On this page
Study tools
Write your answer
Saved on this device. No marking — you are the marker.
Stem
A 17-year-old girl is brought to the emergency department by her parents after a collapse at home. Over the past six months she has restricted her food intake, exercised for two hours daily, and lost 12 kg. She now weighs 39 kg (height 165 cm; BMI 14.3). She is bradycardic (HR 36 bpm), her blood pressure is 92/60 mmHg lying and 74/48 mmHg standing, and her temperature is 34.8 deg C. She is amenorrhoeic. She is preoccupied with food but says she is "too fat". ECG shows a QTc of 480 ms. Blood tests show potassium 2.9 mmol/L, sodium 132 mmol/L, phosphate 0.6 mmol/L, magnesium 0.6 mmol/L, and normal TSH with low T3.
Questions
a) What is the diagnosis and the immediate medical concern? (2 marks) Anorexia nervosa, restricting type, severe (BMI 14.3 — extreme severity by DSM-5-TR, BMI below 15.0). She meets MEED red-flag criteria for high medical risk (BMI under 13 for adults is the threshold here she is above but meets multiple other red flags): HR under 40, postural systolic BP drop over 20 mmHg, QTc over 450 ms, temperature under 35.0 deg C, phosphate under 0.5-0.7 mmol/L. Admit to a medical bed. The immediate medical concern is sudden cardiac death from QTc-prolongation arrhythmia and refeeding syndrome when nutrition is reintroduced.
b) Outline the refeeding protocol you will institute. (3 marks)
- Admit to a medical bed with cardiac monitoring; correct electrolytes slowly.
- Give thiamine 200-300 mg (oral or IV) BEFORE the first feed, plus a high-potency multivitamin/mineral; continue thiamine for at least 10 days.
- Start calories low at about 5-20 kcal/kg/day (NICE NG69 / MARSIPAN / MEED) given her high risk (BMI under 16, hypophosphataemia).
- Supplement phosphate, potassium, magnesium prophylactically (oral phosphate, oral/IV potassium and magnesium).
- Escalate by 200-300 kcal every 24-48 hours only if electrolytes and clinical state are stable.
- Monitor daily: U&E, phosphate, magnesium, glucose, ECG, weight, fluid balance for the first 2 weeks.
- Restrict fluids if oedema develops; manage hypoglycaemia with continuous dextrose, never a bolus.
c) Describe the definitive multidisciplinary management. (3 marks)
- Nutritional rehabilitation with a specialist dietitian; weight restoration target 0.5-1.0 kg/week outpatient, 0.5-1.4 kg/week inpatient.
- Family-based treatment (FBT, the Maudsley model) as first-line for this adolescent (Lock 2010): three phases — weight restoration (parents take control of eating), gradual return of control, normal adolescent development.
- CBT-ED once weight-restored.
- Treat comorbid anxiety, depression, OCD; SSRIs effective only after weight restoration.
- No drug is effective for the core of anorexia; olanzapine 2.5-10 mg may aid weight gain.
- Long-term follow-up; relapse prevention; transition to adult services if needed.
d) What is her prognosis and what are the principal causes of death in anorexia nervosa? (2 marks) Anorexia has the highest mortality of any psychiatric disorder (SMR about 5.9, Arcelus 2011). About 46 percent recover, 33 percent improve, 20 percent are chronic, and 5-6 percent die. One in five deaths is by suicide. Principal causes of death: cardiac arrhythmia (prolonged QTc, hypokalaemia), refeeding syndrome, medical complications of starvation (pneumonia, sepsis), and suicide. Predictors of good prognosis: shorter duration, adolescent onset, restrictive subtype, early weight restoration.