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EATING DISORDERS
Margaret T. Johnson, MD

Eating disorders are most prevalent among adolescent and young adult women. Within this group, the prevalence of anorexia nervosa is 0.5-1% and the prevalence for bulimia nervosa is 1-3%. The prevalence among males in this age range is about one-tenth that of females. The mortality rate in anorexia nervosa is 6%.



I. Classification of Eating Disorders
A. Anorexia Nervosa
1. This disorder is characterized by: 1) a body weight that is below normal (ie, <85% of expected body weight); 2) intense fears of weight gain despite being underweight; 3) body image disturbance resulting in the misperception of one's weight or shape, undue self-evaluation based upon weight, or denial of the seriousness of the current low weight; and 4) in post-menarchal females, the absence of at least three consecutive menstrual cycles. The diagnosis of anorexia nervosa requires all four criteria.
2. Restricting type anorexia nervosa is characterized by restrictive eating patterns. Binge-eating/purging type anorexia nervosa is characterized by binge-eating episodes followed by purging behavior.
3. A binge consists of rapid intake of 2500 calories or 2.5 times the normal amount of food. Binges are characterized by a lack of control over food intake during a period of less than 2 hours.
4. Purging behaviors entail acute and active efforts to eradicate ingested calories and may include self-induced vomiting and/or the use of laxatives, diuretics, or enemas.

B. Bulimia Nervosa
1. Bulimia is characterized by: 1) episodes of binge eating; 2) recurrent inappropriate behaviors that are intended to compensate for the ingested calories or prevent weight gain (eg, self-induced vomiting; use of laxatives, diuretics, or enemas; fasting; excessive exercise); 3) a frequency of bulimic episodes, of at least twice per week for a period of three months; and 4) undue self-evaluation based on body weight or shape. All criteria must be met.
2. Bulimia nervosa is further sub-divided into purging type and non-purging type. Purging type bulimia nervosa, the most frequent eating disorder diagnosis, is characterized by self-induced vomiting or the use of laxatives, diuretics, or enemas. Non-purging type bulimia nervosa is characterized by fasting or excessive exercise.


II. Clinical Evaluation of Anorexia Nervosa
A. Dieting Behavior. Indications of dieting behavior include preoccupation with body weight or specific body areas, attempts to restrict calories and fatty foods, frequent weighings, mirror gazing, preoccupation with food, meal avoidance, preoccupation with clothes size, and attempts to hide weight loss with bulky clothing.
B. Physical examination should include blood pressure, height, and weight. Emaciation and evidence of slowed metabolic and physiological functions may be apparent. Lanugo, a fine, downy body hair, may be prominent on the arms, torso, and face.
C. Cardiovascular complications are the most likely cause of death in anorexia nervosa. Bradycardia, orthostatic hypotension, and mitral valve prolapse are common.
D. Psychological Assessment. The patient may appear indifferent to the weight loss (denial), and mental status examination often reveals a flat affect and pooreye contact. The eyes may have a lackluster appearance due to the effects of starvation. Impairment of concentration, lack of cooperation, limited verbaliza tion, and dysphoric mood are frequent.
E. A general laboratory screen is usually sufficient in the assessment of anorexia nervosa. Among individuals who purge, determination of electrolyte status is the most important concern, particularly serum potassium status. An electrocardiogram is indicated for cardiac symptoms, extremely low body weight, or history of exposure to syrup of ipecac.

Laboratory Abnormalities Associated with Eating Disorders
Anemia Leukopenia
Thrombocytopenia
Reduced erythrocyte sedimentation rate
Impaired cell-mediated immunity
Hypercholesterolemia
Hypocalcemia
Hypomagnesemia
Hypophosphatemia
Hypokalemia (vomiting, laxatives, diuretics)Hypercortisolemia
Hypoglycemia
Elevated growth hormone levels
Reduced estrogen levels
Reduced basal levels of luteinizing and follicle-stimulating hormones
Elevated liver function tests
Elevated amylase (vomiting)


III. Clinical Evaluation of Bulimia Nervosa
A. History of dieting behavior is usually present. Purging behaviors may include self-induced vomiting, the use of laxatives, diuretics, enemas, syrup of ipecac, food restriction, and excessive exercise.
B. Physical examination signs of self-induced vomiting include dental erosion or perimylolysis, resulting in discoloration of tooth enamel, temperature sensitivity of the teeth, spaces or gaps between teeth, loose fillings or amal gams, and a receding distal surface of the upper front teeth.
C. Salivary gland enlargement (parotid and/or submandibular) occurs in some individuals who induce vomiting. Enlargement recedes 4-6 weeks after cessation of vomiting.
D. Small excoriations on the hand may be present when vomiting is induced by a gag reflex using the fingers. Syrup of ipecac contains emetine and, frequent dosing may induce cardiac arrhythmias. Emetine may also cause myopathies, resulting in muscle weakness.
E. Laxative Abuse may cause abdominal discomfort, pain, bloating, nausea, vomiting, and constipation. Chronic laxative abuse may lead to laxative dependence.
F. Laboratory examination with bulimia nervosa is usually unremarkable, with the exception of an occasionally low serum potassium level. Electrocardio grams are indicated in those individuals using syrup of ipecac. Less frequent findings include hyperamylasemia, hypocalcemia, hyperchloremia, and steatorrhea (associated with laxative abuse).

IV. Management of Eating Disorders
A. Anorexia Nervosa
1. The patient should be weighed at each visit. In individuals not previously overweight, weight loss of more than 25% of the previous body weight requires referral to a structured refeeding program in an inpatient or day treatment program. Outpatient psychological management is indicated forlesser degrees of weight loss. In amenorrheic patients, bone mass should be protected with hormonal replacement therapy. Psychological intervention may include a structured outpatient refeeding program, cognitive-behavioral therapy, individual psychotherapy, and/or group or family therapy. Support groups may also be helpful.

2. Suicidal ideation requires psychiatric hospitalization, and depression requires antidepressant treatment. Anti-depressants with anti-obsessional features (ie, selective serotonin reuptake inhibitors) are recommended.


3. Fluoxetine (Prozac) has been used successfully in the therapy of anorexia and bulimia; 10-20 mg PO qAM.

4. For patients who induce vomiting, fluoride treatments may improve dentition. Laxative-dependent patients should be gradually weaned off laxatives, and dietary fiber should be gradually increased and adequate hydration maintained.

B. Bulimia Nervosa
1. Most individuals with bulimia nervosa are within a normal weight range, and weighings may be less frequent than for anorexia nervosa. Electrolyte abnormalities, particularly low serum potassium, should be corrected.

2. Personality disorders (particularly borderline personality), substance abuse, and/or mood disorders also should be treated. Psychological treat ment may entail cognitive-behavioral therapy, individual psychotherapy, group therapy, and nutritional counseling. Most individuals can be treated in an outpatient setting.

3. Fluoxetine, sertraline, or paroxetine (ie, selective serotonin reuptake inhibitors) appear to reduce binge/purge behavior. Selective serotonin reuptake inhibitors also alleviate the ruminative, obsessive psychological style that characterizes many of these patients.


V. Prognosis of Eating Disorders
A. Anorexia Nervosa. About one-third of patients fully recover, one-third improve, and one-third remain impaired. This latter third frequently also have personality disorders or depression.
B. Bulimia Nervosa. Relapse rates are fairly high and parallel increases in psychosocial stressors. One-third of patients relapsed within two years of treatment.

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Anorexia Nervosa

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