Professional Reference articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Bulimia nervosa is an eating disorder characterised by repeated episodes of uncontrolled overeating (binges) followed by compensatory weight loss behaviours.
- Excessive preoccupation with body weight and shape.
- Undue emphasis on weight in self-evaluation.
- Feeling of lack of control over eating.
- Compensatory weight control mechanisms which can be:
- Self-induced vomiting.
- Intensive exercise.
- Abuse of medication such as laxatives, diuretics, thyroxine or amfetamines.
- Bulimia nervosa has an estimated prevalence of 0.5-1% of young women.
- It occurs across all socio-economic groups. It is more common in western societies.
- It occurs in ten times as many females as males.
- It is more common in adolescence and young adulthood.
- Many with bulimia do not seek treatment.
- Exact prevalence figures are difficult to ascertain, owing to the numbers who do not seek medical help, the lack of country-specific data, and the crossover with binge eating disorder (BED).In this separate condition there is bingeing behaviour but without the compensatory purging. Possibly because of the difference in clinical and lay understanding about the meanings of the terms, results based on questionnaire surveys have been variable.
Development of bulimia nervosa appears to be multifactorial and difficult to ascertain. Apart from female gender, potential risk factors include:
- Parental and childhood obesity.
- Family dieting.
- Family history of eating disorders (high heritability shown).
- A history of severe life stresses and possibly sexual or physical abuse.
- Parental and premorbid psychiatric disorder or substance misuse.
- Parental problems, such as high expectations, low care and overprotection, and disruptive events in childhood such as parental death and alcoholism.
- Early experiences of criticism regarding eating habits or body weight.
- Perceived pressure to be thin (from cultural or family sources).
- Recreational pressure (models, jockeys, ballet dancers, athletes).
- Early menarche.
- Premorbid characteristics such as perfectionism, anxiety, obsessional traits, low self-esteem, borderline personality disorder, difficulty in resolving conflict.
The history often dates back to adolescence. The core features include:
- Regular binge eating. Loss of control of eating during binges. (In order to fulfil diagnostic criteria for the Diagnostic and Statistical Manual of Mental Disorders fifth edition (DSM-5), binge eating should occur, on average, at least once a week for three months.)
- Attempts to counteract the binges - eg, vomiting, using laxatives, diuretics, dietary restriction and excessive exercise.
- Body mass index (BMI) is maintained above 17.5 kg/m2.
- Preoccupation with weight, body shape and body image. Self-evaluation is unduly based on body weight and shape.
- Preoccupation with food and diet. This is often rigid or ritualistic and deviations from a planned eating programme cause distress. The affected person therefore starts to avoid eating with others and becomes isolated.
- Mood disturbance and anxiety are common, as are low self-esteem, and self-harm.
- Severe comorbid conditions may be present - eg, depression and substance abuse.
Physical examination is usually normal and is mainly aimed at excluding medical complications such as dehydration or dysrhythmias (induced by hypokalaemia).
Examination must include height and weight (and calculation of the BMI) and blood pressure. In severe cases signs may be present:
- Salivary glands (especially the parotid) may be swollen.
- There may be oedema if there has been laxative or diuretic abuse.
- Russell's sign may be present (calluses form on the back of the hand, caused by repeated abrasion against teeth during inducement of vomiting).
- There may be erosion of dental enamel due to repeated vomiting.
- Binge eating disorder: more common than bulimia in men (although still less common than in women) and affects a wider age range.
- Sporadic bingeing in other psychiatric disorders - eg, depression.
- Anorexia nervosa with bulimic features.
- Other forms of eating disorder which can be difficult to classify - eating disorder not otherwise specified (EDNOS).
- Medical causes of bingeing or vomiting.
- These are usually normal apart from serum potassium, which is often low.
- Renal function and electrolytes should be checked in view of frequent self-induced vomiting.
People with bulimia nervosa should be referred to secondary care for assessment and management. However, primary care has a significant role to play in patient management and support. The great majority of patients with bulimia nervosa can be treated as outpatients. There is a very limited role for the inpatient treatment of bulimia nervosa. This is primarily concerned with the management of suicide risk or severe self-harm, or for low serum potassium.
Guidelines from the National Institute for Health and Care Excellence (NICE) recommend that as a first step, patients should be encouraged to follow an evidence-based self-help programme, with direct encouragement and support from healthcare professionals. Cognitive behavioural therapy for bulimia nervosa (CBT-BN), a specifically adapted form of CBT, should be offered to adults with bulimia nervosa. The course of treatment should be for 16 to 20 sessions over 4 to 5 months. When people with bulimia nervosa have not responded to or do not want CBT, other psychological treatments - eg, interpersonal psychotherapy - should be considered.
As an alternative or additional first step to using an evidence-based self-help programme, adults with bulimia nervosa may be offered a trial of an antidepressant drug, which can reduce the frequency of binge eating and purging; however, the long-term effects are unknown. Selective serotonin reuptake inhibitors (SSRIs), specifically fluoxetine, are the drugs of first choice. The effective dose of fluoxetine is 60 mg daily (not recommended in children and adolescents aged under 18 years). No other drug treatment is recommended.
The evidence base for optimal treatment of bulimia nervosa remains weak.Cochrane reviews seem to demonstrate efficacy of CBT, although quality of evidence is noted to be variable.There is also some evidence for the efficacy of antidepressants, although there is no evidence for using one in favour of another.
General medical aspects
There may be a need for management of physical aspects:
- Patients with bulimia nervosa who are vomiting frequently or taking large quantities of laxatives (especially if they are also underweight) should have their fluid and electrolyte balance assessed frequently. If electrolyte disturbance is detected, it is usually sufficient to focus on eliminating the behaviour responsible.
- Recommend regular dental reviews and dental hygiene (eg, rinse the mouth after vomiting).
- Reduce laxatives slowly.
- Screen for osteoporosis.
- Haematemesis, and metabolic complications (eg, hypokalaemia) following excessive self-induced vomiting.
- Dental erosions.
- There may be painless enlargement of the salivary glands, tetany and seizures.
- Around 10-15% go on to develop anorexia.
About 70% of people with bulimia make a complete recovery. If recovery has not occurred within five years, they are more likely to progress to a chronic course.
The risk of death is significantly lower than that with anorexia nervosa and is estimated at about 0.4%, which is due to the slight increase in suicide.
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Further reading & references
- Primary Care protocol adults with eating disorders; Royal College of Psychiatrists
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