Psychiatry/Behavioral · PANCE / PANRE

Bulimia Nervosa

Recurrent binge eating with inappropriate compensatory behaviors; normal or above-normal weight.

Also known as: bulimia, bulimia nervosa

Overview

An eating disorder characterized by recurrent episodes of binge eating accompanied by recurrent inappropriate compensatory behaviors (vomiting, laxatives/diuretics, fasting, excessive exercise) at least once weekly for 3 months, with self-evaluation unduly influenced by body shape and weight. Patients are typically of normal or above-normal weight.

Epidemiology

Lifetime prevalence ~1-2% in women, ~0.5% in men. Onset typically late adolescence. Frequently comorbid with depression, anxiety, substance use, BPD.

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Risk factors

Female sex, adolescence/young adulthood
Family history of eating, mood, or substance use disorders
Impulsivity, emotion dysregulation
Childhood obesity, early dieting, trauma history
Athletic or appearance-focused environments

Pathophysiology

Dysregulated reward and impulse control with serotonergic and dopaminergic alterations; biopsychosocial model emphasizing dietary restraint as a precipitant for binge episodes followed by guilt-driven compensation.

Clinical presentation

Symptoms

Binge: eating an objectively large amount of food in <2 hours with sense of loss of control
Compensatory behaviors: self-induced vomiting (most common), laxative or diuretic misuse, fasting, excessive exercise
Both occur on average >=1/week for >=3 months
Body shape and weight unduly influence self-evaluation

Signs / physical exam

Russell's sign (knuckle calluses)
Parotid and submandibular gland hypertrophy
Dental erosion (lingual surface of upper teeth), caries
Esophagitis, hematemesis, rare Mallory-Weiss tear or Boerhaave
Electrolyte disturbances: hypokalemia, hypochloremic metabolic alkalosis with vomiting; non-anion gap metabolic acidosis with laxative misuse

Differential diagnosis

Anorexia nervosa binge-purge type — Significantly low weight present
Binge eating disorder — Binges without compensatory behaviors
MDD with binge eating — Episodic eating during mood episodes without compensatory behaviors
Kleine-Levin syndrome — Periodic hypersomnia with hyperphagia, hypersexuality
GI causes of vomiting — Cyclic vomiting syndrome, gastroparesis — no body image disturbance

Diagnostic workup

Diagnostic criteria

DSM-5-TR: (A) Recurrent binge eating — large amount + loss of control; (B) Recurrent inappropriate compensatory behaviors; (C) Both occur on average >=1/week for >=3 months; (D) Self-evaluation unduly influenced by body shape/weight; (E) Disturbance does not occur exclusively during anorexia nervosa episodes. Severity by frequency: mild 1-3, moderate 4-7, severe 8-13, extreme >=14 episodes/week.

Labs

CMP (K, Cl, HCO3, Mg, phosphate), CBC, amylase, lipase
ECG if electrolyte abnormality (QT prolongation, U waves with hypokalemia)
Pregnancy test
Urine sodium/chloride to detect surreptitious vomiting (low Cl)

Imaging

Not routinely indicated; CXR if subcutaneous emphysema or chest pain (Boerhaave)

Diagnostic algorithm

Severity	Episodes/week
Mild	1-3
Moderate	4-7
Severe	8-13
Extreme	>=14

Bulimia nervosa severity by frequency of inappropriate compensatory behaviors per week.

Treatment

First-line

Cognitive behavioral therapy for eating disorders (CBT-ED) — strongest evidence base
Interpersonal therapy (IPT) — alternative
Family-based treatment for adolescents
Fluoxetine 60 mg/day — FDA-approved; reduces binge/purge frequency
Nutritional counseling — structured eating to interrupt restriction-binge cycle

Second-line / adjunct

Other SSRIs at higher doses if fluoxetine not tolerated
Topiramate — weight loss side effect can be problematic; teratogenic
AVOID bupropion (lowers seizure threshold; contraindicated in active bulimia)
Treat electrolyte abnormalities; dental care
Partial hospitalization or residential for severe disease

Complications

Electrolyte: hypokalemia (arrhythmias), hypochloremic metabolic alkalosis, hypomagnesemia
Dental erosion, caries, parotid hypertrophy
Esophagitis, Mallory-Weiss tear, rare esophageal rupture
Cardiac arrhythmias (especially with ipecac or severe electrolyte derangement)
Ipecac-induced cardiomyopathy
Substance use, self-harm, suicidality (elevated suicide risk)
Menstrual irregularity, infertility

PANCE pearls

Bupropion is CONTRAINDICATED in active bulimia and anorexia (seizure risk) — choose fluoxetine for comorbid depression.
Fluoxetine at 60 mg/day (higher than depression dose) is the FDA-approved dose for bulimia.
Most patients are at normal weight — absence of cachexia does not exclude an eating disorder.
Address dietary restriction in treatment — restriction perpetuates the binge cycle.
Screen with SCOFF questionnaire (>=2 positive raises concern).

References

APA 2023 — American Psychiatric Association Practice Guideline for the Treatment of Patients with Eating Disorders, 4th ed. (2023)
NICE NG69 — NICE Guideline 69: Eating disorders: recognition and treatment
Fairburn CBT-E — Fairburn CG. Cognitive Behavior Therapy and Eating Disorders (2008)
DSM-5-TR — American Psychiatric Association. DSM-5-TR (2022)

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