[High alkaline phosphatase in subacute thyroiditis]

Subacute thyroiditis may be hard to diagnose, therefore patients are sometimes misdiagnosed and subjected to unnecessary work-up. We report a 37-year-old man with subacute thyroiditis and a high concentration of serum alkaline phosphatase. After aspirin treatment there was clinical improvement and decrease in rapid ESR, and in high serum thyroxin and alkaline phosphatase. The increased alkaline phosphatase, seen in as many as 50% of patients, is of hepatic origin, and is not caused by high serum thyroxin. Awareness of this relationship may help in diagnosis and may prevent unnecessary diagnostic procedures, which may be invasive.