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 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, gastrointestinal 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.

TREATMENT

Treatment of pulmonary vasculitis requires immunosuppressive therapy. Combination therapy with corticosteroids and either rituximab or cyclophosphamide is recommended for those with organ- or life-threatening disease. After complete remission is obtained, then maintenance therapy with rituximab, methotrexate, azathioprine, or mycophenolate is used.

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. The addition of trimethoprim-sulfamethoxazole (one double-strength tablet by mouth twice daily) to standard therapy may help prevent relapses.