One of the concerns in someone presenting with acute abdominal pain after this surgery is an internal hernia. This used to be seen more commonly than now, due to an iatrogenic defect in the transverse mesocolon where the small bowel was brought up to anastomose onto the stomach. However, the procedure has changed and is now done with an "antecolic" approach meaning that the transverse mesocolon is not breached. However, other small mesenteric defects may still be created - leading to herniation of small bowel loops behind the gastrojejunostomy. This is know as a Petersen's hernia.

This particular case is neither a transmesocolic nor a Petersen's hernia - the hernia is through a mesenteric defect presumably secondary to a defect created at surgery.

Learning points: 

• contrast enhanced CT is the test of choice in someone presenting with abdominal pain following Roux-en-Y gastric bypass surgery.
• keep a high index of suspicion for internal hernia formation