Regression of the nephrotic syndrome in rheumatoid arthritis and amyloidosis treated with azathioprine

Secondary or reactive (AA) amyloidosis is a well‐known complication of certain rheumatic diseases, particularly rheumatoid arthritis (RA). This case report describes a patient with RA complicated by amyloidosis and the nephrotic syndrome, which regressed after treatment with azathioprine. The AA amyloidosis was documented by renal and lymph node biopsies and by the presence of proteinuria. Evaluation for other etiologies of proteinuria was negative. After treatment with azathioprine, the proteinuria resolved and the serum albumin level increased from 1.9 mg/dl to normal. This is the first published report of azathioprine therapy resulting in a reversal of the nephrotic syndrome in a patient with RA and secondary amyloidosis.