Pneumopericardium
- What is it:
- Pneumopericardium refers to the presence of air or gas within the pericardial sac surrounding the heart.
- It is a rare condition that can occur due to trauma, infection, or medical interventions, and it requires prompt evaluation to determine the cause and assess for potential complications such as cardiac tamponade.
- Etymology:
- Derived from the Greek words pneuma (air) and perikardion (around the heart), describing air within the pericardial cavity.
- AKA:
- Air in the pericardium.
- How does it appear on each relevant imaging modality:
- Chest X-ray:
- Air outlining the pericardium, creating a “continuous diaphragm sign” where the pericardial border is visible across the diaphragm.
- Air-fluid levels may be visible if associated with effusion.
- Chest CT:
- Parts: Air surrounding the heart, confined to the pericardial sac.
- Size: Variable amounts of air, ranging from small pockets to large volumes.
- Shape: Circumferential or localized collection of air outlining the heart.
- Position: Confined to the pericardial sac, distinguishing it from pneumomediastinum.
- Character: Typically well-defined air pockets; may coexist with pneumothorax or pneumomediastinum.
- Time: Air may resolve spontaneously (e.g., post-surgical cases) or persist if there is ongoing leakage.
- Ultrasound (Echocardiography):
- May demonstrate echogenic foci with reverberation artifacts within the pericardial sac.
- Chest X-ray:
- These findings reflect:
- Trauma:
- Blunt or penetrating chest trauma causing pericardial injury.
- Infection:
- Gas-producing organisms in infectious pericarditis.
- Iatrogenic:
- Post-cardiac surgery or pericardiocentesis.
- Ventilator-induced barotrauma in mechanically ventilated patients.
- Neoplasm:
- Rarely, from tumor invasion or fistula formation.
- Trauma:
- Differential diagnosis:
- Pneumomediastinum:
- Air in the mediastinum, which can mimic pneumopericardium but lacks the continuous diaphragm sign.
- Pericardial effusion with gas:
- Gas-fluid levels caused by infection or fistula formation.
- Pneumothorax:
- Air within the pleural cavity, which may coexist but is anatomically separate.
- Pneumomediastinum:
- Recommendations:
- Perform Chest CT to confirm diagnosis, delineate the extent of air, and identify associated conditions (e.g., pneumothorax, pneumomediastinum).
- Monitor for complications such as cardiac tamponade, which may require urgent pericardiocentesis.
- Treat underlying causes (e.g., infection, trauma).
- Ultrasound (echocardiography): Useful for bedside evaluation, particularly in unstable patients.
- Key points and pearls:
- The “continuous diaphragm sign” on chest X-ray is a hallmark feature of pneumopericardium.
- While often self-limiting in iatrogenic or minor traumatic cases, pneumopericardium can lead to life-threatening tamponade.
- Always assess for associated injuries such as pneumothorax, pneumomediastinum, or esophageal rupture.
- Time-dependent resolution is common in benign cases but requires close monitoring in traumatic or infectious causes.
Pneumopericardium is the presence of air or gas within the
pericardial sac, the double-layered membrane surrounding the
heart. This rare condition can result from trauma (such as chest
injury or penetrating wounds), surgical procedures, mechanical
ventilation, or esophageal or bronchial perforation, and it can also
occur spontaneously in some cases. Symptoms can range from
being asymptomatic to presenting with chest pain, shortness of
breath, and, in severe cases, cardiac tamponade if the air
compresses the heart and impairs its function. Diagnosis is made
using imaging, such as chest X-rays or CT scans, where air is seen
outlining the heart within the pericardial sac, creating a
characteristic “halo” appearance. Treatment depends on the
underlying cause and severity, ranging from observation and oxygen
therapy to more invasive measures like needle aspiration or surgical
intervention to remove the air and address the source of the leak.