A Case of Intra-abdominal Free Air Diagnosed as Spontaneous Pneumoperitoneum but as Being Caused by Sigmoid Volvulus Seven Months Later

Abstract

A man in his 90s with neck pain and difficulty in moving was transported to the hospital by ambulance, and was diagnosed as having crowned dens syndrome. Although abdominal CT revealed intra-abdominal free air, in the absence of signs of peritonitis, he was diagnosed as having spontaneous pneumoperitoneum and treated conservatively. Upper gastrointestinal endoscopy on day 7 revealed no visible cause, and colonoscopy was not performed as consent could not be obtained. Seven months after discharge, the patient was transported to the hospital with abdominal pain. Abdominal CT revealed an enlarged sigmoid colon, pneumatosis, free air, and ascites. Although imaging suggested sigmoid volvulus, surgery was performed because colonic perforation or necrosis could not be ruled out. Surgery revealed no colonic perforation or necrosis, sigmoid volvulus was repositioned, and the sigmoid colon was removed to prevent recurrence. To diagnose spontaneous pneumoperitoneum without sufficient search for a cause of intra-abdominal free air may lead to the need for emergency treatment in the future.