Eating disorders affect an estimated 5 million Americans every year. It is estimated that about 6% to 10% of all young women have an eating disorder. Eating disorders typically run in adolescent girls or young women; however, 5% to 15% of cases of anorexia and bulimia nervosa occur in young boys and men. The age of onset most commonly is the teenage years, but these diseases also occur in young children and in older adults (e.g., after age 40).

The cause of these disorders has been attributed in part to the great emphasis our society places on thinness. However, the disorders are caused by a combination of genetic, neurochemical, psychological, and sociocultural factors.

Despite profound weight loss, patients with anorexia nervosa usually regard themselves as being too fat. They may be reluctant to admit this and, in fact, often agree to increase their food intake when prompted by relatives and friends. However, they typically continue to avoid food, indulge in excessive physical exercise, and consume medications to inhibit appetite and promote diuresis and catharsis. Emotionally, the anorectic patient tends to be isolated and shuns relationships, whereas the bulimic patient is likely to be outgoing and sociable. Weight may fluctuate in bulimics because of the alternate food binging and purging, but the low points in weight usually do not reach the point of dangerous weight loss that sometimes occurs in anorectics.

Starvation is the most serious complication of anorexia nervosa. Mortality in excess of 5% has been estimated, but this figure may reflect the experience in large referral centers that deal with the most severe cases. Amenorrhea is common, and other organ system abnormalities may develop (Table 59-1). Particularly worrisome are the cardiac arrhythmias, diuretic-induced changes in electrolytes, and complications of vomiting, such as gastric and esophageal rupture and aspiration pneumonia.

The diagnosis of anorexia nervosa or bulimia should be considered when a young woman has had severe weight loss but denies that anything is wrong. A preoccupation with weight and food, distortion of body image, or any of the characteristics mentioned previously strengthens the suspicion.

The physical examination often is normal, unless a serious complication, such as cardiac arrhythmia or aspiration pneumonia, has developed. Patients with anorexia nervosa characteristically are thin or even emaciated, whereas bulimics range from underweight to overweight.