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Post-thyroidectomy hypocalcemia — USMLE Step 3 MCQ

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HardSurgery (post-operative, follow-up)Post-thyroidectomy hypocalcemiaUSMLE Step 3

Eight hours after total thyroidectomy, a 46-year-old woman develops perioral paresthesias, carpopedal spasm, and a corrected calcium concentration of 6.7 mg/dL. ECG shows QTc 528 ms. Oral calcium carbonate was given 1 hour ago, but spasms persist. Which treatment is most appropriate now?

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

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Correct answer: C — Give intravenous calcium gluconate under ECG monitoring, then oral calcium and calcitriol

The best answer is “Give intravenous calcium gluconate under ECG monitoring, then oral calcium and calcitriol”. Tetany and marked QT prolongation indicate severe symptomatic hypocalcemia, so intravenous calcium is required rather than waiting for enteral therapy. After stabilization, oral calcium and active vitamin D treat ongoing postoperative hypoparathyroidism; magnesium should also be checked and corrected.

Reference: American Thyroid Association statement on outpatient thyroidectomy: https://journals.sagepub.com/doi/10.1089/thy.2013.0049