Bulimia nervosa is recurrent binge eating coupled with inappropriate compensatory behaviors to prevent weight gain. DSM-5 criteria: recurrent binge eating (eating amount definitely larger than most people would eat in similar circumstances within a discrete time period, with sense of lack of control); recurrent inappropriate compensatory behaviors (purging through vomiting/laxatives/diuretics, fasting, excessive exercise); both occur at least once weekly for 3 months; self-evaluation unduly influenced by body shape and weight; does not occur exclusively during anorexia nervosa episodes.
Clinical presentation: patient typically of normal or above-normal weight (distinct from anorexia where weight loss is required), binge eating in secret, compensatory behaviors hidden from family and friends. Substantial shame about the pattern. Often present clinically through dental complications, electrolyte abnormalities, or comorbid mood symptoms rather than through eating disorder complaints.
Medical complications:
Oral/dental: enamel erosion from gastric acid exposure (particularly lingual surfaces), parotid swelling ("chipmunk cheeks"), dental caries.
Electrolyte abnormalities: hypokalemia (from vomiting) — cardiac arrhythmia risk; hyponatremia; metabolic alkalosis (from vomiting) or acidosis (from laxative abuse).
Gastrointestinal: esophagitis, Mallory-Weiss tears, rare esophageal rupture (Boerhaave syndrome — life-threatening), constipation rebound after laxative cessation.
Cardiac: arrhythmias from electrolytes, rare cardiomyopathy from ipecac abuse.
Russell's sign — calluses on dorsum of hand from contact with teeth during induced vomiting. Hidden but pathognomonic when noticed.
Treatment:
CBT for Bulimia Nervosa (CBT-BN) is first-line — manualized 20-session protocol. Substantial evidence; effect on binge/purge frequency, body image, and comorbid conditions. Some patients respond to digital or self-help versions.
Fluoxetine 60 mg/day is FDA-approved for bulimia (higher dose than for depression). Substantial effect on binge frequency. Other SSRIs likely effective but lack specific FDA indication. Combined CBT-BN plus fluoxetine often outperforms either alone.
Topiramate has evidence for binge reduction; weight loss as side effect can be beneficial in bulimia (unlike in anorexia where weight loss is problematic).
Address medical complications — electrolyte replacement, dental referral, gastroenterology when esophageal symptoms.
Prognosis is generally better than anorexia. Roughly 50-70% achieve substantial improvement or remission with adequate treatment. Recovery typically occurs over months to years; relapses common, particularly during stress or major life transitions.
Distinction from binge eating disorder: BN includes compensatory behaviors (purging, fasting, excessive exercise); BED does not. Different treatment implications.
Comorbidity: depression (50-70%), anxiety disorders, substance use disorders (alcohol particularly), borderline personality disorder traits, history of trauma. Comprehensive treatment addresses all dimensions.
When you encounter a patient with binge eating plus compensatory behaviors, bulimia nervosa is the diagnosis. Treatment is effective. The shame that often accompanies the disorder is a treatment barrier; empathetic engagement is part of the work.