Anorexia Nervosa and Bulimia Nervosa

Both eating disorders share similar symptoms but have characteristically different food-eating behaviors. Approximately 80% to 85% of patients are women younger than 25 years of age. Others are men or older women.

1. Anorexia nervosa: Syndrome of self-starvation.

2. Bulimia nervosa: Characterized by frequent episodes of binge eating. The patient usually consumes large amounts of food during a defined period (e.g., less than 2 hours) and then uses compensatory measures (e.g., laxatives, diuretics, induced vomiting) to prevent weight gain.

CLINICAL FEATURES

1. Anorexia nervosa: The patient usually weighs less than 85% of the expected weight (e.g., body mass index < 19).

— The patient may present with life-threatening malnutrition, hypotension, or bradycardia.

— Endocrine abnormalities are present, usually amenorrhea.

2. Bulimia nervosa: These patients are often of normal weight or are overweight.

— Serious complications of repeated vomiting (e.g., esophageal rupture, Mallory-Weiss tears, dental decay) may be the presenting complaint.

— Electrolyte imbalances (e.g., hypokalemia) are fairly common secondary to repeated vomiting or laxative or diuretic abuse.

DIFFERENTIAL DIAGNOSES

1. Medical causes of excessive weight loss (e.g., diabetes, Crohn's disease, cancer, thyroid disorders, lupus) must be excluded.

2. Anxiety, schizophrenia, body dysmorphic disorder, and depression can all lead to significant weight changes. Criteria for depressive disorder are found in nearly 50% of patients.

EVALUATION

1. History and physical examination form the basis for the diagnosis of these disorders

— There is often a family history of eating disorders or job pressures to be thin (e.g., professional dancers, and gymnasts).

— The patient is often evasive about purging or the use of laxatives or diuretics. Friends or family members are more likely to mention these behaviors.

2. Laboratory studies: Appropriate studies include a serum electrolyte panel and glucose level as well as renal and thyroid function tests.

3. Electrocardiography: An electrocardiogram is warranted especially in a symptomatic patient.

THERAPY

Intensive psychiatric therapy and frequent monitoring of weight are the cornerstones of treatment for patients with these disorders. Antidepressants are effective in certain patient populations.

DISPOSITION

1. Discharge: Most patients will require outpatient treatment.

2. Admission to the hospital is indicated for any patient with substantial electrolyte imbalances or signs of cardiac abnormalities.