Neonate with abdominal distension

11 day old with abdominal distension.  Initial radiograph and follow-up images below interpreted as normal.

1. Initial showing abnormality; interpreted as normal

2. Follow-up radiograph with worsening abnormality

3. Lateral decubitus radiograph confirming abnormality

Discussion:

This case demonstrates the "football sign" on both frontal images.  The falciform ligament is visible superimposed upon the rounded area of lucency representing pneumoperitoneum.  Other supine signs of free air in the neonate include triangular lucencies and Rigler's sign (outlining of both sides of the bowel wall). 

Differential Diagnosis:

• Post-operative free air
• Necrotizing Enterocolitis
• m/c surgical emergency in infants
• 90% occur in those born <36wk
• 3-7% of NICU patients
• Traumatic bowel injury
• Dissection of pneumothorax/pneumomediastinum
• Medications
• Inodomethacin for PDA can cause decreased GI blood flow and intestinal perforation.
• Iatrogenic
• Infection

Subsequent radiographs demonstrated placement of a second drain in the left lower quadrant with resolution of pneumoperitoneum.