Refeeding Syndrome — FRCA Final MCQ

Instant feedback + full explanation. One question, done properly.

ModerateIntensive Care MedicineRefeeding SyndromeFRCA Final

A 50-year-old woman is admitted to the ICU with severe acute pancreatitis. She has received negligible nutrition for 12 days. Enteral feeding via a nasogastric tube is commenced and advanced to her full estimated requirements within 24 hours. Over the next 48 hours, her serum phosphate falls from 0.90 to 0.35 mmol/L, potassium to 2.8 mmol/L and magnesium to 0.50 mmol/L. She develops new peripheral oedema. Which syndrome best explains these findings?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — Refeeding syndrome

Explanation lettering: E = shown as A · D = shown as C · A = shown as D · C = shown as E

The correct answer is B, refeeding syndrome. Prolonged negligible intake depletes total-body phosphate, potassium, magnesium and thiamine. Rapid carbohydrate delivery stimulates insulin release, which drives phosphate, potassium and magnesium into cells and promotes renal sodium and water retention. The discriminating features are the 12-day starvation period, rapid escalation to full feed, and the temporal fall in phosphate, potassium and magnesium with new oedema after feeding started. NICE CG32 requires high-risk patients to start at no more than 5–10 kcal/kg/day with thiamine and electrolyte supplementation and close monitoring. Tumour lysis (A) and crush syndrome (D) cause cell lysis with HYPERkalaemia and HYPERphosphataemia — the opposite pattern. Milk-alkali syndrome (C) causes hypercalcaemia, metabolic alkalosis and renal impairment from calcium–alkali ingestion. Fanconi syndrome (E) causes proximal tubular wasting (phosphaturia, glycosuria, aminoaciduria, bicarbonate loss) but is not precipitated by restarting nutrition and does not explain the acute post-feeding onset.

Reference: National Institute for Health and Care Excellence. Nutrition support for adults: oral nutrition support, enteral tube feeding and parenteral nutrition. CG32, section 1.4 (refeeding problems). Updated 2017. https://www.nice.org.uk/guidance/cg32/chapter/1-guidance