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Severe Hyperkalaemia — RACP Adult Medicine MCQ

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EasyEmergency MedicineSevere HyperkalaemiaRACP Adult Medicine

A 40-year-old man presents to the emergency department with acute severe hyperkalaemia (K+ 7.5 mmol/L). His ECG shows peaked T waves and widened QRS complexes. What is the first treatment to administer?

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Correct answer: B — IV calcium gluconate 10% 10 mL over 2–3 minutes

With ECG changes indicating cardiac toxicity from severe hyperkalaemia, IV calcium gluconate is the first-line treatment as it provides immediate cardioprotection by stabilising the cardiac membrane (onset within 1–3 minutes). It does NOT lower potassium. Subsequently, IV insulin with glucose (shifts K+ intracellularly), nebulised salbutamol, and sodium bicarbonate (if acidotic) are used to lower potassium. Definitive treatment addresses the underlying cause and may include haemodialysis.

Reference: eTG – 2025 – Nephrology; ARC – 2024 – Emergency Medicine Guidelines