The pericardial cavity in this image is labeled d and is part of the inferior mediastium. Here we can see its relation to the superior mediastinum a, the pleural cavities c, and the diaphragm e.
Anatomy of the pericardium.
  • Air in the pericardium
  • Generally secondary to connection between pericardium and pleural cavity, bronchi, or GI tract
  • Most often found following trauma, severe asthma exacerbation, strangulation, or forceful drug insufflation

Causes of pneumopericardium

Clinical Features

Differential Diagnosis

Thoracic Trauma


Lucent line around the heart extending up to the main pulmonary arteries (solid white arrows). Air may accumulate inferior to the cardiac shadow, which crosses the midline above the diaphragm (i.e. continuous diaphragm sign)
Pneumopericardium on chest x-ray after battery button ingestion.
CT showing tension pneumopericardium, subcutaneous emphysema, bilateral pneumothorax, and a compressed heart.
  • Assess for underlying cause
  • CXR[1]
    • Heart partially or completely surrounded by gas
    • Pericardium sharply outlined by gas density on either side
    • Continuous diaphragm sign may be present (diaphragm seen continuously across the midline
  • PoCUS[2]
    • Bright spots moving along pericardial layer during diastole
    • Comet-tail artefacts extending across heart and disappearing during systole


  • Treat underlying cause
  • Conservative management usually sufficient (usually self-resolves)
  • If tamponade physiology, may require pericardiocentesis
    • If communicating pneumothorax, chest tube placement may resolve both[3]


  • If underlying cause is stable and patient is asymptomatic, may discharge home
  • Most patients will require admission for treatment of underlying cause

See Also


  1. Bell, D. et al. Pneumopericardium. Retrieved March 8 2019.
  2. Bobbia et al. (2013). Pneumopericardium diagnosis by point-of-care ultrasonography. Journal of Clinical Ultrasound, 4(14), May 2013.
  3. Braiteh, F., and Malik, I. (2008). Pneumopericardium. Canadian Journal of Emergency Medicine, 179(10).