Respiratory failure in ANCA-associated vasculitis

Objective: To assess the prevalence, clinical manifestations, and course of respiratory failure in all patients who tested positive for antineutrophil cytoplasmic autoantibodies (ANCA) in our clinics in the period between January 1985 and January 1993. Design: Case-series analysis. Setting: Three teaching hospitals in the Netherlands. Patients: Two hundred twenty consecutive patients suspected of having vasculitis and/or glomerulonephritis who tested positive for ANCA by indirect immunofluorescence and enzyme-linked immunosorbent assay. Results: Sixty-two patients had pulmonary involvement. Acute respiratory failure developed in nine. Respiratory failure was related to infections in two of them and to ANCA-associated vasculitis in seven. These seven patients uniformly presented with pulmonary hemorrhage and diffuse pulmonary infiltrates. The diagnosis of systemic vasculitis was supported by the presence of a pulmonary-renal syndrome in all patients, and by detection of antibodies to the proteinase 3 or myeloperoxidase antigen in all but one patient. Antiglomerular basement membrane antibodies were absent. The mortality was high due to hypoxic respiratory failure, pulmonary superinfections, and concomitant renal failure. Conclusions: Acute respiratory failure due to vasculitis developed in one of every nine patients with ANCA-associated pulmonary disease. Patients usually present with pulmonary infiltrates and hemoptysis. A diagnosis of vasculitis may be further supported by analysis of the urinary sediment and determination of the ANCA target antigen. It remains to be proved that early detection of ANCA favorably affects the outcome.