Arthritis rounds. Pneumocystis carinii associated with polyarteritis and immunosuppressive therapy.

Pneumocystis carinii characteristically causes pneumonia in patients with immunodeficiency disorders. It occurs most often in patients with malignancy or renal transplants whose immune response has been suppressed by corticosteroids or cytotoxic agents. Individuals with connective tissue disease who receive immunosuppressive drugs become susceptible to Pneumocystis. The incidence of Pneumocystis infection in connective tissue disease is low but may increase if immunosuppressive drugs are used more often. Our patient acquired Pneumocystis pneumonia after immunosuppressive therapy for polyarteritis nodosa. Prompt recognition of this condition is essential now that specific therapy is available. Untreated Pneumocystis infection is usually fatal.