Remission of the nephrotic syndrome in a patient with renal amyloidosis due to rheumatoid arthritis treated with prednisolone and methotrexate.

A 46-year-old woman developed nephrotic syndrome secondary to rheumatoid arthritis (RA). A renal biopsy showed deposition of amyloid fibrils in the subendothelial space of the glomerular capillary walls. After treatment with prednisolone (PSL, 40 mg/day), the levels of C-reactive protein (CRP) and serum amyloid A decreased to within normal limits for 2 weeks. However, the nephrotic syndrome persisted for 6 months after the therapy. To maintain the suppression of disease activity and to reduce PSL, methotrexate (5 mg/week) was added. The nephrotic syndrome resolved gradually, and the level of serum albumin returned to normal. Although renal prognosis of patients with nephrotic syndrome due to amyloidosis caused by RA has been considered poor, adequate and long-term treatment of RA with antiinflammatory drugs, including PSL and methotrexate, is useful for patients with secondary amyloidosis complicated by RA.