Pneumomediastinum is the presence of air in the mediastinum, which can lead to pneumothorax, pneumoperitoneum, and pneumopericardium if left untreated in some cases, though that does not always happen and sometimes those conditions actually are the cause, not the result, of pneumomediastinum.
Pneumomediastinum is the presence of air in the mediastinum. The mediastinum can lead to pneumothorax, pneumoperitoneum, and pneumopericardium if left untreated in some cases, though that does not always happen. Those conditions actually are the cause of pneumomediastinum. The cause is not the result.