Loss of parathyroid function after thyroidectomy most commonly causes which electrolyte disturbance?

• A. Hypocalcemia
• B. Hypercalcemia
• C. Hyperkalemia
• D. Hyponatremia

Answer: (A)

Parathyroid hormone is the main regulator that raises serum calcium. When the parathyroids are damaged or removed during thyroidectomy, PTH drops, so calcium can’t be mobilized from bone, renal reabsorption of calcium falls, and activation of vitamin D decreases, leading to reduced intestinal calcium absorption. The net effect is low calcium in the blood, making hypocalcemia the most common electrolyte disturbance after thyroidectomy. This can show up as tingling, muscle cramps, or, in more severe cases, tetany. Management typically includes calcium supplementation and sometimes calcitriol with careful monitoring; acute symptoms may require IV calcium. Hypercalcemia would come from too much PTH, not from loss of parathyroids, and hyperkalemia or hyponatremia aren’t direct consequences of parathyroid failure.