B47-40 Bronchiectasis as the Sentinel Manifestation of Anca-Associated Vasculitis: A Seven-Year Diagnostic Journey

Intro Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) typically presents with systemic features such as pulmonary hemorrhage, nodules, or glomerulonephritis. Bronchiectasis, when present, is usually considered a sequela rather than a harbinger of vasculitic disease. We present a case of chronic, culture-negative bronchiectasis that preceded the diagnosis of AAV by over six years, underscoring the potential for airway-predominant vasculitis as an early manifestation of systemic disease. Description A 74-year-old woman was followed longitudinally for recurrent bronchiectasis exacerbations characterized by productive cough and tree-in-bud nodularity on serial CT scans beginning in 2018. Repeated infectious evaluations, from cultures obtained from both sputum and bronchoalveolar lavage samples, remained negative. Over the years, she experienced intermittent symptomatic improvement with steroids and macrolides, but her imaging gradually demonstrated progression from localized right middle lobe bronchiectasis to multifocal disease with mucus plugging and parenchymal nodules.In March 2025, she presented with hematuria, blood-tinged sputum, and purpura. Laboratory studies revealed acute kidney injury and positive perinuclear ANCA (p-ANCA). Renal biopsy demonstrated pauci-immune crescentic glomerulonephritis with 7% active crescents and acute tubular injury. She was diagnosed with AAV with pulmonary and renal involvement and initiated on rituximab and corticosteroids with subsequent clinical improvement. Discussion This case highlights bronchiectasis as a potential sentinel manifestation of ANCA-associated vasculitis (AAV), preceding systemic involvement by several years. The progression from localized airway disease to systemic vasculitis suggests a shared inflammatory pathway between chronic neutrophilic airway inflammation and ANCA-mediated vascular injury, supported by recent retrospective analyses. Notably, several studies describe bronchiectasis preceding overt vasculitis, raising the hypothesis that the respiratory tract may serve as a site of initiation of anti-myeloperoxidase (MPO) autoimmunity. Chronic airway neutrophilic inflammation and structural damage may expose or modify autoantigens such as MPO, promoting ANCA generation through persistent immune activation. Our patient’s six-year history of culture-negative, steroid-responsive bronchiectasis aligns with this proposed airway-first phenotype of AAV. Clinicians should maintain a high index of suspicion for vasculitis in refractory, culture-negative bronchiectasis—particularly when accompanied by extrapulmonary findings such as purpura, hematuria, or renal dysfunction. Early immunologic evaluation in these scenarios may reduce diagnostic delay and prevent irreversible organ damage. Conclusion This case underscores the need for early immunologic evaluation in unexplained bronchiectasis and expands the spectrum of pulmonary-limited AAV. Longitudinal imaging and clinical follow-up demonstrate the evolution of airway-predominant disease into a systemic vasculitic process, emphasizing the value of multidisciplinary recognition before irreversible organ damage occurs.