Radiology Teaching Files > Case 10219960

Contributed by: Radiology Residency Program Faculty & Staff, Northeastern Ohio Universities College of Medicine-Canton Affiliated Hospitals, Ohio, USA.
Patient: 67 year old male
History: 68 y M was on ventilator. He developed acute respiratory distress and hypoxia.

Fig. 1: Bilateral PTX. Peumomediastinum is seen inferior to the diaphramatic surface of the heart.

Fig. 2: Pneumomediastinum is seen as 'continuous diaphram sign'.
Findings: As image legends.
Discussion: Pneumomediastinum

    • Air in the mediastinal space
      • Most common in infants
      • Rare in adults except in ICU patient!!
        • Result of trauma
          • Rupture of esophagus
          • Rupture of airways
    • Air in mediastinum originates from
      • Lung
        • Most common mechanism in neonates and adults
          • Begins with rupture of alveolus
            • Usually from increased intraparenchymal pressure
          • Air dissects back along perivascular sheaths to hilum and mediastinum
        • Air from ruptured bleb can also extend peripherally into pleural space
          • Pneumothorax
        • Most instances can be related to sudden rise in intrapulmonary pressure
          • Asthma
          • Vomiting
          • Valsalva maneuver
          • Artificial ventilation
          • Closed chest trauma
          • Sudden drop in atmospheric pressure
      • Mediastinal airways

        • Rupture of trachea or mainstem bronchus

          • Usually produced by accidental trauma

      • Esophagus

  • §         Rupture of the esophagus – Boerhaave’s Syndrome             

    §         Can occur with

          • Vomiting

          • Labor
          • Severe asthmatic attacks
          • Strenuous exercise (each of these can produce pneumomediastinum without rupturing the esophagus)
          • Site of perforation
            • Left, posterolateral wall, distal 8 cm


  • Imaging findings


    • Linear density parallel to heart border
      • Separated from heart by air
    • Also ring lucency around aorta or pulmonary artery
      • “Ring around the artery” sign
    • Dissection of air into neck is much less common in infants than adults
    • Dissection into chest wall much less common in neonates than older
    • Air can outline the central portion of the diaphragm
    • “Continuous diaphragm sign”

    • Clinical Findings
      • Abrupt onset of retrosternal pain
        • Usually preceded by episode of vomiting
        • Pain is worse on inspiration
        • Dyspnea could be severe
      • Hamman’s sign – crunching sound heard over the apex of the heart with cardiac cycle
No comments posted.
Additional Details:

Case Number: 10219960Last Updated: 2007-08-20
Anatomy: Chest   Pathology: Iatrogenic
Modality: Conventional RadiographAccess Level: Readable by all users

The reader is fully responsible for confirming the accuracy of this content.
Text and images may be copyrighted by the case author or institution.
You can help keep MyPACS tidy: if you notice a case which is not useful (e.g. a test case) or inaccurate, please contact us.