Benign Pneumoperitoneum Following Mitral Valve Replacement

The pneumoperitoneum refers to the presence of free air inside the abdominal cavity. This finding is usually a sequela of a gastrointestinal tract perforation. Still, in rare instances, it can present after cardiac surgery due to the proximity of the peritoneal cavity and pericardium, allowing air to enter the peritoneal cavity. Our patient was a 63-year-old female who initially presented for revision of the mitral valve replacement. A chest X-ray on postoperative day 13 revealed a 6.6 cm lucency under the right diaphragm suggestive of pneumoperitoneum. She was discharged after serial chest X-rays revealed a decrease in the size of the pneumoperitoneum. Twelve days later, our patient was readmitted, as another chest X-ray revealed that the size of the pneumoperitoneum was again increasing. An endoscopy was performed, but it did not reveal any lesions or etiology that would lead to a leak from the gastrointestinal tract. Finally, due to the benign nature of the pneumoperitoneum and the decrease in its size over the following days, we opted for conservative management, and she was discharged again. This case emphasizes the rare occurrence of benign pneumoperitoneum post-mitral valve surgery. While surgery may not always be required for asymptomatic cases, careful vigilance post-cardiac surgery remains crucial to detect potential abdominal complications promptly.