The Respiratory System in Autoimmune Vascular Diseases.

The respiratory system may be involved in all types of systemic vasculitis with varying significance and frequency. ANCA-associated vasculitis, including granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, and microscopic polyangiitis, affects the respiratory tract more commonly than other vasculitis types. Granulomatosis with polyangiitis is always associated with upper or lower respiratory tract involvement. Pulmonary and ENT involvements are the hallmark feature of the disease and are present in 90 and 80% of cases, respectively, with frequent skin or gastrointestinal involvement. In about 10% of cases, the lung is the only organ affected. Eosinophilic granulomatosis with polyangiitis is always associated with hypereosinophilia and asthma which usually precedes the systemic manifestations by several years; however, onset of asthma and of the vasculitis may be concomitant. Parenchymal infiltrates may be migratory and rapidly resolve upon corticosteroid treatment. Diffuse alveolar hemorrhage and renal failure are typical features of microscopic polyangiitis. The former is the leading manifestation of anti-glomerular basement membrane disease and is usually part of a pulmonary-renal syndrome. Takayasu arteritis has a distinct clinical presentation due to pulmonary arteritis and may present with massive hemoptysis, chest pain, and rarely symptoms of pulmonary hypertension. Behçet disease is the most common cause of pulmonary artery aneurysm and can also cause in situ thrombosis of the pulmonary arteries. Corticosteroids and immunosuppressive agents are the mainstay of treatment. In conclusion, systemic vasculitis is a frequent cause of respiratory system involvement with diverse manifestations of distinct severity and outcome.