Summary

Bulimia Nervosa (BN) is an eating disorder characterised by recurrent episodes of binge eating followed by compensatory behaviours to prevent weight gain, such as self-induced vomiting, misuse of laxatives, excessive exercise, or fasting. Unlike Anorexia Nervosa, individuals with BN are typically of normal or above-normal weight. The disorder is driven by an overvaluation of body shape and weight as central to self-worth. BN is associated with significant physical complications (electrolyte disturbances, dental erosion, cardiac arrhythmias) and psychological comorbidities (depression, anxiety, personality disorders). First-line treatment is Cognitive Behavioural Therapy for Eating Disorders (CBT-ED), with high-dose SSRIs (Fluoxetine 60mg) as pharmacological adjunct.

Key Facts

• Epidemiology: ~1-2% lifetime prevalence. Peak onset late adolescence / early adulthood. Female >>Male (10:1).
• DSM-5 Criteria: Binge eating + Compensatory behaviours at least 1x/week for 3 months.
• Physical Signs: Russell's Sign (Calluses on knuckles), Dental erosion, Parotid swelling, Oesophageal tears.
• Biochemistry: Hypokalaemia, Metabolic Alkalosis (Vomiting), Metabolic Acidosis (Laxative abuse).
• Treatment: CBT-ED (Gold Standard), High-dose SSRI (Fluoxetine 60mg), Family Therapy (Adolescents).
• Prognosis: ~50% recover. ~30% partial recovery. ~20% chronic course.

Clinical Pearls

"Normal Weight, Abnormal Behaviour": Unlike Anorexia, patients with Bulimia are often normal weight. The disorder is hidden – look for the physical clues (Russell's sign, dental erosion).

"Russell's Sign": Calluses on the knuckles from repeated self-induced vomiting. A specific clinical sign.

"Fluoxetine 60mg – Not 20mg": Unlike depression, Bulimia requires high-dose Fluoxetine (60mg OD) for efficacy.

"Hypokalaemia Kills": Purging causes potassium loss. Severe hypokalaemia leads to cardiac arrhythmias and sudden death.

Why This Matters Clinically

Bulimia is often shameful and hidden. Patients may present with dental problems, non-specific GI symptoms, or electrolyte abnormalities before disclosing eating behaviours. Recognising the physical clues, asking sensitively, and knowing the evidence-based treatments can save lives.

DSM-5 Criteria for Bulimia Nervosa

Severity Grading (DSM-5)

• Full Recovery: ~50% at 5-10 year follow-up.
• Partial Recovery / Chronic Course: ~30-50%.
• Mortality: Lower than Anorexia (~1-3%), but still significantly elevated above general population.
• Predictors of Poor Outcome: Longer illness duration, Psychiatric comorbidity, Severe symptoms at presentation.

Managing Comorbidities

Recovery and Relapse Prevention

Key Counselling Points (Extended)

1. It's an Illness, Not a Choice: "Bulimia is a recognised mental health condition. You are not weak or to blame."
2. Regular Eating is the Foundation: "Eating three meals and snacks, even when you don't feel hungry, reduces the urge to binge."
3. Purging Doesn't Work: "Vomiting only removes a fraction of calories eaten. It damages your body and perpetuates the cycle."
4. Recovery Takes Time: "Most people need therapy for 4-12 months. Be patient with yourself."
5. Setbacks are Normal: "A slip doesn't mean failure. Learn from it and get back on track."
6. Tell Someone: "Keeping it secret makes recovery harder. Confiding in someone you trust helps."

Motivational Interviewing: Addressing Ambivalence

Special Populations

Key Guidelines

Evidence for Treatment

Scenario 1:

• Stem: A 22-year-old woman presents with dental erosion, calluses on her knuckles, and intermittent palpitations. BMI is 23. Blood tests show Potassium 2.9 mmol/L. What is the likely diagnosis?
• Answer: Bulimia Nervosa. Russell's sign (Calluses), Dental erosion, Hypokalaemia. Normal BMI.

Scenario 2:

• Stem: What is the first-line psychological treatment for Bulimia Nervosa in adults?
• Answer: CBT-ED (Cognitive Behavioural Therapy for Eating Disorders).

Scenario 3:

• Stem: What is the appropriate dose of Fluoxetine for Bulimia Nervosa?
• Answer: 60mg OD (NOT 20mg as used for depression).

Scenario 4:

• Stem: A patient with Bulimia has just vomited. What dental advice should you give?
• Answer: Do NOT brush teeth immediately – acid softens enamel and brushing causes damage. Rinse with bicarbonate mouthwash instead.

Scenario 5:

• Stem: What are the metabolic consequences of chronic vomiting?
• Answer: Loss of Gastric HCl -> Hypochloraemia, Hypokalaemia, Metabolic Alkalosis.

What is Bulimia Nervosa?

Bulimia Nervosa is an eating disorder where a person has repeated episodes of eating large amounts of food (binge eating) and then tries to prevent weight gain by making themselves sick, using laxatives, or exercising excessively.

What are the signs?

• Eating large amounts of food in secret, then feeling guilty.
• Making yourself sick after eating.
• Sore throat, damaged teeth, swollen cheeks.
• Feeling weak or having palpitations (from low potassium).

How is it treated?

• Talking therapy (CBT): Helps change thoughts and behaviours around eating.
• Medication (Fluoxetine): Can reduce the urge to binge.
• Nutritional support: Helps establish regular eating patterns.
• Medical treatment: To correct any problems with your body's salts (electrolytes).

Will I get better?

Yes. With treatment, about half of people with Bulimia recover fully. Many more improve significantly. Recovery is possible.

Key Counselling Points

1. It's Not Your Fault: "Bulimia is an illness, not a choice. You deserve help."
2. Regular Eating Helps: "Eating regularly reduces the urge to binge."
3. Vomiting is Harmful: "Making yourself sick damages your teeth, throat, and heart."
4. Treatment Works: "CBT and sometimes medication can really help."
5. Seek Help Early: "The sooner you get help, the better the outcome."

• Sir Gerald Russell (1979): First formally described Bulimia Nervosa as a distinct entity (hence "Russell's Sign").
• Separated from Anorexia: Previously considered a variant of Anorexia. Recognised as separate due to normal weight and distinct behaviours.
• Treatment Evolution: CBT developed in the 1980s-90s. SSRIs found effective in 1990s.