Pneumomediastinum

Fig. 1: A chest radiograph of a 29-year-old man with severe vomiting shows subtle streaks of lucencies in the mediastinum (along the left heart border - arrows), and into the cervical region (arrowheads).
Fig. 2: Coronal-reformatted chest CT image confirms the presence of pneumomediastinum (arrows) and cervical emphysema (arrowheads). A small left pneumothorax is noted on CT (not shown). No esophageal, tracheal or major broncheal perforation was noted on esophagoscopy and bronchoscopy.

Radiographic Findings of Pneumomediastinum (= normal mediastinal structures outlined by air)

• Thymic sail sign
• Pneumoprecardium (lateral chest radiograph)
• Ring around the artery sign
• Tubular artery sign
• Continuous diaphragm sign

Sources of Pneumomediastinum

• Intrathoracic: trachea, major bronchi, esophagus, lungs, pleural space
• Extrathoracic: head and neck (sinus), intraperitoneum and retroperitonum (hollow viscus)

In our case, pneumomediastinum was presumed to be due to alveolar rupture from severe vomiting.

Reference:
Zylak CM, Standen JR, Barnes GR, Zylak CJ. Pneumomediastinum revisited. Radiographics 2000;20:1043-1057.