The differential diagnosis for Pyrexia of Unknown Origin (PUO) remains extensive. The most common PUO categories are infectious, neoplastic, rheumatic, and inflammatory. It is important to remember that PUO is far more often caused by an atypical presentation of a rather common disease than by a very rare disease. We report a series of cases of patients with subacute thyroiditis presenting as PUO.
Discussion/Conclusion: All reported cases of PUO had similar findings in each of the patients, well-documented as subacute thyroiditis. Sub-acute thyroiditis should be considered in the diagnostic workup of PUO even in the absence of overt toxic symptoms of thyroid hormone excess. Early recognition and timely anti-inflammatory therapy may help in successful management.