• Pneumopericardium is a rare occurrence and is characterized by gas (typically air) within the pericardium. It’s causes include a fistula between pericardium and air-containing organ (i.e., stomach, esophagus, bronchi), infectious pericarditis with gas generating organisms, penetrating trauma, thoracic surgery and positive pressure ventilation, severe asthma, respiratory distress syndrome, and procedures (including esophagectomy, endomyocardial biopsy, lung transplantation).
• The pericardium contains the heart and proximal parts of the pulmonary trunk and aorta.

History

• Can be symptomatic or asymptomatic.
• Symptoms include dyspnea and pain over the pre-cardiac region.

Physical Exam

• Although unreliable for detecting pneumopericardium, Bruit de Moulin and Hamman’s Crunch are signs that suggest the pathology.
• Assess for Beck’s Triad (Elevated JVP, muffled heart sounds and hypotension). If presenting with Beck’s Triad, consider tension pneumopericardium, a rare but life-threatening complication of pneumopericardium.

Chest X-ray

• Characterized by a well-demarcated/sharply outlined pericardium that is surrounded by gas.
• Can sometimes see a continuous diaphragm sign. Normally the centre portion of the diaphragm is obscured by the cardiac silhouette, however, if the diaphragm is visualized in the midline, it is suggestive of free gas in the mediastinum or pericardium.
• Pneumopericardium is differentiated from pneumomediastinum in that gas cannot track beyond the anatomical limits of the pericardial sac. Another distinguishing feature between the two is that when the x-ray is taken in the lateral decubitus position, the air will shift immediately in the case of pneumopericardium.

Other Imaging Modalities

• If doing a point of care U/S, it will be more challenging to visualize the heart in the presence of surrounding air, so that could be a diagnostic clue suggesting pneumopericardium. Other findings include bright spots and comet tail artifacts throughout the heart, visualized during diastole.
• If clinically suspecting a pneumopericardium and X-ray is inconclusive, CT scan is the preferred modality.

Chest x-ray showing pneumopericardium. Case courtesy of Dr. Henry Knipe, Radiopaedia.org, rID: 44191

• Treat the underlying cause.
• Patients can be discharged if asymptomatic and stable. In a simple asymptomatic pneumopericardium, treatment is ongoing surveillance to ensure it doesn’t progress into a tension pneumopericardium.
• Tension pneumopericardium occurs when the build-up in air results in hemodynamic instability. In the event of a tension pneumopericardium, decompression should be done immediately, either by needle pericardiocentesis or placement of a drain. This decision will likely be made in consultation with Cardiothoracics.
• Signs and symptoms of tension pneumopericardium are similar to that of cardiac tamponade and so should be suspected in the event of hemodynamic instability but no visible effusion.

1. • https://radiopaedia.org/articles/pneumopericardium
   • https://wikem.org/wiki/Pneumopericardium
   
   

1. Anand, R., Brooks, MD, FACS, S., Puckett, Y., Richmond, R., & Ronaghan, C. (2020). Pneumopericardium Resulting From Blunt Thoracic Trauma. Cureus. doi: 10.7759/cureus.11625

   
   

2. Braiteh, F. and Malik, I., 2008. Pneumopericardium. Canadian Medical Association Journal, 179(10), p.1087.

   
   

3. Gołota, J., Orłowski, T., Iwanowicz, K. and Snarska, J., 2016. Air tamponade of the heart. Polish Journal of Cardio-Thoracic Surgery, 13(2), pp.150-153.

   
   

4. Haan, J., & Scalea, T. (2006). Tension Pneumopericardium: A Case Report and a Review of the Literature. The American Surgeon, 72(4), 330-331.

   
   

5. Hazy, R., & Taha, A. (2020). UpToDate. Retrieved 10 January 2022

   
   

6. Radswiki, T., El-Feky, M (2021). Pneumopericardium | Radiology Reference Article | Radiopaedia.org. Retrieved 10 January 2022

   
   

7. Rolim Marques, A., Lopes, L., Martins, M., Carmona, C., Fraga, G. and Hirano, E., 2016. Tension pneumopericardium in blunt thoracic trauma. International Journal of Surgery Case Reports, 24, pp.188-190.