Bulimia Nervosa

Introduction - Binge-Purge Cycle Basics

• Definition: Recurrent episodes of binge eating (large food amount, loss of control) AND recurrent inappropriate compensatory behaviors (e.g., vomiting, laxatives, fasting, excessive exercise) to prevent weight gain.
  • Occurs at least once a week for 3 months.
  • Self-evaluation is unduly influenced by body shape/weight.
• Epidemiology:
  • Prevalence: ~1-1.5% in young women; F:M ratio ~10:1.
  • Age of onset: Late adolescence/early adulthood.
  • Indian context: Underreported; prevalence may be similar to Western countries in urban settings.

⭐ Bulimia Nervosa often co-occurs with mood and anxiety disorders, particularly depression and borderline personality disorder (Cluster B).

Diagnosis - Spotting the Signs

DSM-5 Diagnostic Criteria:

• Purging: Vomiting, laxatives, diuretics.
• Non-purging: Fasting, excessive exercise.

Key Physical Signs:

• Russell's sign: Knuckle calluses (self-induced vomiting).
• Dental enamel erosion (lingual surfaces).
• Parotid gland enlargement (non-tender, bilateral).
• Electrolyte imbalance (e.g., ↓K+, metabolic alkalosis).
• Facial petechiae, subconjunctival hemorrhages (vomiting strain).

Psychological Features:

• Intense fear of weight gain; body shape/weight preoccupation.
• Distorted body image.
• Shame, guilt, secrecy about eating.
• Impulsivity, mood lability.

⭐ Russell's sign (knuckle calluses) indicates self-induced vomiting.

Complications - Body Under Siege

Bulimia Nervosa's (BN) recurrent purging (vomiting, laxatives, diuretics) causes severe multi-systemic damage.

• Metabolic:
  • Hypokalemia ($K⁺ < \textbf{3.5} mEq/L$) - critical cardiac risk!
  • Hyponatremia ($Na⁺ < \textbf{135} mEq/L$)
  • Metabolic alkalosis (vomiting) or acidosis (laxative abuse)
• Dental:
  • Enamel erosion (perimylolysis, especially lingual surfaces)
  • Increased dental caries, periodontitis
  • 
• Gastrointestinal (GI):
  • Esophagitis, Mallory-Weiss tears (esophageal)
  • Salivary gland hypertrophy (sialadenosis, "chipmunk facies")
  • Laxative dependence, chronic constipation
• Cardiovascular:
  • Arrhythmias (often due to hypokalemia)
  • Cardiomyopathy (chronic ipecac use)
• Endocrine & Renal:
  • Menstrual irregularities (amenorrhea, oligomenorrhea)
  • Renal dysfunction, electrolyte wasting

⭐ Hypokalemia ($K⁺ < \textbf{3.5} mEq/L$) is a common, potentially life-threatening complication in BN, primarily from purging behaviors.

Management - Path to Recovery

Multimodal: Psychotherapy, pharmacotherapy, nutritional rehabilitation. Manage medical complications.

• Psychotherapy:
  • CBT-BN: First-line.
  • IPT (Interpersonal Psychotherapy).
• Pharmacotherapy:
  • SSRIs: Fluoxetine 60mg/day (FDA approved).
  • Other antidepressants considered.
• Nutritional Rehabilitation: Essential for healthy eating.
• Medical Complications: Address electrolyte imbalance, dental issues.

⭐ Cognitive Behavioral Therapy tailored for Bulimia Nervosa (CBT-BN) is the most evidence-based psychotherapy.

• Stepped-Care Model:

Differentials & Prognosis - Similar & Future

• Differential Diagnosis:
  • Anorexia Nervosa (binge-eating/purging type): Distinguished by low body weight.
  • Binge Eating Disorder: Lacks compensatory behaviors.
  • Kleine-Levin Syndrome: Episodic hypersomnia, hyperphagia.
  • MDD (atypical features): Mood symptoms primary; overeating present.
  • GI disorders, CNS tumors: Rule out organic causes for vomiting/bingeing.
• Prognosis:
  • Course: Often chronic and fluctuating; relapse common (30-50% within 6 months).
  • Good outcome factors: Shorter illness duration, younger onset, good social support.
  • Poor outcome factors: Comorbid personality disorder (esp. borderline), substance abuse, childhood obesity.

⭐ Unlike Anorexia Nervosa, individuals with Bulimia Nervosa are typically of normal weight or overweight, which can delay diagnosis.

High-Yield Points - ⚡ Biggest Takeaways

• Recurrent binge eating followed by inappropriate compensatory behaviors (e.g., purging, excessive exercise).
• Diagnosis requires episodes at least once a week for 3 months.
• Self-esteem is disproportionately linked to body shape and weight.
• Patients are typically normal weight or overweight, distinguishing from Anorexia Nervosa.
• Key complications: Russell's sign, dental erosion, parotid hypertrophy, hypokalemia, and metabolic alkalosis.
• Cognitive Behavioral Therapy (CBT) is the cornerstone of therapy; Fluoxetine (SSRI) is the drug of choice.
• Often associated with impulsivity, mood disorders, and anxiety disorders.