Giant Cell Arteritis Presenting as PUO.

Giant cell arteritis(GCA) is a primary granulomatous vasculitis affecting the large and medium sized arteries. We present here a case of GCA with pyrexia of unknown origin (PUO) as the presenting manifestation in the absence of other typical features. On evaluation, the patient had raised inflammatory markers with features of large vessel vasculitis on whole body PET-CT scan. The colour doppler ultrasonography(CDUS) of the temporal arteries showed bilateral halo sign. Since bilateral 'halo sign' is more specific for the diagnosis of GCA, temporal artery biopsy is not mandatory. If CDUS is not conclusive, then biopsy can be considered being an invasive procedure.