Eating disorders: refeeding and multidisciplinary care — formative SAQs

SAQ 1 — A 14-year-old admitted for refeeding at 71% median BMI (10 marks)

A 14-year-old girl with a six-month history of restricting-type anorexia nervosa is admitted for nutritional rehabilitation. She weighs 38 kg (71% median BMI for age and sex), reports minimal oral intake for the preceding week, and has lost 6 kg in the last two months. Baseline biochemistry shows phosphate 0.80 mmol/L, potassium 3.3 mmol/L, magnesium 0.70 mmol/L; heart rate is 44 bpm supine rising to 78 bpm on standing, and the ECG shows a QTc of 470 ms. ^{[1] [7]}

Questions

1. Classify her refeeding risk and outline the preparation you complete before starting the feed. (4 marks) ^[1]
2. Describe your refeeding regimen, including the role of thiamine and the schedule for phosphate, potassium and magnesium monitoring, and the evidence base for your calorie-start choice. (4 marks) ^{[3] [4]}
3. State two early signs that she is developing refeeding syndrome and your immediate management. (2 marks) ^[1]

Model answer

Risk and preparation (4). She is high risk for refeeding syndrome: very low %median BMI (71%), negligible intake for a week, rapid recent weight loss (6 kg in two months), and already-low baseline phosphate, potassium and magnesium, with bradycardia and a prolonged QTc. Preparation: give thiamine before or with the first feed (parenteral per local guidance given her risk); correct the baseline phosphate, potassium and magnesium deficits before or as feeding begins; repeat the baseline ECG and document the QTc; confirm the calorie start is matched to her high-risk band; and brief the nursing team on supervised meals, post-meal observation, exercise restriction and bathroom monitoring. ^{[1] [7]}

Refeeding regimen (4). Start calories at a level matched to her high risk. The conservative historical approach begins low and advances slowly; the STRONG multicentre trial and its 1-year follow-up showed higher-calorie refeeding achieves faster weight gain and shorter stays — but only with intensive phosphate/magnesium/potassium monitoring and proactive replacement. The defensible position for a patient this high-risk is a cautious start with daily (consider twice-daily in the first 48–72 hours) phosphate, potassium and magnesium, escalating calories per her biochemical and clinical response, with proactive phosphate replacement if the trend falls. Give thiamine before the first feed, check phosphate/magnesium/potassium daily, daily weight and orthostatic vitals, and repeat the ECG with any derangement. Name the guideline (NICE NG69 / AAP / RANZCP / CPS) for the precise dose. ^{[3] [4]}

Early signs and immediate management (2). Early signs are a falling serum phosphate (the sentinel marker), with or without falling potassium or magnesium, before bedside decompensation; later oedema, palpitations or tachycardia. Immediate management: slow or briefly pause the feed, give intravenous phosphate (and correct potassium and magnesium) per protocol, ensure thiamine has been given, monitor cardiac rhythm, and escalate to high-dependency if there is haemodynamic instability, respiratory compromise or dangerous arrhythmia. ^[1]