Pneumomediastinum in blunt trauma: A review

Pneumomediastinum (PM) is an uncommon finding after blunt trauma to the neck or chest. Motor vehicle collisions are the most common cause in adults, while falls are the most common in children. The majority of traumatic PM results from medial tracking of air from a concomitant pneumothorax. The Macklin effect, of air tracking medially along peribronchial sheaths from alveolar rupture, is responsible for most other cases. Chest pain is the most common symptom, and crepitus the most common sign. The majority of PM will resolve spontaneously, and requires no specific intervention. Only 1—6% of cases result from rupture of the larynx, trachea, bronchi or oesophagus. Hoarseness, dyspnea, persistent lung collapse or air leak should increase suspicion for aerodigestive injury. Computed tomography (CT) can help differentiate benign etiology from those that require surgical correction. High suspicion for aerodigestive injury based on clinical and/or CT findings should prompt diagnostic bronchoscopy and/or oesophagram.