9-27: Pulmonary Vasculitis

Antineutrophil cytoplasmic autoantibody (ANCA)–associated vasculitides include granulomatosis with polyangiitis, microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis. All are associated with ANCA and similar features of glomerulonephritis.

Granulomatosis with polyangiitis is a small vessel vasculitis manifested in the upper and lower respiratory tracts. Chronic sinusitis, arthralgias, fever, skin rash, and weight loss are frequent presenting symptoms. Specific pulmonary complaints occur less often. The most common sign of lung disease is nodular pulmonary infiltrates, often with cavitation, seen on chest radiography. Tracheal stenosis and endobronchial disease are sometimes seen. The diagnosis is most often based on serologic testing and biopsy of lung, sinus tissue, or kidney with demonstration of necrotizing granulomatous vasculitis (Chapter 20).

Eosinophilic granulomatosis with polyangiitis (formerly Churg-Strauss syndrome) is an idiopathic multisystem vasculitis of small and medium-sized arteries that occurs in patients with asthma. The skin and lungs are most often involved, but other organs, including the paranasal sinuses, the heart, GI tract, liver, and peripheral nerves, may also be affected. Peripheral eosinophilia greater than 1500 cells/mcL (greater than 1.5 × 10⁹/L) or greater than 10% of peripheral WBCs is the rule. Abnormalities on chest radiographs range from transient opacities to multiple nodules. This illness may be part of a spectrum that includes polyarteritis nodosa. The diagnosis requires demonstration of histologic features, including fibrinoid necrotizing epithelioid granulomas and eosinophilic granulomas.

Anti-glomerular basement membrane (anti-GBM) antibody disease (also called Goodpasture syndrome) is a small-vessel vasculitis resulting from circulating antibodies against an antigen component of the basement membrane of the glomerulus and alveoli. It is rare, seen in young adults, and has a slight male predominance. It causes diffuse alveolar hemorrhage, rapidly progressive glomerulonephritis, and kidney failure.

TREATMENT

Treatment of patients with pulmonary vasculitis requires immunosuppressive therapy. Combination therapy with corticosteroids and either rituximab or cyclophosphamide is recommended for induction. Then patients should be transitioned to maintenance therapy with rituximab, methotrexate, azathioprine, or mycophenolate. For anti-GBM antibody disease, the use of plasmapheresis during induction has been shown to improve outcomes.

PROGNOSIS

Five-year survival rates in patients with these vasculitis syndromes have been improved by combination therapy. Complete remission can be achieved in over 90% of patients with granulomatosis with polyangiitis.