Pneumomediastinum

The presence of free air or gas within the mediastinum, usually resulting from disruption of alveolar, tracheobronchial, or esophageal structures. It may progress to tension pneumomediastinum.

Causes

• Increased intrathoracic pressure

  • Airway obstruction

  • Asthma exacerbation

  • Chronic obstructive pulmonary disease (COPD)

  • Severe coughing

  • Forceful sneezing

  • Vomiting

  • Weightlifting

  • Valsalva maneuver

  • Childbirth

• Traumatic causes

  • Blunt chest trauma

  • Penetrating chest trauma

  • Tracheobronchial injury

  • Esophageal rupture

  • Facial or neck trauma

• Iatrogenic causes

  • Mechanical ventilation

  • Bronchoscopy

  • Upper gastrointestinal endoscopy

  • Chest surgery

  • Abdominal surgery

  • Central venous catheter placement

  • Other invasive thoracic procedures

• Barotrauma-related causes

  • Scuba diving

  • High-altitude flying

  • Rapid changes in ambient pressure

• Inhalational drugs associated with forceful inhalation

  • Marijuana

  • Crack cocaine

• Pneumothorax with mediastinal air extension