RESPIRATORY-FAILURE IN ANCA-ASSOCIATED VASCULITIS

Objective: To assess the prevalence, clinical manifestations, and cour se of respiratory failure in all patients who tested positive for anti neutrophil cytoplasmic autoantibodies (ANCA) in our clinics in the per iod between January 1985 and January 1993. Design: Case-series analysi s. Setting: Three teaching hospitals in the Netherlands. Patients: Two hundred twenty consecutive patients suspected of having vasculitis an d/or glomerulonephritis who tested positive for ANCA by indirect immun ofluorescence and enzyme-linked immunosorbent assay. Results: Sixty-tw o patients had pulmonary involvement. Acute respiratory failure develo ped in nine. Respiratory failure was related to infections in two of t hem and to ANCA-associated vasculitis in seven. These seven patients u niformly presented with pulmonary hemorrhage and diffuse pulmonary inf iltrates. The diagnosis of systemic vasculitis was supported by the pr esence of a pulmonary-renal syndrome in all patients, and by detection of antibodies to the proteinase 3 or myeloperoxidase antigen in all b ut one patient. Antiglomerular basement membrane antibodies were absen t. The mortality was high due to hypoxic respiratory failure, pulmonar y superinfections, and concomitant renal failure. Conclusions: Acute r espiratory failure due to vasculitis developed in one of every nine pa tients with ANCA-associated pulmonary disease. Patients usually presen t with pulmonary infiltrates and hemoptysis. A diagnosis of vasculitis may be further supported by analysis of the urinary sediment and dete rmination of the ANCA target antigen. It remains to be proved that ear ly detection of ANCA favorably affects the outcome.