PULMONARY CAPILLARITIS AND ALVEOLAR HEMORRHAGE - UPDATE ON DIAGNOSIS AND MANAGEMENT

Pulmonary vascular inflammatory disorders may involve all components o f the pulmonary vasculature, including capillaries. The principal hist opathologic features of pulmonary capillaritis include capillary wall necrosis with infiltration by neutrophils, interstitial erythrocytes, and/or hemosiderin, and interalveolar septal capillary occlusion by fi brin thrombi. Immune complex deposition is variably present. Patients often present clinically with diffuse alveolar hemorrhage, which is ch aracterized by dyspnea and hemoptysis; diffuse, bilateral, alveolar in filtrates on chest radiograph; and anemia. Pulmonary capillaritis has been reported with variable frequency and severity as a manifestation of Wegener's granulomatosis, microscopic polyarteritis, systemic lupus erythematosus, Goodpasture's syndrome, idiopathic pulmonary renal syn drome, Behcet's syndrome, Henoch-Schonlein purpura, IgA nephropathy, a ntiphospholipid syndrome, progressive systemic sclerosis, and diphenyl hydantoin use. In addition to history, physical examination, and routi ne laboratory studies, certain ancillary laboratory tests, such as ant ineutrophil cytoplasmic antibodies, antinuclear antibodies, and antigl omerular basement membrane antibodies, may help diagnose an underlying disease. Diagnosis of pulmonary capillaritis can be made by fiberopti c bronchoscopy with transbronchial biopsy, but thoracoscopic biopsy is often employed. Since many disorders can result in pulmonary capillar itis with diffuse alveolar hemorrhage, it is crucial for clinicians an d pathologists to work together when attempting to identify an underly ing disease. Therapy depends on the disorder that gave rise to the pul monary capillaritis and usually includes corticosteroids and cyclophos phamide or azathioprine. Since most diseases that result in pulmonary capillaritis are treated with immunosuppression, infection must be exc luded aggressively.