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Life-threatening hyperkalaemia — MCCQE Part 1 MCQ

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HardWeaknessLife-threatening hyperkalaemiaMCCQE Part 1

A 58-year-old man with end-stage kidney disease misses dialysis and presents with weakness. Potassium is 7.1 mmol/L and the ECG shows broad QRS complexes with peaked T waves. He is connected to a cardiac monitor and has intravenous access. Which plan best addresses both the immediate cardiac threat and definitive potassium removal?

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Reveal the answer and explanation

Correct answer: B — Give intravenous calcium now, promptly add insulin with dextrose, and arrange urgent dialysis

This is a hyperkalaemic emergency because severe hyperkalaemia is accompanied by QRS widening and weakness. Intravenous calcium is given immediately to stabilise the myocardium; it does not lower the potassium. Insulin with dextrose is then started promptly to shift potassium intracellularly, with glucose monitoring because hypoglycaemia is a material risk. In end-stage kidney disease the temporary shift does not remove potassium, so urgent nephrology involvement and dialysis planning are required. Neither a repeat result, normal blood pressure nor a slow gastrointestinal binder justifies delaying cardiac membrane stabilisation.

Reference: Emergency Care BC, Hyperkalemia — Diagnosis and Treatment: https://emergencycarebc.ca/clinical_resource/clinical-summary/hyperkalemia-diagnosis-and-treatment/