A patient undergoes total thyroidectomy for a large multinodular goitre. On post-operative day 1, she develops perioral tingling, carpopedal spasm, and a positive Trousseau sign. Corrected serum calcium is 6.8 mg/dL. What is the mechanism of parathyroid insufficiency MOST likely in this setting?

• A Devascularization or inadvertent removal of parathyroid glands ✓
• B Autoimmune destruction of parathyroid glands during surgery
• C Suppression of PTH synthesis by excess thyroid hormone
• D Hungry bone syndrome from pre-operative hypercalcemia

Explanation

Post-thyroidectomy hypoparathyroidism results from devascularization (disruption of the delicate blood supply to parathyroids, usually from inferior thyroid artery branches), inadvertent excision, or trauma to the parathyroid glands during dissection. This is the most common endocrine complication of total thyroidectomy, occurring transiently in 20-30% and permanently in 1-3% of cases. Hungry bone syndrome causes hypocalcemia post-parathyroidectomy (not thyroidectomy) when rapid bone remineralization occurs. Emergency management involves IV calcium gluconate followed by oral calcium and calcitriol.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.