Dictionary

amazia A condition wherein the breast tissue is absent, but the nipple is present. Amazia is typically a result of radiation or surgery.

amaurotic familial idiocy An outdated term for Tay-Sachs disease (TSD). See Tay-Sachs disease.

amaurosis fugax A symptom that is often described as a shade coming down over the eye. Amaurosis fugax is a partial or complete loss of sight that is temporary. Amaurosis fugax is usually caused by arteriosclerosis in the blood vessels that supply the brain. It can also occur with excessive acceleration, as in flight, and…

amastia A rare condition wherein the normal growth of the breast or nipple does not occur. Unilateral amastia (absence of one breast) is often associated with absence of the pectoral muscles. Bilateral amastia (absence of both breasts) is associated with multiple birth defects involving other parts of the body. See also amazia.

AMA American Medical Association, a professional organization for physicians that sets widely accepted standards of practice and ethics and that publishes the weekly journal JAMA ( Journal of the American Medical Association).

Alzheimer’s disease A progressive degenerative disease of the brain that leads to dementia. On a cellular level, Alzheimer’s disease is characterized by the finding of unusual helical protein filaments in nerve cells of the brain. These twisted filaments are called neurofibrillary tangles. In the brain, Alzheimer’s disease involves degeneration of the cortical regions, especially the…

alveolus A tiny air sac in the lungs. Plural alveoli.

alveolitis Inflammation of the alveoli, the air sacs in the lungs.

altitude sickness Sickness caused by being at a high altitude, usually above 2,400 meters (approximately 8,000 feet). The cause of altitude sickness is a matter of oxygen physiology. At sea level the concentration of oxygen is about 21 percent, and the barometric pressure averages 760 mm Hg. As altitude increases, the concentration remains the same,…

altitude illness See altitude sickness.

altitude, acclimatization to See acclimatization to altitude.

alternative medicine Healing arts not taught in traditional Western medical schools that promote options to conventional medicine that is taught in these schools. An example of an alternative therapy is using a special diet to treat cancer instead of undergoing surgery, radiation, or chemotherapy that has been recommended by a Western physician. Complementary medicine is…