Abstract: PUB268
A Forgotten Foe: Glomerulopathy in Untreated Rheumatoid Arthritis
Session Information
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Mwarangu, Edward, The University of Kansas Medical Center, Wichita, Kansas, United States
- Short, Levi, The University of Kansas Medical Center, Wichita, Kansas, United States
Introduction
Glomerulonephritis (GN) was once a relatively common and serious complication of rheumatoid arthritis (RA), often leading to significant morbidity. However, in the modern era—in which RA is typically diagnosed early and treated aggressively with disease-modifying antirheumatic drugs (DMARDs)—the incidence of GN has markedly declined. Literature suggests that glomerular disease now affects fewer than 5% of patients with RA.
Case Description
A 78-year-old female with poorly treated, long-standing seropositive RA, hypertension, and chronic kidney disease (CKD) presented with nephrotic syndrome. Laboratory findings included a urine protein-to-creatinine ratio of 5.8 g/g, serum albumin of 2.5 g/dL, normal C3 (100 mg/dL), low C4 (7 mg/dL), positive antinuclear antibody, elevated rheumatoid factor at 1299 IU/mL, anti-cyclic citrullinated peptide >250 U/mL, and an increase in serum creatinine from a baseline of ~1.4 mg/dL to 2.8 mg/dL. Serologic testing was negative for anti-double-stranded DNA, monoclonal proteins, anti-glomerular basement membrane antibodies, Phospholipase A2 receptor antibodies (PLA2R), myeloperoxidase, proteinase 3, HIV, hepatitis viruses, and cryoglobulins, normal A1C. Renal biopsy revealed immune complex-mediated glomerulonephritis (ICGN) with mesangial proliferation and rare segmental endocapillary proliferative features, but no necrosis or crescents. Immunofluorescence staining was positive for IgG, IgM, C3, and C1q in a granular pattern along the glomerular capillary walls, consistent with membranous pattern. PLA2R staining was negative. A diagnosis of RA-associated ICGN was made based on biopsy and serologic data, excluding other etiologies such as lupus, cryoglobulinemia, or infections. The patient initiated treatment with rituximab after counseling and remains under close follow-up, with serum creatinine stabilizing at 3.0 mg/dL.
Discussion
ICGN in RA is rare in the DMARD era but should remain in the differential for RA patients presenting with proteinuria and renal dysfunction, particularly in poorly controlled disease. Renal manifestations can include mesangial proliferative GN, membranous GN, or amyloidosis. This case emphasizes the importance of early recognition and biopsy-based diagnosis to guide treatment and prevent irreversible renal decline. Increased awareness and research are needed to better understand the incidence and management of RA-associated glomerulopathy.