Anorexia nervosa

Background

• Associated with body image disturbance
• Usually seen in adolescent girls
  • 3rd most common chronic condition in adolescent girls
  • Life long risk
• Body image is predominate measure of self worth
• Mortality 6-20%, highest of any psychiatric disorder

Clinical Features

Patient with anorexia nervosa.

Diagnostic Criteria

1. Restriction of energy intake relative to requirements, leading to a significantly low body weight in the context of age, sex, developmental trajectory, and physical health. Significantly low weight is defined as a weight that is less than minimally normal or, for children and adolescents, less than that minimally expected.
2. Intense fear of gaining weight or of becoming fat, or persistent behavior that interferes with weight gain, even though at a significantly low weight.
3. Disturbance in the way in which one’s body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or persistent lack of recognition of the seriousness of the current low body weight.

Symptoms

• Constipation
• Abdominal pain
• Fatigue
• Weakness
• Amenorrhea
• Depression
• Hair loss

Signs

• Fine facial and body hair (lanugo)
• Brittle hair and nails
• Dry, scaly skin
• Loss of subcutaneous fat
• Breast and vaginal atrophy

Differential Diagnosis

• Gastrointestinal disease
• Hyperthyroidism
• Occult malignancies
• AIDS
• Major depressive disorder
• Schizophrenia
• Substance abuse
• Social anxiety disorder
• Obsessive-compulsive disorder
• Bulimia nervosa

Evaluation

• Exclude: Inflammatory bowel disease, hyperthyroidism, chronic infection, diabetes mellitus, and Addison’s disease
• CBC
  • Anemia, leukopenia in severe disease
• Chem 10
  • Hypoglycemia, hypophosphatemia in severe disease
• ECG

Management

• Treat medical complications
  • Cardiovascular
    • Bradycardia due to increased vagal tone
    • Other serious dysrhythmias
    • Decreased cardiac muscle from malnutrition --> cardiac dysfunction, mitral valve prolapse
    • Caution with rate of IVF (risk of pulmonary edema)
  • Fluid/Electrolytes
    • Serious electrolyte abnormalities can occur
      • Hypophosphatemia can impair cardiac and diaphragmatic muscle contractions--> respiratory/cardiac arrest
      • Hypomagnesemia, hypokalemia and alterations with refeeding can cause arrhythmia
    • Refeeding syndrome risk
    • Even 1L of d5 NS could harm patient subsisting on <400kcal daily
  • Gastrointestinal
    • Delayed gastric/colonic emptying--> gastroparesis, distension, GERD, constipation, SMA syndrome
  • MSK
    • Osteoporosis due to HPA dysfunction
    • Risk of fracture with minimal or no trauma
• Must avoid use of bupropion as it may lead to seizures in patients with eating disorders

Disposition

• Inpatient management for:
  • Extremely low weight (<75% of expected body weight) or rapid weight loss
  • Hypotension (<80/50 mmHg)
  • Hypothermia (<96 degrees F)
  • Severe electrolyte imbalances
  • Cardiac disturbances
  • Bradycardia <50
  • Acute medical disorders
  • Severe or intractable purging
  • Psychosis or a high risk of suicide

Also See

• Bulimia nervosa
• General psychiatric workup