Pneumomediastinum Due to Indirect Blunt Chest Trauma, Diagnostic Challenge and Understanding of Pathophysiology

Pneumomediastinum, also known as mediastinal emphysema, refers to collection of air in the mediastinum. Pneumomediastinum is reported in up to 10% of patients with severe blunt chest trauma (1,8). Although injury to the tracheobronchial tree is assumed to be the commonest aetiology, it has been reported in only less than 10% of patients (2). In most cases, the cause of pneumomedi astinum after blunt trauma remains obscure. A recent paper attributed the cause to what is known as the Macklin effect (2). Although CT scanning remains the gold standard to identify the aetiology and the extent of the injury, bronchoscopy and upper gas¬trointestinal endoscopy may be needed to rule out other injuries. We report a case of mediastinal emphysema due to blunt trauma in which we discuss the possible aetiology, investigations, differential diagnosis and management.