C52-23 Pneumopericardium: An Elusive Diagnosis in the Polytrauma Patient

Abstract Pneumopericardium refers to the presence of air or gas within the pericardial sac. It most commonly results from a fistulous connection between the pericardium and air-containing structures like the thoracic cavity or GI tract, though congenital causes exist. Approximately 60% of cases are trauma-related, predominantly due to penetrating injuries. Blunt trauma can also lead to pneumopericardium, typically via the Macklin effect—retrograde air dissection along bronchovascular sheaths into the mediastinum and pericardium. Diagnosis is primarily through imaging, with CT being most sensitive for differentiating air from fluid. Most cases resolve without intervention, but patients must be monitored for signs of tension physiology, which can manifest as cardiac tamponade. This case highlights a self-resolving pneumopericardium, likely secondary to pneumothorax, in a motorcycle trauma patient. A 26-year-old male motorcyclist struck by a vehicle presented alert, stable blood pressure, unexplained Bradycardia, and GCS of 15. Initial findings included a right femoral fracture, bilateral upper extremity fractures, left-sided rib fractures, pneumothorax, pulmonary contusions, and a positive FAST. CT imaging further revealed pneumopericardium, pneumomediastinum, a Grade IV splenic laceration, vertebral fractures, and an aortic arch injury. Central line was placed; chest tube insertion followed due to worsening pneumothorax. The patient remained asymptomatic with normal EKG and no clinical signs of tamponade.Surgical interventions for orthopedic injuries were completed and was non-weight bearing in both lower extremities and the right upper extremity. Trauma course included rhabdomyolysis, transient AKI, anemia, thrombocytopenia, and hypertension requiring IV and oral medications. Chest tube was removed on day 4, and he remained stable throughout hospitalization. Pneumopericardium is rare, especially from blunt trauma, and can be fatal if it progresses to tension physiology. The Macklin effect explains air dissecting into the pericardial sac without pleural rupture. Though often benign, the condition demands vigilance due to its potential to evolve into tamponade. Radiographic signs such as the “continuous diaphragm sign” can aid diagnosis, especially in stable patients. Risk factors for progression include intubation and concurrent pneumothorax.Tension pneumopericardium causes a rise in pericardial pressure; tamponade symptoms manifest when pressure exceeds ∼265 mmHg (or 150 cc of air). Mortality is high when tamponade develops. Cummings et al. reported a 56% mortality in 37% of patients with tamponade physiology. Timely pericardiocentesis or surgical decompression is critical when symptoms arise.Trauma clinicians must maintain a high index of suspicion and be familiar with management pathways for pneumopericardium, ensuring early recognition and intervention to prevent fatal outcomes. This abstract is funded by: N/A