It is often considered a triad of necrotizing granulomatous vasculitis of the tissues of the upper and lower respiratory tract and focal segmental glomerulonephritis. However, limited forms occur that may affect only one of these areas, and other tissues may also be involved. Small arteries and veins are the predominant vessels affected.
Patients often present with nonspecific findings of fever, malaise, weight loss, arthralgias, myalgias and chronic rhinitis or worsening sinusitis. Pain over the sinus areas and purulent or bloody nasal discharge are typical upper respiratory symptoms. Nasal or oral mucosal ulcerations are early findings. Destructive changes lead to a saddle-nose deformity. Pulmonary involvement may be asymptomatic or may cause chest pain, shortness of breath, bloody or purulent sputum and haemorrhage. Tracheal lesions and, in particular, subglottic involvement may produce stenosis. Eye symptoms include episcleritis, uveitis and proptosis due to orbital granulomas. Cranial nerve deficits may be the result of granulomatous inflammation in or near the upper airways. Cutaneous findings include nodules, purpura and ulcerations. Arthritis is infrequent and usually transient.
The incidence of glomerulonephritis with polyangiitis appears to be increasing, but it is unclear whether this simply represents better case recognition. Geographical differences in incidence in Europe have been described, glomerulonephritis with polyangiitis being more common in northern Norway (10.5/million) than in Spain (4.9/million). The reasons for this difference are unclear.
(Carette S., 2004, J.Rheumatol. 31:792-794).