Subacute thyroiditis – A rare cause of pyrexia of unknown origin

Pyrexia of unknown origin is a challenging problem to the physicians and rarely endocrine causes such as subacute thyroiditis can present as a pyrexia of unknown origin. It is usually a self-limiting condition and following post viral inflammatory process. It is common in young adults to middle age and does not involve in any autoimmune pathology. It has a self-limiting nature and symptomatic treatment is adequate. We report a 34 year old presented with a one month history of fever found to have high ESR and CRP with high free thyroxine level and treated as subacute thyroiditis with NSAID and she recovered completely from the acute illness.