A 15-year-old boy begins induction chemotherapy for precursor B-cell ALL. On day 3 he develops nausea and oliguria. Labs: potassium 6.9 mEq/L, phosphate 9.5 mg/dL, calcium 6.2 mg/dL, uric acid 16 mg/dL, creatinine 2.4 mg/dL. Which agent most directly addresses the hyperuricaemia?
- A Allopurinol
- B Rasburicase ✓
- C Calcium gluconate
- D Sodium bicarbonate infusion
Correct answer: B. Rasburicase
Explanation
This is tumour lysis syndrome from rapid lysis of a highly proliferative lymphoblast burden. Rasburicase, a recombinant urate oxidase, converts existing uric acid to soluble allantoin and is the definitive agent for established severe hyperuricaemia. Allopurinol only prevents new uric acid formation and cannot lower the level already present. Calcium gluconate stabilizes cardiac membrane against hyperkalaemia, and bicarbonate alkalinizes urine but risks calcium-phosphate precipitation.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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