Abstract: SA-PO0867
When the Tubulointerstitium Speaks: A Rare Renal Manifestation and Outcome of Myeloperoxidase-ANCA-Associated Vasculitis
Session Information
- Glomerular Case Reports: ANCA, IgA, IgG, and More
November 08, 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
- Sharawi, Said, Marshall University, Huntington, West Virginia, United States
- Khabbaz, Omar, Marshall University, Huntington, West Virginia, United States
- Satoskar, Anjali A., The Ohio State University, Columbus, Ohio, United States
- Khitan, Zeid, Marshall University, Huntington, West Virginia, United States
Introduction
Antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV) typically manifests as pauci-immune crescentic glomerulonephritis with rapidly progressive renal dysfunction. However, isolated tubulointerstitial nephritis (TIN) without glomerular involvement is a rare presentation. This form is characterized by interstitial inflammatory infiltrates, edema, and fibrosis, often affecting elderly patients. We present a rare case and outcome of Myeloperoxidase (MPO)-ANCA-associated interstitial nephritis without glomerular lesions.
Case Description
A 71-year-old female with DM2, CKD stage 3a presented with pleuritic chest pain, dyspnea, cough with yellow sputum, chills, fatigue, nausea, headaches, lower limb edema, blanching nonpainful petechiae on extremities and dark urine with reduced urine output. Labs were significant for creatinine of 3.4 from 1.3 a month earlier, BUN 54, positive P-ANCA and MPO, low C4, elevated RF. Active UA. Rest of serology, blood and sputum cultures were negative. Negative renal US. CT chest showed severe bilateral pulmonary infiltrations with pleural effusions, no lymphadenopathy. Normal Echo. Kidney biopsy showed widespread interstitial granulomatous inflammation with giant cells, geographic necrosis, necrotizing vasculitis, negative IF and EM. She had dialysis and 5 plasmapheresis sessions. The treatment regimen was pulse steroids, taper and Rituximab. Skin lesions resolved. Patient died from a cerebral hemorrhage despite no hypertension.
Discussion
This is one of several reported cases where MPO-AAV shows up as isolated TIN, with no glomerular involvement.
Clinically, isolated TIN cases tend to have a milder course than AAV glomerulonephritis, with lower serum creatinine, less hematuria and low proteinuria. The pathophysiology underlying this atypical presentation remains unclear.
Due to its rarity, standardized diagnostic and treatment protocols are lacking. However, these cases have shown favorable responses to immunosuppressive therapy, often requiring lower doses. This highlights the importance of recognizing atypical presentations of AAV with tubulointerstitial disease and the need for further research to clarify the disease mechanism and optimize treatment strategies.