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Kidney Week

Abstract: TH-PO137

A Rare Case of PR3-ANCA Vasculitis in the Setting of Mycobacterium Avium Complex (MAC) Infection

Session Information

  • AKI: Mechanisms - I
    November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Kaur, Gurpreet, Alameda Health System, Oakland, California, United States
  • Bapat, Manasi, Alameda Health System, Oakland, California, United States
Introduction

Anti-neutrophilic cytoplasmic antibody (ANCA) associated vasculitis is the most common systemic small vessel vasculitis to occur in adults. While the etiology is not always known, a variety of possible associations between infection and vasculitis have been reported. We present a case of PR3-ANCA vasculitis in the setting of Mycobacterium Avium Complex (MAC) infection.

Case Description

A 66-year-old man with history of Parkinson’s disease and well controlled childhood asthma was admitted to the intensive care unit with acute dyspnea, fever and cough and was found to have ground-glass opacities throughout the right lung on CT chest. Given pulmonary infiltrates and history of sinusitis, ANCA titers were sent. Titers showed elevated c-ANCA titers 1:640 (normal <1:20), Proteinase 3 Ab > 100U/ml (normal 0 to 3.5 U/ml) and negative Myeloperoxidase. During hospitalization, he developed an AKI with creatinine increasing from 0.95 to 1.45 mg/dL (normal 0.50-1.30mg/dL) and microscopic hematuria. Kidney biopsy showed pauci-immune crescentic glomerulonephritis. Given kidney biopsy findings in the setting of elevated c-ANCA, the diagnosis of granulomatosis with polyangiitis (GPA) was made. Patient was started on induction therapy with Rituximab and high-dose steroids. Cultures obtained from bronchoscopy later returned positive for Mycobacterium Avium Complex (MAC). Given that the patient’s respiratory symptoms had completely resolved, antimicrobial therapy for MAC was not initiated and patient was subsequently initiated on Rituximab based maintenance therapy for ANCA vasculitis. Patient achieved remission of hematuria as well as improvement in lung radiological findings with normalization of ANCA titers.

Discussion

Pulmonary infection may trigger vasculitis through induction on ANCA antigen expression on the surface of neutrophils. ANCA associated vasculitis (AAV) secondary to MAC is very rare and only a few cases have been reported so far. Kidney involvement in AAV is typically with rapidly progressive glomerulonephritis (RPGN) however our patient only had transiently elevated creatinine with hematuria without RPGN. Our case highlights the importance of considering AAV and testing for ANCA in a patient with hematuria and pulmonary symptoms even in the absence of characteristic RPGN.