Hungry bone syndrome is characterized by which process after prolonged time?

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

Answer: (B)

Hungry bone syndrome happens when the skeleton suddenly starts taking up minerals after a period of high bone turnover, such as following treatment for long-standing hyperparathyroidism (for example, parathyroidectomy). When PTH levels fall abruptly, osteoblasts and osteoclasts shift into a remineralization mode, pulling calcium (and phosphate) from the blood into bone to rebuild it. The result is low serum calcium—hypocalcemia—and often low phosphate as well, even though the bones are rebuilding. This is why the correct description is a fall in blood calcium after prolonged bone turnover. Hypercalcemia or hyponatremia wouldn’t fit this pattern, and while phosphate can drop due to deposition into bone, the hallmark is hypocalcemia from mineral uptake into bone.