Rheumatoid arthritis preceding polyangiitis: two case reports.

Introduction. - Although joint manifestations are common in microscopic pol yangiitis (MPA), including arthralgia reported in 15-65% of cases and arthr itis in 6-17%, there have been only two published cases of polyarthritis as the first manifestation of the disease. We report on two new cases. Exegesis. - A 71-year-old woman had symmetric polyarthritis of the hands wh ich initially suggested the existence of seronegative rheumatoid arthritis. A 52-year-old woman had seropositive asymmetric oligoarthritis. The diagno sis was not established until renal insufficiency appeared, prompting a ren al biopsy which showed in both cases an extra-capillary glomerulonephritis and an anti-myeloperoxydase (p-ANCA) assay which was positive in both patie nts. The incidence and specificity of antineutrophil cytoplasmic antibodies (ANCA), including MPA, in rheumatoid arthritis are reviewed. Conclusion. - Our two observations show that in cases of polyarthritis or o ligoarthritis with renal involvement, testing for and typing of ANCA should be performed so as not to misdiagnose vasculitis. (C) 2000 Editions scient ifiques et medicales Elsevier SAS.