Internal Medicine => Geriatrics
Geriatrics, specialized branch of medicine that deals with the diseases of older persons and their therapy. The study of the aging process itself is called gerontology. Increased interest in geriatrics is due largely to the greater number of older persons in society, which is in turn a result of social and medical changes that have extended the life expectancy in the U.S. from an average of 47 years in 1900 to 75.6 years in 1990. The elderly population is expected to increase rapidly over the next 30 years, with the number of persons over 85 growing most rapidly.
In 1975 the U.S. Congress established the National Institute on Aging (NIA) to sponsor research on aging and on therapy for the problems of older persons. In 1978 the Institute of Medicine of the National Academy of Sciences issued a report recommending greater integration of knowledge on aging and geriatrics into the curriculum of medical schools. Some physicians have advocated establishing special geriatric care units in hospitals and outpatient health clinics. Nevertheless, Robert Butler, the first director of the NIA, identified one of the limits to advancing the study of geriatric medicine when he observed that traditional medical education trains physicians to think in terms of cure. This concept is not usually applicable in geriatrics, as many medical conditions of elderly persons can only be ameliorated, not cured.
One problem of the elderly is intellectual impairment. A 1980 task force of the NIA stated that 10 percent of persons over the age of 65 years have some serious mental impairment. They disputed, however, the notion of the inevitability of the process and stated that normal aging does not include gross intellectual impairment, confusion, depression, hallucinations, or delusions. The task force estimated that intellectual impairment can be reversed in close to 20 percent of these cases. Treatable causes of mental deterioration include alterations in functioning of the thyroid gland, sleep disorders, depression resulting from bereavement, infectious and metabolic diseases, and the side effects of therapeutic drugs. This last cause is especially important, because the average person over the age of 65 takes 13 different medicines in a year. Because some of these drugs may interact and cause toxic effects, and because the human metabolism clears drugs from the body less rapidly as people get older, an increased probability exists of interference with mental function. The NIA task force stressed that physicians treating older persons must be alert to these effects.
Mental changes in the elderly may also be due to irreversible conditions, such as the degenerative brain disease called Alzheimer's disease. No cure exists and the course of the illness is variable, usually leading to death within five to ten years. Mental impairment can also result from multiple small strokes (see Stroke).
Older persons are also more susceptible to diseases found in people of all ages, as witnessed by their increased risk of death from influenza infection or exposure to cold. Heat, too, is more dangerous to the elderly. In the heat wave of 1980 the mortality rate among persons over the age of 65 was found to be more than ten times greater than that among other age groups.
In addition, progressive diseases tend to become more severe in old age. These include heart disease (see Heart; arthritis; diabetes mellitus; glaucoma), and cataracts (see Cataract). The weakening of the immune system may lead to an increased incidence of cancer in older persons. See also aging.