Hungry bone syndrome after thyroidectomy for thyroid storm

A 39-year-old man was admitted to our hospital with the diagnosis of thyroid storm due to Graves' disease. Near-total thyroidectomy was performed after 1 month's pharmacological treatment, and he presented with tetany next morning. Serum corrected calcium value was 5.7 mg/dL. Procollagen type 1 N-terminal propeptide increased considerably, while tartrate-resistant acid phosphatase 5b decreased. These changes indicated that bone formation exceeded bone resorption in reverse after thyroidectomy. Calcium gluconate was administered intravenously for 14 days, before the patient was discharged. Oral administration of calcium and active forms of vitamin D was continued for 4 months. Rapid skeletal uptake of calcium from blood caused severe and persistent hypocalcaemia, which is called hungry bone syndrome. When patients with Graves' disease have severe thyrotoxicosis, high serum alkaline phosphatase levels and low bone mineral densities, they are at high risk for hungry bone syndrome after thyroidectomy, and should be educated for the symptoms of hypocalcaemia.