Hungry bone syndrome is an uncommon metabolic syndrome characterized by prolonged and significant hypocalcemia, hypophosphatemia, and hypomagnesemia following surgical parathyroidectomy for severe primary or tertiary hyperparathyroidism. The condition results from the sudden decrease in parathyroid hormone release, resulting in increased mineral uptake by bones.

Risk factors for developing hungry bone syndrome include volume of parathyroid removed, elevated preoperative blood urea nitrogen (BUN), and/or older age. Signs and symptoms include proximal muscle weakness, fatigue, and vitamin D deficiency.

Calcium levels typically reach a low 2-4 days postoperatively and may remain decreased for up to 3 months.