An uncommon endocrine cause of pyrexia of unknown origin.

We report a previously healthy 43 yr old male who presented with prolonged fever, weight loss and neck pain for 3 weeks. Even after extensive work up for the possible causes of pyrexia, the cause remained elusive. In view of persistent tachycardia and neck pain, possibility of subacute thyroiditis was suspected. Thyroid function test (TFT) revealed thyrotoxicosis, which on further evaluation was found to be secondary to DeQuervains thyroiditis. He was treated with NSAIDs, beta-blockers and steroids. He improved rapidly but went on to develop hypothyroidism on follow-up and required levothyroxine replacement.