Two days after removal of a 4 g parathyroid adenoma in a patient with a preoperative calcium of 14.2 mg/dL and radiological osteitis fibrosa cystica, the serum calcium falls to 6.1 mg/dL. Phosphate is 1.8 mg/dL (low) and intact PTH is undetectable. Intravenous calcium infusion produces only transient correction. What is the diagnosis?

• A Citrate toxicity from perioperative transfusion
• B Permanent hypoparathyroidism from accidental gland removal
• C Vitamin D deficiency unmasked after surgery
• D Hungry bone syndrome ✓

Explanation

Hungry bone syndrome is prolonged, refractory hypocalcaemia after parathyroidectomy in patients with severe, long-standing hyperparathyroidism and high bone turnover. Rapid mineralisation of osteoid sequesters calcium and phosphate, so the hallmark is hypocalcaemia with HYPOphosphataemia and suppressed PTH. Permanent hypoparathyroidism would show a HIGH phosphate from loss of phosphaturic PTH action, and this distinction is what kills the best distractor.

Reference: Williams Textbook of Endocrinology, 14th ed.

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Written and medically reviewed by the StethoPrep medical team.