Bulimia Nervosa

Introduction

Bulimia nervosa is an eating disorder characterised by episodes of binge eating, where a person suffers a loss of control and eats more than usual.

This often goes alongside compensatory mechanisms to prevent excess weight gain. These can include self-induced vomiting, using laxatives and heavy exercise.¹

Bulimia is most common in women in their 20s and 30s.² The peak age of onset is age 15-25. In Europe, the prevalence of bulimia is reported to be under 1-2%.³

Aetiology

The aetiology of eating disorders isn’t fully understood, but we know that there is not a single definitive cause for the development of bulimia.

Numerous genetic, social and psychological factors often play a role in the development of an eating disorder.

Risk factors

There are often numerous factors that contribute to a person developing bulimia. 

Genetic risk factors for bulimia include:

• Family history of eating disorders
• Family history of mental illness
• Family history of impulse control disorders

Psychosocial risk factors for bulimia include:⁴

• Prior mental health diagnosis
• Poor self-esteem
• History of abuse or trauma
• Having a career or hobby dependent on appearance
• History of engaging in restricting and bingeing cycles

Clinical features

History

Typical symptoms of bulimia nervosa include:⁴

• Engaging in binge eating behaviours
• Distress over body image
• Frequent bathroom trips following meals
• Uncomfortable eating food in the presence of others
• Mood disturbance: irritability, depression, suicidal ideation and self-harm behaviours

The term ‘purging’ is used in relation to bulimia. This refers to an individual engaging in binge eating behaviours followed by ‘purging’ behaviours such as self-induced vomiting, strenuous exercise, using laxatives, enemas or diuretics to counteract their food binge.⁴

Other important areas to cover in the history include:

• Past medical history: including any past psychiatric diagnoses or admissions and any medical conditions (particularly of diabetes)
• Drug history: regular and over the counter medicine (e.g. laxatives)
• Social history: social support networks, family circumstances, alcohol and drug use

Clinical examination

Typical clinical findings in bulimia nervosa may include:

• People with bulimia often have a normal body weight, often accompanied by weight fluctuations
• Tooth erosion
• Swollen salivary glands
• Mouth ulcers
• Gastro-oesophageal reflux and irritation
• Alkalosis: due to loss of hydrochloric acid from the stomach
• Hypokalaemia
• Russel’s sign: calluses on the knuckles where they have scraped against the teeth

Differential diagnoses

Differential diagnoses for bulimia include:

• Anorexia nervosa: patients with anorexia often present with a severely low BMI, unlike in bulimia where the BMI is usually normal or raised. In anorexia, there is a restriction of energy intake, whereas in bulimia recurrent episodes of binge eating with compensatory mechanisms are evident.
• Body dysmorphic disorder
• Depression
• Obsessive-compulsive disorder

Investigations

Bedside investigations

Relevant bedside investigations include:

• Height and weight: to calculate BMI
• Basic observations: including blood pressure and heart rate
• Urinalysis: may show ketones if the patient has co-morbid diabetes mellitus. Some patients may skip insulin to control their weight. This is often referred to as ‘diabulimia’.
• ECG: important to perform if there is a severe deficiency in potassium or magnesium. Features of hypokalaemia include increased P wave amplitude, prolonged PR interval, ST depression and T wave flattening/inversion and prominent U waves.

Laboratory investigations

Relevant laboratory investigations include:

• Urea & electrolytes: these may show hypokalaemia and/or increased creatinine. Elevated bicarbonate usually indicates alkalosis due to loss of gastric acid.
• Magnesium: may be low
• Full blood count: may show anaemia
• Liver function tests: may be abnormal as excess exercise can elevate aminotransferases

Diagnosis

The ICD-11 criteria for bulimia include the following features:¹

• Preoccupation with controlling body weight
• Repeated bouts of overeating
• Compensatory behaviours after overeating, including self-induced vomiting, using laxatives and excessive exercise

These binge eating and compensatory behaviours usually occur at least once weekly for three months.²

Management

As with all mental health conditions, it is helpful to think of management as a biopsychosocial approach, this helps to ensure that management is holistic.

Biological therapies

Selective serotonin-reuptake inhibitors (SSRIs) are used for the pharmacological management of bulimia. Fluoxetine is typically used first-line, followed by sertraline if this is poorly tolerated.

These may be used when cognitive behaviour therapy (CBT) isn’t available or when it has been tried and the patient hasn’t seen any improvement.

The medications should be given at a time of day when they are unlikely to be purged.²

SSRIs are also useful in the case of comorbid disorders (e.g. depression and anxiety).

Psychological therapies

Cognitive behavioural therapy is seen as the optimal first-line treatment for bulimia. This is offered alongside nutritional and meal support (delivered by a trained dietician).

Children with bulimia should be offered bulimia nervosa focused family therapy.²

Social therapies

It is important to provide education about bulimia to the patient and their family. Online resources such as the Beat website are useful sources of patient information and support.

Complications

Complications of bulimia include:⁴

• Irregular menstrual cycles and fertility issues
• Mental health conditions such as depression and anxiety
• Gastric ulcers
• Osteoporosis
• Heart issues including arrhythmias, heart attacks or failure and cardiomyopathy

Reviewer

Dr William Davies

Psychiatry Registrar (ST6)

Editor

Dr Chris Jefferies

References

1. ICD-11. Bulimia nervosa. (2021). Available from: [LINK]
2. BMJ Best Practice. Bulimia nervosa. (2021). Available from: [LINK]
3. NICE CKS. Eating disorders: How common is it?. (2019). Available from [LINK]
4. Eating Disorder Hope. What is bulimia: Symptoms, Complications and Causes. Available from: [LINK]