Idiopathic Membranous Nephropathy Preceding the Onset of Rheumatoid Arthritis: a Case Report

Abstract

Introduction: Membranous nephropathy (MN) in the context of rheumatoid arthritis (RA), is often an iatrogenic complication due to the nephrotoxic effects of antirheumatic drugs. Rare cases of non-iatrogenic association between these two diseases were reported in the literature.
Case report: A 30-year-old female patient presented in September 2005 with nephrotic syndrome. Renal biopsy showed features consistent with MN. Search for etiology was negative, particularly lupus serology which remained negative throughout the course of her illness. Accordingly, she was diagnosed as a case of idiopathic MN. Initially, she was treated with angiotensin converting enzyme inhibitors and angiotensin receptor blockers which maintained her protein excretion below nephrotic range for two years. Her nephrotic syndrome then relapsed and was treated with steroids and chlorambucil, according to the Ponticelli protocol. A few months later, she presented with early morning joint stiffness, polyarthritis involving the small joints of the hands, and strongly positive rheumatoid factor, fulfilling the diagnostic criteria of rheumatoid arthritis (RA). Her serum creatinine remained normal and a second renal biopsy revealed the same features of MN. Her RA was treated with pulsed methylprednisolone followed by oral steroids and methotrexate resulting in remission of the joints disease and the nephrotic syndrome. Remission was maintained for the last two years up to the time of this report.
Conclusion: We hereby report a case of secondary membranous nephropathy that preceded the onset of rheumatoid arthritis by three years.

Keywords: Auto-immunity; Membranous nephropathy; Rheumatoid arthritis