Pediatric Pneumopericardium

Etiology: Recent cardiothoracic surgery (most common), barotrauma (rare)
Imaging CXR:
–Subset of pneumomediastinum
— Air in pericardial space which does not rise above great vessels and outlines heart, aorta, pulmonary artery
— Continuous diaphragm sign
DDX:
Complications: Can cause compromise of venous return which leads to cardiac tamponade which leads to death
Treatment: Cardiocentesis if large
Clinical:

Radiology Cases of Pneumopericardium

CXR of esophageal perforation from nasogastric tube placement — CXR AP shows air outlining the heart in the pericardial space, air outlining the thymus in the mediastinum, and air in the bilateral pleural spaces.

CXR of pneumopericardium — CXR AP (above) shows a large amount of air around the heart. CXR AP obtained after pericardiocentesis (below) shows a decreased amount of air around the heart and the diaphragm can be continuously traced across the image.

CXR of pneumopericardium and right pulmonary interstitial emphysema which resulted in a right tension pneumothorax — CXR AP at 2 days of age (above) shows air surrounding the heart and not rising above the great vessels. Air is also present in the right pulmonary interstitium in a branching pattern from the hilum to the periphery. CXR AP at 3 days of age (below) shows air no longer surrounding the heart and interval development of a large amount of lucency in the right pleural space with mediastinal shift to the left.

CXR of respiratory syncytial virus pneumonia / RSV — CXR AP and lateral (above) shows right upper lobe collapse and air outlining the inferior border of the heart (continuous diaphragm sign). Left lateral decubitus CXR (below) shows a small right pneumothorax.