Bulimia Nervosa
An eating disorder involving repeated binge eating followed by purging to avoid weight gain, usually in individuals of normal weight.
Emergency Management: Severe hypokalemia (<2.5 mEq/L) or ECG changes require immediate ER evaluation for IV potassium repletion and continuous cardiac monitoring.
An eating disorder characterized by a cycle of recurrent episodes of binge eating followed by inappropriate compensatory behaviors (such as self-induced vomiting, misuse of laxatives/diuretics, fasting, or excessive exercise) to prevent weight gain. The individual's self-evaluation is unduly influenced by body shape and weight.
Detailed Overview
Unlike patients with anorexia nervosa, individuals with bulimia nervosa typically maintain a normal weight or are slightly overweight (BMI > 18.5). The disorder is driven by an intense fear of gaining weight and a distorted body image. The chronic cycle of binging and purging leads to severe medical complications, primarily electrolyte imbalances (hypokalemia), gastrointestinal disturbances, and dental erosion.
Epidemiology & Demographics
Lifetime prevalence is 1-1.5% in women and 0.5% in men. The peak age of onset is late adolescence or early adulthood (18-20 years). Highly prevalent among individuals in professions that emphasize body image (e.g., dancers, athletes).
Etiological Mechanism
Multifactorial. Biological factors include dysregulation of serotonin and dopamine pathways. Psychological factors involve low self-esteem, perfectionism, and poor affect regulation. Sociocultural factors include Western beauty standards emphasizing thinness.
Primary Causes
["Genetic vulnerability (higher concordance in monozygotic twins)", "History of childhood trauma or abuse", "Societal pressure and internalized body ideal"]
Binge eating temporarily relieves emotional distress but is followed by intense guilt and fear of weight gain, prompting purging. Repeated self-induced vomiting causes loss of gastric hydrochloric acid leading to hypochloremic hypokalemic metabolic alkalosis. Laxative abuse causes loss of bicarbonate and potassium, leading to hyperchloremic non-anion gap metabolic acidosis.
Diagnostic Criteria & Guidelines
DSM-5 Criteria: 1) Recurrent episodes of binge eating. 2) Recurrent inappropriate compensatory behaviors to prevent weight gain. 3) Both occur, on average, at least once a week for 3 months. 4) Self-evaluation is unduly influenced by body shape and weight. 5) Disturbance does not occur exclusively during episodes of anorexia nervosa.
Cognitive Behavioral Therapy specifically adapted for eating disorders (CBT-ED) is the gold standard psychotherapy. Pharmacotherapy: Fluoxetine is FDA approved for bulimia. Dose is typically 60 mg orally daily (higher than the standard depression dose of 20 mg). Correct electrolyte imbalances (oral or IV Potassium Chloride based on severity).
Second-Line & Adjunctive Therapy
Sertraline or Topiramate (which reduces binge/purge frequency). Interpersonal psychotherapy (IPT).
Surgical & Procedural Management
None, unless treating complications like esophageal rupture (emergent thoracotomy).
Patient Counseling & Advice
Educate the patient that laxatives do not significantly prevent calorie absorption; they mostly cause water and colon mucosal loss. Inform them about the fatal risks of hypokalemia and esophageal rupture.
Follow-Up & Monitoring Schedule
Weekly or biweekly visits with a multidisciplinary team (psychiatrist, therapist, dietician). Routine monitoring of orthostatic vitals and BMP/ECG to check potassium levels.
Preventive Strategies
Promoting body positivity and healthy self-esteem in adolescents. Early intervention for anxiety or dieting behaviors.
About 50-70% achieve remission with combined therapy. However, relapse is common (up to 30%), especially during periods of high stress. Mortality rate is ~2% per decade, largely due to suicide or cardiac arrhythmias.