Anorexia nervosa: practical implications for the anaesthetist

Anorexia nervosa (AN) is a psychiatric eating disorder characterised by a severe restriction of energy intake because of the intense fear of gaining weight.1
There are two subtypes: the ‘restricting’ type (weight loss through dieting, with or without excessive exercise) and the ‘binge eating and purging’ type (binge eating in combination with self-induced vomiting or laxatives). Although a low body mass index (BMI) is not part of the diagnosis, most patients are (severely) underweight (BMI <17 kg m−2). Anorexia nervosa predominantly affects women (>90%). The reported incidence of AN varies from 0.5 to 318 cases per 100,000 women-years, and it is suggested that the incidence of AN in young women is increasing.2
This phenomenon may be the result of several factors, including the increase in social media creating serious body image concerns and the COVID-19 pandemic with its associated consequences of increased social isolation, negatively influencing mental health and harmful eating habits. Although often diagnosed during adolescence, about 20% progress to chronic AN during adulthood.3
Unfortunately, AN has the highest mortality rate of all psychiatric diagnoses, mainly resulting from the medical complications of chronic malnutrition.4
The exact prevalence and type of surgery being undertaken in patients with AN are uncertain; to date, there are only 12 published case reports.5
However, anaesthetists may be confronted with a patient diagnosed with AN presenting for (semi)elective or emergency surgery. This review describes the pathophysiological consequences of AN and the perioperative issues for the anaesthetist caring for the patient with AN undergoing surgery .