Spontaneous pneumoperitoneum: Discerning from radiological imaging

Background: Pneumoperitoneum without any gastrointestinal (GI) perforation or peritonitis is entitled spontaneous pneumoperitoneum. We aimed to describe a radiological perspective in spontaneous pneumoperitoneum. Methods: This case series presented data of 4 cases of spontaneous pneumoperitoneum managed at our institution. Results: There were 85 patients with a provisional diagnosis of necrotizing enterocolitis (NEC) and/or pneumoperitoneum. Out of these, there were 4 patients with the final diagnosis of spontaneous pneumoperitoneum; three males and 1 female. At presentation, respiratory distress was seen in 3. It was preceded by mechanical ventilation in 3 patients. All 4 had soft abdominal distension, absence of features suggestive of peritonitis, and the presence of free air with an absence of air-fluid level in peritoneal cavity on erect abdominal radiographs. The Rigler sign was present in 3 patients. Abdominocentesis followed by abdominal drain placement was performed in 2 patients. Laparotomy was performed in 1 patient which could not point to any pathology (negative). An unfavorable outcome was seen in one patient with associated esophageal atresia. No patient had any evidence (either ultrasound/radiological or on laparotomy) of leakage of contents from the GI tract. Conclusions: In infants, especially preterm neonates, presenting with soft abdominal distension with abrupt onset of pneumoperitoneum, without clinical features of peritonitis and preceded by mechanical ventilation, diagnosis of spontaneous pneumoperitoneum should be considered.