Abstract
Rheumatoid arthritis (RA) is accompanied by a variety of nephropathies. It is often difficult to distinguish between disease-associated and drug-associated renal diseases. Three hundred and seventy-six RA patients with renal involvement were included in our study; they were subjected to full history and clinical examination, kidney function, 24-h urinary protein, and kidney biopsy. All our patients were on methotrexate, low dose steroids, and nonsteroidal anti-inflammatory drugs, in addition to the previous medications. About 79.3%, 20.7%, 6.9%, and 5.9% of our patients were on leflunomide, hydroxychloroquine, etanercept, and infliximab, respectively. Renal presentation was in the form of nephrotic syndrome (33.5%), persistent subnephrotic proteinuria (12.2%), persistent proteinuria and recurrent hematuria (13.3%), acute nephritis (23.9), recurrent hematuria (7.4%), and creatinine >1.5 mg/dL (10.6%). Renal biopsies were glomerular amyloidosis (28.1%), mesangioproliferative (19.1%), membranous (6.1%), crescent (16.8%), focal segmental glomerulosclerosis (18.6%), and minimal changes (11.7%). There was a statistically significant difference in the incidence of membranous nephritis between patients who took leflunomide, and hydroxychloroquine and those did not. Etanercept in our study seems not to be related to any form of renal involvement, while infliximab is related to focal segmental sclerosis and amyloidosis of tubulointerstitial type. Kidney involvement in RA is not a rare complication. Any type of histopathological changes can be present, with amyloidosis on top of the list. Hydroxychloroquine and leflunomide are accused in membranous nephropathy. Infliximab is associated with focal segmental sclerosis and amyloidosis of tubulointerstial type, and etanercept appear to be safe as regards kidney affection.