A weight loss of at least 15% of the baseline or ideal body weight is necessary to establish the diagnosis of anorexia nervosa. In addition to weight loss, a number of physical signs of anorexia nervosa can be attributed to weight loss, malnutrition, and generalized stress. Amenorrhea or oligomenorrhea, independent of weight loss and often preceding initial weight loss, is always present in women. Anorexia Nervosa with premenarcheal onset often results in short stature and delayed breast development. Prolonged amenorrhea in women with anorexia nervosa may lead to the development of osteoporosis. Patients frequently complain of epigastric distress, and gastric emptying time is indeed prolonged. Vomiting, constipation, cold intolerance, headache, polyuria, and sleep disturbances are also commonly reported. In addition to emaciation, physical findings may include edema, lanugo, dehydration, low blood pressure, bradycardia, arrhythmias, diminished cardiac mass, and infantile uterus. Males with anorexia frequently have hemorrhoids and experience loss of libido.
Laboratory findings include abnormalities of vasopressin secretion, prepubertal plasma levels of follicle-stimulating hormone and luteinizing hormone, and a diminished response to gonadotropin-releasing hormone. Estrogen is at postmenopausal levels. Males have low testosterone. There is abolition or reversal of the normal circadian rhythm of plasma cortisol, the metabolic clearance rate of cortisol is reduced, and there is incomplete suppression of adrenocorticotropin and cortisol by dexamethasone. There is diminished growth hormone response to insulin-induced hypoglycemia, arginine stimulation, and levodopa. Glucose tolerance test curves may be flat. Plasma levels of triiodothyronine (T3) are reduced, and levels of plasma reverse-T3 may be elevated. Blood urea nitrogen and creatinine may be elevated, renal calculi may form, the glomerular filtration rate may be reduced, and renal failure is possible. Hematological abnormalities may include leukopenia with a relative lymphocytosis, thrombocytopenia, and anemia. Bone marrow aspiration reveals hypocellularity with large amounts of gelatinous acid mucopolysaccharide. The erythrocyte sedimentation rate is low, and plasma fibrinogen levels are reduced. Hypercarotenemia, hypercholesterolemia, and hypomagnesemia are common findings. Hypophosphatemia if present is an ominous sign, associated with rapid decompensation. Self-induced vomiting may produce a metabolic hypo-kalemic alkalosis. Electroencephalographic patterns may be abnormal, and the electrocardiogram may show flat or inverted T waves, ST depression, and increased intervals.
Refeeding edema frequently complicates the treatment of anorexia nervosa and, when severe, may increase the risk of congestive heart failure. Death, which occurs in 10-22% of patients, is caused by starvation and its complications (including pneumonia and other infections, cardiac arrhythmia, congestive heart failure, and renal failure) or by suicide. Patients who purge by vomiting or by abusing laxatives or diuretics are at risk for sudden death due to fluid and electrolyte imbalance.
Revision date: July 9, 2011
Last revised: by Dave R. Roger, M.D.