Constrictive bronchiolitis attributable to inhalation of toxic agents: Considerations for a case definition

Objective: We identified cases of constrictive bronchiolitis (CB), an inflammatory injury obliterating the small airways, in adults caused by inhalational exposure to determine an appropriate case definition. Methods: We performed a systematic review with meta-analysis for these cases from 1990 to 2017. Publications were included if there was 1) inhalational exposure; 2) respiratory symptoms/signs; 3) pulmonary function test results; and 4) computerized tomographic chest imaging. Many had a lung biopsy. Results: Two hundred seventy-four articles were retrieved; 22 manuscripts comprising 102 cases were included. Diagnostic criteria from cases associated with military deployment to southwest Asia were statistically different from criteria of other etiologies. Conclusion: In three cases, the scan was consistent with CB, the biopsy nondiagnostic, yet the diagnosis was made. CB associated with military deployment presented with diagnostic features statistically different from features in the other cases.