Based on the theory of pneumatization, which originated in the study on the structure and reaction of the mastoid cells, a following new theory on the pathogenesis of bronchiectasis and emphysema is experimentally and theoretically proposed.
Both bronchiectasis and emphysema can be recognized as a repneumatization process following apneumatosis. Bronchiectasis is a manifestation of repneumatization of the pulmonary alveolar system under the condition of severe apneumatosis with organization, and emphysema is that of repneumatization under the condition of mild apneumatosis, in which alveolar epithelial cells are still remaining. In the former, reactive proliferation of the lung tissue occurs in the peripheral portion of the bronchioles, and in the latter, reactive proliferation takes a form of alveolar enlargement. Both are manifestations of active repneumatization in the lung, and the morphologic difference comes only from the difference of the apneumatic condition in the lung. Senile emphysema, however, is different from these secondary changes and it is due to physiological alveolar proliferation in the lung of the aged.
Currently, bronchiectasis and emphysema are considered as having two different pathogeneses, and the morphologic alteration is understood only by passive mechanism of the lung tissue. Challenging to these contemporary theories, we would like to introduce a new idea of active pneumatization as the pathogenesis of both bronchiectasis and emphysema.
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