Constrictive bronchiolitis in soldiers returning from Iraq and Afghanistan

Abstract

Background: In this descriptive case series, 80 soldiers from Fort Campbell, Kentucky, with inhalational exposures during service in Iraq and Afghanistan were evaluated for dyspnea on exertion that prevented them from meeting the U.S. Army's standards for physical fitness.

Methods: The soldiers underwent extensive evaluation of their medical and exposure history, physical examination, pulmonary-function testing, and high-resolution computed tomography (CT). A total of 49 soldiers underwent thoracoscopic lung biopsy after noninvasive evaluation did not provide an explanation for their symptoms. Data on cardiopulmonary-exercise and pulmonary-function testing were compared with data obtained from historical military control subjects.

Results: Among the soldiers who were referred for evaluation, a history of inhalational exposure to a 2003 sulfur-mine fire in Iraq was common but not universal. Of the 49 soldiers who underwent lung biopsy, all biopsy samples were abnormal, with 38 soldiers having changes that were diagnostic of constrictive bronchiolitis. In the remaining 11 soldiers, diagnoses other than constrictive bronchiolitis that could explain the presenting dyspnea were established. All soldiers with constrictive bronchiolitis had normal results on chest radiography, but about one quarter were found to have mosaic air trapping or centrilobular nodules on chest CT. The results of pulmonary-function and cardiopulmonary-exercise testing were generally within normal population limits but were inferior to those of the military control subjects.

Conclusions: In 49 previously healthy soldiers with unexplained exertional dyspnea and diminished exercise tolerance after deployment, an analysis of biopsy samples showed diffuse constrictive bronchiolitis, which was possibly associated with inhalational exposure, in 38 soldiers.

Figure 1. Characteristics and Outcomes of 80 Soldiers Referred for the Evaluation of Shortness of Breath on Exertion

Among the three soldiers in whom disorders other than those listed here were diagnosed, one had peribronchial scarring, one had an endobronchial stricture, and one had a necrotizing granuloma surrounded by normal lung parenchyma.

Figure 2. Constrictive Bronchiolitis, Arteriopathy, and Peribronchial Pigment Deposition

The photomicrographs show some of the pathological features seen in the 38 soldiers in whom constrictive bronchiolitis was diagnosed. The disorder was associated with subepithelial fibrosis (Panel A, arrow; hematoxylin and eosin), smooth-muscle hypertrophy (Panel B, arrow; hematoxylin and eosin), fibrosis between the epithelium and the muscle layer (Panel C, arrow; stained red with Masson's trichrome), smooth-muscle hypertrophy (Panel D, black arrow) with marked intimal fibrosis and medial hypertrophy of the adjacent pulmonary artery (white arrow) and peribronchiolar pigment deposition (arrowhead; hematoxylin and eosin), and smooth-muscle hypertrophy (Panel E, arrow) with adjacent pigment deposition (arrowhead; hematoxylin and eosin). Panel F shows the field shown in Panel E with the pigment refringent under polarized light.