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Severe hyperkalaemia with ECG changes — SCE Acute Medicine MCQ

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ModerateAcute Renal and Metabolic EmergenciesSevere hyperkalaemia with ECG changesSCE Acute Medicine

A 68-year-old man with CKD presents with weakness. Potassium is 7.1 mmol/L and ECG shows broad QRS complexes with peaked T waves. He is taking ramipril and spironolactone. What is the most important immediate action?

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Correct answer: C — Give intravenous calcium gluconate with cardiac monitoring

ECG changes in severe hyperkalaemia require immediate IV calcium to stabilise the myocardium, followed by potassium-shifting and potassium-removal measures. Potassium binders act more slowly and do not protect the heart immediately. Waiting risks malignant arrhythmia. The pearl is that calcium buys time; it does not lower serum potassium.

Reference: UK Kidney Association Hyperkalaemia guideline 2023; BNF