Eating disorders are abnormalities in eating habits, in the context of a person’s distorted view of their own body image. The common subtypes are anorexia nervosa (AN) and bulimia nervosa (BN). There is overlap in the symptom pattern. Some may have a clinical picture that is initially consistent with AN but becomes consistent with BN after a period of time. If all the diagnostic criteria are not fully met, the terms ‘atypical anorexia’, ‘atypical bulimia’ or ‘unspecified eating disorder’ may be used to describe the condition. The following article gives information about BN. Please refer to our [separate article](http://behindthemedicalheadlines.com/articles/eating-disorders-anorexia-nervosa) for more information on AN. ####How common is bulimia nervosa? The prevalence of BN is about 1%.[1,2] About 90% of those diagnosed with BN are women.[1] Contrary to a common misconception, eating disorders have not been shown to be more prominent in any particular social class.[3] ####What causes it? The cause of BN is probably multifactorial. In those who have BN, there is a higher rate of a history of physical or sexual abuse, obesity, parental obesity, mood disorder, substance misuse, low self-esteem, perfectionism, disturbed family dynamics, parental weight or shape concern and early first menstrual bleeding.[4] It is difficult to say whether these are causal relationships or whether they are associations. ####Why is it important to recognise and treat BN? It is important to treat and recognise BN since it can cause a high degree of morbidity. Bulimia nervosa can cause many physical problems, including teeth erosion, hoarseness, mouth ulcers, throat bleeding, swollen cheeks, acid reflux, tiredness, fits, fainting, blackouts, muscle twitching, numb fingers and toes, swollen feet and ankles, dry skin, dehydration, irregular menstrual periods, diarrhoea, chronic constipation, stomach perforation, irregular heart rhythms, palpitations, chest pain and kidney damage.[5] It is associated with emotional and cognitive problems, such as depression, anxiety, irritability and poor concentration. ####Diagnosis People with BN often try to hide their symptoms from family or friends, so initially it may be hard for others to notice the illness. People with BN often have a normal weight. The features of BN include a persistent preoccupation with eating, and an irresistible craving for food; the patient succumbs to episodes of overeating in which large amounts of food are consumed in short periods of time. People with BN attempt to counteract the ‘fattening’ effects of food by one or more of the following methods: self-induced vomiting; laxative abuse; alternating periods of starvation; and the use of drugs such as appetite suppressants, thyroid preparations or diuretics. People with BN have a dread of fatness. There is often a history of an earlier episode of AN.[6] Bulimia nervosa may present with depression, amenorrhoea (lack of menstrual periods), infertility or physical complications. Bulimia nervosa sufferers may present to gastroenterologists or gynaecologists. They can become pregnant even when they are amenorrhoeic. Weight gain and body shape changes during pregnancy can provoke extreme distress in those with BN. There is also a higher prevalence of BN and sub-threshold eating disorder in those with insulin-dependent diabetes.[7] Eating disorders are associated with insulin omission for weight loss and impaired metabolic control in those with diabetes.[7] ####Referral It is very important to prepare patients prior to a referral, to improve the attendance rate. Referrals should be made to the nearest eating disorder service. The referrer should provide height, weight and recent blood results. If an eating disorder service is not available locally, referrals should be made to a mental health service. A referral to a dietician with expertise in eating disorders should also be made. ####Investigations The following investigations should be made: * Height and weight; * A thorough physical examination (look for dry skin and signs of dehydration; check for erect and supine blood pressure, pulse, temperature; perform cardiovascular, respiratory, gastro-intestinal and neurological examinations); * Blood tests (full blood count, urea and electrolytes, calcium, albumin, magnesium, phosphate, liver function tests, glucose, erythrocyte sedimentation rate, thyroid function tests, vitamin B12 and folate); * Electrocardiogram (look for QT interval, arrhythmias or changes associated with abnormal electrolytes). ####Treatment It is important to provide education about the effects of BN and healthy eating principles. Some patients will benefit from an evidence-based self-help programme.[8] There are better outcomes when these programmes are guided (that is, with encouragement and support from a healthcare professional). There is a good evidence base for both cognitive-behavioural therapy and interpersonal therapy in the treatment of BN.[8] Concurrent conditions such as depression should also be treated. Antidepressants (for example, fluoxetine) may reduce bulimic symptoms and depressive symptoms.[1] A daily dose of 60 mg fluoxetine may be required. Antidepressants should be discontinued if there is no benefit, remembering that many of the BN population are of child-bearing age. ####Complications People with BN may suffer from the following complications: * Electrolyte abnormalities from purging; * Neurological complications, such as fits from purging; * Gastrointestinal complications, such as stomach perforation from repeated vomiting, are rare but possible; * Cardiac complications, such as arrhythmias from deranged electrolytes; * Dental erosion from self-induced vomiting. ####Illness course and prognosis About 50% of patients recover, 30% making a full recovery and 20% continuing to have some symptoms.[9] Symptoms tend to fluctuate over time. Indicators of good prognosis are a shorter duration of illness, younger age of onset, higher social class and a family history of alcoholism. Indicators of poor prognosis are substance misuse (including alcohol), premorbid obesity, paternal obesity and personality disorder.[1] ####Useful links * Royal College of Psychiatrists. [Eating disorders](http://www.rcpsych.ac.uk/mentalhealthinfoforall/problems/eatingdisorders/eatingdisorders.aspx) (an information leaflet on anorexia and bulimia) * Quality Improvement Scotland. [Eating disorders in Scotland – recommendations for management and treatment]( http://www.nhshealthquality.org/nhsqis/qis_display_findings.jsp?pContentID=3255&p_applic=CCC&p_service=Content.show) * National Institute of Clinical Excellence. [*Eating disorders: core interventions in the treatment and management of anorexia nervosa, bulimia nervosa and related eating disorders.*](http://www.nice.org.uk/CG009) * Self help websites: [Beat eating disorders](http://www.b-eat.co.uk) (B-EAT) and [Disordered eating](www.disordered-eating.co.uk/) 2009-10-01T10:48:35Z Dr Wong has received funding from Wyeth for the research project 'Functional Imaging Biomarkers of Cognitive Enhancer Efficacy', led by Prof. Stephen Lawrie. 114 2009-10-01T00:00:00Z 2009-10-19T08:53:32Z eating-disorders-bulimia-nervosa 2009-10-19T08:53:32Z

Bulimia nervosa is an eating disorder characterised by an intense dread of fat and an irrestible craving for food, resulting in a cycle of binges and purging. In the second of two linked article on eating disorders, Drs Dichelle Wong and Katharine Logan discuss the prevalence, causes, diagnosis and treatment of this condition.

2009-10-19T08:53:32Z