Interstitial reactions of the lungs in chronic bronchitis as viewed in the differential diagnostic aspect

Interstitial reactions in chronic bronchitis consist of edema, swelling, fibrillary untwining and thickening of fibrous interlayers lying along the circumference of the large and medium calibre bronchi, vessels, lobules and segments of the lung. Macroscopically and roentgenographically these changes appear in the form of an intensified pulmonary pattern that It not accord with the notion of interstitial pneumonia, for this type of interstice lies outside the alveolar tissue, has a scant capillary bed and, therefore, cannot serve as a source for the development of inflammation. From interstitial pneumonia or infiltrative peribronchioliths and peribronchitis, that stem from an inflammatory infiltration of the capillary bed in the alveolar septa or the whole of the bronchilar wall thickness, the inflammation passes to the ambient alveolar tissue. In this process the barrier-air-blood becomes involved. Macroscopically and roentgenographically this process is not demonstrable, unless it is attended by exudative pneumonia with dystonia of the myoelastic stroma in the respiratory bronchioles manifesting itself in the form of contractile atelectases and focal emphysema.