Bronchiolitis obliterans (BO) is generally thought to be a marker of chronic airway rejection in patients who have undergone lung transplantation. Bronchoscopic biopsy specimens, by virtue of their small size, may sample only BO and not a lesion of bronchiolitis obliterans organizing pneumonia (BOOP). A role for ongoing chronic infection or aspiration has also been suggested, and the distinction of these etiologies may be difficult clinically and pathologically.
To investigate the etiology of BO and BOOP in lung transplantation patients who had chronic aspiration.
This is a clinicopathologic study of 7 patients who had undergone lung transplantation in which biopsy findings suggested the possibility of chronic airway rejection but in which aspiration was subsequently proven as a cause of the bronchiolar disease.
All patients were men, who ranged in age from 19 to 57 years. A clinical diagnosis of aspiration was considered based on history, acid reflux testing, and radiographic findings in all 7 patients. Three patients had BO and 4 patients had BOOP. Histiocytic giant cells or foreign material was absent. The interval from transplantation to BO ascribed to aspiration ranged from 2.5 months to 7 years. The patients were treated aggressively with medication for gastroesophageal reflux disease. Their respiratory function and chest radiography results improved.
Although BO may be a manifestation of rejection, it may also be a manifestation of aspiration. Because the latter is potentially correctable, aspiration should be considered etiologically in lung transplantation patients with either BO or BOOP. Reliable distinction between aspiration-related or rejection-related BO and BOOP cannot be made on morphologic grounds alone. Clinical and radiologic correlations are indicated to establish the distinction.