Table of contents
Bronchiolitis obliterans syndrome
What's new
Updated 2024 ATS guidelines for the diagnosis of bronchiolitis obliterans syndrome after pediatric hematopoietic stem cell transplantation.
Background
Overview
Definition
BOS is a form of chronic lung allograft dysfunction characterized by progressive airflow obstruction in the absence of acute rejection, infection, or other coexistent conditions.
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Pathophysiology
BOS is caused by immune-mediated injury (alloimmune T-cell reactivity, humoral immunity, autoimmunity, pulmonary innate immunity) and environmental insults.
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Disease course
BOS manifests as progressive dyspnea and cough, with imaging features of constrictive bronchiolitis, airway distortion, and subepithelial fibrosis.
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Prognosis and risk of recurrence
Severe BOS is associated with a mortality of 66.6%.
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Guidelines
Key sources
The following summarized guidelines for the evaluation and management of bronchiolitis obliterans syndrome are prepared by our editorial team based on guidelines from the American Thoracic Society (ATS 2024), the European Respiratory Society (ERS/EBMT 2024), the British Thoracic Society (BTS 2020), and the European Respiratory Society (ERS/ATS/ISHLT 2014).
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Screening and diagnosis
Pre-transplant evaluation, spirometry: as per ATS 2024 guidelines, obtain pre-HSCT spirometry, assessment of static lung volumes, and DLCO in pediatric patients able to perform them.
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Pre-transplant evaluation (multiple breath washout)
Pre-transplant evaluation (chest CT)
Post-transplant surveillance
Diagnostic investigations
Multiple breath washout: as per ATS 2024 guidelines, consider obtaining multiple breath washout as part of post-HSCT diagnostic evaluation of suspected BOS, either as a complementary tool to spirometry or alone if spirometry is not feasible, at centers with adequate technical expertise to perform multiple breath washout.
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Chest CT
Diagnostic procedures
Bronchoalveolar lavage: as per ATS 2024 guidelines, consider performing bronchoscopy with bronchoalveolar lavage to assess for infection as part of the BOS evaluation.
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Lung biopsy
Medical management
High-dose corticosteroids: as per ATS/ERS/ISHLT 2014 guidelines, do not use long-term, high-dose corticosteroids in lung transplant recipients with a decline in FEV1 consistent with the onset of BOS.
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Tacrolimus
Azithromycin
Surgical interventions
Fundoplication: as per ATS/ERS/ISHLT 2014 guidelines, consider referring lung transplant recipients with a decline in FEV1 consistent with the onset of BOS and having confirmed gastroesophageal reflux to an experienced surgeon to evaluate for potential fundoplication of the GEJ.
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Re-transplantation