A 21-year-old man with B-cell acute lymphoblastic leukaemia starts induction chemotherapy. On day 3 he develops nausea and oliguria. Labs: potassium 6.6 mEq/L, phosphate 8.4 mg/dL, calcium 6.2 mg/dL, uric acid 16 mg/dL, creatinine 2.4 mg/dL. ECG shows peaked T waves. After cardiac stabilisation, which agent best addresses the underlying cause?

• A Rasburicase intravenously ✓
• B Intravenous sodium bicarbonate infusion
• C Allopurinol orally
• D Furosemide intravenously

Explanation

Established tumour lysis syndrome with severe hyperuricaemia and renal impairment calls for rasburicase, a recombinant urate oxidase that converts uric acid to soluble allantoin and lowers urate far faster than allopurinol, which only prevents new uric acid formation. Alkaline diuresis with bicarbonate is avoided because it promotes calcium phosphate deposition in tubules. Rasburicase must not be given in G6PD deficiency, where haemolysis occurs, but that caveat does not change first-line use here.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.