IS Case 346: Pneumoperitoneum

Stephanie Soehnlein, MD

Imaging Sciences URMC

2009 URMC Imaging Sciences
Publication Date: 2009-11-09

History

Patient is a newborn, full-term male, delivered by cesarean section, complicated by maternal hypertension. He was transferred to our hospital with increased abdominal distention.

On supine imaging in neonates, pneumoperitoneum will rise to the least dependent portion of the abdomen anteriorly. This creates what is known as the "football sign," representing a large amount of intraperitoneal free air. This often outlines the falciform ligament, seen as a linear opacity within the upper abdomen. Also outlined are the median umbilical ligament comprising the urachal vestige, the medial umbilical ligament comprising the umbilical arteries, or the lateral umbilical ligament comprising the inferior epigastric vessels. These structures make up the laces of the American football.

Since this sign is only seen with a large amount of pneumoperitoneum, it is more commonly seen in neonates that cannot fully express their pain and discomfort. Most commonly in neonates, pneumoperitoneum is secondary to iatrogenic or spontaneous bowel perforation. Other causes in the neonatal period include necrotizing enterocolitis, obstruction of the bowel secondary to Hirschsprungs disease, meconium ileus, atresia, or malrotation with midgut volvulus, as well as mechanical ventilation with barotrauma.