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Tumour Lysis Syndrome — RACP Adult Medicine MCQ

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HardHaematologyTumour Lysis SyndromeRACP Adult Medicine

A 55-year-old man with peripheral T-cell lymphoma develops tumour lysis syndrome 24 hours after commencing chemotherapy. His potassium is 6.8 mmol/L, phosphate 3.2 mmol/L, urate 0.85 mmol/L, calcium 1.6 mmol/L, and creatinine 350 µmol/L. He was NOT commenced on TLS prophylaxis. What is the definitive treatment?

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Correct answer: A — Haemodialysis

Established tumour lysis syndrome with severe metabolic derangements (hyperkalaemia with ECG changes, hyperuricaemia, hyperphosphataemia with secondary hypocalcaemia, and AKI) requires aggressive management. While rasburicase (recombinant urate oxidase) rapidly lowers urate and aggressive hydration is critical, severe/refractory TLS with oliguria, refractory hyperkalaemia, or severe hyperphosphataemia requires haemodialysis. Rasburicase should be given but dialysis is often needed for the electrolyte emergencies. Allopurinol is prophylactic only – it prevents urate formation but does not break down existing urate (unlike rasburicase).

Reference: eTG – 2025 – Haematology; Howard et al – 2011 – TLS Guidelines