Abstract: PUB254
Rheumatoid Arthritis-Associated Nephritis or Rhupus? A Diagnostic Dilemma
Session Information
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Bowling, Carly M, Walter Reed National Military Medical Center, Bethesda, Maryland, United States
- Nguyen, Julia, Walter Reed National Military Medical Center, Bethesda, Maryland, United States
- Loncharich, Michael, Walter Reed National Military Medical Center, Bethesda, Maryland, United States
- Watson, Maura A., Walter Reed National Military Medical Center, Bethesda, Maryland, United States
- Joshi, Megha Raj, Walter Reed National Military Medical Center, Bethesda, Maryland, United States
Introduction
Extra-articular manifestations of rheumatoid arthritis (RA) can include glomerular lesions. Historically, RA associated glomerulonephritis (RAA-GN) is due to secondary amyloidosis or medication induced from non-steroidal anti-inflammatory drugs, penicillamine, gold, and cyclosporine. Drug induced GN incidence has declined with RA therapy advancements, while primary GNs - mesangial (MesGN), membranous, and focal segmental glomerulosclerosis, are increasingly reported. Rhupus, a rare syndrome where RA and systemic lupus co-exist, adds diagnostic complexity in patients presenting with GN.
Case Description
A 30-year-old male with seropositive, non-erosive RA, and suspected lupus overlap syndrome, presented with hematuria and sub-nephrotic proteinuria. He had rheumatoid nodules, polyarticular synovitis and skin rash with a neutrophil-rich dermatosis on biopsy consistent with subacute cutaneous lupus. RA with lupus overlap therapies included methotrexate, tocilizumab and hydroxychloroquine. Blood pressure was 144/89 mmHg. ANA titer was elevated (1:1,280), with negative anti-double stranded DNA antibody, low complement levels (C3 91 mg/dL; C4 10 mg/dL), eGFR 97ml/min/1.73m2 and spot urine protein/creatinine ratio (uPCR) 2.85 g/g. Urine sediment had pyuria, non-dysmorphic hematuria, fine granular casts, and Maltese crosses. Secondary work-up for proteinuria was negative. Renal biopsy revealed mesangial proliferative GN without immune complex deposition (ICD) and negative amyloid staining. He was continued on anti-RA therapy and started on an angiotensin receptor blocker and SGLT2 inhibitor with subsequent reduction in proteinuria.
Discussion
RAA-GNs are rare diagnoses of exclusion with primary MesGN reported. Their rarity, especially in lupus overlap syndrome, requires a broad differential diagnostic approach. The lack of ICD on renal biopsy assisted differentiation between RA-nephritis and lupus nephritis in this case. RA with lupus overlap syndromes add diagnostic complexity in differentiating lupus nephritis from RA nephritis, making renal biopsy essential in guiding accurate diagnosis.
The views expressed in this abstract are those of the author(s) and do not necessarily reflect the official policy of the Department of Defense or the United States Government.