Idiopathic pneumoperitoneum diagnosed following high-energy motor vehicular trauma : a case report

Intra-abdominal free gas is a finding of extra-intestinal gas in the abdominal cavity on radiography or CT, mainly suggesting gastrointestinal perforation and necessitating emergency surgery. Idiopathic pneumoperitoneum is diagnosed when there is no obvious gastrointestinal perforation, but there is presence of free gas in the abdominal cavity with an unidentifiable cause. Herein, we report a case of idiopathic pneumoperitoneum secondary to high-energy trauma following a car rollover accident. A 95-year-old man was transferred to our clinic after a car-to-car rollover accident. He had abrasions on his right upper arm and left abdomen that appeared to be the result of the accident ; however, no other apparent traumatic injuries were noted. There was no pain in the abdomen, and peritoneal irritation symptoms were also not noted. A CT scan showed fine free air. Although idiopathic pneumoperitoneum could not be ruled out, considering the patient’s background and the possibility of traumatic small bowel perforation, emergency surgery was performed. A thorough search of the abdominal cavity was performed ; however, the surgery was completed without an obvious perforation site. Idiopathic pneumoperitoneum should be considered as a differential disease in cases who have free air on abdominal CT but clinically lack obvious inflammatory reaction findings.