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Severe hyperkalaemia in a haemodialysis patient — MRCEM SBA MCQ

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HardResuscitation and critical illnessSevere hyperkalaemia in a haemodialysis patientMRCEM SBA

A 64-year-old man receiving maintenance haemodialysis has missed two sessions because of a transport problem. He is alert, with a blood pressure of 126/74 mmHg and a palpable pulse of 54/min. He is anuric. A non-haemolysed laboratory sample shows potassium 7.3 mmol/L and glucose 8.2 mmol/L. His ECG shows new broad QRS complexes and tall, peaked T waves. He has a patent intravenous cannula, is on continuous cardiac monitoring and has not yet received treatment. Which immediate management plan is most appropriate?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: D — Give 30 mL of 10% calcium gluconate IV, then insulin–glucose IV, and arrange urgent haemodialysis.

This is immediately dangerous hyperkalaemia: the potassium is 7.3 mmol/L and the new QRS widening and peaked T waves indicate cardiac toxicity, despite the preserved blood pressure and pulse. Give the full **30 mL of 10% calcium gluconate slowly IV** to stabilise the myocardium, then promptly give insulin with glucose to shift potassium into cells. Continue ECG, potassium and glucose monitoring. Calcium does not lower potassium, and its protective effect is temporary. Because he is anuric and already receives haemodialysis, arrange urgent dialysis rather than waiting to see whether temporary medical measures suffice. ([gov.uk](https://www.gov.uk/drug-device-alerts/national-patient-safety-alert-potential-risk-of-underdosing-with-calcium-gluconate-in-severe-hyperkalaemia-natpsa-slash-2023-slash-007-slash-mhra?utm_source=openai)) A gives an inadequate calcium-gluconate dose: 10 mL of 10% calcium *chloride*, not gluconate, supplies the calcium dose equivalent to 30 mL of 10% gluconate. B delays myocardial protection while insulin takes effect. C includes an appropriate adjunct, salbutamol, but omits insulin–glucose from the initial potassium-shifting treatment. E correctly starts medical treatment but delays the dialysis decision in a dialysis-dependent patient with severe hyperkalaemia. Repeat ECG assessment after calcium is also necessary; persistent adverse changes may require another calcium dose. ([gov.uk](https://www.gov.uk/drug-device-alerts/national-patient-safety-alert-potential-risk-of-underdosing-with-calcium-gluconate-in-severe-hyperkalaemia-natpsa-slash-2023-slash-007-slash-mhra?utm_source=openai))

Reference: National Patient Safety Alert: Potential risk of underdosing with calcium gluconate in severe hyperkalaemia (27 June 2023) — https://www.gov.uk/drug-device-alerts/national-patient-safety-alert-potential-risk-of-underdosing-with-calcium-gluconate-in-severe-hyperkalaemia-natpsa-slash-2023-slash-007-slash-mhra Calcium chloride, calcium gluconate: potential risk of underdosing with calcium gluconate in severe hyperkalaemia (27 June 2023) — https://www.gov.uk/drug-safety-update/calcium-chloride-calcium-gluconate-potential-risk-of-underdosing-with-calcium-gluconate-in-severe-hyperkalaemia Diagnosis and management of acute hyperkalaemia (21 August 2026) — https://www.bmj.com/content/394/bmj-2026-100287.full.pdf