Subacute thyroiditis with increased serum alkaline phosphatase.

Three patients had subacute thyroiditis and elevated serum alkaline phosphatase, presumably related to the thyroiditis. Concomitant elevation of the serum gamma-glutamyl transferase suggested that the alkaline phosphatase was of hepatic origin. The elevation of the serum alkaline phosphatase could not be definitely related to the degree or duration of elevation of the serum thyroxine. The combination of elevated serum alkaline phosphatase with the systemic symptoms of subacute thyroiditis may obscure the diagnosis, especially if patients have little or no neck pain.