Pyrexia of unknown origin and pulmonary fibrosis as a presentation of MPO-ANCA associated vasculitis.

The authors report the case of a 72-year-old man presenting with chronic dyspnoea and pyrexia of unknown origin (PUO). After extensive investigation, he was found to have pulmonary fibrosis with usual interstitial pneumonia pattern on high-resolution CT imaging and positive myeloperoxidase antineutrophil cytoplasmic antibodies (MPO-ANCA) with no infectious cause or other evidence of vasculitis organ involvement. His pyrexia and symptoms settled with oral systemic corticosteroid treatment. To the authors' knowledge this is the first case of MPO-ANCA positive vasculitis presenting as PUO and pulmonary fibrosis alone. The authors review the recent literature regarding the association of pulmonary fibrosis with ANCA-positive vasculitides with regards to pathogenesis, prognosis and treatment.