Two days after the first cycle of chemotherapy for Burkitt lymphoma, a 22-year-old man develops arrhythmia, tetany, and oliguria. Labs show potassium 6.8 mmol/L, phosphate 3.2 mmol/L, uric acid 0.95 mmol/L, and calcium 1.7 mmol/L. What is the immediate priority in management?

• A Give intravenous calcium gluconate to stabilise the myocardium while correcting hyperkalaemia ✓
• B Start allopurinol and await serial potassium levels
• C Administer fresh frozen plasma to correct the coagulopathy
• D Begin broad-spectrum antibiotics for sepsis

Explanation

This is tumour lysis syndrome: rapid tumour cell lysis releases potassium, phosphate, and nucleic acids, causing hyperkalaemia, hyperphosphataemia, hyperuricaemia, and hypocalcaemia, with risk of fatal arrhythmia. Hyperkalaemia with ECG changes demands immediate cardiac membrane stabilisation with IV calcium gluconate, followed by insulin dextrose, then urate lowering with rasburicase or allopurinol. Allopurinol alone is far too slow when potassium is 6.8 mmol/L with symptoms.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.