A post-operative patient who has had a right hemicolectomy is being commenced on parenteral nutrition (TPN) on day 2. He is malnourished (serum phosphate 0.6 mmol/L, albumin 2.8 g/dL). Which complication is most likely to occur if TPN is started at full rate without caution?

• A Refeeding syndrome (hypophosphataemia, hypomagnesaemia, hypokalaemia, fluid overload) ✓
• B Hypercalcaemia
• C Hyperchloraemic metabolic acidosis
• D Thiamine toxicity

Explanation

Refeeding syndrome occurs when nutrition is reintroduced rapidly to severely malnourished patients; the sudden carbohydrate load stimulates insulin release, driving phosphate, potassium, and magnesium intracellularly, causing severe hypophosphataemia (the hallmark). This leads to cardiac arrhythmias, respiratory failure, and neurological dysfunction. NICE guidelines recommend starting TPN at no more than 50% of target rate in high-risk patients, supplementing electrolytes and thiamine before commencing nutrition.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.