[Pulmonary vasculitis]

Following an international consensus conference held in Chapel Hill, North Carolina, USA, vasculitides have been divided based on the size of the vessel involved in the inflammatory process. Thus, the terms large, medium and small vessel vasculitis emerged. Wegener's granulomatosis, microscopic polyangitis and Churg-Strauss syndrome are described as small vessel vasculitides. Pulmonary involvement is a characteristic feature of both Wegener's granulomatosis and Churg-Strauss syndrome, less so in microscopic polyangitis. A pathognomonic feature is alveolar haemorrhage, which encompasses the trias: 1) bilateral acinar pulmonary infiltrates reminiscent of pulmonary edema, 2) anemia and 3) haemoptysis, which however may be absent. Bronchoalveolar lavage typically returns lavage fluid that remains hemorrhagic even after sequential sampling. The discovery that antineutrophil cytoplasmic antibodies (ANCA) are strongly associated with vasculitic disorders and their subsequent characterisation has led to improved understanding of the pathogenic mechanisms underlying vasculitis. This paper will review clinical aspects of pulmonary involvement in the systemic vasculitides.