Anorexia nervosa

A 30-year-old woman presents for elective surgery. She is 170 cm tall, weighs 35 kg and has a long history of an eating disorder. The following statements about this patient are true EXCEPT for which one?

a) She is more likely to have mitral valve prolapse than a similar patient with a normal

body mass index (BMI)

b) She is more likely to be bradypnoeic and bradycardic than a similar patient with a

normal BMI

c) She is likely to be anaemic and leucopaenic

d) Her gastric emptying time is likely to be slower compared to a similar patient with a

normal BMI

e) Common electrocardiogram (ECG) findings in this patient would include

atrioventricular block, QT prolongation, ST segment depression and T-wave

inversion

Answer: c

Explanation

The prevalence of anorexia in 15 to 30-year-old women in the UK is between 5 and

10%. Bulimia has a prevalence of 3 to 30% in the same population. The prevalence in

males is approximately 1% for each condition. These conditions carry a significant

morbidity and mortality due to the associated multiorgan dysfunction. Hypothermia is

a routine finding as is sinus bradycardia, hypotension and bradypnoea, the latter as

respiratory compensation for the metabolic alkalosis that occurs. ECG changes are seen

in up to 80% of anorexia nervosa sufferers with atrioventricular block, QT prolongation,

ST segment depression and T-wave inversion all being common. Mitral valve

prolapse (probably due to a decrease in ventricular volume and mass) is more

commonly seen in this population as are cardiac arrhythmias. The glomerular filtration

rate in anorexic patients is reduced and proteinuria is seen in approximately two-thirds

of these patients. Delayed gastric emptying is common as is thrombocytopaenia and

leucopaenia. Surprisingly anaemia is an uncommon finding and if it does occur it is

generally mild and secondary to bone marrow hypoplasia. Endocrine abnormalities

are also common with elevated growth hormone and cortisol levels as well as impaired

thermoregulation with resting core temperatures often less than 36.3 °C. Of interest,

some patients suffering with anorexia nervosa report decreased pain sensitivity but

this is probably linked with disturbances of thermoregulation rather than impaired

nociception.

Reference

Seller CA, Ravalia A. Anaesthetic implications of anorexia nervosa. Anaesthesia 2003;

58(5): 437–43.