Pulmonary involvement in microscopic polyangiitis.

Purpose Of Review: Microscopic polyangiitis is a systemic necrotizing vasculitis that affects small vessels, resulting in a wide spectrum of organ involvement including the kidneys and the lungs. This paper reviews recent insights and observations into the pathogenesis, clinical manifestations, and treatment of pulmonary involvement in microscopic polyangiitis.

Recent Findings: The spectrum of clinical presentations ranges from antecedent interstitial fibrosis to frank hemoptysis secondary to capillaritis. Computerized tomography imaging reveals a variety of pulmonary findings, including ground-glass attenuation, consolidation, thickening of bronchovascular bundles, and honeycombing. Antineutrophil cytoplasmic antibodies are important in diagnosis as well as in the pathogenesis and prognosis of microscopic polyangiitis. There is more evidence to support the various therapeutic modalities currently used in pulmonary manifestations of microscopic polyangiitis, including induction therapy with cyclophosphamide, the use of other novel pharmacologic agents such as the tumor necrosis factor-alpha blockers and rituximab, and nonpharmacologic modalities such as plasmapheresis and ventilatory management.

Summary: The pulmonary manifestations of microscopic polyangiitis are diverse and often difficult to manage; however, as our understanding and experience grows so does our ability to successfully diagnose and treat these patients.