Pneumopericardium

Background

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

• GI malignancy
• PUD
• Esophageal diverticula
• Barotrauma
  • Mechanical ventilation
  • Vigorous bag-mask ventilation
  • SCUBA diving/rapid ascent
  • Drug insufflation (especially associated with crack cocaine)
• Asthma
• Valsalva
• Infection pericarditis with gas-producing bacteria
• Thoracic surgery
• Pericardial fluid drainage
• Blast injury
• Blunt or penetrating thoracic trauma
• Neonatal respiratory distress syndrome

Clinical Features

• May present with tamponade physiology depending on size
• Other features include:
  • Dyspnea
  • Cyanosis
  • Chest pain
  • Pulsus paradoxus
  • Bradycardia
  • Tachycardia
  • May have subcutaneous emphysema
  • May have succussion splash if there is also a pericardial effusion
  • May have Hamman crunch

Differential Diagnosis

Thoracic Trauma

• Airway/Pulmonary
  • Bronchial injury
  • Diaphragmatic trauma
  • Hemothorax
  • Pneumomediastinum
  • Pulmonary contusion
  • Tracheal injury
  • Trachobronchial injury
  • Traumatic pneumothorax
    • Tension pneumothorax
• Cardiac/Vascular
  • Cardiac injury
    • Blunt cardiac injury
      • Cardiac contusion
      • Commotio cordis
    • Penetrating cardiac injury
    • Cardiac tamponade
  • Traumatic aortic transection
• Musculoskeletal
  • Clavicle fracture
    • Clavicle fracture (peds)
  • Rib fracture
    • Flail chest
  • Scapular fracture
  • Scapulothoracic dissociation
  • Sternoclavicular dislocation
  • Sternum fracture
  • Thoracic and lumbar fractures and dislocations
• Other
  • Esophageal injury or Perforation
  • Pneumomediastinum
  • Pneumopericardium
  • Traumatic asphyxia

Evaluation

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
  • 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
  • Bright spots moving along pericardial layer during diastole
  • Comet-tail artefacts extending across heart and disappearing during systole

Management

• 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

Disposition

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

See Also

• Thoracic trauma