetic narcotic). The disorder is also termed paralysis agitans, or shaking palsy.

Parkinson's disease is a debilitating and progressive disorder in which the chemicals that facilitate electrical transmission between nerve cells are depleted. It was the first disease to be treated by drugs that replace deficient neurotransmitters. Symptoms usually begin in middle to later life with trembling of the lips and hands, loss of facial expression, and muscular rigidity. As it progresses it may bring on body tremors, particularly in muscles at rest. Movements become slow and difficult; walking degrades to a shuffle. After many years physical incapacity may occur. Dementia occurs in at least 50% of the patients; depression is also common.

When drugs such as levodopa (L-Dopa) are taken orally, many of the worst symptoms are lessened. New drugs such as pramipexole (Mirapex) and ropinirole (Requip) can delay the need for levodopa. Apomorphine (Apokyn) is used treat episodes of reduced mobility in patients with advanced Parkinson's that responds less effectively to levodopa. Future approaches to treatment include a focus on early detection and slowing progression of the disease. Encouraging results have been reported from surgical insertion of a pacemakerlike device deep in the brain to suppress uncontrolled movements, but surgical transplantation of fetal dopamine-producing cells failed to show significant benefits in a controlled study. Traditional surgery can alleviate some tremors, and physical therapy may help mobility.











[B][U]pellagra[/U][/B]

pellagra is deficiency disease due to a lack of niacin (nicotinic acid), one of the components of the B complex vitamins in the diet. Niacin is plentiful in yeast, organ meats, peanuts, and wheat germ. The disease manifests itself in lesions of the skin and mucous membrane, diarrhea and other gastrointestinal symptoms, neurological derangement, and mental confusion. It is most common in areas where the diet consists mainly of corn, which, unlike other grains, lacks niacin as well as the amino acid tryptophan, which the body uses to synthesize the vitamin. Treatment includes large doses of niacin and the institution of a proper diet to prevent recurrences.









[B][U]pelvic inflammatory disease[/U][/B]

pelvic inflammatory disease (PID), infection of the female reproductive organs, usually resulting from infection with the bacteria that cause chlamydia or gonorrhea. The infection typically first affects the cervical area, then spreads to the uterus, fallopian tubes, ovaries, and abdomen. Symptoms may be absent but usually include pelvic pain and vaginal discharge. PID can cause abscesses and scarring in the fallopian tubes that can block fertilization or interrupt the egg's progress, resulting in ectopic (tubal) pregnancy and loss of the fetus. Over 1 million women are diagnosed with PID each year in the United States; 100,000 typically become infertile.












[B][U]peritonitis[/U][/B]

An acute or chronic inflammation of the peritoneum, the membrane that lines the abdominal cavity and surrounds the internal organs. It is caused by invasion of bacterial agents or irritant foreign matter during rupture of an internal organ, by spreading infection from the female genital tract, by penetrating injuries of the abdominal wall, by dissemination of infections through the blood and lymphatic channels, or by accidental pollution during surgery. Typically, peritonitis is a serious complication of another abdominal disorder, such as appendicitis, ulcers, colitis, or rupture of the gall bladder. Severe abdominal pain, vomiting, prostration, and high fever are predominant symptoms. Treatment includes antibiotic therapy and the identification and elimination of the cause of the infection.











[B][U]phenylketonuria[/U][/B]

An inherited metabolic disorder caused by the absence of a specific enzyme (phenylalanine hydroxylase). The absence of this enzyme, a recessive trait, prevents the body from making use of phenylalanine, one of the amino acids in most protein-rich foods, and almost always leads to mental retardation and schizoid changes; convulsions also commonly occur. Early diagnosis and treatment, which includes a carefully regulated low-phenylalanine diet begun during the first few weeks of life, may prevent serious mental deficiency. Positive improvement has been seen even when therapy is started in well-established cases. Most states have made the PKU blood or urine test mandatory for all newborn infants.












[B][U]phlebitis[/U][/B]

An inflammation of a vein. Phlebitis is almost always accompanied by a blood clot, or thrombus, in the affected vein, a condition known as thrombophlebitis. Blood-clot formation may follow injury or be associated with infections. Thrombophlebitis of deep veins, usually in the legs or pelvis, may occur in patients recovering from childbirth, surgery, or other conditions requiring prolonged bedrest; the clotting mechanism is thought to be impaired when the legs are immobilized. Pregnancy or the use of oral contraceptives predisposes some women to thrombophlebitis. The major danger is that a clot originating in the leg vein may dislodge and travel to the lung, a condition known as pulmonary embolism. To avoid the risk of embolism, thrombophlebitis is usually treated with anticoagulants.











[B][U][COLOR="blue"]pimple[/COLOR][/U][/B]

small pointed elevation of the skin that may or may not contain pus. The formation of pimples is frequently associated with infection, irritation, or overactivity of the sebaceous and sweat glands. Repeated eruptions of pimples are often termed acne.










[COLOR="blue"][B][U]plague[/U][/B][/COLOR]

any contagious, malignant, epidemic disease, in particular the bubonic plague and the black plague (or Black Death), both forms of the same infection. These acute febrile diseases are caused by Yersinia pestis (Pasteurella pestis), discovered independently by Shibasaburo Kitasato and Alexandre Yersin in 1894, a bacterium that is transmitted to people by fleas from rats, in which epidemic waves of infection always precede great epidemics in human populations. Sylvatic plague, still another form, is carried by other rodents, e.g., squirrels, rabbits, chipmunks, in rural or wooded areas where they are prevalent.

Bubonic plague, the most common form, is characterized by very high fever, chills, prostration, delirium, hemorrhaging of the small capillaries under the skin, and enlarged, painful lymph nodes (buboes), which suppurate and may discharge. Invasion of the lungs by the organism (pneumonic plague) may occur as a complication of the bubonic form or as a primary infection. Pneumonic plague is rapidly fatal and is the only type that can be spread from person to person (by droplet spray) without intermediary transmission by flea. In the black form of plague, hemorrhages turn black, giving the term “Black Death” to the disease. An overwhelming infection of the blood may cause death in three or four days, even before other symptoms appear.

In untreated cases of bubonic plague the mortality rate is approximately 50%–60%; pneumonic plague is usually fatal if not treated within 24 hours. Such antibiotics as streptomycin and tetracycline greatly reduce the mortality rate. Vaccine is available for preventive purposes. Rodent control is important in areas of known infection.


[B]History[/B]

The earliest known visitation of the plague to Europe may have occurred in Athens in 430 B.C., but it is unclear if the disease that afflicated Athens was caused by Yersina pestis. A disastrous epidemic occurred in the Mediterranean during the time of the Roman emperor Justinian; an estimated 25% to 50% of the population is reported to have succumbed. The most widespread epidemic began in Constantinople in 1334, spread throughout Europe (returning Crusaders were a factor), and in less than 20 years is estimated to have killed three quarters of the population of Europe and Asia. The great plague of London in 1665 is recorded in many works of literature. Quarantine measures helped contain the disease, but serious epidemics continued to occur even in the 19th cent. The disease is still prevalent in parts of Asia, and sporadically occurs elsewhere (approximately 2,500 cases worldwide annually). In Surat, India, in 1994, 5,000 cases of pneumonic plague were reported in an outbreak; an estimated 100 people died, and more than 400,000 people fled the city. Because the number of cases of plague has been increasing annually, it is categorized as a re-emerging infectious disease by the World Health Organization.












[B][U]pleurisy[/U][/B]

inflammation of the pleura (the membrane that covers the lungs and lines the chest cavity). It is sometimes accompanied by pain and coughing. The inflammation may be dry or it may be accompanied by an effusion, or fluid, that fills the chest cavity; when the effusion is infected, the condition is known as empyema. The dry type of pleurisy usually occurs in association with bacterial infections such as pneumonia. Pleurisy with effusion is often associated with such chronic lung conditions as tuberculosis or tumors. Immune disorders such as lupus and rheumatic fever tend to have recurrent pleurisy, with or without effusion. Epidemic pleurodynia, a pleurisy attributed to a virus, is a mild disease of short duration. Treatment of pleurisy is directed at the underlying condition as well as the symptoms.












[B][U]pneumoconiosis[/U][/B]

chronic disease of the lungs. Primarily an occupational disease of miners, sandblasters, and metal grinders, it is a result of repeated inhalation of dusts, including iron oxides (e.g., rust and filings), silicates (e.g., talc and rock dust), and carbonates (especially coal dust). Particles collect in the lungs and become sites for the formation of fibrous nodules. As the disease progresses, fibrous tissue increasingly replaces elastic lung tissue. Loss of lung function is signaled by shortness of breath, wheezing, coughing, and difficulty in expectorating. A heart deficiency called cor pulmonale may develop in severe cases. Sufferers are particularly vulnerable to infectious lung diseases such as tuberculosis. Pneumoconiosis is incurable and treatment is purely symptomatic. Because the inhaled dusts cause darkening of the lung tissue, the disease is also known as black lung. Silicosis, the form of the disease prevalent among miners, is commonly called miner's lung.












[B][U]pneumothorax[/U][/B]

collapse of a lung with escape of air into the pleural cavity between the lung and the chest wall. The cause may be traumatic (e.g., gunshot or stab wound), spontaneous (rupture due to disease or localized weakness of the lung lining), or environmental (extreme change in atmospheric pressure). The only symptom may be a sudden pain in the chest. Physical and radiological examination reveals characteristic signs of lung collapse. Simple pneumothorax of only one lung generally requires only rest; the break in the pleura usually heals quickly after collapse of the lung has taken place. In tension pneumothorax (where there is high intrapleural pressure), or if both lungs are collapsed, it is mandatory to remove the air from the pleural cavity immediately. An artificial pneumothorax is one deliberately induced, as in the treatment of tuberculosis of the lung before modern drugs became available, or in the diagnosis of lung disease.












[B][U]pneumonia[/U][/B]

acute infection of one or both lungs that can be caused by a bacterium, usually Streptococcus pneumoniae. or by a virus, fungus, or other organism. The causal organisms reach the lungs through the respiratory passages. Usually an upper respiratory infection precedes the disease. Alcoholism, extreme youth or age, debility, immunosuppressive disorders and therapy, and compromised consciousness are predisposing factors. When one or more entire lobes of the lung are involved, the infection is considered a lobar pneumonia. When the disease is confined to the air spaces adjacent to the bronchi, it is known as bronchopneumonia. Aspiration pneumonia is the pathological consequence of the abnormal entry of fluids, particulate matter, or secretions in the lower airways.

The symptoms of pneumonia are high fever, chills, pain in the chest, difficulty in breathing, cough, and sputum that is pinkish at first and becomes rust-colored as the infection progresses. The skin may turn bluish because the lungs are not sufficiently oxygenating the blood. Complete bed rest and good supportive care are important. Oxygen helps to relieve severe respiratory difficulty.

Immunization for pneumococcal pneumonia is recommended for children under two years old, adults 65 or older, and others at risk. Penicillin is most commonly used to treat pneumococcal pneumonia and other pneumonias caused by bacteria and, with the other antibiotic and sulfa drugs, is responsible for the marked decline since the mid-20th cent. in mortality figures. Nevertheless, pneumonia is still a serious disease, especially in elderly and debilitated persons (who usually acquire bronchopneumonia) or when complicated by bacterial invasion of the bloodstream, membranes of the heart, or the central nervous system.

Viral pneumonia, generally milder than the bacterial form, is the result of lower respiratory infection and has been the cause of more than 90% of deaths for individuals over 65. Pneumocystis carinii pneumonia, which is caused by an organism traditionally thought to be a parasitic protozoan but now suspected to be a fungus, generally only occurs in patients who have AIDS or leukemia or whose immune system is otherwise suppressed.

[B][U]poison[/U][/B]

any agent that may produce chemically an injurious or deadly effect when introduced into the body in sufficient quantity. Some poisons can be deadly in minute quantities, others only if relatively large amounts are involved. Factors of importance in determining the severity of a poison include the nature of the poison itself, the concentration and amount, the route of administration, the length of exposure, and the age, size, and physical health of the individual. If poisoning is suspected a physician or poison control center should be called immediately. The remainder of the poison and its container should be saved; the label may list ingredients, first aid measures, or antidotes. For most ingested poisons emptying the stomach is the most important treatment; vomiting is best accomplished in the conscious individual by administering syrup of ipecac with large quantities of water. The major exceptions to this treatment are in cases of ingestion of corrosives, such as lye, and certain hydrocarbons, such as kerosene. In corrosive ingestions a small amount of milk may be given, but vomiting should not be induced since the damage that may have already been sustained by the mucous membranes of the esophagus and stomach may advance to perforation; the patient should be seen by a physician as soon as possible. Hydrocarbons are extremely volatile, and the dangers of their being aspirated into the lungs when vomiting is induced are greater than their toxicity if absorbed into the body. In gas or vapor poisoning the patient should be carried to a nonpolluted atmosphere; artificial respiration should be employed if necessary. If any poison has been absorbed through the skin, all contaminated garments should be removed immediately and the skin washed with soap and water. Poisoning is a significant cause of accidental death in children and is best treated by prevention; potential poisons in the home should be stored in locked cabinets. In chemistry, poison refers to a substance that inhibits or slows a chemical reaction. See separate articles on botulism; carbon monoxide; food poisoning; lead poisoning; mercury poisoning; poison gas; poison ivy; snakebite; toxin.












[B][U][COLOR="blue"]poliomyelitis[/COLOR][/U][/B]

poliomyelitis or polio,or infantile paralysis is an acute viral infection, mainly of children but also affecting older persons. There are three immunologic types of poliomyelitis virus; exposure to one type produces immunity only to that type, so infection with the other types is still possible. Spread of the infection is primarily through contact with an infected person. Most people who contract polio either exhibit no symptoms or experience only minor illness; however, such individuals can harbor the virus and spread it to others. Less than 1% of the people who get infected develop paralysis.

The virus enters the body by way of the mouth, invades the bloodstream, and may be carried to the central nervous system, where it causes lesions of the gray matter of the spinal cord and brain. The illness begins with fever, headache, stiff neck and back, and muscle pain and tenderness. If there is involvement of the central nervous system, paralysis ensues. Of those patients who develop paralytic poliomyelitis, about 25% sustain severe permanent disability, another 25% have mild disabilities, and 50% recover with no residual paralysis. The disease is usually fatal if the nerve cells in the brain are attacked (bulbar poliomyelitis), causing paralysis of essential muscles, such as those controlling swallowing, heartbeat, and respiration. There is no specific drug for treatment. For reasons not clearly understood, some people who have had severe polio experience postpolio syndrome, a condition in which new weakness and pain occurs years later in previously affected muscles.

The incidence of poliomyelitis declined radically in the United States when a mass immunization program with the Salk vaccine, a preparation made from killed organisms and injected, was begun in 1955. By 1961 the Sabin vaccine, a preparation made from weakened living organisms and taken orally, was released for use. Since then the disease has been virtually eliminated in the Americas, Europe, and Australasia, but vaccination programs continue because of polio's existence in other parts of the world (mainly South Asia and parts of East and West Africa) and the ease of travel.

In 1988 the World Health Organization began a global vaccination campaign to eradicate the disease—which continued to paralyze hundreds of thousands of children each year—by 2000. Although the date of eradication was later pushed back to 2005 (and even later a set deadline was abandoned), by 2003 there were less than a thousand new cases of polio worldwide. In 2003–4 the campaign was slowed when Muslim states in N Nigeria refused to use vaccines they believed would sterilize women, leading to an increase in cases there and in neighboring countries and to outbreaks of the disease in 17 countries including Yemen and Indonesia. Some other African countries also experienced new outbreaks of the disease from other sources. However, by early 2007, polio was, according to WHO, endemic in India, Pakistan, Afghanistan, and Nigeria. Other experts also classified cases in Somalia and Ethiopia as endemic, and the status of the disease in Congo (Kinshasa), where civil war had long disrupted medical care, was unclear.










[B][U]polycythemia[/U][/B]

condition characterized by an increase in the production of red blood cells, or erythrocytes, in the blood. Primary polycythemia, also called erythremia, or polycythemia vera, is a chronic, progressive disease, most common in middle-aged men. It is characterized by overgrowth of the bone marrow, abnormally increased red blood cell production, and an enlarged spleen. Symptoms, include headache, inability to concentrate, and pain in the fingers and toes. There is a danger of blood clotting or hemorrhage (see thrombosis). Primary polycythemia is treated by radiation, periodic removal of some blood (phlebotomy), or chemotherapy with antimetabolite drugs, e.g., Cytoxan. In secondary polycythemia, or erythrocytosis, the proliferation of red blood cells results from the body's attempt to compensate for other conditions, such as prolonged lack of oxygen at high altitudes or chronic lung or heart insufficiency. Certain tumors are also associated with increased red blood cell production. In secondary polycythemia the treatment is directed toward the underlying cause.












[B][U][COLOR="blue"]polyp[/COLOR][/U][/B]

polyp, in medicine, a benign tumor occurring in areas lined with mucous membrane such as the nose, gastrointestinal tract (especially the colon), and the uterus. Some polyps are pedunculated tumors, i.e., they grow on stems; others, attached by a broad base, are called sessile. Nasal polyps are usually associated with an allergic condition; since they interfere with breathing, it is advisable that they be removed. Uterine and gastrointestinal polyps are likely to cause bleeding, but, more important, they may undergo malignant degeneration and for this reason are also usually removed.













[COLOR="blue"][B][U]prostate cancer[/U][/B][/COLOR]

The canceroriginating in the prostate gland. Prostate cancer is the leading malignancy in men in the United States and is second only to lung cancer as a cause of cancer death in men. It occurs predominantly in older men; the median age at diagnosis is 72 years. Black men have a higher incidence than white men. The cause of prostate cancer is unknown, but the incidence varies markedly by geographic region, an indication that there are environmental factors that may trigger the disease. For example, men in China and Japan have a low rate of prostate cancer, but the incidence rises in Chinese and Japanese men who move to the United States. The hormone testosterone is believed to have a role in the development of prostate cancer, and studies have shown a relationship between high dietary fat intake and increased testosterone levels. Prostate tumors are often slow growing. Around 95% are classified as adenocarcinomas (arising from epithelial glandular tissue). The most common site of metastasis is the bone.


[B]Screening and Diagnosis[/B]

Traditionally, prostate cancer screening consisted of digital-rectal examination. Since 1986, however, a blood test for a tumor marker called prostate-specific antigen (PSA) has greatly increased the number of early-stage prostate cancers diagnosed. An elevated level of PSA can indicate the presence of prostatic malignancy. Elevated PSA is further investigated by an ultrasound test and needle biopsy, in which a fine needle is inserted into the gland and cells are extracted for laboratory analysis. In some cases a bone scan is also performed to rule out metastatic disease. Because PSA tests detect not only aggressive cancers but slow-growing cancers that are not life-threatening, many people disagree with routine PSA testing of asymptomatic men, fearing that the test might lead to unnecessary anxiety or treatments that compromise quality of life without assuring a longer life than a man ignorant of his condition would enjoy.


[B]Treatment[/B]

For most patients with localized tumors, surgical removal of the prostate gland (prostatectomy) is the initial treatment, despite possible side effects of urinary incontinence and impotence. Localized prostate cancer can often be cured. After surgery, a repeated blood test for protein-specific antigen can indicate whether any cancer remains. In metastatic disease, other treatments are employed depending on the stage of the disease and the age and health of the patient. Treatment options include external-beam radiation, implantation of radioactive isotopes, and palliative surgery. Hormonal manipulation by giving estrogens or other drugs, or by orchiectomy (removal of the testes), is sometimes used to decrease levels of testosterone. Very small cancers or slow-growing cancers in older men are sometimes watched, but not treated, without compromising life expectancy. Experimental treatments under investigation include cryosurgery, destroying the tumor by freezing.











[B][U]premenstrual syndrome[/U][/B]

premenstrual syndrome (PMS), any of various symptoms experienced by women of childbearing age in the days immediately preceding menstruation. It is most common in women in their twenties and thirties. Some 70%–90% of menstruating women are said to have PMS on a cyclical basis. There are over 150 symptoms associated with the syndrome, including behavioral changes, eating binges, moodiness, irritability, fatigue, fluid retention, breast tenderness, and headaches. Some women have mild symptoms; others have symptoms that interfere with work or home life. A few are completely incapacitated, a condition called premenstrual dysphoric disorder. The symptoms vary from woman to woman, and each woman's symptoms may vary from month to month, making diagnosis difficult.

The exact cause is unknown. Hormonal imbalances, nutritional deficiencies, and neurotransmitter (serotonin and norepinephrine) fluctuations are being studied. PMS patients who have had hysterectomies may continue to have symptoms, but the symptoms in all patients disappear with menopause. There is no cure for PMS. In some women, dietary changes and exercise provide some relief through the loss of water weight, the alleviation of stress, and an increase in the production of endorphins. Antidepressants or antianxiety drugs are sometimes prescribed. In severe cases hormones that induce a premature menopause may be administered.











[B][U][COLOR="blue"]prickly heat[/COLOR][/U][/B]

prickly heat (miliaria), inflammatory skin eruption due to obstruction of the sweat glands by keratin, the substance that forms the horny cells of the epidermis. It consists of blisterlike elevations with burning and itching, and is common in infants, obese persons, and those exposed to a hot, moist atmosphere for long periods of time. Relief may be obtained by applying soothing and drying lotions.











[B][U]prion[/U][/B]

An infectious agent thought to cause a group of diseases known as prion diseases. or transmissible spongiform encephalopathies. Well-known prion diseases are Creutzfeldt-Jakob disease (CJD) and kuru in humans, scrapie in sheep, bovine spongiform encephalopathy (BSE), also called “mad cow disease,” in cattle, and chronic wasting disease in deer and elk (wapiti). There is no effective treatment for any prion disease.

Sometimes taking more than 30 years to display symptoms, the diseases slowly attack brain tissue, often leaving spongelike holes. They are characterized by accumulations of abnormal forms of a protein, called prion protein, which, unlike viruses or bacteria, contain no genetic material and have no known ability to reproduce themselves. Normal prion proteins occur naturally in brain tissue. The abnormal form differs in shape from the normal prions and is not susceptible to enzymes that normally break down proteins. In the brain, abnormal prions appear to increase their number by directly converting normal prions.

Prion diseases have both infectious and hereditary components. The gene that codes for prions can mutate and be passed on to the next generation. Most of the diseases also can be acquired directly by infection, but unlike other infectious agents, prions provoke no immune response.

An epidemic of BSE in Great Britain that was diagnosed in 1986 and infected some 178,000 cows appears to have been caused by a protein feed supplement that contained rendered remains of scrapie-infected sheep brains. In 1996 a suspicion that BSE had been transmitted to humans who died of a variant of CJD in Britain caused a scientific and economic furor as the European Union imposed a ban (1996) on the export of British beef, which was partially lifted in 1999 and fully lifted in 2006. The U.S. Dept. of Agriculture banned the import of cattle and many cattle byproducts from most European nations because of BSE. Instances of BSE in cattle have also occurred in many other European countries, Canada, the United States, and Japan, but the vast majority of cases occurred in Britain in the 1980s. There is now compelling evidence that BSE is the same disease as variant CJD (vCJD), which ultimately killed more than 130 people, but it is not yet known exactly how the disease is passed from animals to humans.

The idea of disease-causing protein particles was first put forward in 1981 by Stanley B. Prusiner, the neurologist who coined the term prion (from proteinaceous infectious particle). The prion theory has been controversial from the beginning, and although scientific evidence for the existence of such infectious particles has increased, an exact causal link between prions and the diseases they are believed to cause remains to be established. Critics believe that these diseases are caused by unidentified viruses.











[B][U]prostatitis[/U][/B]

The inflammation of the prostate gland. Acute prostatitis is usually a result of infection in the urinary tract or infection carried by the blood; in many cases the infection spreads from the urethra and is contracted through sexual transmission. Symptoms include fever, low back pain, and difficulty or pain in urination; the gland is tender and swollen. Infection, caused by a variety of pathogenic bacteria and certain protozoans, is treated by an appropriate antibiotic. Healing is usually complete, but the condition may become chronic if the infecting organism persists.










[B][U]psittacosis[/U][/B]

psittacosis or parrot fever is an infectious disease caused by the species of Chlamydia psittaci and transmitted to people by birds, particularly parrots, parakeets, and lovebirds. In birds the disease takes the form of an intestinal infection, but in people the illness runs the course of a virus pneumonia; infection follows inhalation of dust from feathers or cage contents or the bite of an infected bird. Human psittacosis, which can be transmitted to others by cough droplets and sputum, is treated the same as pneumonia. The mortality rate may run as high as 30%. Restrictions on bird importation and attention to infected flocks of pigeons have been used to control the disease. Treatment with tetracycline antibiotic is usually effective.









[B][U]psoriasis[/U][/B]

occasionally acute but usually chronic and recurrent inflammation of the skin. The exact cause is unknown, but the disease appears to be an inherited, possibly autoimmune disorder that causes the overproduction of skin cells. Psoriasis may occur at any age but is uncommon in children. The characteristic lesion is a scaly “mother-of-pearl” patch, appearing anywhere on the body. Involvement may range from a single plaque to numerous patches that cover most of the skin. A variety of treatments are used for patients with mild to moderate cases. Treatments directed at the symptoms include the application of ointments and exposure to sunlight and ultraviolet (UVB) light. Retinoids help stabilize follicular epithelial cells. Vitamin D analogs and metabolites, although effective in treatment, have side effects. Photochemotherapy (psoralen combined with UVA radiation) is also effective, but increases the risk of skin cancer. Alfacept and other drugs that interfere with T-cell activation, and etanercept, infliximab, and other drugs that block tumor-necrosis factor are effective in many patients with moderate to severe psoriasis.









[B][U]pus[/U][/B]

thick white or yellowish fluid that forms in areas of infection such as wounds and abscesses. It is constituted of decomposed body tissue, bacteria (or other micro-organisms that cause the infection), and certain white blood cells. These white cells form one of the defense mechanisms of the body. Known as phagocytes, they rush to the area of infection and engulf the invading bacteria in a process called phagocytosis. Many white cells themselves succumb in the process and become one of the constituents of pus.











[B][U]pyorrhea[/U][/B]

inflammation and degeneration of the gums and other tissues surrounding the teeth. The onset of the disease is marked by bleeding of the gums. As the disease proceeds, the gums recede from the teeth, loosening of the teeth occurs, and the bone supporting the teeth is resorbed. Pus is discharged from pockets in the gums, which are formed as the jawbone recedes from the roots of the teeth. Pyorrhea, known medically as pyorrhea alveolaris, is most common in persons over 40. There are numerous possible causes, toward which therapy is directed, including poor nutrition, poor oral hygiene, ill-fitting dentures, and irritation of the tissues by dental tartar.

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[B][U]rabies[/U][/B]

rabies or hydrophobia is an acute viral infection of the central nervous system in dogs, foxes, raccoons, skunks, bats, and other animals, and in humans. The virus is transmitted from an animal to a person, or from one animal to another, via infected saliva, most often by biting but also by the contact of torn skin with infected saliva. The virus travels from the bite or contact location to the spinal cord and brain. In humans the incubation period ranges from 10 days to a year or more. Symptoms are fever, uncontrollable excitement, and pronounced spasms of the throat muscles. Salivation is extreme, and despite great thirst the victim cannot swallow water; hence the misnomer hydrophobia (fear of water). Once symptoms develop, death (caused by convulsions, exhaustion, or paralysis) is usually inevitable.

Following a bite from a rabid or possibly rabid animal, preventive treatment involves administration of immune globulin for passive immunization followed by vaccinations over several weeks for active immunization. The only treatment after symptoms appear is rest and sedation. Dogs have been immunized from the time Louis Pasteur demonstrated a successful vaccine in 1885. Since then, human rabies has become rare in the United States and other industrialized countries due to comprehensive vaccination programs for domestic animals. Mass vaccination of susceptible animals in the wild with vaccine-laced bait has been used in an effort to stem an increase of rabies cases in the United States and Canada that began in the late 1980s. A similar wild animal vaccination program has been used with some success in parts of Europe.






[B][U]radiation sickness[/U][/B]

A harmful effect produced on body tissues by exposure to radioactive substances. The biological action of radiation is not fully understood, but it is believed that a disturbance in cellular activity results from the chemical changes caused by ionization (see ion). Some body tissues are more sensitive to radiation than others and are more easily affected; the cells in the blood-forming tissues (bone marrow, spleen, and lymph nodes) are extremely sensitive. Radiation sickness may occur from exposure to a single massive emanation such as a nuclear explosion (such as Hiroshima and Nagasaki), or it may occur after repeated large exposure or to even very small doses in a plant or laboratory, since radiation effects are cumulative. Moreover, exposure to the ultraviolet radiation of the sun can cause tissue destruction and trigger mutations that can lead to skin cancer. Radiation sickness may be fairly mild and transitory, consisting of weakness, loss of appetite, vomiting, and diarrhea. Since even in a mild dose of radiation the blood-forming tissue is destroyed to some extent, there is a reduction in the supply of blood cells and platelets. This increases the tendency to bleed and reduces the body's defense against infection. After a massive dose of radiation the reaction may be so severe that death quickly ensues. This is usually due to severe anemia or hemorrhage, to infection, or to dehydration. Extremely high doses damage the tissues of the brain, and death usually follows within 48 hr, as was demonstrated at Chernobyl. There is no treatment for radiation sickness, although it is sometimes possible for persons to survive otherwise lethal doses of radiation if bone marrow transplants are performed. Potassium iodide is to protect against thyroid cancer from radiation exposure, but the drug should ideally be taken four hours prior to the exposure. Exposure to radiation can cause genetic mutation; the progeny of those subjected to excessive radiation tend to show deleterious genetic changes. The genetic damage from the atomic bombs dropped on Japan is still evident and such damage will continue to surface in people directly affected by the nuclear diasaster at Chernobyl. Persons working with radioactive materials or X rays protect themselves from excessive exposure to radiation by shields and special clothing usually containing lead. Processes involving radioactive substances are observed through thick plates of specially prepared glass that exclude the harmful rays. A dosimeter, a device measuring the amount of radiation to which an individual has been exposed, is always worn by persons working in radioactive areas.










[B][U][COLOR="blue"]rash[/COLOR][/U][/B]

nonspecific term for an eruption of the skin. It may result from skin allergy, skin irritation, or skin disease, or it may be a symptom of a systemic disease like measles, smallpox, or scarlet fever. A rash may appear as discolored spots or a general redness, or as blisters or pustules, either flat or raised above the surface of the skin. The rash may cause skin irritation—itching, tingling, burning, or pain—or it may not cause any discomfort. The appearance and distribution of a rash are often important factors for consideration in diagnosing a particular disease.










[B][U]repetitive stress injury[/U][/B]

repetitive stress injury or repetitive strain injury(RSI), injury caused by repeated movement of a particular part of the body. Often seen in workers whose physical routine is unvaried, RSI has become epidemic since computers have entered the workplace in large numbers. Many RSIs develop when the sheaths that cover muscle tendons swell and press on nerves. Constant typing can cause one form of RSI, carpal tunnel syndrome, a sometimes disabling pain and tingling in the thumb and first two fingers. It is caused by swelling and pressure on the median nerve passing through the wrist. Other common problems are rotator cuff injury, from overuse of the shoulder; tennis elbow, inflammation of a tendon in the elbow from overuse of the forearm; and back injuries from repeated heavy lifting. A 1998 report by the National Academy of Sciences in the United States called RSI a serious national problem, with financial costs ranging up to $20 billion annually.

Treatment of RSI usually begins with attempts to change the conditions that caused the injury. Often, exercises and anti-inflammatory drugs are prescribed; in some cases surgery is necessary. Many workers' compensation cases and lawsuits relating to RSI have been brought against employers and product manufacturers. To avoid the high costs of RSI, some businesses have introduced ergonomic workstations and enforced rest periods.










[B][U]Reye's syndrome[/U][/B]

rare but life-threatening disease characterized by acute encephalopathy and fatty infiltration of internal organs, especially the liver. It occurs almost entirely in children under age 15. The cause is unknown, but the disease usually follows an acute viral infection (particularly influenza or chicken pox), especially when aspirin or other salicylates have been given. The symptoms, which occur about a week after the virus infection, are vomiting and disorientation; these may be followed by seizures, coma, and respiratory arrest. Treatment is directed toward reducing brain swelling, correcting blood chemistry changes due to liver damage, and providing respiratory support if needed. Doctors recommend that children be given acetaminophen rather than aspirin for viral infections or fever.












[B][U]rheumatic fever[/U][/B]

systemic inflammatory disease, extremely variable in its manifestation, severity, duration, and aftereffects. It is frequently followed by serious heart disease, especially when there are repeated attacks. Rheumatic fever usually affects children. It is closely related to a preceding streptococcal infection (e.g., streptococcal tonsillitis or pharyngitis). Some of its symptoms are tenderness and inflammation about the joints, fever, jerky movements, nodules under the skin, and skin rash. If inflammation of the heart, or myocarditis, is mild, there is no permanent heart damage, but if the valves of the heart become inflamed, they may become scarred and deformed, permanently impairing their function. Such heart damage can sometimes be corrected by surgery.













[COLOR="blue"][B][U]rickets[/U][/B][/COLOR]

bone disease caused by a deficiency of vitamin D or calcium. Essential in regulating calcium and phosphorus absorption by the body, vitamin D can be formed in the skin by ultraviolet rays contained in sunlight; it can also be consumed in such foods as fish oils, eggs, and butter. Since calcium and phosphorus are essential for proper development and hardening of bones, the disease manifests itself in children as softening of bones, abnormal bone growth, and enlargement of cartilage at the ends of long bones. Where bones must support weight, such as the legs and pelvis, the skeleton is likely to become bent or deformed. The result is often knock-knees, bowlegs, and deformities of the chest and pelvis. In temperate climates or the tropics, vitamin-D deficiency usually results from poor diet rather than from lack of exposure to ultraviolet rays of sunlight. Rickets is no longer common in developed countries because milk is readily obtained and is usually fortified with vitamin D; infants commonly receive vitamin D as a supplement. Treatment of rickets is largely preventive, i.e., by early recognition and by including adequate amounts of vitamin D and calcium in the diet.










[COLOR="blue"][B][U]rickettsia[/U][/B][/COLOR]

any of a group of very small microorganisms, many disease-causing, that live in vertebrates and are transmitted by bloodsucking parasitic arthropods such as fleas, lice (see louse), and ticks. Rickettsias are named after their discoverer, the American pathologist Harold Taylor Ricketts, who died of typhus in Mexico after confirming the infectious agent of that rickettsial disease. Rickettsias are gram-negative, coccoid-shaped or rod-shaped bacteria; unlike other bacteria, but like viruses, they require a living host (a living cell) to survive. Rickettsias from infected vertebrates, usually mammals, live and multiply in the gastrointestinal tract of an arthropod carrier but do not cause disease there; they are transmitted to another vertebrate, possibly one of another species, by the arthropod's mouthparts or feces.

[B]Types of Rickettsial Diseases[/B]

Rickettsia prowazekii causes louse-borne typhus, carried from person to person by two species of lice. Flea, or murine, typhus, caused by R. mooseri, is transmitted from rodents to people by fleas. Trench fever, caused by R. quintana, was an epidemic disease in World War I; it is transmitted by the rat flea from rat to person or from person to person. Trench fever disease reservoirs (perpetuation of the disease in wild animal populations) exist in some parts of E Europe, Mexico, and N Africa. Various typhuslike rickettsial diseases, such as Rocky Mountain spotted fever and African tick typhus, are transmitted by ticks from animal hosts to people. Mite-borne rickettsial infections include rickettsialpox, caused by Rickettsia akari and transmitted from house mice to people, and scrub typhus, or tsutsugamushi fever, caused by R. tsutsugamushi and found in Japan and SE Asia. Q fever, caused by Coxiella burnetii, a more hardy rickettsia viable outside the living host, is usually transmitted to humans by inhalation of contaminated airborne particles or from contaminated materials, often from infected livestock; it is an occupational hazard among dairy farm and slaughterhouse workers. A new rickettsia, Ehrlichia chaffeenis, which results in human ehrlichiosis, was identified in 1986.


[B]Symptoms and Treatment[/B]

The similar symptoms of rickettsial infections often make it difficult to distinguish one disease from another. In people the organisms grow in cells lining blood and lymph vessels; a rash, fever, and flulike symptoms are usually present. Q fever also causes lung damage. All rickettsial diseases respond to treatment with antibiotics such as doxycycline (a tetracycline) and chloramphenicol.










[B][U]rigor mortis[/U][/B]

rigidity of the body that occurs after death. The onset may vary from about 10 min to several hours or more after death, depending on the condition of the body at death and on factors in the atmosphere, particularly temperature. Rigor mortis affects the facial musculature first and then spreads to other parts of the body. It is caused by chemical changes in the muscle tissue. The state of rigor usually lasts about 24 hours or until muscle decomposition takes place by acid formation.











[B][U]ringworm[/U][/B]

superficial eruption of the skin caused by a fungus, chiefly Microsporum, Trichophyton, or Epidermophyton. Any area of the skin may be affected, including the scalp and nails, but the most common site is the feet. That disorder is often called athlete's foot in the belief that the infection is contracted during the use of communal shower facilities. Actually, fungi are present on the bodies of most persons, but some individuals are more resistant to fungus invasion than others. Moreover, a prolonged moist, airless condition caused by excessive perspiration may subject a formerly resistant person to fungus invasion. Ringworm infection causes dry, scaly patches or blisterlike elevations, usually with burning or itching. Griseofulvin, a modified form of penicillin, is effective against scalp infection but is ineffective against foot fungi. In mild cases of athlete's foot, often the only treatment is to keep the feet scrupulously dry. In more persistent cases local antifungal ointments, sprays, or soaks are recommended.










[B][U]river blindness[/U][/B]

river blindness or onchocerciasis means disease caused by the parasitic nematode worm Onchocerca volvulus. The worm larvae are transmitted by the bites of blackflies (genus Simulium) that live in fast moving streams. Inside the body the worms form disfiguring skin nodules, where they mate. Their tiny larvae, or microfilariae, migrate through the skin, causing severe itching. If the infection reaches the area of the eye, allergic reaction to the microfilariae can cause blindness.

Tests can now detect infestation before the disease has progressed, and the new drugs ivermectin, which kills the larvae, and amocarzine, which kills adult forms, have begun to help control the disease. Blackfly eradication programs have had limited success because the flies can quickly develop resistance to pesticides.

River blindness, which occurs primarily in Africa, Central and South America, and Yemen, affects an estimated 18 million people. In Africa, two strains have been identified, a savanna strain and a forest strain. The forest strain does not usually lead to blindness, but it does cause severe skin symptoms (lesions, itching, discoloration, change in texture) that can result in social ostracism.








[B][U]rubella[/U][/B]

rubella or German measles can be defined as acute infectious disease of children and young adults. It is caused by a filterable virus that is spread by droplet spray from the respiratory tract of an infected individual. Rubella is a much milder infection than rubeola (measles) and the rash, appearing after an incubation period of two to three weeks, rarely lasts more than three days. The lymph nodes behind the ears become tender and swollen, but otherwise German measles is almost always uncomplicated. However, during the first trimester of pregnancy it is associated with an increased risk of congenital damage to the fetus, producing stillbirths, abortion, low birth weight, and such malformations as cardiac defects, eye defects (especially cataracts), and mental retardation. During the first 16 weeks of pregnancy the infection has been estimated to carry a risk of fetal damage of between 30% and 35%. Pregnant women who have been exposed to rubella are given gamma globulin in an effort to prevent the disease. Research to develop a vaccine that would confer immunity was spurred by an epidemic of rubella in 1964 and the evidently related rise in the number of birth deformities. A live attenuated vaccine has been developed and is given to girls from 15 months to puberty and often to boys as well. Approximately 13% to 15% of women develop acute arthitis from vaccination. Before the vaccine can be administered to an adult woman it must be determined that she is not pregnant, and the test for the presence of rubella antibodies (which would indicate immunity to the disease from previous exposure) is given. Birth control should be practiced for at least three months after receiving the vaccine.

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[B][U]salmonellosis[/U][/B]

any of a group of infectious diseases caused by intestinal bacteria of the genus Salmonella, including typhoid fever, paratyphoid fever, blood poisoning, and food poisoning (gastroenteritis).

Typhoid fever, caused by S. typhi, is spread by fecal contamination of water or milk or by food handlers who are carriers. It is characterized by a high fever and a rash on the chest and abdomen and can be fatal. Paratyphoid fever, caused by S. paratyphi, is also spread in the feces of victims or carriers. Outbreaks often occur where adequate hygiene, especially in food preparers, is not practiced. Paratyphoid is characterized by mild fever and a rash on the chest. Bacteremia is characterized by the presence of S. choleraesuis, S. typhimurium, or S. heidelberg in the blood. All three diseases are treated with the antibiotic chloramphenicol.

The most common form of salmonellosis is food poisoning caused by S. typhimurium and other Salmonella species. Sources of infection include eggs, beef, poultry, unpasteurized dairy products, and fruits and vegetables. In 1998 a new product called CF-3, or Preempt, which could reduce but not eliminate Salmonella in chickens, was approved for sale to poultry farmers. Delivered as a spray to newly hatched chicks, it consists of a mixture of beneficial bacteria that the mother hen normally transferred to her chicks before the advent of factory farms.

Outbreaks of salmonellosis food poisoning occasionally result from contaminated institutional or other mass-prepared food. In the home the bacteria can spread via contaminated cooking areas. Carriers and household pets, especially pet reptiles, can also spread the disease. Symptoms arise 6 to 72 hours after exposure and include severe diarrhea, fever and chills, vomiting, and abdominal cramps. Symptoms usually last three to five days.









[B][U]sarcoma[/U][/B]

highly malignant tumor arising in connective- and muscle-cell tissue. It is the result of oncogenes (the cancer causing genes of some viruses) and proto-oncogenes (cancer causing genes in human cells). It may affect bone, cartilage, blood vessels, lymph nodes, and skin.










[B][U]SARS[/U][/B]

SARS or severe acute respiratory syndrome is a communicable viral disease that can progress to a potentially fatal pneumonia. The first symptoms of SARS are usually a high fever, headache and body aches, sore throat, and mild respiratory symptoms; diarrhea may occur. A dry cough and shortness of breath typically develop two to seven days after the first symptoms, and in most persons pneumonia develops in a lobe of the lungs. In 10%–20% of all patients, the pneumonia spreads to other lobes, and death occurs in about 9% of all cases. The death rate is higher among older persons. There is no vaccine or treatment for the virus that causes the disease.

SARS is caused by a coronavirus, one of a group of viruses that are responsible for about one third of all cases of the common cold. The variety that causes SARS had not been previously identified, and may have been transmitted to humans from a civet species in whose blood the virus is also found. Civets are considered a delicacy in SE China, where the disease originated. Infection with SARS mainly occurs when a person in close contact with someone who has the disease is exposed to exhaled droplets. The spread of the disease has been controlled by isolating infected patients and quarantining those exposed to them.

The disease apparently first occurred in Nov., 2002, in Foshan, Guangdong prov., China, but provincial authorities withheld information about it, and when it spread to Beijing local authorities there acted similarly. In Feb., 2003, the World Health Organization first noted reports of cases of atypical pneumonia from China, but Chinese officials did not begin cooperating fully with international experts until April. SARS subsequently spread to some 30 countries on five continents, and affected the economies of China, Hong Kong, and Toronto, where cases were the highest; Taiwan and Singapore were also hard hit. The rapid international spread of the 2002–3 outbreak was facilitated by air travel and the lack of prompt, early information about SARS from Chinese officials.










[B][U]starvation[/U][/B]

condition in which deprivation of food has forced the body to feed on itself. Causes are famine, fasting, malnutrition, or abnormalities of the mucosal lining of the digestive system. Famines are often compounded by political strifes that restrict the distribution of aid and imports, as has been demonstrated in Ethiopia, Somalia, Iraq after the Persian Gulf War, and the conflict between the Serbs and Croats in former Yugoslavia. Fasting, usually conducted as a religious discipline or political protest, results in dizziness, weakness, and loss of bone mass; these lead to malnutrition. First to be lost are fat deposits and large quantities of water. The liver, spleen, and muscle tissue then suffer the greatest loss of weight. The heart and brain show little loss proportionately. The starving person becomes weak and lethargic. Body temperature, pulse rate, blood pressure, and basal metabolism continue to fall as starvation progresses, and death eventually ensues.












[B][U]strabismus[/U][/B]

inability of the eyes to focus together because of an imbalance in the muscles that control eye movement; also called squint. It is a consequence of weakness or uneven development of one or more of the six small muscles that surround the eye. One or both eyes may be affected. Horizontal strabismus is caused when the eyes do not move together laterally; this condition is known as cross-eye if the eye turns inward or walleye if the eye turns outward. Vertical strabismus results when the eye rolls upward or downward in its socket. There is also torsional strabismus in which the eyes do not rotate together about their optical axes. Strabismus is usually present at birth and becomes apparent early in infancy, but it may also result from illness or injury. Because the condition results in perception of a double image, there is a tendency to use only one eye. It is important that treatment be started as soon as possible to prevent loss of sight in the unused eye. Corrective therapy includes exercise that strengthens eye muscles and prescription of corrective lenses. Sometimes a patch is placed alternately on each eye so that neither is allowed to become completely unused. If necessary, the eye muscles may be shortened or lengthened surgically.









[B][U][COLOR="blue"]stroke[/COLOR][/U][/B]

The destruction of brain tissue as a result of intracerebral hemorrhage or infarction caused by thrombosis (clotting) or embolus (obstruction in a blood vessel caused by clotted blood or other foreign matter circulating in the bloodstream); formerly called apoplexy. Cerebral hemorrhage or thrombosis occurs most often in elderly persons with constricted arteries, although either may also be caused by inflammatory or toxic damage to the cerebral blood vessels. Cerebral embolism may occur at any age, even in children.

Symptoms of stroke develop suddenly. In cases of severe brain damage there may be deep coma, paralysis of one side of the body, and loss of speech, followed by death or permanent neurological disturbances after recovery. If the brain damage sustained has been slight, there is usually complete recovery, but most survivors of stroke require extensive rehabilitation. Hypertension, which is a major cause of intracranial hemorrhage and stroke, can be treated by preventive measures using diet (e.g., increasing nutrients such as antioxidants and folate), drug therapy, and stress reduction techniques. Other preventive measures for people at high risk include daily aspirin to retard clot formation and surgical correction of the narrowed carotid artery. Sometimes surgical removal of the clot is possible on larger vessels, but it is usually pointless after the stroke or when blockage is widespread. The thrombolytic drug tissue plasminogen activator, widely used to treat heart attacks, has been approved for use within three hours of the onset of strokes caused by clots.







[B][U]sty[/U][/B]

in medicine terms, acute localized infection of one or more of the glands of the eyelid, with pain, swelling, and redness of the lid margin, usually caused by a staphylococcus infection. An external sty usually releases its pus and disappears in a day or so. Hot or cold compresses and antibiotic ointments are used to treat sties. Recurring sties are usually due to uncorrected refractive errors, poor general health, or infection elsewhere in the body. If a sty does not disappear in a few days, a physician should be consulted.










[B][U]scabies[/U][/B]

highly contagious parasitic skin disease caused by the itch mite (Sarcoptes scabiei). The disease is also known as itch. It is acquired through close contact with an infested individual or contaminated clothing and is most prevalent among those living in crowded and unhygienic conditions. The female mite burrows her way into the skin, depositing eggs along the tunnel. The larvae hatch in several days and find their way into the hair follicles. Itching is most intense at night because of the nocturnal activity of the parasites. Aside from the burrows, which are usually clearly visible, there are a variety of skin lesions, many of them brought on by scratching and infection. All clothing and bedding of the victim and his household should be disinfected. Disinfestation of the skin is accomplished by applying creams or ointments containing gamma benzene hexachloride or benzyl benzoate. A variety of S. scabiei causes mange in animals.











[B][U]scar[/U][/B]

fibrous connective tissue that forms at the site of injury or disease in any tissue of the body. Scar tissue may replace injured skin and underlying muscle, damaged heart muscle, or diseased areas of internal organs such as the liver. Dense and thick, it is usually paler than the surrounding tissue because it is poorly supplied with blood, and although it structurally replaces destroyed tissue, it cannot perform the functions of the missing tissue. Scar tissue may therefore limit the range of muscle movement or prevent proper circulation of fluids when affecting the lymphatic or circulatory system. Extensively scarred tissue may lose its ability to function normally.










[COLOR="blue"]to be continued[/COLOR]

[B][U]scarlet fever[/U][/B]

scarlet fever or scarlatina,an acute, communicable infection, caused by group A hemolytic streptococcal bacteria that produce an erythrogenic toxin. The disease is now uncommon, probably because antibiotic therapy has lessened the likelihood of spread. It occurs in young children, usually between two and eight years of age, and is spread by droplet spray from carriers and from individuals who have contracted the disease. The incubation period is from three to five days, and infectivity lasts about two weeks. Scarlet fever may be mild or severe, but it is rarely fatal if treated. Typical symptoms are sore throat, headache, fever, flushed face with a ring of pallor about the mouth, red spots in the mouth, coated tongue with raw beefy appearance and inflamed papillae underneath it (strawberry tongue), and a characteristic eruption on the body. The streptococcal bacterium that causes scarlet fever is identical to the streptococcal pharyngitis (strep throat) organism, the difference being the production of a toxin to which the patient is susceptible in the case of scarlet fever. Severe infections are occasionally complicated by rheumatic fever, kidney disease, ear infection, pneumonia, meningitis, or encephalitis. Mild scarlet fever requires only bed rest, antibiotics, analgesics or antipyretics, and symptomatic treatment. Antibiotics, immune serum, and antitoxin may be required for severe cases.









[B][U]schistosomiasis[/U][/B]

schistosomiasis OR bilharziasis,or snail fever,parasitic disease caused by blood flukes, trematode worms of the genus Schistosoma. Three species are human parasites: S. mansoni, S. japonicum, and S. haematobium. The disease is prevalent in Asia, some Pacific islands, Africa, the West Indies, South America, Spain, Puerto Rico, and Cyprus. The larvae of the parasite are harbored by snails, which serve as intermediate hosts, and infect humans who bathe in or otherwise come in contact with infested waters. The larvae enter through the skin, migrate via the blood vessels, and mature in the lungs. From there they travel to the veins of the upper or lower intestine or bladder and reproduce. Some eggs pass out in the feces. Others are carried into the liver, where the body surrounds them with white blood cells, forming hundreds of tiny ball-like granulomas that eventually impair the liver's ability to function. It is believed that the flukes settle in blood vessels that have a particular human immune substance, tumor necrosis factor, that they require in order to reproduce.

The disease is characterized by a skin eruption at the site of entry, fever, diarrhea, and other symptoms, depending on the tissues affected; cirrhosis of the liver is common. The disease can be cured with the drug praziquantel, but reinfection can occur. Although symptoms vary according to the species of infecting fluke, all forms can result in general weakening and eventual death. Control of the disease is difficult, but attempts have been made to eradicate the snail hosts. Proper sanitation and disposal of human wastes are also important.










[B][U]sciatica[/U][/B]

severe pain in the leg along the sciatic nerve and its branches. It may be caused by injury or pressure to the base of the nerve in the lower back, or by metabolic, toxic, or infectious disease. Treatment is for the underlying condition; measures for the relief of pain include bed rest, immobilization of the leg, heat, and sedation.








[B][U]scurvy[/U][/B]

deficiency disorder resulting from a lack of vitamin C (ascorbic acid) in the diet. Scurvy does not occur in most animals because they can synthesize their own vitamin C, but humans, other primates, guinea pigs, and a few other species lack an enzyme necessary for such synthesis and must obtain vitamin C through their diet. Vitamin C is widespread in plant tissues, with particularly high concentrations occurring in citrus fruits (oranges, lemons, limes, grapefruits); tomatoes, potatoes, cabbages, and green peppers are also good sources of this vitamin.

Scurvy results in the weakening of capillaries, which causes hemorrhages into the tissues, bleeding of the gums, loosening of the teeth, anemia, and general debility. In infants there is also interference with bone development. Severe phases of the disorder can result in death. Scurvy is treated with large doses of vitamin C. Modern methods of transporting and preserving foods have made a diet rich in vitamin C available everywhere throughout the year, and even infants' diets include orange juice. Vitamin C is also available in tablet or syrup form.

Scurvy was a serious problem in the past, when fresh fruits and vegetables were not available during the winter in many parts of the world. It was especially common among sailors in the days when only nonperishable foods could be stocked aboard ship. More than half the crew of Vasco da Gama died from scurvy on his first trip (1497–99) around the Cape of Good Hope. In 1747 the Scottish naval surgeon James Lind treated scurvy-ridden sailors with lemons and oranges and obtained dramatic cures. In 1795 the British navy began to distribute regular rations of lime juice during long sea voyages (hence the name limeys for British sailors), a measure that was largely successful in preventing scurvy. It was probably the first disease to be definitely associated with a dietary deficiency.











[B][U]serum sickness[/U][/B]

hypersensitive response that occurs after injection of a large amount of foreign protein. The condition is named for the serum taken from horses or other animals immunized against a particular disease, e.g., tetanus or diphtheria. Such serum, which contains antibodies against the disease toxins, was formerly widely used to temporarily immunize humans. However, the antibodies from the animal serum are also foreign proteins that can act as antigens when injected into humans. The recipient's body responds by producing, within 8 to 12 days, antibodies that react against the animal serum proteins; the reaction causes injury to blood vessel walls and such allergic symptoms as rash, itching, and swelling of the lymph nodes. Fever, joint pain, spleen enlargement, and even shock may occur. The reaction subsides as continued production of antibodies removes foreign protein from circulation. A person who has once had a serum injection is sensitized to the serum antigens, and a second injection can bring on the acute reactions typical of anaphylaxis. Today, serum preparations are rarely used. Instead, inoculations of tetanus and diphtheria toxoids are given in childhood; they confer active immunity against those diseases. Serum sickness may occur in response to proteins other than those found in serum.











[B][U]senility[/U][/B]

deterioration of body and mind associated with old age. Indications of old age vary in the time of their appearance. Stooped posture, wrinkled skin, decrease in muscle strength, changes in the lens and muscles of the eye, brittleness of bone and stiffness of the joints, and hardening of the arteries (arteriosclerosis) are among the physical changes associated with old age. The mental changes associated with senility include impairment of judgment, loss of memory, and sometimes childish behavior. The psychological changes are thought to be related to aging of the cortical brain cells. Whereas the physical changes associated with aging occur in all individuals to some extent, evidence of psychological degeneration is not universal. In common usage, the term senility is applied only to mental deterioration.









[B][U]septicemia[/U][/B]

invasion of the bloodstream by virulent bacteria that multiply and discharge their toxic products. The disorder, which is serious and sometimes fatal, is commonly known as blood poisoning. The invasive organisms are usually streptococci or staphylococci but may be any type of bacteria. Septicemia occurs most often in older people who have underlying disease that makes them more susceptible to the infection. The primary causes of septicemia are infection within the walls of the blood vessels, rapidly progressing tissue infections (osteomyelitis, cellulitis), virulent systemic disease (meningitis, typhoid), and local infections (abscess, carbuncle) that the defense mechanisms of the body are unable to contain. The microorganisms usually spread to other organs, such as the lungs, liver, and brain.

Symptoms of septicemia are fever (usually quite high), chills, low blood pressure, confusion, and rash; it often results in multiple organ failure if not treated promptly with antibiotics. The diagnosis can be confirmed with blood cultures for the organism or with blood tests for antibodies or high levels of white blood cells.








[B][U]shock[/U][/B]

any condition in which the circulatory system is unable to provide adequate circulation to the body tissues, also called circulatory failure or circulatory collapse. Shock results in the slowing of vital functions and in severe cases, if untreated, in death. It may be caused by inadequate pumping by the heart, by reduction of the blood volume due to dehydration or to loss of blood or plasma, or by reduced blood pressure resulting from dilation of the blood vessels. Inadequate pumping may occur as a result of various kinds of heart disease. Blood loss may result from injuries or from such internal conditions as bleeding ulcers. Burns produce extensive plasma loss from blood vessels into the burned area; crush injuries may result in loss of blood and plasma into the injured tissues. Dilation of blood vessels may be caused by injury to the nervous system, or by pain or emotional stress. Fainting is a form of shock brought about by a sudden reduction of the blood supply to the brain. Symptoms of shock include weakness, pallor, cold and moist skin, and thirst. The arterial blood pressure is reduced, the pulse is weak and rapid, and the surface veins of the limbs may collapse. Emergency aid for shock victims includes maintaining a clear breathing passage, administering oxygen, controlling bleeding, and keeping the patient warm and in a supine position with legs elevated. Therapy may include blood or plasma transfusion to restore the normal circulation, as well as treatment of the underlying cause of shock. The term shock is also applied to a variety of other conditions such as electric shock, allergic shock, and emotional shock.










[B][U]Siamese twins[/U][/B]

congenitally united organisms that are complete or nearly complete individuals. They develop from a single fertilized ovum that has divided imperfectly; complete division would produce identical twins, having the same sex and general characteristics. Siamese twins remain attached at the abdomen, chest, back, or top of the head, depending on where the division of the ovum has failed. In some instances the individuals are joined only by a band of musculofibrous tissue and can be separated surgically, but in other instances they share vital organs and separation may not be possible. Sometimes an ovum divides in such a way that an organism develops having one body and two heads, or one head and two sets of limbs; such organisms are known as monsters. Only rarely do Siamese twins survive birth. When they do, fatal illness in one dooms the other unless separation is possible. The name Siamese twins derives from the most famous of conjoined male twins, Chang and Eng, born in Siam of Chinese parents in 1811. They were exhibited in Barnum's circus for many years; although never separated, they married and fathered a total of 22 children. They died within 2 hours of each other in 1874.








[COLOR="blue"][B][U]sickle cell disease[/U][/B][/COLOR]

sickle cell disease or sickle cell anemia,inherited disorder of the blood in which the oxygen-carrying hemoglobin pigment in erythrocytes (red blood cells) is abnormal. This “hemoglobin-S” crystallizes in small capillaries, where the concentration of oxygen in the blood is low (but sufficient for normal hemoglobin), causing the red blood cells to assume distorted, sicklelike shapes. Linus Pauling discovered the chemical abnormality of the hemoglobin molecule that causes the erythrocyte sickling in 1949.

The sickled red blood cells tend to clog small blood vessels, depriving the tissues they serve of blood and oxygen. Painful “crises” result, with symptoms depending on the site affected (e.g., joint and abdominal pain or kidney damage). Strokes or seizures can occur if the brain is affected. Lung infections resulting from the patient's disinclination to take painful deep breaths are a frequent complication. In addition, the sickled erythrocytes are fragile and subject to rupture and destruction, leading to hemolytic anemia (reduction of oxygen-carrying hemoglobin caused by premature destruction of red blood cells) and such symptoms as fatigue, jaundice, and headaches.


[B]Treatment[/B]

There is no cure for the disease, but advancements in treatment have improved median survival to 42 years for men and 48 years for women. Cerebral hemorrhage or shock is the usual cause of mortality in children. Recent studies have indicated that regular blood transfusions can prevent strokes in children. Anemia is treated with folic acid. Sickle cell crises may be treated with intravenous hydration, pain medication, antibiotics, oxygen, and transfusions. Hydroxyurea, formerly used as a cancer treatment, has been helpful to many adults with the disease, lessening the frequency and severity of crises. New drugs for reducing the severity of crises are being tested as well. One acts as a lubricant, allowing sickled cells to flow more easily through tiny vessels. The other helps to prevent tissue deprived of blood from dying during a crisis.


[B]Incidence[/B]

The disease is confined mainly to blacks, especially those of W African descent, but it also occurs in persons of Mediterranean, Middle Eastern, and Indian origin. The mutation may at one time have had an advantageous effect; those afflicted with the abnormality have a higher survival rate in malaria-infested zones.

Under normal circumstances the disease occurs only in those patients who inherit the gene for the abnormal hemoglobin from both parents. This so-called homozygous form of the disease occurs in 1 in 400 African Americans. About 8% of African Americans have sickle cell trait; that is, they are heterozygotes, usually symptomless carriers who have inherited a normal hemoglobin gene from one parent and hemoglobin-S from the other. There are also intermediate forms of the disease that result when a gene for hemoglobin-S is inherited from one parent and a gene for any of several other abnormal kinds of hemoglobin is inherited from the other. Genetic screening is recommended for prospective parents at risk of passing on the disease. If both parents are carriers (i.e., have sickle cell trait), then each child has a one in four chance of having sickle cell disease.











[B][U]silicosis[/U][/B]

occupational disease of the lungs caused by inhalation of free silica (quartz) dust over a prolonged period of time. Free silica is dispersed in the air and inhaled by workers engaged in the mining of lead, hard coal, and gold, in cutting sandstone and granite, in sandblasting, and in the manufacture of silica abrasives. The irritative action of the silica in the lung results in the formation of nodular lesions; these may coalesce and form massive areas of fibrous tissue. In advanced cases patients experience difficult breathing, coughing with sputum, chest pain, and a tendency to develop tuberculosis or repeated attacks of pneumonia. Once fibrosis has developed there is no cure, and treatment is directed at the management of symptoms. Preventive measures adopted in industries where the hazard of silicosis exists have greatly reduced its incidence.











[B][U][COLOR="blue"]skin cancer[/COLOR][/U][/B]

malignant tumor of the skin. The most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma, and melanoma. Rarer forms include mycosis fungoides (a type of lymphoma) and Kaposi's sarcoma. Overexposure to the sun is the primary cause of the common skin cancers, and the popularity of tanning since the 1930s lies behind the rise in skin cancer rates. The depletion of the earth's protective ozone layer also plays a role. The most effective way of preventing skin cancer is to avoid exposure to the sun's ultraviolet rays by consistently applying effective sunscreens (see sunburn) and wearing protective clothing.


[B]Basal and Squamous Cell Carcinomas[/B]

Basal and squamous cell carcinomas are the most common types of cancer. Both arise from epithelial tissue. They are rare in dark-skinned people; light-skinned, blue-eyed people who do not tan well but who have had significant exposure to the rays of the sun are at highest risk. Both types usually occur on the face or other exposed areas.

Basal cell carcinoma typically is seen as a raised, sometimes ulcerous nodule. The nodule may have a pearly appearance. It grows slowly and rarely metastasizes (spreads), but it can be locally destructive and disfiguring. Squamous cell carcinoma typically is seen as a painless lump that grows into a wartlike lesion, or it may arise in patches of red, scaly sun-damaged skin called actinic keratoses. It can metastasize and can lead to death.

Basal and squamous cell carcinomas are easily cured with appropriate treatment. The lesion is usually removed by scalpal excision, curettage, cryosurgery (freezing), or micrographic surgery in which successive thin slices are removed and examined for cancerous cells under a microscope until the samples are clear. If the cancer arises in an area where surgery would be difficult or disfiguring, radiation therapy may be employed. Genetic scientists have discovered a gene that, when mutated, causes basal cell carcinoma.


[B]Melanoma[/B]

Melanoma is the most virulent type of skin cancer and the type most likely to be fatal. As with the other common skin cancers, melanoma can be caused by exposure to the sun, and its incidence is increasing around the world. There also appears to be a hereditary factor in some cases. Although light-skinned people are the most susceptible, melanomas are also seen in dark-skinned people. Melanomas arise in melanocytes, the melanin-containing cells of the epidermal layer of the skin. Melanin is the pigment that gives skin color and that helps to protect the skin from sun damage. In light-skinned people, melanomas appear most frequently on the trunk in men and on the arms or legs in women. In blacks melanomas appear most frequently on the hands and feet. It is unknown whether melanoma in blacks is related to sun exposure. It is recommended that people examine themselves regularly for any evidence of the characteristic changes in a mole that could raise a suspicion of melanoma. These include asymmetry of the mole, a mottled appearance (variations in color from shades of brown to a bluish tint), irregular or notched borders, and oozing or bleeding or a change in texture. Surgery performed before the melanoma has spread is the only effective treatment for melanoma.











[COLOR="blue"]to be continued[/COLOR]

[B][U]sleep apnea[/U][/B]

episodes of interrupted breathing during sleep. Obstructive sleep apnea is a common disorder in which relaxation of muscles in the throat repeatedly close off the airway during sleep; the person wakes just enough to take a gasping breath. This process is repeated many times during sleep and usually is not remembered the next day. Those suffering from severe obstructive sleep apnea typically complain of sleepiness, irritability, forgetfulness, and difficulty in concentrating. They may have difficulties in their occupational or social lives and be prone to motor vehicle accidents.

Most people with obstructive sleep apnea tend to be obese and snore loudly. The disorder has been medically linked to hypertension, which in turn puts people at greater risk of heart failure and stroke. Weight reduction in persons who are overweight is an important factor in effective treatment. Alcoholic drinks near bedtime and sleeping pills should be avoided. Sometimes obstructive sleep apnea can be treated by surgically correcting the narrowing of the airway. Another option is continuous positive airway pressure, which involves wearing a mask over the nose and mouth during sleep; this treatment keeps the airway open by forcing air into the nasal passages. A different type of sleep apnea, called central sleep apnea, is believed to be caused by an abnormality in the brain's regulation of breathing during sleep.








[B][U]slow virus[/U][/B]

technically a virus, such as a lentivirus, that causes symptoms in an infected host long after the original infection and progresses slowly. Although many viruses fit this description, the term slow virus is usually reserved for the first recognized lentiviruses, such as the virus that causes visna (a disease of sheep). A slow virus was proposed as a cause for those diseases now generally recognized as prion diseases (e.g., Creutzfeld-Jacob disease and scrapie).











[B][U]slipped disc[/U][/B]

rupture or herniation of an intervertebral disc. These discs separate and cushion the vertebrae, the segments of the spinal column. They are composed of an outer rim of fibrous connective tissue and a gelatinlike inner core. If the fibrous rim breaks the core may leak into the spinal canal, resulting in severe pain that is aggravated by bending, straining, or coughing. Material from the disc may press on spinal nerves and cause numbness or tingling, weakness, or paralysis in the area of the body enervated by those nerves. Slipped discs occur as a result of severe strain or without any apparent stress at all. They are most common in the lower back and neck. Treatment consists of bed rest, usually with a hard board placed beneath the mattress, local application of heat, and the administration of muscle relaxants to relieve spasms. If natural healing fails to occur surgery may be required to remove the disc, and the affected vertebrae fused to keep them from rubbing together.







[B][U][COLOR="blue"]smallpox[/COLOR][/U][/B]

acute & highly contagious disease causing a high fever and successive stages of severe skin eruptions. The disease dates from the time of ancient Egypt or before. It has occurred worldwide in epidemics throughout history, killing up to 40% of those who contracted it and accounting for more deaths over time than any other infectious disease. Spreading to the New World with European colonization, it killed huge numbers of the indigenous people, who had no immunity, greatly contributing to the annihilation of native cultures.

Smallpox is caused by a virus that may be airborne or spread by direct contact. After an incubation period of about two weeks, fever, aching, and prostration occur, lasting two or three days. An eruption then appears and spreads over the entire body; the lesions become blisterlike and pustular within a week. The lesions then open and crust over, causing itching and pain. When the crusts fall off, usually in another one or two weeks, the extent of permanent damage to the skin (pockmarks) becomes evident. There is no specific treatment for smallpox; an antibiotic may be administered to prevent secondary bacterial infection.

A crude vaccination method began with Emanuel Timoni, a Greek physician, in the early 18th cent. Edward Jenner modified the procedure (1796) by using the related cowpox virus to confer immunity. By 1977, vaccination programs, such as those by the World Health Organization (WHO), had eliminated the disease worldwide.

After 1980, when WHO officially declared smallpox eradicated as a disease, scientists retained some samples of the virus in laboratories for study. They mapped the genetic sequence of three strains of smallpox, and the destruction of the remaining samples of the live virus was scheduled and postponed several times. Owing to fears of a new natural outbreak or of the potential use of smallpox as a terrorist weapon against populations no longer vaccinated, research with the virus continued. The last declared samples of live virus are now stored by the U.S. and Russian governments under strict security, but it is believed that some nations may have secret stores of the virus that they could use as biological weapons. Responding to these concerns, WHO postponed the scheduled 1999 destruction of all remaining stocks of the smallpox virus until 2002. The 2001 bioterror attacks in the United States with anthrax led the United States and other nations to stockpile doses of smallpox vaccine out of concern that the smallpox virus might be used by terrorists, and WHO agreed to delay the destruction of virus stocks beyond 2002 to allow for the development of new vaccines. In 2002, because of bioterrorism concerns, the G. W. Bush administration decided to vaccinate frontline military personnel and health-care and emergency workers against smallpox.








[B][U][COLOR="blue"]smoking[/COLOR][/U][/B]

inhalation and exhalation of the fumes of burning tobacco in cigars and cigarettes and pipes. Some persons draw the smoke into their lungs; others do not. Smoking was probably first practiced by the indigenous peoples of the Western Hemisphere. Originally used in religious rituals, and in some instances for medicinal purposes, smoking and the use of tobacco became a widespread practice by the late 1500s. Tobacco was introduced into Europe by the explorers of the New World; however, many rulers prohibited its use and penalized offenders. By the end of the 19th cent. mass production of cigarettes had begun, and the smoking of cigarettes became prevalent as the use of cigars and pipes declined. Despite controversy as to the effects of smoking and bans on smoking by certain religious groups, the use of tobacco continued to increase.


[B]Health Effects[/B]

Smoking is considered a health hazard because tobacco smoke contains nicotine, a poisonous alkaloid, and other harmful substances such as carbon monoxide, acrolein, ammonia, prussic acid, and a number of aldehydes and tars; in all tobacco contains some 4,000 chemicals. In 1964 definitive proof that cigarette smoking is a serious health hazard was contained in a report by the Surgeon General's Advisory Committee on Health, appointed by the U.S. Public Health Service. The committee drew evidence from numerous studies conducted over decades. They concluded that a smoker has a significantly greater chance of contracting lung cancer than a nonsmoker, the rate varying according to factors such as the number of cigarettes smoked per day, the number of years the subject smoked, and the time in the person's life when he or she began smoking. Cigarette smoking was also found to be an important cause of cancers of the esophagus, nasopharynx, mouth, larynx, kidney, and bladder as well as a cause of chronic obstructive pulmonary disease, emphysema, and heart disease, stroke, and other cardiovascular diseases. Since then it has been found to be an independent risk factor in male impotence. Smoking also increases risks associated with oral contraceptive use and exposure to occupational hazards, such as asbestos. Pipe and cigar smokers, if they do not inhale, are not as prone to lung cancer as cigarette smokers, but they are as likely to develop cancers of the mouth, larynx, and esophagus. Those who use snuff or chewing tobacco (sometimes called “smokeless tobacco”) run a greater risk of developing cancer of the mouth.

Inhalation of tobacco smoke by nonsmokers has been found to increase the risk of heart disease and respiratory problems; this has created a movement for smokeless environments in public spaces, including government buildings, office buildings, and restaurants. Fetal damage can be caused if a mother smokes or is exposed to smoke during pregnancy. Children of smokers have a higher risk of asthma and lung disease.



[B]Regulation of Smoking[/B]

Because of mounting evidence of health risks, television advertisements for cigarettes were banned beginning in 1971. In the 1980s, Congress began to require stronger warning labels on all print advertising; soon afterward it banned smoking on domestic air flights. A 1988 report of the Surgeon General of the United States recognized nicotine as an addictive substance, leading the Food and Drug Administration (FDA) to consider treating nicotine as any other addictive drug and implementing stricter regulations. The authority of the FDA to regulate smoking was, however, denied by the Supreme Court. The habit of smoking continues to increase in the young despite the illegality of cigarette sales to those under 18 years of age in all 50 states.

The Framework Convention on Tobacco Control, a treaty adopted by World Health Organization members in 2003, will establish international standards for antismoking measures once it is ratified. The convention creates restrictions on the marketing and sale of tobacco products and require health warnings on packages of cigarettes. Indoor air quality laws, high taxes on tobacco, and meansures against cigarette smuggling are encouraged under the pact.


[B]Legal Battles[/B]

In the mid- and late 1990s the tobacco industry in the United States faced grave legal and financial threats. Under heavy attack from states seeking compensation to recover costs for smoking-related health care, from the federal government seeking further regulation, and from individual smokers seeking damages for illness, the major cigarette producers sought ways to protect themselves. After a tentative $368 billion settlement (1997) with state attorneys and plaintiffs' lawyers fell apart, lawsuits were brought against the industry by Florida, Minnesota, Mississippi, and Texas; the suits were settled for $40 billion, to be paid over 25 years. In 1998 the remaining 46 states accepted a $206 billion plan to settle lawsuits they had filed against the industry. Individual lawsuits continued to pose potential significant financial threats. The Framework Convention on Tobacco Control, which came into affect in 2005 and has been ratified by more than 55 nations, seeks to reduce the number of tobacco-related illnesses and deaths by such measures as banning tobacco product advertising and putting warning labels on tobacco packaging. The treaty has been signed, but not ratified, by the United States.








[B][U][COLOR="blue"]snakebite[/COLOR][/U][/B]

wound inflicted by the teeth of a snake. The bite of a nonvenomous snake is rarely serious. Venomous snakes have fangs, hollow teeth through which poison is injected into a victim. All types of snake venom contain a toxin that affects the nerves and tends to paralyze the victim. In addition, the venom of the coral snake, the cobra, and the South American rattlesnake contains constituents that damage blood cells and dissolve the linings of the blood vessels and the lymphatic vessels, causing severe or fatal internal hemorrhage and collapse. First aid for venomous snakebites consists of retarding the spread of the poison through the circulatory system by applying a constricting band or an ice pack, or by spraying ethyl chloride on the wound. It is essential that the patient avoid exertion and the taking of stimulants, as both increase the pulse rate. The constricting band should be applied above the swelling caused by the wound; it should be tight, but not tight enough to stop the pulsing of the blood. If only a few minutes have passed since the infliction of the bite, it is possible to remove much of the poison by suction. Antivenins, which counteract the toxins, are available for most types of snake venom. The two main groups of poisonous snakes in the United States are the coral snakes, which rarely attack humans unless provoked, and the pit vipers (copperhead, cottonmouth moccasin, the various rattlers), which require no provocation.









[B][U][COLOR="blue"]sneeze[/COLOR][/U][/B]

involuntary violent expiration of air through the nose and mouth. It results from stimulation of the nervous system in the nose, causing sudden contraction of the muscles of expiration. The stimulus can include any irritating factor in the nose—inflammation of the tissues as the result of a cold or infection, allergic irritants (hay fever), or irritating substances such as dust or pollutants in the air. An occasional sneeze usually has little significance. Repeated sneezing indicates that some condition of the nose or in the immediate atmosphere requires attention.







[B][U][COLOR="blue"]snoring[/COLOR][/U][/B]

rough & vibratory sounds made in breathing during sleep or coma. The noisy breathing is the result of an open mouth and a relaxation of the palate; it is frequently induced by lying on one's back. Snoring may indicate some obstruction to nasal breathing such as enlarged adenoids; this is especially true in children. In some individuals it is merely a poor breathing habit and usually disappears when the person lies on his side.










[B][U]streptococcal sore throat[/U][/B]

infection and inflammation of the pharynx caused by certain streptococcal bacteria. These organisms are known as hemolytic streptococci because they secrete toxins that dissolve, or cause hemolysis of, red blood cells. Acute streptococcal sore throat is usually characterized by an extremely painful throat, enlarged tonsils, and sometimes gastrointestinal disturbances. Scarlet fever, which is caused by the same streptococcal bacteria, occurs when the microorganisms produce a toxin that, in sensitive individuals, causes appearance of a characteristic rash. Complications of streptococcal infection, which include rheumatic fever and sometimes arthritis and nephritis, can be prevented by early, vigorous treatment with penicillin or other suitable antibiotics.








[B][U]spasm[/U][/B]

involuntary rigid muscle contraction, often persistent and often accompanied by pain. It usually has some underlying physical cause such as disease, strain, or injury to the muscle or nearby tissues, impairment of circulation, or a disturbance of body chemistry. The spasm may be confined to one group of muscles or it may be severe and fairly generalized, as in convulsions. Painless localized spasms are called tics. These purposeless movements, usually of some part of the face, may begin as purposeful movement in response to some stimulus but eventually are carried out automatically, apparently without reason. They may disappear spontaneously after a time, or may require the elimination of some physical or psychic cause.






[B][U]spastic paralysis[/U][/B]

form of paralysis in which the part of the nervous system that controls coordinated movement of the voluntary muscles is disabled. In spastic paralysis the nerves controlling muscle movement are hyperirritable and do not function in a coordinated manner, so that impulses from them cause spasmodic muscle contraction. Extreme spastic paralysis occurs after various kinds of brain damage, e.g., stroke. Spinal cord injury, such as that produced by inflammatory diseases of nerve tissue, can injure motor neuron fibers in the spine and cause spastic paralysis. Congenital spastic paralysis, or cerebral palsy, is often a result of intrauterine disease or birth injury, or occasionally some inherited nervous system defect.







[B][U]speech defect[/U][/B]

any condition that interferes with the mental formation of words or their physical production. Speech defects in children generally become apparent in the early school years. Speech problems may arise from organic or functional abnormalities, but in practice the two are often hard to differentiate. Organic defects include deafness, cleft palate, dental abnormalities, and brain damage; most functional problems are basically psychological. Speech defects are generally categorized as disorders of sound production; disorders of voicing, e.g., loudness, pitch, and quality deviations; disorders of rhythm, such as stuttering and stammering; and disorders of language formulation and expression, including aphasia, the inability to use words as symbols of ideas. Treatment of a speech defect may include correction of organic conditions, psychotherapy, and training in proper articulation; it is rarely limited to a single type of therapy









[B][U]sprain[/U][/B]

stretching or wrenching of the ligaments and tendons of a joint, often with rupture of the tissues but without dislocation. Sprains occur most commonly at the ankle, knee, or wrist joints, causing pain, swelling, and difficulty in moving the involved joint. Treatment consists of application of ice bags or cold compresses, elevation of the injured part, and strapping or bandaging to substitute for the support usually given by the ligaments. A severe ankle sprain may require a cast to immobilize the joint for healing.







[B][U]sprue[/U][/B]

chronic disorder of the small intestine caused by impaired absorption of fat and other nutrients. Two forms of the disease exist. Tropical sprue occurs in central and northern South America, Asia, Africa, and other specific locations. No cause has been identified, but suggested causes include infection, parasitic infestation, vitamin deficiency, and food toxin. Tropical sprue responds to antibiotic and folic acid therapy. Nontropical sprue, also called celiac disease, is primarily a disease of young children and usually begins between the ages of 6 and 18 months. It is a hereditary congenital disorder caused by a sensitivity to the gliadin fraction of gluten, a cereal protein. Nontropical sprue can be fatal, particularly if growth abnormalities are ignored or unrecognized. It is not known if scrupulous adherence in this disease decreases the likelihood of intestinal lymphoma, but the deletion of gluten from the diet and the intake of vitamin, mineral, and hematinic supplements facilitate remission. Steroid treatments are often used if a gluten-free diet is ineffective; if steroid treatment is ineffective the prognosis is not good. The symptoms of both types of sprue are generally the same: diarrhea with bulky, frothy, foul-smelling stools containing large amounts of fatty acids and soaps, and later weight loss, anemia, and other symptoms related to malabsorption of vitamins. X-ray examination of the small intestine revealing dilation, segmentation, and other typical changes is used in diagnosis.








[COLOR="blue"][B][U]sudden infant death syndrome[/U][/B][/COLOR]

sudden infant death syndrome (SIDS) or crib death,sudden, unexpected, and unexplained death of an apparently healthy infant under one year of age (usually between two weeks and eight months old). SIDS accounts for 10% of infant deaths and is the second highest cause of death (after accidents) in infancy. The risk is higher in males, in low-birth-weight infants, in lower socioeconomic levels, during cold months, and for babies who sleep face down.

Causal theories suggest that the infant may have immature or hypersensitive lungs, may have a defect in brain-stem control of breathing, or may be rebreathing carbon dioxide. Recent studies have shown persistent high levels of an infant form of hemoglobin in babies with known risk factors for the condition.

SIDS victims are thought to have brief episodes of apnea (breathing stoppage) before the fatal one. An alarm system that detects breathing abnormalities is sometimes used with infants suspected of being prone to SIDS. The American Academy of Pediatrics has recommended that babies be laid to sleep on their backs or sides.









[B][U]sunburn[/U][/B]

inflammation of the skin caused by actinic rays from the sun or artificial sources. Moderate exposure to ultraviolet radiation is followed by a red blush, but severe exposure may result in blisters, pain, and constitutional symptoms. As ultraviolet rays penetrate the skin, they break down collagen and elastin, the two main structural components of the skin, a process that results in the wrinkled appearance of sun-damaged skin. In addition, the sun damages the DNA of the exposed skin cells. In response, the cells release enzymes that excise the damaged parts of the DNA and encourage the production of replacement DNA (a process that can go wrong and result in skin cancer). At the same time, the production of melanin increases, darkening the skin. Melanin, the pigment that gives skin its color, acts as a barrier to further damage by absorbing ultraviolet light. A suntan. results from this attempt by the skin to protect itself. Light-skinned persons and infants are especially susceptible to ultraviolet rays because they lack sufficient protective skin pigment. Certain diseases and drugs may also increase photosensitivity.

Due to the increase in the incidence of skin cancer and the effects of ozone layer depletion, more attention is being placed on protecting the skin from the sun's ultraviolet rays with broad spectrum sunscreens or clothing. Broad spectrum sunscreens block both UVA and UVB rays (two of the three bands of ultraviolet radiation). The relative UVB protection of a sunscreen is indicated by its SPF (sun protection factor) number; a higher number indicates a more effective sunscreen. Some products may contain opaque formulations of zinc oxide or titanium dioxide that physically block all rays.

[B][U][CENTER][SIZE="5"]T[/SIZE][/CENTER][/U][/B]



[B][U][COLOR="blue"]tapeworm[/COLOR][/U][/B]

name for the parasitic flatworms forming the class Cestoda. All tapeworms spend the adult phase of their lives as parasites in the gut of a vertebrate animal (called the primary host). Most tapeworms spend part of their life cycle in the tissues of one or more other animals (called intermediate hosts), which may be vertebrates or arthropods.


[B]Anatomy and Function[/B]

An adult tapeworm consists of a knoblike head, or scolex, equipped with hooks for attaching to the intestinal wall of the host (which may be a human), a neck region, and a series of flat, rectangular body segments, or proglottids, generated by the neck. The chain of proglottids may reach a length of 15 or 20 ft (4.6–6.1 m). Terminal proglottids break off and are excreted in the feces of the host, but new ones are constantly formed at the anterior end of the worm. As long as the scolex and neck are intact the worm is alive and capable of growth. A rudimentary nervous system and excretory system run the length of the worm, through the proglottids. However, there is no digestive tract; the worm absorbs the host's digested food through its cuticle, or outer covering.


[B]Reproduction[/B]

Each proglottid contains a complete set of male and female reproductive organs that produce the sex cells. Fertilization is internal; in most species cross fertilization between two adjacent worms is necessary, but in a few species self-fertilization may occur between two proglottids of the same worm, or within the same proglottid. In some species the fertilized eggs are shed continuously and leave the host's body in the feces; in others the fertilized eggs are stored until the proglottid is filled with them and the entire proglottid is then shed. The eggs develop into embryos with a hard outer shell; these do not hatch until they are eaten by a suitable intermediate host.


[B]Humans as Tapeworm Hosts[/B]

Human tapeworm infestations are most common in regions where there is fecal contamination of soil and water and where meat and fish are eaten raw or lightly cooked. In the case of the human tapeworm most common in the United States (the beef tapeworm, Taenia saginata) the usual intermediate host is a cow, which ingests the proglottid while drinking or grazing. The round-bodied embryos, equipped with sharp hooks, hatch and bore through the cow's intestinal wall into the bloodstream, where they are carried to the muscles. Here each embryo encloses itself in a cyst, or bladder; at this stage it is called a bladder worm. During the bladder worm stage the embryo develops into a miniature scolex; it remains encysted until the muscle is eaten by a primary host, in this case a human. If the scolex has not been killed by sufficient cooking of the meat, it sheds its covering and attaches to the intestinal wall, where it begins producing proglottids.

A human tapeworm common in Mexico, the pork tapeworm (T. solium), has a similar life cycle, with a pig as the usual intermediate host. The fish tapeworm, Diphyllobothrium latum, transmitted to humans from fish, especially pike, is common in Asia and in Canada and the northern lake regions of the United States. This tapeworm has a more elaborate life cycle, involving both a fish and a crustacean as intermediate hosts. The dwarf tapeworm, Hymenolepsis nana, is transmitted through fecal contamination and is common in children in the southeastern United States. There are also several tapeworms for whom humans the usual intermediate host; among these, the dog tapeworm, Echinococcus granulosis, spends its adult phase in the intestines of dogs.


[B]Consequences of Infestation[/B]

Intestinal tapeworm infestation frequently occurs without symptoms; occasionally there is abdominal discomfort, diarrhea, constipation, or weight loss. The presence of tapeworm proglottids in clothing, bedding, or feces is the usual sign of infestation. Treatment is with quinacrine hydrochloride (Atabrine) or niclosamide, which kill the worm.

The most serious tapeworm infestation in humans is caused by the ingestion of T. solanum eggs through fecal contamination, which results in the person serving as the intermediate, rather than the primary, host. The embryos migrate throughout the body, producing serious illness if they lodge in the central nervous system. The embryos of the dog tapeworm encyst in various internal organs of humans, most commonly in the liver. The cysts produced by these embryos are called hydatid cysts, and the infestation of the liver is called hydatid disease.















[B][U]tartar, dental[/U][/B]

precipitate of saliva that accumulates around teeth at the gum line. Composed primarily of calcium salts, tartar forms as a hard brownish substance that irritates gums and causes them to recede. Inflammation of this tissue may lead to the recession and infection of the bones in which teeth are imbedded and result in the loosening and loss of teeth. As symptoms may not become apparent until serious damage has occurred, periodic dental visits for the removal of tartar are recommended.










[COLOR="blue"][B][U]Tay-Sachs disease[/U][/B][/COLOR]

rare hereditary disease caused by a genetic mutation that leaves the body unable to produce an enzyme necessary for fat metabolism in nerve cells, producing central nervous system degeneration. The disease is named for a British ophthalmologist, Warren Tay, who first described the disease, in 1881, and a New York neurologist, Bernard Sachs, who first described the cellular changes and the genetic nature of the disease, in 1887. In infants, it is characterized by progressive mental deterioration, blindness, paralysis, epileptic seizures, and death, usually between ages three and five. Late-onset Tay-Sachs occurs in persons who have a genetic mutation that is similar but allows some production of the missing enzyme. There is no treatment for Tay-Sachs.

[B]Course of the Disease[/B]

The enzyme involved in Tay-Sachs is called hexosaminidase A. Its absence allows a lipid called GM2 ganglioside to build up in the brain, destroying the nerve cells. The process starts in the fetus; the disease is clinically apparent in the first few months of life. Initial symptoms vary, but usually include a general slowing of development and loss of peripheral vision. By the age of one, most children are experiencing convulsions. The damage to the nervous system progresses inexorably, bringing with it an inability to swallow, difficulty in breathing, blindness, mental retardation, and paralysis.

In late-onset Tay-Sachs, which is often misdiagnosed, the symptoms (ataxia, dysarthria, and muscle weakness) usually become apparent late in childhood or early in adulthood. About 40% of the patients display symptoms of bipolar disorder. Life expectancy does not appear to be affected.


[B]Genetic Basis and Screening[/B]

Tay-Sachs disease occurs primarily among Jews of Eastern European descent but is also found in French Canadians whose roots are in the St. Lawrence region, certain Cajuns in Louisiana, and some Amish communities. Tay-Sachs is an autosomal recessive disorder; a person must have two defective genes (one from each parent) in order for the disease to occur. Carriers, people with only one gene for the disorder, are physically unaffected. When both parents are carriers, each child has a 25% chance of getting the disease. If only one parent is a carrier, there is no chance that the child will get the disease, but there is a 50% chance that the child will be a carrier. The gene may be carried by many generations without a manifestation. For this reason, plus the historical lack of accurate diagnosis and routinely high infant mortality of past generations, there is often no known family history of the disease.

Genetic screening for the disease has been possible since the early 1970s and is encouraged in high-risk populations. Blood tests of carriers reveal a reduced amount of the hexosaminidase A. If a couple elects to go forward with a pregnancy, fetal status (again utilizing hexosaminidase A levels) can be ascertained via chorionic villus sampling or amniocentesis. Genetic screening and counseling has greatly reduced the incidence of the disease.












[B][U]tetanus[/U][/B]

acute infectious disease of the central nervous system caused by the toxins of Clostridium tetani. The organism has a widespread distribution and is common in the soil, human and animal feces, and the digestive tracts of animals and humans; however, the toxin is destroyed by intestinal enzymes. Infection with the tetanus bacillus may follow any type of injury, whether incurred indoors or out, including nail puncture wounds, insect bites, splinter injuries, gunshot wounds, burns, lacerations, and fractures. Deep puncture wounds are most dangerous, since the bacillus thrives in an anaerobic environment.

The tetanus toxin, one of the most potent poisons known, acts on the motor nerves and causes muscle spasm at the site of infection and in other areas of the body. The most frequent symptom is stiffness of the jaw (lockjaw) and facial muscles. Difficulty in breathing and severe convulsions may ensue. The mortality rate is very high, especially in the very young and the aged; overall it is about 40%. Treatment with tetanus antitoxin should be started promptly in conjunction with human immune globulin. It is preferable, however, to prevent the disease by active immunization (including booster shots) with tetanus toxoid (see vaccination).











[B][U]tetany[/U][/B]

condition of mineral imbalance in the body that results in severe muscle spasms. Tetany occurs when the concentration of calcium ions (Ca++) in extracellular fluids such as plasma falls below normal. The nervous system becomes increasingly excitable, and nerves discharge spontaneously, sending impulses to skeletal muscles and causing spasmodic contractions. Mild tetany is characterized by tingling in the fingers, toes, and lips; acute tetany, consisting of severe muscular contractions, tremors, and cramps, can result in death. Abnormally low extracellular calcium ion concentration can result from failure of the parathyroid glands to release parathyroid hormone, the substance responsible for the regulation of calcium concentration in the body; a deficiency in vitamin D, which facilitates calcium ion absorption from the gastrointestinal tract; or alkalosis, an excessively alkaline state of body fluids resulting from persistent vomiting, rapid breathing, or excess activity of the hormone aldosterone. Most forms of tetany can be treated with calcium, vitamin D, and a controlled diet. Muscle tetany is also caused by the pathogenic bacterium Clostridium tetani in the disease tetanus.









[B][U]thrombosis[/U][/B]

obstruction of an artery or vein by a blood clot (thrombus). Arterial thrombosis is generally more serious because the supply of oxygen and nutrition to an area of the body is halted. Thrombosis of one of the arteries leading to the heart (heart attack; see infarction) or of the brain (stroke) can result in death and, in a vessel of the extremities, may be followed by gangrene. Acute arterial thrombosis often results from the deposition of atherosclerotic material in the wall of an artery, which gradually narrows the channel, precipitating clot formation (see arteriosclerosis). A thrombus that breaks off and circulates through the bloodstream is called an embolus.











[B][U]thrush[/U][/B]

in medicine, infection caused by the fungus Candida albicans, manifested by white, slightly raised patches on the mucous membrane of the tongue, mouth, and throat. The mucous membrane beneath the patches is usually raw and bleeding. The overgrowth of this fungus results when the balance in the normal oral microbe population is disturbed by antibiotic therapy or disease. It occurs most frequently in infants, in adults suffering from chronic illnesses, in the debilitated, in the immunosuppressed, and in individuals on long-term antibiotic, corticosteroid, or antineoplastic therapy. It is often an early symptom of AIDS. Treatment is with antifungal drugs, such as nystatin.

[B][U]toxemia[/U][/B]

disease state caused by the presence in the blood of bacterial toxins or other harmful substances. The effects of the bacterial toxins known as endotoxins are relatively uniform, regardless of which bacterial species the toxin comes from, and are separate from the effects caused by the infecting bacterium itself. A small amount of endotoxin (released by dead bacteria) produces one or more fever episodes, thought to be caused by release of a fever-inducing substance from damaged white blood cells. Large quantities of endotoxin cause shock and death. Exotoxins are proteins released by bacteria that have specific effects on target tissues, e.g., botulinus toxin affects the nervous system.

The term toxemia is also used for a disorder occurring during the latter half of pregnancy characterized by high blood pressure, the appearance of protein in the urine, and edema. If not treated it can result in convulsions and coma. The cause of toxemia of pregnancy has not been established with certainty.









[B][U]toxic shock syndrome[/U][/B]

toxic shock syndrome (TSS). acute, sometimes fatal, disease characterized by high fever, nausea, diarrhea, lethargy, blotchy rash, and sudden drop in blood pressure. It is caused by Staphylococcus aureus, an exotoxin-producing bacteria. Toxic shock was initially identified among menstruating women using high-absorbency tampons that contained synthetic materials, now no longer used, that bound and removed magnesium from the surrounding bodily environment. The resulting lower magnesium levels encouraged bacterial exotoxin production. Slightly more than half of all cases now occur in menstruating women; nonmenstruating women, men, and children may also develop TSS, as a result of infection after surgery and other causes. Treatment mainly involves supportive measures, such as intravenous fluids and, if necessary, kidney dialysis, but may include antibiotics and immunoglobulin.













[B][U]trachoma[/U][/B]

infection of the mucous membrane of the eyelids caused by the bacterium Chlamydia trachomatis. Trachoma infects more than 150 million people worldwide. An estimated 6 million people have become blind because of it, making the disease the second leading cause of blindness, after cataracts. It is most common in parts of Africa, the Middle East, and Asia. In the United States it has occurred sporadically among Native Americans and in mountainous areas of the South.

Trachoma is highly contagious in its early stages and is transmitted by direct contact with infected persons or articles (e.g., towels, handkerchiefs) and possibly also by flies. It begins as congestion and swelling of the eyelids with tearing and disturbance of vision. The cornea is often involved. If left untreated, scar tissue forms, which causes deformities of the eyelids and, if there is corneal involvement, partial or total blindness. The disease has been effectively treated with tetracycline ointment and with the newer oral drug azithromycin (Zithromax). The World Health Organization began a campaign in 1998 to eradicate the disease worldwide by the year 2020. The strategy includes use of azithromycin and sanitation improvements in water supplies.












[B][U]trench mouth[/U][/B]

common term for Vincent's infection, an ulcerative membranous infection of the gums and mouth, by noncontagious infection, associated with a fusiform bacillus and a spirochete. Poor oral hygiene, nutritional deficiencies, insufficient rest, heavy smoking, and debilitating diseases are predisposing factors to the disease. Epidemics often occur in crowded unsanitary environments, and in former years among soldiers in the field, hence the name “trench mouth.” In addition to ulcerations on the gums and mouth, which are painful and bleed freely, there are usually foul breath, increased salivation, and difficulty in swallowing and talking. The acute phase of the disease yields to antibiotic treatment and oxygenating mouth rinses, but attention must also be paid to the underlying dental and medical factors.













[B][U]trichinosis[/U][/B]

parasitic disease caused by the roundworm Trichinella spiralis. It follows the eating of raw or inadequately cooked meat, especially pork. The larvae are released, reach maturity, and mate in the intestines, the females producing live larvae. The parasites are then carried from the gastrointestinal tract by the bloodstream to various muscles, where they become encysted. It is estimated that 10% to 20% of the adult population of the United States suffers from trichinosis at some time. In many people the disease exhibits no symptoms and is discovered only at autopsy. In others it causes diarrhea and other gastrointestinal symptoms as the worms multiply in the digestive tract. When the larvae circulate through the bloodstream, the patient experiences edema, irregular fever, profuse sweating, muscle soreness and pain, and prostration. There may be involvement of the central nervous system, heart, and lungs; death occurs in about 5% of clinical cases. Once the larvae have imbedded themselves in the muscle tissue, the cysts usually become calcified; however, the infestation usually causes no further symptoms except fatigue and vague muscular pains. There is no specific treatment.










[B][U][COLOR="blue"]tuberculosis[/COLOR][/U][/B]

tuberculosis (TB), contagious, wasting disease caused by any of several mycobacteria. The most common form of the disease is tuberculosis of the lungs (pulmonary consumption, or phthisis), but the intestines, bones and joints, the skin, and the genitourinary, lymphatic, and nervous systems may also be affected.

There are three major types of tubercle bacilli that affect humans. The human type (Mycobacterium tuberculosis), first identified in 1882 by Robert Koch, is spread by people themselves. It is the most common one. The bovine type (M. bovis) is spread by infected cattle but is no longer a threat in areas where pasteurization of milk and the health of cattle are strictly supervised. The avian type (M. avis) is carried by infected birds but can occur in humans. The tubercle bacillus can live for a considerable period of time in air or dust. The most common means of acquiring the disease is by inhalation of respiratory droplets.


[B]Course of the Disease[/B]

Tuberculosis of the lungs usually results in no or minimal symptoms in its early stages. In most persons the primary infection is contained by the body's immune system, and the lesion, called a tubercle, becomes calcified. In many the infection is permanently arrested. In others the disease may break out again and become active years later, usually when the body's immune defenses are low. Untreated, the infection can progress until large areas of the lung and other organs are destroyed. Symptoms of the disease include cough, sputum, bleeding from the lungs, fever, night sweats, loss of weight, and weakness.

[B]Incidence[/B]

The incidence of tuberculosis of the lungs, the “white plague” that formerly affected millions of people, declined from the 1950s until 1984; sanatoriums were closed and routine screening was abandoned in the United States. Then, between 1984 and 1992, the incidence increased by 20%, chiefly because of immigration from countries where it is common and because of AIDS, which leaves people particularly vulnerable to the disease. Renewed efforts at control and advances in treatment have been rewarded with incidence declines each year, amounting to a total decline of 31% from 1992 to 1998.

Worldwide the outlook has been far less encouraging. In 1993 the World Health Organization declared TB a global health emergency. Approximately one third of the world's population is infected, and an estimated 1.6 million die each year. The vast majority of new cases occur in sub-Saharan Africa. Spread of TB is especially rapid in areas with poor public health services and crowded living conditions. In homeless shelters and prisons, crowded conditions and inadequate treatment often go together. Areas where living conditions are disrupted by wars, famine, and natural disasters also are heavily affected.

Especially alarming has been the spread of drug-resistant strains of TB. By the late 1990s scientific experts and international health officials warned that drug-resistant strains were spreading faster than had been anticipated. Bacteria can survive and become drug resistant in patients whose treatment is not properly monitored and seen to completion. Multidrug resistant TB strains are resistant to two or more of the commonly prescribed first-line drugs, while extreme drug resistant strains are also resistant to three or classes of the more toxic second-line drugs. Some believe that unless major new treatment strategies are initiated in source countries, drug-resistant TB will eventually become epidemic even in areas with good control programs, such as Europe and America.

[B]Diagnosis and Treatment[/B]

Diagnosis is made by a tuberculin skin test. It can be confirmed by X rays of the chest and sputum examination. Ideally, treatment begins after a skin test signals exposure but before active disease has developed. The treatment of choice for prevention and for active cases is the antimicrobial drug isoniazid (INH), available since 1956. In infected individuals it is usually used in combination with other antituberculosis drugs such as rifampin, pyrazinamide, and ethambutol. Tuberculosis drugs have to be taken regularly, typically for 6 to 12 months. Many patients abandon their treatment when they feel better; similarly, preventive treatment is often abandoned because of the inconvenience. Such noncompliance is believed to be the main reason for the upsurge in drug-resistant strains of the TB bacilli, many of which are resistant to more than one drug. Drug-resistant TB is difficult to treat and has a much higher death rate; extreme drug resistant TB is especially worrisome because it can be essentially untreatable.

The combination drug rifater (rifampin, isoniazid, and pyrazinamide) has simplified drug administration. Directly observed treatment, where health-care workers watch patients take each dose of medicine, has proved effective in eliminating the problem of noncompliance in the United States, but monitoring has been less effective in many other parts of the world.

[B]Prevention of Tuberculosis[/B]

Preventive measures include strict standards for ventilation, air filtration, and isolation methods in hospitals, medical and dental offices, nursing homes, and prisons. If someone is believed to have been in contact with another person who has TB, preventive antibiotic treatment may have to be given. Infected persons need to be identified as soon as possible so that they can be isolated from others and treated.

An antituberculosis vaccine, bacille Calmette-Guérin, or BCG vaccine, was developed in France in 1908. Although there is conflicting evidence as to its efficacy (it appears to be effective in 50% of those vaccinated), it is given to over 80% of the world's children, mostly in countries where TB is common; it is not generally given in the United States. Federal health officials in the United States have stated (1999) that a new vaccine is essential to TB prevention. It is hoped that the determination of the complete DNA (genome) sequence of Mycobacterium tuberculosis, achieved in 1998, will hasten the development of an effective vaccine.













[B][U]typhus[/U][/B]

any of a group of infectious diseases caused by microorganisms classified between bacteria and viruses, known as rickettsias. Typhus diseases are characterized by high fever and an early onset of rash and headache. They respond to antibiotic treatment with tetracycline and chloramphenicol and can be prevented by vaccination. Epidemic typhus, the most serious in the group, is caused by Rickettsia prowazeki, which is transmitted in the feces of body lice. It occurs in crowded, unsanitary conditions and has historically been a major killer in wartime. It occurs more commonly in cooler climates and seasons. Brill's disease, also called recrudescent typhus, is believed to be a milder recurrence of epidemic typhus. Endemic murine typhus is primarily a disease of rodents and is spread to humans by rat fleas. The symptoms are milder than those of epidemic typhus. Scrub typhus (Tsutsugamushi fever) is carried to humans by infected mites. It occurs primarily in East Asia and the Southeast Pacific islands.












[COLOR="blue"]
[B][U]typhoid fever[/U][/B][/COLOR]

generalized infection caused by Salmonella typhi. The main sources of infection are contaminated water or milk and, especially in urban communities, food handlers who are carriers. The symptoms of typhoid appear 10 to 14 days after infection; they include high fever, rose-colored spots on the abdomen and chest, diarrhea or constipation, and enlargement of the spleen. Complications, especially in untreated patients, may be numerous, affecting practically every body system, and they account for the mortality rate of 7% to 14%. Perforation of the intestine with hemorrhage is not uncommon. Chloramphenicol is the most effective drug in combating typhoid, and in very toxic patients a cortisone derivative may be helpful. Skilled nursing care is still of the utmost importance, as is a high caloric diet to prevent wasting of the body. Vaccination against typhoid is a valuable preventive measure, especially for persons in military service and for those who travel to poorly sanitized regions.









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[B][U]ulcer[/U][/B]

open sore or circumscribed erosion, usually slow to heal, on the skin or mucous membranes. It may develop as a result of injury; because of a circulatory disturbance, e.g., in varicose veins or after prolonged bed rest; or in association with such diseases as tuberculosis, syphilis, or leprosy. Corneal ulcers, which result from infection, allergy, or foreign objects in the eye, can cause visual impairment if not treated promptly. Some ulcers may develop into cancer. The underlying cause must be treated as well as the ulcerous lesion.

Peptic ulcer occurs in the mucous membrane of the intestinal tract. An estimated 90% of peptic ulcers are caused by infection with a bacterium, Helicobacter pylori, strains of which promote the formation of ulcers by causing an inflammtory response in the cells of the stomach wall, making it more susceptible to the hydrochloric acid secreted by the stomach. Most commonly, it occurs in the stomach (gastric ulcer) or at the beginning of the small intestine (duodenal ulcer, the most common form) and causes abdominal pain, especially between meals.

Infection with the H. pylori bacterium, which is also associated with some stomach cancer, is very common, but not all strains promote the formation of ulcers. Approximately 50% of those over 60 in developed countries are infected; in developing countries the infection rate is much higher, and infection usually occurs earlier in life. Experts are as yet uncertain how the bacterium is spread. Around 20% of those infected develop ulcers. Peptic ulcer is found more frequently in men. Heavy aspirin or ibuprofen use and smoking increase the risk of ulcer development.

The connection of H. pylori infection with peptic ulcer was made in the early 1980s by Australian scientists Barry J. Marshall and J. Robin Warren; it previously was believed that peptic ulcers were caused by emotional stress. Marshall and Warren were awarded the Nobel Prize in physiology or medicine in 2005 for their work. Treatment changed accordingly and now typically consists of antibiotics (such as clarithromycin or amoxicillin) plus metronidazole (Flagyl) and bismuth subsalicylate (e.g., Pepto-Bismol). For the relief of symptoms, drugs such as ranitidine (Zantac), famotidine (Pepcid), cimetidine (Tagamet), and omeprazole (Prilosec) may also be used. Hemorrhage or perforation of peptic ulcers requires emergency medical treatment.

The full set of genes (genome) of H. pylori was determined in 1997. This achievement will help researchers design new drugs to treat and prevent diseases caused by the bacterium.












[B][U]uremia[/U][/B]

condition resulting from advanced stages of kidney failure in which urea and other nitrogen-containing wastes are found in the blood. Uremia can be caused by NSAIDs (nonsteroid anti-inflammatory drugs), especially in older patients treated primarily with ibuprofen for arthritis. Some of the early signs of uremia are lethargy, mental depression, loss of appetite, and edema; later symptoms include diarrhea, anemia, convulsions, coma, and a gray-brown coloration. Treatment of uremia, which is directed at the underlying kidney disease, is usually with dialysis and renal transplantation. Treatments with genetically engineered erythropoietin decrease the complication of anemia.

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[B][U]varicose vein[/U][/B]

superficial vessel that is abnormally lengthened, twisted, or dilated, seen most often on the legs and thighs. Varicose veins develop spontaneously, and are usually attributed to a hereditary weakness of the vein; the valves in the vein that keep the blood circulating upward toward the heart are usually incompetent. Increased pressure from long standing or exertion, or internal factors such as pregnancy, or lessened support by the tissues surrounding the veins that occurs with aging and obesity causes the weakened veins to dilate. Mild varicosities often cause no discomfort. Persons with more severe cases may develop swelling of the legs, ankles, and feet, and local eczema or ulcers. Mild varicosities may be treated with rest, elevation of the legs, and the use of elastic bandages or stockings. In severe cases surgical treatment may be necessary. Traditional surgery involves tying off and removing a vein segment. Varicose veins may now also be treated without removing them through an endoscopic surgical procedure that uses the heat produced by radio waves or a laser to seal off the veins. Varicose veins that occur around the rectum are called hemorrhoids, and those that form in the scrotum are called varicoceles.











[B][U]vertigo[/U][/B]

sensations of moving in space or of objects moving about a person and the resultant difficulty in maintaining equilibrium. True vertigo, as distinguished from faintness, lightheadedness, and other forms of dizziness, occurs as a result of a disturbance of some part of the body's balancing mechanism, located in the inner ear (e.g., vestibule, semicircular canals, auditory nerves). Labyrinthitis, or infection and irritation of the middle and inner ear, is a common cause of vertigo. Elimination of infectious, toxic, or environmental factors underlying the disturbance is essential for permanent relief.










[COLOR="blue"][B][U]vomiting[/U][/B][/COLOR]

ejection of food and other matter from the stomach through the mouth, often preceded by nausea. The process is initiated by stimulation of the vomiting center of the brain by nerve impulses from the gastrointestinal tract or other part of the body. The vomiting center then sends out nerve impulses that precipitate spasmodic muscular contractions of the stomach wall and downward spasms of the diaphragm. The pressure generated then forces up the contents of the stomach. The vomiting mechanism may be in response to local irritation (diseases or disorders of the gastrointestinal tract, overburdening of the capacity and digestive capabilities of the stomach, ingestion of harmful foods or substances) or result from a metabolic disturbance (as in pregnancy) or from disorders or stimulation of the nervous system (e.g., migraine, motion sickness, infectious disease, brain tumor or injury, disagreeable odors). Vomiting may also be a reflex action to other spasmodic conditions (whooping cough, gagging).

[B][U][CENTER][SIZE="5"]W[/SIZE][/CENTER][/U][/B]


[B][U]wart[/U][/B]

circumscribed outgrowth of the skin caused by a filterable virus that is readily transmitted. Warts may appear anywhere on the skin but are most common on the hands. Sexually transmitted diseases and human papillomavirus produce warts in the genital area; these are often precancerous growths. Some warts disappear spontaneously; others persist for many years. However, there is also a tendency to develop new lesions. Warts are treated by surgical excision (sometimes by electrocautery), bloodless removal by freezing with liquid nitrogen, or repeated applications of ointments or creams. Those on the soles of the feet (plantar warts) are the most painful and most difficult to treat, since on pressure-bearing areas they may become depressed beneath the surface of the skin.










[B][U]wen[/U][/B]

benign, slow-growing, painless cyst of the skin resulting from obstruction of the sebaceous gland ducts. It is frequently found on the scalp, ears, face, back, or scrotum. Usually no treatment is required. Large wens may be surgically removed.










[B][U]West Nile virus[/U][/B]

microorganism and the infection resulting from it, which typically produces no symptoms or a flulike condition. The virus is a flavivirus and is related to a number of viruses that cause encephalitis. It usually is transmitted through the bite of several mosquito species, and can infect humans and more than 200 animal species, including alligators, horses, and many common birds. A number of North American bird species, including the blue jay, crow, and house sparrow, act as reservoirs of the virus.

About one fifth of humans infected with the virus develop West Nile fever, which in most people is characterized by fever, headache, muscle ache, joint pain, nausea and vomiting, and in some cases rash and swollen lymph nodes (swollen glands). Less than 1% of all persons infected may develop a severe case, progressing to encephalitis or meningitis, about a week after the initial symptoms of West Nile fever appear. Loss of vision, tremors and convulsions, paralysis, coma, and, in some cases, death may result. Older persons and persons with a weakened immune system are most susceptible to severe cases of the disease, and they may suffer from longer-term effects including weakness and fatigue, headaches, memory loss and confusion, and depression. There is no treatment or vaccine for the virus except to alleviate the symptoms; controlling the mosquitoes that carry the disease is the most effective way to limit its spread.

West Nile virus was first identified in 1937 in the West Nile district of Uganda. It was subsequently found in much of the rest of Africa, the Middle East, and warmer regions of Asia and Europe. Its first recorded appearance in the United States was in Queens, N.Y., in 1999, and it since has spread to most of the United States and neighboring areas in North America.











[COLOR="blue"][B][U]whooping cough[/U][/B][/COLOR]

whooping cough or pertussis,highly communicable infectious disease caused by the bacterium Bordetella pertussis. The early or catarrhal stage of whooping cough is manifested by the usual symptoms of an upper respiratory infection with bronchial involvement. After about two weeks the cough becomes paroxysmal; 10 to 15 coughs may follow in rapid succession before a breath is taken, which is the characteristic high-pitched crowing “whoop.” An attack of coughing is accompanied by a copious discharge of mucus and, often, vomiting. Antibiotics and hyperimmune human serum are valuable in treatment. Rest and proper nutrition (especially if there is frequent vomiting) are important.

Whooping cough is a serious disease, especially in children under four years of age, since it may give rise to such complications as pneumonia, asphyxia, convulsions, and brain damage. For these reasons, it is recommended that all infants be actively immunized at as early an age as possible (one to two months). The whole-cell pertussis vaccine available in the United States since the 1940s (see vaccination) became the subject of controversy when it was learned that a toxin contained in it could cause serious side effects and rarely death. A new, acellular vaccine, which uses only the parts of the bacterium that stimulate immunity and is less likely to cause side effects, was approved for use in 1996. It is now believed that adults whose childhood vaccinations are no longer completely effective and whose symptoms are less diagnostic may be the main carriers for the disease; booster vaccinations are recommended for 11- and 12-year-olds and adults as a means of ameliorating this situation.













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[B][U]yaws[/U][/B]

tropical infection of the skin caused by a spirochete (Treponema pertenue) closely related to that causing syphilis. Yaws, however, is not a sexually transmitted disease, i.e., it is not contracted by sexual contact; transmission is through ordinary contact with infected persons or their clothing and by insects. An ulcerating lesion (“mother yaw”) appears at the site of contact. The second stage of the disease begins 6 to 12 weeks later, when similar ulcerating lesions appear all over the body. If the disease is not treated, the third stage develops several years later, nodular and ulcerating lesions affecting the soles of the feet (“crab yaws”) and penetrating the bones with destructive changes. The first and second stages of yaws are easily treated with penicillin and other antibiotics. Yaws is rarely fatal; however, it can lead to chronic disfigurement and disability.










[B][U]yellow fever[/U][/B]

acute infectious disease endemic in tropical Africa and many areas of South America. Epidemics have extended into subtropical and temperate regions during warm seasons. In 1878 a severe outbreak in the Mississippi Valley killed about 20,000; the last epidemic in the United States occurred in New Orleans in 1905. Yellow fever is caused by a virus transmitted by the bite of the female Aedes aegypti mosquito, which breeds in stagnant water near human habitations. A form of the disease called sylvan yellow fever is transmitted in tropical jungles by other species of mosquitoes that live in trees.

At the end of the 19th cent., yellow fever was highly prevalent in the Caribbean, and a way of controlling it had to be found before construction of the Panama Canal could be undertaken. In 1900 an American commission headed by Walter Reed and including James Carroll, Jesse Lazear, and Aristides Agramonte gathered in the U.S. Army's Camp Columbia in Cuba. Through their experiments they proved the theory of C. J. Finlay that yellow fever was a mosquito-borne infection. Within the next few years, W. C. Gorgas, an army physician and sanitation expert, succeeded in controlling the disease in the Panama Canal Zone and other areas in that part of the world by mosquito-eradication measures. The later development of an immunizing vaccine and strict quarantine measures against ships, planes, and passengers coming from known or suspected yellow-fever areas further aided control of the disease.

Yellow fever begins suddenly after an incubation period of three to five days. In mild cases only fever and headache may be present. The severe form of the disease commences with fever, chills, bleeding into the skin, rapid heartbeat, headache, back pains, and extreme prostration. Nausea, vomiting, and constipation are common. Jaundice usually appears on the second or third day. After the third day the symptoms recede, only to return with increased severity in the final stage, during which there is a marked tendency to hemorrhage internally; the characteristic “coffee ground” vomitus contains blood. The patient then lapses into delirium and coma, often followed by death. During epidemics the fatality rate was often as high as 85%. Although the disease still occurs, it is usually confined to sporadic outbreaks.










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Jaundice
 

[I]Newborn jaundice is not as dangerous as we thought 20 years ago. We used to start phototherapy at 12 where now we start treating it at 19 blood level of bilirubin (jaundice). It is more severe in breast fed babies and infants with uncommon blood disorders. It is helped by indirect light from a window. It is also lowered by giving one bottle of formula a day in the evenings (it will not turn them off to breast feeding.) Jaundice hits it’s peak usually around 3-4 days of age but there are exceptions. A small amount of jaundice can persist for 2 months with breast fed babies. There are rare liver disorders that can cause increased jaundice at 6-8 weeks of age. The face and chest get yellow at very low levels of jaundice. Press on the bottom of their feet and then release it. If that area of their feet that you pressed on looks yellow then call to get a blood test on the baby to see if it is real high.

Then the babies get yellow around 9-15 months old from the yellow vegetables. Their eyes are not yellow and this in not jaundice. It is Carotenemia from the carotene (Vit. A) found in squash, carrots and sweet potatoes. This is not dangerous and does not need to be treated. Older children who get hepatitis A hardly ever turn jaundiced. They have an upset stomach for a week and get over it. The main reason I diagnose it in children is so I can give a shot to the parents to prevent them from getting it. Although a mild illness in children, it is very serious in adults and 1/500 die! Like many illnesses, it is usually worse in adults. Ever seen chicken pox in a child verses an adult. Just like the Flu: 30+ children die of the flu in all of America, but 35,000 adults die of the flu every year. The press can scare you more with the children than with adults dieing. We now recommend the vaccine of Hepatitis A for those living in the counties of Texas that boarder Mexico and those children and adults going to underdeveloped countries for a while.

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