Hypercalcemia due to subacute thyroiditis

To describe a patient who had hypercalcemia attributable to subacute thyroiditis.

A case history, including detailed results of laboratory tests, is presented, and the findings are discussed.

A young woman with neck pain and fever was found to have increased free thyroxine and triiodothyronine levels but a decreased thyrotropin value. Concurrently, the serum calcium concentration was increased. Subacute thyroiditis was diagnosed. Within 1 month, the free thyroxine and serum calcium levels were normal.

Thyrotoxicosis is a known cause of hypercalcemia. All previously reported cases of hypercalcemia due to hyperthyroidism involved Graves' disease, toxic multinodular goiter, or a toxic adenoma as the cause of the hyperthyroidism. The current case shows that short-term subacute thyroiditis can cause hypercalcemia.