Pulmonary Vasculitides

The systemic vasculitides (SV) are a heterogeneous group of rare affections, characterized by a primary process of inflammation and damage of the vessel wall, resulting in blood flow impairment and, ultimately, in ischemia of the distal tissues. Pulmonary vasculitis usually is a component of a systemic small vessel vasculitis. Pulmonary vasculitides can be classified into three major groups: a) those in which lung is the major organ involved, b) those in which lung may be involved as part of a systemic vasculitis, c) diseases in which pulmonary vasculitis may be part of the spectrum of pathology1. Three major forms of small vessel vasculitis that often affect the lungs are Wegener’s granulomatosis (WG), microscopic polyangiitis (MPA) and ChurgStrauss syndrome (CSS). These forms of vasculitis are strongly associated with antineutrophil cytoplasmic auto antibodies (ANCA) directed against enzymes contained in the primary granules of neutrophils and peroxidasepositive lysosomes of monocytes). Large vessel vasculitides, such as giant cell arteritis and Takayasu’s arteritis, occasionally affect the lungs. Medium-sized vessel vasculitis, such as polyarteritis nodosa and Kawasaki disease rarely affect the lungs. The immunologic mechanisms that cause vasculitis include cell-mediated inflammation, immune complexmediated inflammation and inflammation induced by ANCA. ANCA associated vasculitis is more common cause for pulmonary vasculitis.