[Infection--clinico-pathological profile of diffuse aspiration bronchiolitis (DAB)]

In order to investigate the clinico-pathological profile of the inflammatory disease of the intermediate zone of broncho-pulmonary system, a retrospective study was conducted in consecutively autopsied cases at Tokyo University Hospital (n = 495) and Tokyo Metropolitan Geriatrics Center Hospital (n = 1178). We analyzed clinical findings, laboratory tests, pulmonary function tests and chest roentgenograms. In addition, morphologic changes were assessed semiquantitatively as to the grade as well as the localization of inflammation in the lungs. Aspiration pulmonary diseases were found in 7% of all autopsied cases and diffuse aspiration bronchiolitis (DAB) was observed in 16% (1% of all cases). Macroscopic findings of DAB in an autopsied lung were similar to those found in diffuse panbronchiolitis (DPB). The clinical symptoms and tests were, however, a complex mixture of DPB and aspiration pneumonia. As a result, differential diagnosis of bronchial asthma in the elderly among aspiration pulmonary diseases seemed crucial for the proper management of DAB. Histologic findings of DAB were characterized by more predominant localization of inflammation in bronchioli and the invariable presence of foreign body or related giant cells in this region of the lungs. In view of these findings, the occurrence of DAB might be related to recurrent aspiration of small amounts with superimposed infection of the airways.