Bulimia Nervosa – High-Yield Notes

Bulimia Nervosa – High-Yield Notes for USMLE, NCLEX, NEET PG exams

Introduction

• Definition: Bulimia nervosa is an eating disorder characterized by recurrent episodes of binge eating followed by inappropriate compensatory behaviors to prevent weight gain.
• Etiology: Multifactorial, involving genetic, environmental, and psychological factors.
• Epidemiology: More common in females, typically onset in late adolescence or early adulthood.

Pathophysiology

• Binge-Purge Cycle:
  1. Binge Eating: Consumption of an excessively large amount of food in a discrete period, often with a sense of lack of control.
  2. Compensatory Behaviors: Self-induced vomiting, misuse of laxatives, diuretics, fasting, or excessive exercise to prevent weight gain.
• Psychological Factors: Body image distortion, low self-esteem, and high levels of impulsivity and perfectionism.

Clinical Features

• Behavioral Symptoms:
  • Recurrent episodes of binge eating
  • Recurrent inappropriate compensatory behaviors
  • Preoccupation with body weight and shape
• Physical Signs:
  • Normal to slightly overweight body weight (BMI 18.5-29.9)
  • Parotid gland enlargement
  • Dental erosion (from vomiting)
  • Russell’s sign (calluses on knuckles from inducing vomiting)
  • Electrolyte imbalances (hypokalemia, hypochloremia, metabolic alkalosis)
  • Gastroesophageal reflux disease (GERD)
  • Menstrual irregularities

Risk Factors

• Genetic predisposition
• Family history of eating disorders
• Psychiatric comorbidities: Depression, anxiety disorders, substance abuse
• Sociocultural factors: Emphasis on thinness and body image in media and society

Diagnosis

• DSM-5 Criteria:
  • Recurrent episodes of binge eating, as characterized by both:
    • Eating, within any 2-hour period, an amount of food that is definitively larger than what most individuals would eat in a similar period of time under similar circumstances.
    • A feeling that one cannot stop eating or control what or how much one is eating.
  • Recurrent inappropriate compensatory behaviors in order to prevent weight gain such as self-induced vomiting; misuse of laxatives, diuretics, or other medications; fasting or excessive exercise.
  • The binge eating and inappropriate compensatory behaviors occur, on average, at least once a week for 3 months.
  • Self-evaluation is unjustifiability influenced by body shape and weight.
  • The disturbance does not occur exclusively during episodes of anorexia nervosa.
• Laboratory Tests:
  • Electrolyte panel (to detect imbalances)
  • Complete blood count (CBC)
  • Liver function tests (LFTs)
  • Amylase levels (elevated in vomiting)

Treatment

• Psychotherapy:

Cognitive-behavioral therapy (CBT): First-line treatment; focuses on altering dysfunctional thoughts and behaviors related to eating.

• Pharmacotherapy:
  • SSRIs (e.g., fluoxetine): FDA-approved for bulimia nervosa
  • Antidepressants: To manage comorbid depression and anxiety
• Nutritional Counseling: Establishing regular eating patterns and addressing nutritional deficiencies.
• Medical Monitoring: Regular monitoring of electrolytes and physical health.

Complications

• Electrolyte Imbalances: Hypokalemia, hypochloremia, metabolic alkalosis
• Cardiac Arrhythmias: Due to electrolyte disturbances
• Esophageal Tears: Mallory-Weiss syndrome
• Gastrointestinal Complications: GERD, constipation, bloating
• Dental Problems: Enamel erosion, caries
• Psychiatric Complications: Depression, anxiety, substance abuse

Prognosis

• Outcome: Variable; with appropriate treatment, many patients achieve remission.
• Factors Affecting Prognosis: Early intervention, adherence to treatment, presence of comorbid conditions.

Prevention

• Education and Awareness: Promoting healthy body image and eating habits.
• Early Detection: Screening for eating disorders in at-risk populations.

Mnemonics

• BINGE for features of Bulimia Nervosa:

• Binge eating
• Inappropriate compensatory behaviors
• Normal weight range
• Guilt and shame about eating
• Electrolyte imbalances

Chart: Diagnostic Approach to Bulimia Nervosa

Step	Diagnostic Tool	Purpose
1	Clinical Examination	Identify physical signs and symptoms
2	DSM-5 Criteria	Confirm diagnosis
3	Laboratory Tests	Detect electrolyte imbalances, organ damage
4	Psychological Assessment	Evaluate comorbid psychiatric conditions

Table: Treatment Modalities for Bulimia Nervosa

Treatment Modality	Example(s)	Remarks
Psychotherapy	Cognitive-Behavioral Therapy (CBT)	First-line treatment
Pharmacotherapy	Fluoxetine (SSRI)	FDA-approved, helps reduce binge-purge cycles
Nutritional Counseling	Dietitian support	Establishes regular eating patterns
Medical Monitoring	Regular electrolyte checks	Monitor for complications

Key Points

• CBT is the first-line treatment for bulimia nervosa.
• Fluoxetine is the only FDA-approved medication for bulimia nervosa.
• Electrolyte monitoring is essential due to the risk of severe imbalances.
• Early intervention can significantly improve outcomes.

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