Takayasu Arteritis in the Pre-Pulseless Phase Presenting as Pyrexia of Unknown Origin.

Pyrexia of unknown origin (PUO) or fever of unknown origin (FUO) is clinically challenging for a treating physician; it is also a conundrum for the patient until a definitive diagnosis is made. Despite extensive investigations, many cases of PUO may remain undiagnosed for a long time. In a resource-limited country like India, due to the limited availability of various diagnostic tests, a great many fever cases are classified as PUO. Here, we present a case report of Takayasu arteritis in its pre-pulseless phase, presented as PUO. Takayasu arteritis presenting as PUO in the absence of a pulse deficit is uncommon and rarely reported. The patient's fever responded to steroids with methotrexate. The patient didn't develop any vascular complications during the follow-up.