An atypical pneumonia.

We describe a patient with underlying HIV presenting with progressive respiratory distress and acute renal failure. A unifying diagnosis of microscopic polyangiitis was made. Following immunosuppression induction with plasma exchange and intravenous corticosteroid and subsequent maintenance immunosuppression with intravenous cyclophosphamide in conjunction with renal replacement therapy he achieved remission. To our knowledge this is the first documented case of microscopic polyangiitis occurring in the context of underlying HIV, and raises interesting possibilities regarding the development of vasculitis in this patient.