Bulimia Nervosa
Definition | Aetiology | Pathophysiology | Risk factors | Signs and symptoms | Investigations | Management
Definition
Bulimia Nervosa is an eating disorder characterised by recurrent episodes of binge eating followed by inappropriate compensatory behaviours such as self-induced vomiting, excessive exercise, or misuse of laxatives to prevent weight gain.
Aetiology
- Genetic factors: family history of eating disorders or mood disorders.
- Neurobiological factors: serotonin and dopamine dysregulation affecting impulse control and appetite regulation.
- Psychosocial factors: low self-esteem, perfectionism, and societal pressure regarding body image.
- Environmental factors: history of dieting, weight-related teasing, or childhood trauma.
Pathophysiology
- Dysregulation of serotonin pathways affecting satiety and mood.
- Altered reward processing in the brain, leading to binge-purge cycles.
- HPA axis dysregulation, contributing to heightened stress response and compulsive behaviours.
Risk factors
- Family history of eating disorders or depression.
- Previous or ongoing restrictive dieting.
- Personality traits such as impulsivity, perfectionism, or emotional instability.
- Exposure to media promoting unrealistic body ideals.
- History of trauma, abuse, or bullying.
Signs and symptoms
- Recurrent binge eating episodes, typically in secret.
- Compensatory behaviours such as vomiting, excessive exercise, or laxative misuse.
- Preoccupation with weight, body shape, and dieting.
- Gastrointestinal issues such as bloating, constipation, or acid reflux.
- Calluses on knuckles (Russell’s sign) from self-induced vomiting.
- Dental erosion due to repeated exposure to stomach acid.
- Electrolyte imbalances leading to palpitations, weakness, or seizures.
Investigations
- Clinical assessment: full eating disorder history, weight trends, and menstrual irregularities.
- Blood tests: U&Es, FBC, LFTs, TFTs, glucose, calcium, phosphate to check for metabolic disturbances.
- ECG: to assess for arrhythmias due to electrolyte imbalance.
- Bone density scan (DEXA): if prolonged history of malnutrition.
Management
1. Psychological therapies:
- Cognitive Behavioural Therapy for Eating Disorders (CBT-E) as first-line treatment.
- Interpersonal therapy (IPT) to address emotional distress.
- Dialectical Behaviour Therapy (DBT) for those with comorbid emotional dysregulation.
2. Pharmacological management:
- First-line: Selective serotonin reuptake inhibitors (SSRIs) (e.g., fluoxetine) to reduce binge-purge episodes.
3. Nutritional rehabilitation:
- Regular meal planning to normalise eating patterns.
- Dietary education to prevent restrictive eating cycles.
- Hydration and electrolyte monitoring.
4. Referral:
- Eating disorder services: for structured therapy and nutritional support.
- Dietitian: for meal planning and dietary advice.
- Psychiatrist: if severe psychiatric comorbidities or treatment resistance.