Consensus Statements on Deployment-Related Respiratory Disease, Inclusive of Constrictive Bronchiolitis: A Modified Delphi Study

Abstract

Background: The diagnosis of constrictive bronchiolitis (CB) in previously deployed individuals, and evaluation of respiratory symptoms more broadly, presents considerable challenges, including using consistent histopathologic criteria and clinical assessments.

Research question: What are the recommended diagnostic workup and associated terminology of respiratory symptoms in previously deployed individuals?

Study design and methods: Nineteen experts participated in a three-round modified Delphi study, ranking their level of agreement for each statement with an a priori definition of consensus. Additionally, rank-order voting on the recommended diagnostic approach and terminology was performed.

Results: Twenty-five of 28 statements reached consensus, including the definition of CB as a histologic pattern of lung injury that occurs in some previously deployed individuals while recognizing the importance of considering alternative diagnoses. Consensus statements also identified a diagnostic approach for the previously deployed individual with respiratory symptoms, distinguishing assessments best performed at a local or specialty referral center. Also, deployment-related respiratory disease (DRRD) was proposed as a broad term to subsume a wide range of potential syndromes and conditions identified through noninvasive evaluation or when surgical lung biopsy reveals evidence of multicompartmental lung injury that may include CB.

Interpretation: Using a modified Delphi technique, consensus statements provide a clinical approach to possible CB in previously deployed individuals. Use of DRRD provides a broad descriptor encompassing a range of postdeployment respiratory findings. Additional follow-up of individuals with DRRD is needed to assess disease progression and to define other features of its natural history, which could inform physicians better and lead to evolution in this nosology.

Keywords: Delphi technique; bronchiolitis; dyspnea; environmental exposure; military deployment.

Figure 1

Study flow diagram of the modified Delphi technique used in this study.

Figure 2

Diagram showing recommended complexity level (1-3) and location (standard or specialty referral center) of diagnostic assessments for the deployed individual seeking treatment with unexplained respiratory symptoms. BD = bronchodilator; CPET = cardiopulmonary exercise test; Environ-Occup = environmental and occupational; HRCT: high-resolution CT; Qx = questionnaire.

Figure 3

Illustration showing reported features of deployment-related respiratory disease (DRRD). A variety of changes within the respiratory system have been reported in previously deployed individuals with respiratory symptoms^,,, that we subsume under the overarching term deployment-related respiratory disease. Diagnoses consistent with DRRD can be identified via functional physiologic testing and imaging (anatomic right), whereas other findings are identified in pathologic specimens obtained by more invasive procedures (anatomic left). Finally, dyspnea or other respiratory symptoms may be the result of nonrespiratory conditions or may persist in the absence of any clearly correlated physiologic, imaging, or pathologic findings.