DIAGNOSIS, MANAGEMENT, AND OUTCOMES IN BIOPSY PROVEN BRONCHIOLITIS

Abstract

TOPIC: Diffuse Lung Disease TYPE: Original Investigations PURPOSE: Bronchiolitis refers to a variety of inflammatory diseases affecting the small airways. Patients usually present with subtle symptoms including shortness of breath, cough or wheezing, often misdiagnosed as asthma. We performed a retrospective review to describe diagnostic characteristics, treatment patterns, and outcomes of biopsy-proven bronchiolitis METHODS: We searched the electronic medical records of the Advanced Lung Disease Clinic at Baylor University Medical Center. We examined charts of patients with VATS biopsy-proven bronchiolitis between Feb 2001 and February 2021. Cases that developed following bone-marrow or solid organ transplant were excluded RESULTS: Forty patients met criteria. The median age was 61(±9), and 90% were female. 45% of patients had a history of smoking. The most common presenting symptom was shortness of breath, followed by cough. More than half of the patients were treated for asthma prior to diagnosis of bronchiolitis. 50% of patients had airflow limitation noted on spirometry, defined as an FEV1/FVC < 0.7, 40% had FVC< 60%. Fifty percent of subjects had no positive connective tissue disease serologies; the remainder had positive rheumatoid factor (12), ANA (6), anti-RNP (3), anti-Scl-70 (2). ESR and CRP was elevated in 50% of the patients. High-resolution computed tomography was available in 36 patients. The most commonly identified abnormalities were: air trapping (80%), ground-glass opacities (22%), centrilobular nodules (32%), and pleural abnormalities (22%). Forty percent of patients underwent bronchoscopy with bronchoalveolar lavage. Lymphocytosis (defined as >15%) was noted in 5 patients (31%) and eosinophilia (defined as >1%) was noted in 4 patients (10%). Lung pathology revealed constrictive bronchiolitis in 33 patients (83%), follicular bronchiolitis in 7 (17%), organizing pneumonia in 7 (17%), and granulomas in 5 (10%) patients. Fourteen (35%) patients were treated with azithromycin, 6 (15%) with oral prednisone, 16 (40%) with mycophenolate mofetil (MMF), 1 (2.5%) with azathioprine, and 1 (2.5%) with rituximab. Seven (50%) patients on azithromycin and 8 (50%) patients on MMF had spirometric improvement (defined as > 10% improvement in FVC at 6-month follow-up spirometry). Two underwent lung transplantation, and three patients died. The rest of the patients were treated with inhaled bronchodilators or inhaled steroids. Most of the patients remained stable at 6 months follow up, one had decline in FVC by 10%. Follow-up PFTs were missing in five of the patients. CONCLUSIONS: Bronchiolitis is often misdiagnosed as asthma before a definitive pathologic diagnosis is made, and so a high index of suspicion is important in patients who do not respond to usual asthma therapies. The most common imaging finding was air trapping, and lung function testing most commonly indicated restriction or a mixed obstructive and restrictive pattern. The most common pathologic finding was constrictive bronchiolitis. No significant difference in outcome noted in patients on immunosuppression or macrolides compared to not on any treatment. Patients with follicular pathology tend to do better compared to constrictive pathology. CLINICAL IMPLICATIONS: Bronchiolitis is often misdiagnosed as asthma before a definitive pathologic diagnosis is made, and so a high index of suspicion is important in patients who do not respond to usual asthma therapies. DISCLOSURES: No relevant relationships by Susan Mathai, source=Web Response no disclosure on file for Mark Millard; No relevant relationships by Joon Yong Moon, source=Web Response No relevant relationships by Sofiya Rehman, source=Web Response No relevant relationships by Ciara Wisecup, source=Web Response