Eating Disorders

Question 1

Anorexia Nervosa

Answer 1

In patients with anorexia nervosa, the person feel they are overweight despite evidence of normal or low body weight. It involves obsessively restricting calorie intake with the intention of losing weight. Often the person exercises excessively and may use diet pills or laxatives to restrict absorption of food.

Features of anorexia nervosa:

Excessive weight loss
Amenorrhoea
Lanugo hair is fine, soft hair across most of the body
Hypokalaemia
Hypotension
Hypothermia
Changes in mood, anxiety and depression
Solitude
Cardiac complications include arrhythmia, cardiac atrophy and sudden cardiac death.

Question 2

Bulimia

Answer 2

Bulimia Nervosa
Unlike with anorexia, people with bulimia often have a normal body weight. Their body weight tends to fluctuate. The condition involves binge eating, followed by “purging” by inducing vomiting or taking laxatives to prevent the calories being absorbed.

Features of bulimia nervosa:

Alkalosis, due to vomiting hydrochloric acid from the stomach
Hypokalaemia
Erosion of teeth
Swollen salivary glands
Mouth ulcers
Gastro-oesophageal reflux and irritation
Calluses on the knuckles where they have been scraped across the teeth. This is called Russell’s sign.
TOM TIP: There are some unique examination findings with patients that have bulimia, which makes it a popular spot diagnosis in exams. Look out for the teenage girl with a normal body weight that presents with swelling to the face or under the jaw (salivary glands), calluses on the knuckles and alkalosis on a blood gas. The presenting complaint may be abdominal pain or reflux.

Question 3

Refeeding Syndrome

Answer 3

Refeeding Syndrome
Refeeding syndrome occurs in people that have been in a severe nutritional deficit for an extended period, when they start to eat again. Patients are at higher risk if they have a BMI below 20 and have had little to eat for the past 5 days. The lower the BMI and the longer the period of malnutrition, the higher the risk.

Metabolism in the cells and organs dramatically slows during prolonged periods of malnutrition. As the starved cells start to process glucose, protein and fats again they use up magnesium, potassium and phosphorus. This leads to:

Hypomagnesaemia
Hypokalaemia
Hypophosphataemia
These patients are also at risk of cardiac arrhythmias, heart failure and fluid overload.

Management will be according to the local protocol under specialist supervision:

Slowly reintroducing food with restricted calories
Magnesium, potassium, phosphate and glucose monitoring along with other routine bloods
Fluid balance monitoring
ECG monitoring may be required in severe cases
Supplementation with electrolytes and vitamins, particularly B vitamins and thiamine