Introduction

Anorexia nervosa is the most common cause of admissions to child and adolescent psychiatric wards.

Epidemiology

  • Incidence: 37.00 cases per 100,000 person-years
  • Peak incidence: 20-30 years
  • Sex ratio: more common in females 5:1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features

Anorexia nervosa is associated with a number of characteristic clinical signs and physiological abnormalities which are summarised below

Features
  • reduced body mass index
  • bradycardia
  • hypotension
  • enlarged salivary glands

Physiological abnormalities
  • hypokalaemia
  • low FSH, LH, oestrogens and testosterone
  • raised cortisol and growth hormone
  • impaired glucose tolerance
  • hypercholesterolaemia
  • hypercarotinaemia
  • low T3

Diagnosis

Diagnosis is now based on the DSM 5 criteria. Note that BMI and amenorrhoea are no longer specifically mentioned:
  • 1. Restriction of energy intake relative to requirements leading to a significantly low body weight in the context of age, sex, developmental trajectory, and physical health.
  • 2. Intense fear of gaining weight or becoming fat, even though underweight.
  • 3. Disturbance in the way in which one's body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or denial of the seriousness of the current low body weight.

Management

For adults with anorexia nervosa, NICE recommend we consider one of:
- individual eating-disorder-focused cognitive behavioural therapy (CBT-ED)
- Maudsley Anorexia Nervosa Treatment for Adults (MANTRA)
- specialist supportive clinical management (SSCM).

In children and young people, NICE recommend 'anorexia focused family therapy' as the first-line treatment. The second-line treatment is cognitive behavioural therapy.

Prognosis

The prognosis of patients with anorexia nervosa remains poor. Up to 10% of patients will eventually die because of the disorder.