USMLE Guide: Bulimia Nervosa

Introduction

Bulimia Nervosa is an eating disorder characterized by recurrent episodes of binge eating followed by inappropriate compensatory behaviors to prevent weight gain. This USMLE guide aims to provide a comprehensive overview of Bulimia Nervosa, including its diagnostic criteria, epidemiology, pathophysiology, clinical features, and management.

Diagnostic Criteria

To diagnose Bulimia Nervosa according to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5), the following criteria must be met:

• Recurrent episodes of binge eating, characterized by both of the following:
  • Eating an excessive amount of food within a discrete period (e.g., 2 hours).
  • A lack of control over eating during the episode.
• Recurrent inappropriate compensatory behaviors to prevent weight gain, such as self-induced vomiting, excessive exercise, or misuse of laxatives, diuretics, or other medications.
• Binge eating and inappropriate compensatory behaviors occur, on average, at least once a week for three months.
• Self-evaluation is unduly influenced by body shape and weight.
• The disturbance does not occur exclusively during episodes of Anorexia Nervosa.

Epidemiology

• Bulimia Nervosa typically begins in adolescence or early adulthood.
• Prevalence is higher in females, with a male-to-female ratio of approximately 1:10.
• Lifetime prevalence is estimated to be around 1-3% in the general population.

Pathophysiology

• The exact etiology of Bulimia Nervosa is unclear, but it likely involves a combination of genetic, environmental, and psychosocial factors.
• Neurotransmitter dysregulation, particularly involving serotonin, is thought to play a role in the development and maintenance of the disorder.

Clinical Features

• Patients with Bulimia Nervosa are usually of normal weight or slightly overweight.
• Binge eating episodes are often characterized by consuming large quantities of high-calorie, easily ingested foods.
• Inappropriate compensatory behaviors can lead to various complications, including electrolyte abnormalities, dental erosion, esophageal tears, and gastrointestinal disturbances.
• Psychological symptoms may include body dissatisfaction, mood swings, and a preoccupation with body shape and weight.

Management

• Psychotherapy, particularly cognitive-behavioral therapy (CBT), is the mainstay of treatment for Bulimia Nervosa.
• Nutritional counseling and education regarding healthy eating patterns are essential components of management.
• Medications, such as selective serotonin reuptake inhibitors (SSRIs), may be considered in conjunction with psychotherapy for patients who do not respond to initial treatment.
• Hospitalization may be required in severe cases with medical instability or lack of response to outpatient therapy.

Conclusion

Bulimia Nervosa is a serious eating disorder characterized by recurrent episodes of binge eating and inappropriate compensatory behaviors. Understanding the diagnostic criteria, epidemiology, pathophysiology, clinical features, and management of Bulimia Nervosa is crucial for healthcare professionals to provide appropriate care and support to affected individuals.