Hypercalcaemia Cardiac Risk — FRCA Final MCQ

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ModeratePreoperative AssessmentHypercalcaemia Cardiac RiskFRCA Final

A 55-year-old woman (ASA III) with chronic kidney disease stage 4 is scheduled for a parathyroidectomy. Her calcium is 3.1 mmol/L. She is taking amlodipine for hypertension. Which perioperative risk is specifically increased by hypercalcaemia?

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Correct answer: E — Cardiac arrhythmias (shortened QT, heart block, cardiac arrest)

Hypercalcaemia causes dose-dependent cardiac effects: shortened QT interval, PR prolongation, widened QRS, T-wave flattening, and at severe levels (>3.5 mmol/L) heart block, ventricular arrhythmias, and cardiac arrest. Other effects include: polyuria/dehydration, confusion, abdominal pain, constipation, pancreatitis, and renal calculi. Pre-operative calcium reduction (IV saline hydration ± furosemide, bisphosphonates, calcitonin) may be indicated. ECG monitoring is essential. Hypercalcaemia also potentiates digoxin toxicity and shortens the duration of non-depolarising muscle relaxants.

Reference: RCOA – 2023 – Endocrine anaesthesia; NICE – 2019 – Hyperparathyroidism guidelines