Causes of Extraperitoneal Air

The extraperitoneum is a potential space, and therefor extraperitoneal air is always pathologic. The most common cause of extraperitoneal air is bowel perforation. The two most common causes of bowel perforation are inflammatory disease and ulcerative disease. Other causes include trauma, iatrogenic manipulation, and a foreign body. In a perforated duodenal ulcer, the first part of the duodenum is the most common region affected. In a patient presenting with an acute abdomen and a history of inflammatory or ulcerative disease, bowel perforation should be a consideration. If bowel perforation is due to obstruction, the perforation typically occurs proximal to the obstruction. In progressing pneumoperitoneum, a major complication to be aware of is abdominal compartment syndrome.