Bronchiolitis Obliterans
Bronchiolitis obliterans (BO) is a general term used to describe widespread inflammatory or fibrotic obstruction of small airways, resulting in progressive occlusion.
Bronchiolitis obliterans may be idiopathic with or without organizing pneumonia; it may also follow infection or inhalation of toxic fumes or be associated with connective tissue disease, organ transplantation, or lung lesions.
In young pediatric patients, BO may follow severe viral infections, especially due to measles and adenoviruses. After a transient remission, the disease progresses to chronic respiratory failure. Prognosis depends upon early diagnosis and aggressive treatment.
Pulmonary function tests show largely irreversible airflow obstruction and reduced total lung capacity. Impaired gas exchange, hypoxemia, and hypocapnia are typical complications of BO.
Clinical manifestations of BO commonly include sputum hypersecretion and productive cough, followed by progressive dyspnea. In pediatric patients and in adults with advanced disease, secretion retention exacerbates complications.
Retained secretions provide a culture medium for bacterial pathogens. Consequent infections produce still more mucus, initiating a vicious cycle of mucus obstruction, recurrent bouts of pneumonia, bacterial colonization and, finally, respiratory failure.
In addition to measures to treat underlying causes and to manage infection, treatment of patients with BO must include aggressive bronchial hygiene, including daily airway clearance therapy. Such therapy is recognized as an essential component in managing and minimizing the obstruction, infection, and inflammation which contribute significantly to medical care costs, morbidity, and mortality in afflicted individuals.
Sources
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