Hungry bone syndrome after parathyroidectomy is listed as a cause of which electrolyte disturbance?

• A. Hypomagnesemia
• B. Hyperkalemia
• C. Hypophosphatemia
• D. Hypocalcemia

Answer: (A)

When parathyroid hormone levels fall after parathyroidectomy, the bones rich in calcium begin to remineralize rapidly. This shifts calcium from the blood into bone, causing a fall in serum calcium known as hungry bone syndrome. The primary and most clinically important electrolyte disturbance is hypocalcemia, which can produce symptoms like tingling, muscle cramps, tetany, and even seizures. While calcium, phosphate, and magnesium can all be affected and levels of phosphate and magnesium may also drop as minerals move into bone, the defining and most characteristic disturbance in this scenario is low calcium. Hyperkalemia doesn’t fit the mechanism, and although hypophosphatemia or hypomagnesemia can occur, they are secondary to the dominant issue of hypocalcemia.