Biopsy

Biopsy, surgical removal of living body tissue for study and diagnosis with a microscope. Biopsies are performed on organs to analyze the cause and nature of disease, and on tumors, or abnormal tissue growths, to determine if they are a type of cancer. For patients diagnosed with certain diseases, follow-up biopsies are used to study the effectiveness of a chosen course of medical treatment. Biopsies are vital in diagnosing and monitoring a wide range of illnesses, including muscular dystrophy, characterized by gradual wasting away of skeletal muscle, and Crohn’s disease, the chronic inflammation of the intestines.

An external biopsy specimen is taken by cutting or scraping a piece of tissue from an affected area of skin. When a sample is needed from an area well below the surface of the skin, the procedure is called internal biopsy, and viewing techniques such as ultrasound or computer axial tomography are often used to help the physician guide a hollow needle to the exact location.

In a procedure called aspiration biopsy, a needle is attached to a hypodermic syringe. A tissue sample is collected in the barrel of the syringe by using the suction that is created when the plunger of the syringe is pulled out. In a needle biopsy, the tissue sample is collected by rotating the needle, trapping a small but sufficient amount of tissue within the needle itself. In a punch biopsy, a sharp-edged instrument is used to recover a round piece of tissue from a specific depth below the skin.

Beriberi

Beriberi, diet-deficiency disease caused by a lack of vitamin B1. Chronic deficiency is known to cause two distinct forms of beriberi. When associated with low calorie intake and inactivity, the disease tends to affect the nervous system. This form, termed dry beriberi, is characterized by neuritis in the lower extremities, often with muscle atrophy, poor coordination, and eventually paralysis. The second form of beriberi, known as wet beriberi, is usually associated with extremely high activity levels and a high carbohydrate intake. Symptoms of wet beriberi include sweating, warm skin, and elevated heart rate; heart failure and death may follow.

Beriberi is especially prevalent in those parts of the world where the diet consists mainly of polished rice. Recovery is complete in about 50 percent of cases when adequate amounts of vitamin B1 are restored to the diet.

Anorexia Nervosa

Anorexia Nervosa, mental illness in which a person has an intense fear of gaining weight and a distorted perception of their weight and body shape. People with this illness believe themselves to be fat even when their weight is so low that their health is in danger. A person with anorexia nervosa severely restricts food intake and usually becomes extremely thin.

People with anorexia nervosa—who are sometimes known as anorectics or anorexics—have a preoccupation with food, weight, dieting, and body image. They are dissatisfied with their bodies, perceive themselves to be fat regardless of their actual weight, and are obsessed with becoming thin. Many are so focused on outward appearance that they have little awareness of internal sensations such as hunger and fullness. Anorexics usually undertake strict diets, severely restricting food intake and avoiding certain foods they deem taboo. They may also undergo intense, strenuous exercise regimens and weigh themselves frequently.

Addiction

Addiction, habitual repetition of excessive behavior that a person is unable or unwilling to stop, despite its harmful consequences. People can be physically addicted to a drug, meaning they may suffer ill physical effects if they stop taking the drug. They also can be psychologically addicted to drugs, gambling, or other behaviors, meaning they feel overwhelmingly deprived if they attempt to stop.

Diarrhea

Diarrhea, frequent passage of abnormally loose, watery stool. Diarrhea usually develops suddenly and may last from several hours to a few days. It is often accompanied by abdominal pains, low fever, nausea, and vomiting. If the attacks are severe or increasingly frequent, exhaustion and dehydration can result. In normal digestion the large intestine absorbs excess water from liquid food residues produced by earlier phases of the digestive process before excreting semisolid stools. When the mucous membrane lining the large intestine is irritated or inflamed, food residues move through the large intestine too quickly and the resulting stool is watery because the large intestine cannot absorb the excess water.

Diarrhea is not a disease. It is a symptom of numerous disorders, such as food poisoning from contaminated foods or beverages, infections by viruses and bacteria, or anxiety. Chronic diarrhea, which lasts weeks or months, may be caused by amoebic dysentery (intestinal infection), tumors, and other serious intestinal disorders such as Crohn’s disease, ulcerative colitis, or irritable bowel syndrome. Except in the case of irritable bowel syndrome, the stool may contain blood or pus.

The usual treatment for diarrhea consists of bed rest, drinking liquids to replace fluids and salts lost from the body, and eating soft foods. Dehydration is a serious concern in infants and the elderly. If the condition lasts more than a few days, a physician should be consulted.

Myxedema

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Myxedema (Greek myxa, “slime”; oidema, “swelling”), deficiency disease caused by insufficient or lack of production of hormone by the thyroid gland. Patients with myxedema complain of fatigue, lethargy, sleepiness, poor tolerance to cold, mental sluggishness, a tendency to gain weight, and generalized aches and pains. Their faces often look puffy and waxy. Their skin is dry and coarse; their hair is coarse, dry, and brittle, and it tends to fall out easily. Often patients also lose the outer portion of their eyebrows. These and other symptoms are caused by a low metabolic rate resulting from a deficiency of the thyroid hormone that stimulates metabolism. Myxedema differs from cretinism in that it develops after birth and produces less severe cerebral inadequacy. The disease may occur in several members of a single family. Any condition that decreases the elaboration of thyroid gland hormone may bring on myxedema. The disease is treated by the administration of thyroxine, other thyroid extracts, or a synthetic preparation such as levothyroxine.

Goiter

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Goiter, disease of the thyroid gland, characterized by an enlargement of the gland, visible externally as a swelling on the front of the neck. In simple goiter the basal metabolic rate is somewhat lowered, and in toxic goiter it is elevated.

Iodine deficiency in the body can cause goiter. Treatments include the ingestion of small doses of iodine, or, in extreme cases, the removal of the thyroid gland.

SIMPLE GOITER

This condition is characterized by an enlargement of the entire gland, or of one of its two lobes, caused by a deficiency of iodine in the diet. The disease is especially apt to appear in adolescence. Prevention requires taking small doses of iodine for long periods. Ingestion of iodine during pregnancy prevents development of the disease in the infant as well as in the mother. Public health measures, including the addition of iodine to water supplies and to table salt, have helped to reduce the incidence of simple goiter in certain areas. Iodine is most effective when administered to children who have the disease. Thyroidectomy, or surgical removal of the gland, may be necessary in cases in which the gland has become greatly enlarged.

TOXIC GOITER

This disease, also called exophthalmic goiter, hyperthyroidism, thyrotoxicosis, or Graves' disease, for the Irish physician Robert James Graves, is caused by an excess of thyroxine secretion. The cause of the excessive secretion is obscure. In some cases it may result from excessive stimulation by the pituitary gland. The symptoms of toxic goiter may include a rapid heartbeat, tremor, increased sweating, increased appetite, weight loss, weakness, and fatigue. Some patients have eye problems, such as staring or protrusion. Thiouracil and iodine are sometimes used in the treatment of toxic goiter, as is irradiation of the gland by radioactive iodine.

See also Myxedema.