Acute pulmonary interstitial and mediastinal emphysema (airblock) and pneumothorax in infancy and early childhood

D URING acute and chronic disease of the respiratory tract, or states of excessive strain on the pulmonary apparatus, or following trauma, air may suddenly escape under pressure from the alveolar structures into the interstitial tissues of the lungs, the mediastinum, their fascial extensions, and the pleural spaces. The mechanism leading to the production of the resulting pulmonary interstitial and mediastinal emphysema, or airblock, and of pneumothorax has been described by Hamman 1' ~ and by the Macklins2, 4 The condition may develop unsuspectedly in infants and children, and may be exhibited clinically only by persistent dyspnea and cyanosis of a severity not accounted for by physical signs on examination. Roentgenography of the chest may provide the initial clue to the presence of extravasations of air that underlie the acute respiratory and circulatory embarrassment. To illustrate this sequence of events and to demonstrate some representative .causes of airblock, the following case histories are presented.