II. INTERLOBULAR OR EXTRA-VESICULAR EMPHYSEMA.
Interlobular or extra-vesicular emphysema is, as has been previously stated, an affection differing anatomically and pathologically from the form of disease already described. In the vesicular form air is present where it normally belongs, but in undue amount; in the interlobular form it is present where it ought not to be—that is, in the meshes of the connective tissue between the lobules, beneath the pleura, and around the bronchial tubes and pulmonary vessels. These situations may be reached by the air through a rupture of the vesicles, and thus in some cases vesicular may be associated with interlobular emphysema, the rupture having occurred from violent cough; or the emphysematous infiltration may be gaseous, as the result of gangrene occurring during life or of decomposition after death.
DIAGNOSIS.—The presence of air in the connective tissue of the lungs cannot be determined by any signs or symptoms; if, however, it should be discovered in the subcutaneous tissue of the neck, face, or chest, giving rise to puffiness and crackling of the integument, its presence in the areolar tissue of the lungs may be suspected, especially if there be coexisting vesicular emphysema, the air having passed into the mediastinum and thence into the tissue beneath the skin.
The existence of interlobular emphysema is not, in general, of serious significance, as the air commonly disappears from the subcutaneous tissue in a few days; whence it may be inferred that it likewise disappears from the connective tissue of the lung, the opening which had admitted it there having become closed. If present in large amount in the lung-substance, it may, however, increase the difficult breathing of an emphysematous subject by compressing a number of the air-vesicles. Or, again, if the interstitial emphysema be subpleural, the bulla may burst, and the air, escaping into the cavity of the chest, may occasion pneumothorax, or even hydro-pneumothorax, from the resulting inflammation. Such an occurrence is, however, very uncommon.
Even when the diagnosis of interlobular emphysema is established, no treatment is needed or practicable.
COLLAPSE OF THE LUNG (ATELECTASIS).
BY SAMUEL C. CHEW, M.D.