Pneumoperitoneum in a neonate weighing less than 500 g. What do we really know about it?

Pneumoperitoneum in preterm infants is a surgical emergency as it is usually indicative of intestinal perforation. Rare cases of idiopathic pneumoperitoneum have been described in the literature, the underlying causes and pathophysiology of which remain uncertain. We present a case of pneumoperitoneum in an extremely preterm infant with severe growth restriction. This occurred while she was receiving high frequency oscillatory ventilation. She had respiratory distress syndrome with pulmonary interstitial emphysema. The pneumoperitoneum occurred in isolation. Despite the insertion of two surgical drains and two exploratory laparotomies in which no obvious intestinal perforation was noted, the free air in the abdomen reaccumulated. A decision was made to manage it conservatively. She was successfully extubated on the fourth week of life and the pneumoperitoneum resolved spontaneously. She was discharged home on day 136 of life. This case highlights our limited understanding of the intricate physiology of extremely low birthweight preterm neonates.