半月体形成を伴う糸球体腎炎を発症した慢性関節リウマチ患者の3例

抄録

We experienced 3 cases of rheumatoid arthritis (RA) developing glomerulonephritis with crescent formation. All of them, aged over 50 years, had long-term histories of RA with involvement of multiple joints and had never been pointed out the abnormalities of urinary findings. In 2 of them proteinuria with granular casts and pedal edema developed abruptly, accompanying cutaneous vasculitis lesions (skin ulcer and purpura). Serum levels of IgG-rheumatoid factor increased in both patients. Percutaneous renal biopsies were performed and the glomerular involvements were characterized by crescent formation with fibrinoid deposits and mild mesangial proliferation. The percentage of glomeruli affected by crescent formation was 37% and 61%, respectively. The treatment with prednisolone and/or cyclophosphamide led them to clinical improvements of vasculitis and glomerulonephritis. In these cases, glomerulonephritis with crescent formation developed in association with cutaneous vasculitis which suggests that the renal lesion may be regarded as a' complication of rheumatoid vasculitis. The third patient noted general weakness and pedal edema after one month of increasing arthralgia Laboratory investigations showed renal dysfunction and renal biopsy revealed severe crescentic glomerulonephritis with fibrinoid deposits. Despite of prednisolone therapy, renal function was progressively aggravated and maintenance hemodialysis was need. Although it was unclear whether the patients had complicating vasculitis, the increasing symptomes of polyarthritis reflected the active stage of RA, in which vasculitis and other complications were likely to develop. In this case active RA seems likely compared to coincidental development of idiopathic crescentic glomerulonephritis as the cause of the renal lesion. Diffuse or focal crescentic glomerulonephritis may be a part of the spectrum of active RA with vasculitis and this complication may not be as rare as generally considered.