Abstract: TH-PO0795
Concurrent Fibrillary Glomerulopathy (FGN) and Infection-Related Glomerulonephritis (IRGN) in Rapidly Progressive Glomerulonephritis (RPGN): A Diagnostic and Therapeutic Conundrum
Session Information
- Glomerular Case Reports: Membranous, PGN, GBM, and More
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Wei, Khaing San, University of Arkansas System, Little Rock, Arkansas, United States
- Gokden, Neriman, University of Arkansas System, Little Rock, Arkansas, United States
- Ayub, Fatima, University of Arkansas System, Little Rock, Arkansas, United States
Introduction
Fibrillary glomerulopathy is a rare glomerular disease characterized by the deposition of randomly arranged, non-congophilic microfibrils in the mesangium and glomerular basement membrane.The etiology of FGN is frequently unknown, but it has been associated with various conditions, including chronic infections. We present a challenging case of RPGN in a patient with osteomyelitis-associated IRGN and FGN.
Case Description
A 66-year-old male with a history of type II DM, recurrent osteomyelitis of the foot requiring multiple toe amputations,and hypertension was admitted with AKI and new-onset dependent edema. Initial labs showed an unremarkable CBC and BMP except for BUN at 56mg/dL and creatinine at 6.1mg/dL(Cr 0.9 mg/dL 3.5 months earlier).UA revealed RBC>18 per HPF and 3+ proteinuria, UPCR 5.7g/g. Serologies for ANA, ANCA, HIV, hepatitis, and syphilis were negative, as were blood cultures.C3 and C4 levels were also normal, whereas the ESR and CRP levels were elevated. Wound culture grew Proteus and Staphylococcus aureus. A renal biopsy revealed hypercellular glomeruli, with thickened capillary loops, multiple cellular crescents, numerous intraluminal RBC and wbc casts, and 40% IFTA .Granular staining of the capillary loops and mesangium for IgG, IgA, and C3 was observed, with DNAJB9-positive fibrils in the GBM.
Discussion
Diagnosing the cause of RPGN is crucial for early and effective treatment. However, etiologies can sometimes complicate or hinder the effective therapies.In this case, it was challenging to determine whether the FGN or IRGN was driving the patient’s progressive renal dysfunction.The relationship between the chronic infection and FGN was also unclear; that is, was the FGN secondary to recurrent osteomyelitis(Occam's razor), or were they independent, coexisting pathologies(Hickam's dictum).This distinction has significant therapeutic implications. Because our patient had refractory, partially treated infection, we deemed it unsafe to initiate immunosuppression for FGN and he was treated solely with antibiotics. His osteomyelitis, unfortunately, did not resolve, thus leading to a below-knee amputation. He remains on hemodialysis. This case illustrates the difficulties in managing RPGN when competing pathologies require diametrically opposite therapeutic strategies.