Bulimia Nervosa

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Introduction

Bulimia nervosa (BN) 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

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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, for example, there is a 3.7Β times increased risk of developing BN if a relative has the disorder.Β 


Risk factors

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

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
  • Co-morbid impulse control disorder
  • Having a career or hobby dependent on appearance
  • History of engaging in restricting and bingeing cycles

Clinical features

History

Typical symptoms of bulimia nervosa may include:4

  • Engaging in binge eating behaviours
  • Distress over body image
  • Low self-esteemΒ 
  • Frequent bathroom trips following meals
  • Uncomfortable eating food in the presence of others
  • Ritualistic eating habits andΒ exercise routines
  • Use of substances to manipulate metabolism: anabolic, stimulants, thyroxine
  • Mood fluctuations: especially post-binge, including a sense of β€˜relief’ or reduced anxiety post-purge
  • Irritability: around food, questions about food, anticipation of meals
  • Shame, embarrassment and guilt over binging
  • Intrusive thoughts about needing to binge
  • Intrusive thoughts fixating on restricted foodsΒ Β 

The term β€˜purging’ is used in relation to bulimia. This refers to an individual engaging in binge eating behaviours (consumption of a large volume of often restricted foods in one sitting) followed by β€˜purging’ behaviours such as self-induced vomiting, strenuous exercise, using laxatives, enemas or diuretics to counteract their food binge.4

These binges can be objective (i.e. a large amount of food for even a healthy individual) or subjective (i.e. the amount consumed is not a lot compared to a healthy individual but is to the sufferer).

Additionally, binges can occur even when the individual is not physically hungry and often continue to a painful point beyond the state of physical fullness.Β 

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
Screening questionnaires

While they don’t provide a definite diagnosis, screening questionnaires can be used to identify patients who may have an eating disorder such as bulimia nervosa.

One example of this is the SCOFF questionnaire:5

  • Do you make yourself Sick because you feel uncomfortably full?
  • Do you worry you have lost Control over how much you eat?
  • Have you recently lost more than One stone (6.35kg) in three months?
  • Do you believe yourself to be Fat when others say you are too thin?
  • Would you say Food dominates your life?

Answering “yes” to two or more questions means that further investigation is needed into a potential eating disorder. Two further questions can be asked that have a high sensitivity and specificity for bulimia nervosa:

  • Are you satisfied with your eating patterns?
  • Do you ever eat in secret?

Another example is the EDE-Q 6.0 (Eating Disorder Examination Questionnaire), which assesses eating behaviours over the last 28 days.6

Risk assessment

It is important to perform a risk assessment in all patients with a suspected eating disorder, as it is with any mental health disorder.

This includes determining their risk of self-harm, suicidal actions or self-neglect. It is common for eating disorders to co-exist with other mental health disorders such as depression and anxiety.

For more information, see the Geeky Medics guide to suicide risk assessment.

Clinical examination

People with bulimia often have normal body weight, which may be accompanied by weight fluctuations.

Typical clinical findings in bulimia nervosa may include:

  • Periorbital petechiae post-purging
  • Tooth erosion
  • Swollen salivary glands
  • Sore throat
  • Mouth ulcers
  • Halitosis
  • 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 (AN): patients with anorexia often present with a severely low BMI, unlike 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.
  • Binge eating disorder: though these individuals do share the pattern of generally secretive episodic binges in response to emotional distress and feel deep shame around their behaviours, those with binge eating disorder do not engage in compensatory behaviours to negate the episodes of binging.
  • 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
  • Blood glucose: may show hypoglycaemia
  • 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 β€˜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, 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

  • Frequent recurrent distressing binge eating episodes (> once a week for > 1 month) during which an individual feels a loss of control overeating
  • Repeated inappropriate compensatory behaviours to prevent weight gain i.e. laxative abuse, self-induced purging, excessive exercise, substance misuse
  • Excessive preoccupation with weight and or shape.
  • Behaviours and the associated distress are significant enough to impair functioning across many aspects of life
  • Symptoms do not meet AN criteria

Management

As with all mental health conditions, it is helpful to think of management as a biopsychosocialΒ 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.

Diabetes and bulimia

Patients with diabetes need input from an endocrinologist for glycemic control and insulin management. Admission to hospital may be required.2


Complications

Complications of bulimia include:4

In terms of recovery, 45%Β do so fully, 27% make significant improvement, and 23%Β unfortunately suffer chronically with the disorder.


Reviewers

Dr William Davies

Psychiatry Registrar (ST6)

Dr Louisa Ward

CAMHS SpR


Editor

Dr Jess Speller


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]
  5. The BMJ. The SCOFF questionnaire: assessment of a new screening tool for eating disorders. 1999. Available from: [LINK]
  6. Inside Out. Eating Disorder Examination Questionnaire. 2023. Available from: [LINK]

 

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