Kidney Week

Abstract: PUB137

Atrial Fibrillation to Crescentic Glomerulonephritis: Myeloperoxidase (MPO)-ANCA Vasculitis Unmasked

Session Information

• Publication Only

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Elrefy, Omar A., Jefferson Einstein Philadelphia Hospital, Philadelphia, Pennsylvania, United States

Omar A. Elrefy, MD

• Anwar, Amna, Jefferson Einstein Philadelphia Hospital, Philadelphia, Pennsylvania, United States

Amna Anwar, MD

• Ahmed, Zahoor, Jefferson Einstein Philadelphia Hospital, Philadelphia, Pennsylvania, United States

Zahoor Ahmed, MD

• Laroia, Aprajita, Jefferson Einstein Philadelphia Hospital, Philadelphia, Pennsylvania, United States

Aprajita Laroia, MD, MBBS

• Mubin, Fareeha, Jefferson Einstein Philadelphia Hospital, Philadelphia, Pennsylvania, United States

Fareeha Mubin, MD

• Gupta, Saurabh, Jefferson Einstein Philadelphia Hospital, Philadelphia, Pennsylvania, United States

Saurabh Gupta, MD

• Chewaproug, Daranee, Jefferson Einstein Philadelphia Hospital, Philadelphia, Pennsylvania, United States

Daranee Chewaproug, DO, FASN

• Saini, Manu Krishan Dev, Jefferson Einstein Philadelphia Hospital, Philadelphia, Pennsylvania, United States

Manu Krishan Dev Saini, MD

Introduction

ANCA-associated vasculitis (AAV) comprises a group of rare, potentially life-threatening autoimmune diseases, with a global incidence of approximately 17.2 per million person-years and a prevalence of ~198 per million. MPO-ANCA–associated vasculitis typically presents with multiorgan involvement in over 80% of cases; however, renal-limited AAV represents a distinct subset characterized by a lower relapse rate compared to systemic disease. Patients with ANCA-associated vasculitis have a significantly higher cumulative incidence of atrial fibrillation (16.4% vs. 11.5% in controls), with the greatest risk occurring within the first 90 days of diagnosis, suggesting that active systemic inflammation contributes to arrhythmogenesis.

Case Description

A 61-year-old man, recently diagnosed with atrial fibrillation and on apixaban, presented with acute kidney injury (serum creatinine 3.2 mg/dL, increased from 1.6 mg/dL one week prior) and a three-week history of low-grade fever. Urinalysis showed 11–20 red blood cells per high-power field, a urine protein-to-creatinine ratio of 1.4 g/g, and a serum albumin of 1.8 g/dL. An extensive infectious and immunological workup revealed low C4 levels, a total leukocyte count of 18,000/µL, a p-ANCA titer >1:640, and an MPO-ANCA level of 189.6 AI. Hemodialysis was initiated due to oliguria with volume overload. Kidney biopsy showed pauci-immune necrotizing and crescentic glomerulonephritis consistent with MPO-ANCA-associated vasculitis. Treatment with pulse steroids, plasmapheresis, cyclophosphamide, and rituximab resulted in significant clinical improvement.

Discussion

Unexplained AKI with microscopic hematuria warrants comprehensive immunological evaluation, even in the absence of classic systemic features. Early recognition and aggressive treatment with immunosuppression, and plasmapheresis in severe cases, may optimize renal outcomes.
Hematuria in anticoagulated patients should not be reflexively attributed to anticoagulation, particularly when accompanied by AKI and elevated systemic inflammatory markers.
Although AAV is classically pauci-immune, low C4 in this case suggests complement activation may occur independently of immune complex deposition. Additionally, new-onset atrial fibrillation with constitutional symptoms (e.g., low-grade fever) may indicate underlying systemic vasculitis before overt renal involvement.