Pulmonary capillaritis and hemorrhage in patients with systemic vasculitis.

Thirteen patients with prominent pulmonary signs and symptoms had pulmonary capillaritis and extensive hemorrhage demonstrated by open-lung biopsy or autopsy. Vasculitis was demonstrated in other organs before or after the lung biopsy or at autopsy. Although there were several suspected causes for the pulmonary capillaritis and different final clinicopathologic diagnoses, the histopathologic features in the lung were similar in all cases and distinctive enough to separate capillaritis from other causes of hemorrhagic lung. All patients were treated with prednisone or cyclophosphamide, or both. Six patients died of their vasculitis, five in respiratory failure and one in renal failure. None of the seven survivors had a clinical recrudescence of pulmonary hemorrhage. By extrapolation from these 13 cases, one may histopathologically recognize pulmonary capillaritis when it causes hemorrhagic lung in a patient without clinically evident extrapulmonary vasculitis. One can then proceed to investigate the patient and possibly determine the nature of the vasculitis.