A case report of pneumopericardium secondary to suspected bronchopericardial fistula post lung resection: diagnosis and management guided by transthoracic echocardiography.

Pneumopericardium is a rare, life-threatening condition characterized by abnormal gas accumulation in the pericardial cavity, most commonly secondary to trauma, surgical procedures, or fistulous communications with adjacent hollow organs. We report a 59-year-old male patient who presented with chest pain. Initial transthoracic echocardiography (TTE) only detected minimal pericardial effusion, failing to identify pneumopericardium. Subsequent serial TTE monitoring progressively revealed pathognomonic signs of pneumopericardium, including microbubble swirl, air gap artifact, and a definitive fluid-gas level. Notably, the microbubble swirl sign is a typical marker for the early diagnosis of pneumopericardium, and its presence should raise an immediate suspicion of this condition. The diagnosis was ultimately confirmed, and computed tomography (CT) was further performed to corroborate these echocardiographic findings. Therapeutically, ultrasound-guided pericardiocentesis was successfully conducted to drain the pericardial gas. However, post-procedural recurrent pneumopericardium occurred, prompting suspicion of an underlying persistent fistula, specifically a bronchopericardial fistula. Despite aggressive clinical interventions, the patient ultimately succumbed to the disease following voluntary withdrawal of care. This case highlights three key clinical implications: (1) Serial TTE monitoring is of critical value in the dynamic diagnosis of pneumopericardium, particularly when initial imaging yields non-diagnostic results; (2) TTE serves as a dual utility tool-guiding emergent therapeutic interventions (e.g., ultrasound-guided pericardiocentesis) and facilitating etiological investigation (e.g., identifying fistula-related gas recurrence); (3) Clinicians should maintain heightened vigilance for underlying pathological causes (e.g., bronchopericardial fistula) in patients with recurrent pneumopericardium to optimize treatment strategies.