Anorexia nervosa

Anorexia nervosa is characterised by a refusal to maintain weight at or above a minimally normal weight (less than 85% of expected weight for age and height, or body mass index (BMI) less than 17.5 kg/m2) or a failure to show the expected weight gain during growth. In assocation with this, there is often an intense fear of gaining weight, perceived body image, preoccupation with weight, denial of the current low weight and its adverse impact on health, and amenorrhoea. Two subtypes of anorexia nervosa: binge–purge and restricting, have been defined. Appendix 7.1 lists the diagnostic criteria for anorexia nervosa according to the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders.

INVESTIGATIONS

The following investigations are recommended in women with anorexia nervosa:

1. • erythrocyte sedimentation rate (ESR) is usually low in this condition; hence, this test can be somewhat useful in differentiating anorexia nervosa from other medical conditions causing anorexia

2. • electrocardiogram (ECG) is important to assess for the impact of low potassium and starvation on the heart

3. • computed tomography or magnetic resonance imaging to exclude the presence of cerebral tumours

4. • endocrine status (thyroid function and other pituitary tests)

5. • stool and urine tests for laxative abuse might also be useful for women suspected of such abuse

6. • bone density studies can be useful to further assess the physical impact of the woman's eating disorder.