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.

Try two board-style Bulimia Nervosa questions

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Question 1PsychiatryMedium
A 35-year-old woman with a history of bulimia nervosa in remission for 2 years has a BMI of 38 and asks about pharmacotherapy for weight loss. Which of the following medications is most clearly contraindicated given her history of bulimia nervosa?
  • APhentermine-topiramate
  • BOrlistat
  • CBupropion-naltrexone
  • DSemaglutide
Reveal answer & full explanation
Correct answer: C — Bupropion-naltrexone
  • APhentermine-topiramate
  • BOrlistat
  • CBupropion-naltrexone
  • DSemaglutide

Why bupropion-naltrexone is correct

  • A current or prior eating disorder (bulimia or anorexia nervosa) is a labeled contraindication to bupropion-naltrexone, so her remitted bulimia makes this the agent that is most clearly contraindicated
  • The bupropion component lowers the seizure threshold, and eating disorders carry electrolyte disturbances (e.g., from purging) that further raise seizure risk
  • The contraindication applies to prior disease, not only active disease, so 2 years of remission does not remove it

Why the others are wrong

  • Phentermine-topiramate — eating disorder is not a labeled contraindication, and topiramate actually reduces binge-eating behavior; picking it is buzzword-matching "weight-loss stimulant" rather than the specific eating-disorder contraindication
  • Orlistat — has no eating-disorder contraindication; the trap is premature closure on a theoretical concern about misuse in active purging, but this patient is in remission and the drug carries no formal contraindication
  • Semaglutide — a glucagon-like peptide-1 (GLP-1) agonist with no eating-disorder contraindication and generally considered a safer option here; chosen if the learner assumes any weight-loss drug is risky in this history
Question 2PsychiatryEasy
A 30-year-old female has recurrent episodes of binge eating large amounts of food in under 2 hours with loss of control, followed by self-induced vomiting. She is normal weight. Labs show hypokalemia and metabolic alkalosis. Physical exam shows bilateral parotid gland enlargement and dental enamel erosion. Which of the following is the most likely diagnosis?
  • APurging disorder
  • BBinge eating disorder
  • CAnorexia nervosa
  • DBulimia nervosa
Reveal answer & full explanation
Correct answer: D — Bulimia nervosa
  • APurging disorder
  • BBinge eating disorder
  • CAnorexia nervosa
  • DBulimia nervosa

Why Bulimia nervosa is correct

  • Bulimia nervosa (BN): recurrent binge eating plus compensatory behaviors (purging, laxatives, excessive exercise) plus normal or near-normal weight
  • Medical complications include hypokalemia with metabolic alkalosis from vomiting, dental erosion, parotid hypertrophy, and Russell sign (calluses on dorsum of hand)

Why the others are wrong

  • A) Purging disorder — involves purging without binge eating episodes; this patient has clear binge-eating episodes with loss of control
  • B) Binge eating disorder — involves recurrent binge eating without compensatory behaviors; this patient self-induces vomiting
  • C) Anorexia nervosa — characterized by low body weight and restrictive eating; this patient is normal weight

Additional high-yield points

  • Treatment: enhanced cognitive behavioral therapy (CBT-E) is most effective with 40-50% remission
  • Fluoxetine 60 mg is the only FDA-approved medication for BN
  • Combination CBT plus fluoxetine is superior to either alone
  • Bupropion is avoided in BN due to lowered seizure threshold and risk from electrolyte imbalances with purging
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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

SeverityEpisodes/week
Mild1-3
Moderate4-7
Severe8-13
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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