Objective: To analyze retrospectively the clinical course and outcome of 10 consecutive Chinese patients with microscopic polyarteritis (MPA) admitted to our hospital over a period of 3 years.
Methods: Ten patients with MPA who presented 1990-93 were studied. Their serum antineutrophil cytoplasmic autoantibody levels were assayed.
Results: The male to female ratio was 1:1 and the mean age was 61 years. Eight patients (80%) had renal impairment on presentation and 5 of them (50%) were dialysis dependent. Seven patients (70%), during their clinical course, had pulmonary hemorrhage. Six patients (60%) had hypoxic lung disease requiring ventilatory support. All 10 patients were pANCA positive; 8 patients were tested for antimyeloperoxidase antibody and were all positive. Seven patients were treated with immunosuppressants consisting of steroid and cyclophosphamide with additional plasma exchange. Nine patients died after a mean survival of 9 months (range 1-33); causes of death were respiratory failure (5), infection (2), uremia (one), and stroke (one). The ANCA level reflected the disease activity of the vasculitis.
Conclusion: MPA in Chinese patients appeared to be a more severe disease with a poor prognosis. This may be related to the older age group, and the more frequent and severe pulmonary and renal manifestations of MPA in these patients.