Wegener's granulomatosis and pulmonary vasculitis

The most frequent types of systemic vasculitis to affect the lung are Wegener's granulomatosis, microscopic polyangiitis, and the Churg-Strauss syndrome. Although all three typically affect the small vessels, Wegener's granulomatosis and, frequently, Churg-Strauss syndrome have characteristic necrotizing granulomatous features. All three syndromes lack immune complex deposits but are associated with anti-neutrophil cytoplasmic antibodies, which have been implicated in their pathogenesis. The initial disease phase of Wegener's granulomatosis is usually dominated by symptoms resulting from the necrotizing granulomatous inflammation affecting the respiratory tract. This initial phase frequently responds to trimethoprim-sulfamethoxazole. During the generalized vasculitic phase of Wegener's granulomatosis, immunosuppression with the standard regimen consisting of oral prednisone and cyclophosphamide is required. Alternative immunosuppressive regimens have been tried because of the high toxicity rate of the standard regimen. Plasma exchange and, most recently, intravenous immunoglobulin have been used in patients not responding to standard immunosuppression with mixed results. Most cases of Churg-Strauss syndrome respond promptly to oral glucocorticoids alone.