Anorexia nervosa - a clinical review of its diagnosis and management

A recent BMJ review looks at the diagnosis and management of anorexia nervosa.Anorexia nervosa is the most common cause of weight loss in young women, and has an average age of onset of 15 years. It has the highest mortality rate of any psychiatric disorder. It is often the role of the general practitioner to recognise and diagnose the disorder, but specialist referral and advice is often required. Researchers Morris and Twaddle review the current evidence on the treatment and management of anorexia nervosa.They describe the hallmarks of anorexia as the extreme over-evaluation of shape and weight by patients as well as the physical capacity to tolerate extreme self-imposed weight loss. The authors point out that food restriction is only one aspect of weight loss, noting that over-exercise and over-activity are also commonly employed to burn calories. Purging techniques such as vomiting, misuse of laxatives, diuretics and weight loss medicines are another common element to the disease. Patients may also practice repeated weighing, measuring, and mirror gazing to reassure themselves that they are thin.The International Classification of Diseases (ICD; 10th edition) formally list that all five of the following criteria be present for a diagnosis of anorexia nervosa:•Body weight maintained at least 15% below expected, or a body mass index (BMI) of <17.5•Weight loss is self-induced•Body image is distorted and the dread of fatness persists as an intrusive, over-valued idea with a low, self-imposed weight threshold• A widespread endocrine disorder involving the hypothalamic-pituitary-gonadal axis is manifest in women as amenorrhoea and in men as loss of sexual interest and potency. Concentrations of growth hormone and cortisol may be raised, and changes in the peripheral metabolism of thyroid hormone and abnormalities of insulin secretion may also be seen• Delayed or arrested pubertal events if onset is before puberty. After recovery, puberty will often complete normally.Morris and Twaddle point out that the diagnosis of 'psychologically driven weight loss' is normally made without the need for a battery of complex investigations to reach a diagnosis of exclusion, and they note that general practitioners may benefit from early specialist referral for more detailed assessment and advice. They point out that such referral can often reinforce the message to the patient that their illness is of genuine concern.There is no safe cut-off weight or BMI, with survival analyses demonstrating that death is less common where low weight, even with a BMI below 12, is maintained through starvation. However, rapid weight fluctuations, binge-purge methods and substance misuse greatly influence risk of mortality. Furthermore, comorbidity is associated with a poorer prognosis.They note that to date, no drugs are available that are effective at treating anorexia. Medication has little benefit in anorexia and the risk of dangerous side effects is high in malnourished patients. Short-term structured treatments such as cognitive behaviour therapy are not effective, and longer-term therapies that incorporate motivation enhancement techniques are recommended. Focussed family work has been shown to be effective for adolescents and young adults where counselling can involve the whole family or the family and the patient can be counselled separately."Even when a person has developed the crucial motivation to tolerate weight gain and explored the possibility of living with values other than those imposed by the cult of thinness, psychological recovery is difficult as the challenges of a rekindled adolescence must be faced," they surmised.Reference...