Unusual pressure-induced rupture of colonic volvulus in a patient with long-term corticosteroid therapy.

Perforation due to colonic volvulus is typically considered to occur following ischemic necrosis of the intestinal wall. In this report, we report a rare case of sigmoid colon volvulus rupture caused by increasing intraluminal pressure without any sign of ischemia. The patient was an 88-year old Japanese male, who had been treated with 5 mg of oral prednisolone daily for 8 years. He consulted for severe abdominal pain that had lasted for three days. X-ray and computed tomography showed free peritoneal air, suggesting peritonitis. He was diagnosed with sigmoid colon volvulus perforation and underwent emergency surgery. Pathological examination showed no ischemic necrosis around the perforations in the resected intestine. As a result, we came to believe that the fragility of the colonic wall, caused by the patient's long-term use of corticosteroid, had lowered the threshold for pressure-induced colonic rupture.