Pneumomediastinum

Excerpt

Pneumomediastinum is defined as air present in the mediastinum and less frequently referred to as mediastinal emphysema. The mediastinum is the space in the central thorax bounded laterally by the parietal pleura of the lungs, superiorly by the thoracic outlet, inferiorly by the diaphragm, anteriorly by the sternum, and posteriorly by the thoracic vertebral column. Vital structures, such as the heart, tracheobronchial tree, and the esophagus, reside within the mediastinum. Pneumomediastinum develops when air extravasates from within the airways, lungs, or esophagus and migrates into the mediastinal space. Extravasated air may then dissect contiguously into the neighboring cervical subcutaneous tissues, epidural space, pericardium, or the peritoneal cavity. As a clinical entity, pneumomediastinum is rare and typically self-limited. Once diagnosed and serious concomitant pathology excluded, management is largely focused on symptomatic treatment.