• Refusal to eat, with resultant weight loss or failure to gain weight
• Intense fear of gaining weight or becoming fat
• Misperception of body size
• In females, amenorrhea

• Person does not usually engage in binge eating or purging behaviors.
• Patients are characterized as more obsessive-compulsive, stoical, perfectionistic, introverted, and emotionally inhibited.

• Person regularly engages in binge eating or purging behavior
• Patients are described as impulsive, depressive, socially dysfunctional, sexually adventurous, and as substance misusers, with high levels of general emotional distress.

• Mildly distorted body image
• Weight >90% of average weight for height
• No symptoms or signs of excess weight loss
• Healthy weight loss methods
• (>1000 cal/day, moderate exercise, no purging)

• Moderate distortion of body image unchanged with weight loss
• Weight 90% of average weight for height with refusal to stop additional weight loss
• Symptoms or signs of weight loss associated with denial of any problem existing
• Unhealthy means to lose weight (consuming <1000 cal/day, excessive exercise or purging)

• Grossly distorted body image unchanged with weight loss
• Weight 85% of average weight for height associated with refusal to stop weight loss
• Symptoms or signs of extreme malnutrition, often coexisting with denial regarding thinness
• Unhealthy means of losing weight (consuming <1000 cal/day, excessive exercise or purging)

• Worldwide: 1 case/100,000 people
• White, pubertal females in Western countries: 1 case/200 people
• Prevalence rate for adolescent girls in the United States is 0.48%
• Female to male ratio: 9–10:1
• Mean onset is 13.75 (range 10–25) years
• Coincides with changes of puberty

• Hypothyroidism
• Hypogonadotropic hypogonadism
• Hypoestrogenism

• Bradycardia
• Nodal rhythm
• First- and second-degree heart block
• Intraventricular conduction disturbances
• Bundle-branch block
• Ventricular ectopic beats

• Delayed gastric emptying
• Decreased intestinal motility

• Hypocholoremic, hypokalemic metabolic alkalosis

• Muscle weakness
• Peripheral neuropathy
• Abnormal thermoregulation
• Reduced basal temperature

• Impaired concentration and alertness
• Distractibility
• Apathy
• Sleeping problems

• Amenorrhea

• Osteopenia

• Enamel erosion
• Salivary gland enlargement

• Lanugo hair
• Pedal or pretibial edema
• Orange skin
• Brittle hair and nails
• Calluses on knuckles (Russell syndrome; due to vomiting)

• Mortality: 5.9%
• 50% have good outcome, 25% have intermediate outcome, and 25% do poorly.

• High educational achievement
• Early age of onset
• Good emotional adjustment
• Improvement in body image after weight gain
• Good initial ego strength
• Supportive family

• Late age of onset
• Continued distortion of body image
• Premorbid obesity
• Vomiting or laxative abuse
• Significant depression, obsessive behavior
• Family dysfunction
• Male gender
• Very low body mass indexes at initiation of therapy

• Tuberculosis

• Cerebral neoplasm

• Hyperthyroidism or hypothyroidism
• Addison disease
• Diabetes mellitus

• Depression
• Malabsorptive states
• Gastroesophageal obstruction

Question: Assess self-esteem, reason for dieting, ways of controlling weight, and frequency of weighing.
Significance: Determine degree of eating disorder psychopathology.

Question: Does patient exercise, binge/purge, use laxatives, diuretics, or emetics, or have food rituals or particular eating behaviors?
Significance: Assesses eating disorder stereotypical behavior

Question: Does patient have symptoms of weakness, fatigue, cold intolerance, headaches, dizziness, abdominal pain, or constipation?
Significance: Addresses common physical symptoms of anorexia nervosa

Question: Is there any history of depression, mood disorder, anxiety disorder, suicide attempt, or substance use by the patient?
Significance: Addresses common psychological symptoms of anorexia nervosa.

Finding: Vital signs to assess for hypotension, bradycardia, hypothermia
Significance: Signs of malnutrition and dehydration

Finding: Weight 15% below ideal
Significance: Consider hospitalization

Finding: Short stature
Significance: Malnutrition, reduced growth, retardation

Finding: Degree of emaciation
Significance: Consider hospitalization

Finding: Dry skin
Significance: Hypothyroidism

Finding: Edema
Significance: Hypoproteinemia

Finding: Yellow skin
Significance: Carotenemia

Laboratory assessment should be done as part of the initial diagnostic evaluation.

Test: Electrolytes, including calcium, magnesium, phosphate
Significance: Demonstrates electrolyte abnormalities from poor intake or laxative and/or diuretic use

Test: BUN and creatinine
Significance: Assess degree of dehydration

Test: Liver function tests
Significance: Patient may have mild elevation of hepatic enzymes

Test: Cholesterol, lipids
Significance: May have hypercholesterolemia

Test: Total protein, albumin
Significance: May be hypoproteinemic

Test: Thyroid function tests, LH and FSH
Significance: Tend to see hypothyroidism and hypogonadotropic hypogonadism

Test: Electrocardiogram
Significance: All patients should have a baseline ECG because cardiac abnormalities are the major medical cause of morbidity and mortality.

Test: Chest x-ray (optional)
Significance: Evaluates for TB

• A multidisciplinary approach is needed to make the diagnosis of anorexia nervosa. Include a psychotherapist and a nutritionist when evaluating and treating these patients.
• Malnourished adolescents with anorexia nervosa are hypometabolic, and initial energy requirements may be as low as 800–1000 kcal/d.
• Calorie intake should be increased by 200–300 kcal every 2 to 3 days as tolerated.
• Expected rate of weight gain will vary, but a rate of 0.36 lb/d has been shown to be safe in adolescents with anorexia nervosa.

• Assess and monitor diet and weight loss plan.
• Refer to nutritionist, if indicated, for education and meal planning.
• Establish weight loss limit at patient’s own weight goal.
• Reevaluate in 1 to 2 months.

• Perform medical and nutritional assessment of weight loss, including laboratory studies.
• Establish weight gain goal (target weight, 85% of average; rate of weight gain, 1–2 lb/week).
• Provide specific guidelines for structure of daily activities (e.g., eating schedule, exercise, after-school activities, sports, and recreation).
• Provide medical, nutritional, and mental health counseling that considers the developmental stage and needs of the patient.
• Establish follow-up every 1 to 2 weeks to monitor health and to maintain therapeutic relationship with patient and parents.
• Consult with eating disorder specialists, with referral if necessary.
• Establish criteria for hospitalization.

• Perform medical and nutritional assessment of weight loss, including laboratory studies.
• Refer to eating disorder specialists.

• Hypovolemia and hypotension
• Hypothermia (temperature <36°C)
• Electrolyte imbalance, dehydration
• Heart rate <55 beats/min
• Grey-out (a fuzzy light-headed feeling) or syncope
• Weight below 75% ideal body weight (IBW)
• Uncontrollable binging and purging
• Acute food refusal
• Persistent weight loss

• Estrogen and calcium replacement to correct osteopenia
• Stool softeners for constipation; no laxatives
• Antidepressants such as fluoxetine (Prozac) have been helpful in treatment if there is concomitant depression.

• Weight loss or failure to gain weight after institution of dietary program
• Electrolyte abnormalities
• Willful behavior and acting out
• Increased depression or mood disturbance

• Gonadotropins are usually at a prepubertal level.
• T₃ is low and reverse T₃ is elevated, reflecting increased conversion of T₄ to reverse T₃ and decreased conversion of T₄ to T₃.
• Liver transaminases rise during refeeding.
• Acute decreases in phosphorus during refeeding can indicate refeeding syndrome. Use supplementation if necessary.

Q: Should the patient with amenorrhea be started on hormonal replacement?
A: Yes, adolescents should begin hormone therapy. Oral contraceptive pills are easiest to use. Often the patient does not wish to take hormones because she is fearful that she will gain weight.

Q: Should the patient be allowed to exercise as an outpatient?
A: Exercise should be restricted until the patient’s weight has improved sufficiently to preclude bradycardia or other cardiac arrhythmias. Often exercise can be used as a bargaining tool in the behavioral management of these patients. If the patient maintains a minimum of 91% ideal body weight, he or she may exercise. If the weight decreases, exercise is again restricted.

Garner DM. Pathogenesis of anorexia nervosa. Lancet 1993;341(8861):1631–1635.

Harper G. Eating disorders in adolescence. Pediatr Rev 1994;15(2):72–77.

Sullivan PF. Mortality in anorexia nervosa. Am J Psychiatry 1995;152(7):1073–1074.