Pneumomediastinum. A report of 28 cases and review of the literature

Pneumomediastinum is an entity in which free air is found within the mediastinum. It occurs principally in healthy young men and parturient women and is found most frequently without apparent precipitatory cause. Functionally, however, alveolar hyperpressure, pulmonary capillary hypotension, or aveolar wall defects on a localized basis may occur as a result of, or may be associated with an acute, transient, respiratory obstruction, a type found most commonly in parturition, simple cough, emesis, or asthma. The most common symptoms are pain and dyspnea. Fever and leukocytosis without apparent infection are also frequently encountered. With obvious extrathoracic sources of mediastinal air excluded, the criteria for the diagnosis of pneumomediastinum should include the combination of roentgenographic free mediastinal air and subcutaneous emphysema.