Obliterative Bronchiolitis

Abstract

Obliterative bronchiolitis (OB) is a clinical syndrome marked by progressive dyspnea and cough with the absence of parenchymal lung disease on radiographic studies. Pulmonary function testing reveals an obstructive ventilatory defect that is typically not reversed by inhaled bronchodilator. Transbronchial biopsies are insufficiently sensitive to achieve diagnosis, and in most cases, clinical, physiological, and radiological data obviate the need for the increased risk associated with open lung biopsy. This diagnosis has been documented in a variety of exposures, including fumes from flavoring plants, smoke from burn pits, and environmental sulfur gas. Among lung transplant recipients, "bronchiolitis obliterans syndrome," a disorder with clinical and histopathological similarity to OB, represents the leading cause of long-term allograft dysfunction and mortality. After hematopoietic stem cell transplantation, chronic graft versus host disease of the lung manifests most frequently with similar clinical and pathological features. In all circumstances, immunologic and nonimmunologic mechanisms are thought to lead to airway epithelial dysfunction, which results in progressive airflow obstruction and debility. Augmentation of immunosuppression is occasionally effective in slowing or reversing the progression of disease though a significant number of patients will be nonresponders. Other immunomodulatory methods have been attempted in each circumstance where this pathology has been identified. Unfortunately, OB is poorly understood and often results in sufficient progression of disease to warrant evaluation for lung transplantation (or retransplantation). Here, we review what is known regarding pathophysiology and discuss clinical, pathological, radiological, and therapeutic factors associated with the spectrum of OB-related disease with a particular focus on lung transplantation.

Azithromycin for the Treatment of Obliterative Bronchiolitis after Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-Analysis

“…The risk factors, initial evaluation and therapeutic options for patients who develop OB/BOS following HSCT have been recently reviewed elsewhere 11, 23 . Unfortunately, no therapeutic options have been shown to consistently improve symptoms, lung function or survival in patients with OB/BOS.…”

“…Reference lists of included studies and recent comprehensive narrative reviews were reviewed 11, 23 . The search was conducted from database inception and last updated on June 28, 2016.…”

Association Between Promoter Polymorphisms in CD46 and CD59 in Kidney Donors and Transplant Outcome

“…A potential explanation for the opposite effect of this SNP in kidney and lung transplantation could apply to the timing of the effect and the fact that acute and chronic rejection (including BOS) are two distinct entities ( 43 – 45 ). Chronic rejection is a much more multifactorial process requiring multiple hits, resulting in gradual parenchymal fibrosis and obliterative vasculopathy and progressive graft dysfunction ( 43 , 46 ), whereas acute rejection is identified by cellular and humoral attack resulting in rapid graft damage when untreated ( 43 , 47 ). In our kidney transplant cohort, the observed effect of the CD59 promoter SNP occurred in the first weeks posttransplantation without an effect thereafter.…”

Constrictive bronchiolitis presenting with a mixed obstructive and restrictive pattern, associated with acid reflux

“…Chest radiography can often be normal and chest CT may or may not show air trapping, bronchial wall thickening or mosaic attenuation 6. Due to the sporadic nature of the inflammation and fibrosis in CB, a transbronchial biopsy is insufficiently sensitive to make the diagnosis 10. Thus, an open lung biopsy is the only way to definitively diagnose CB 3…”