Glomerular involvement in rheumatoid arthritis has been known to be associated with treatment side effects from medications and secondary amyloidosis. However, limited basic science and clinical studies have been performed to address the potential disease specific immune-mediated mechanisms causing secondary glomerular pathology, its various types of presentation, and the potential treatments.
A 41-year-old man with chronic active rheumatoid arthritis presented with nephrotic syndrome and was found to have membranous nephropathy with eosinophilic intracapillary thrombi on renal biopsy. Proteinuria persisted despite complete withdrawal from non-steroidal anti-inflammatory drugs (NSAIDs) and disease-modifying anti-rheumatic drugs (DMARDs). Throughout the disease course, he developed cryoglobulinemic vasculitis and pulmonary sarcoidosis, both of which achieved clinical resolution with glucocorticoids. However, only partial improvement was observed in proteinuria with treatment of steroids and Rituximab.
Our case presented a unique and complicated clinical phenotype of active rheumatoid arthritis, with clinical features of cryoglobulinemic vasculitis, histopathologic features of membranous and cryoglobulinemic nephropathy in the absence of DMARDs use, as well as pulmonary sarcoidosis. We speculate that there is a wider spectrum of glomerular disease in patients with untreated rheumatoid arthritis. In addition, the potential association between rheumatoid arthritis and cryoglobulinemic vasculitis should probably be revisited and requires further studies to elucidate the underlying mechanisms and treatment options.