Pancolitis is usually due to infection or inflammatory bowel disease, and less commonly ischemia. Multiple features here allow a radiological diagnosis of Clostridioides difficile colitis to be made: recent treatment of a LRTI, no known history of IBD, and in particular, haustral thickening with ascites. This pattern of findings is seen relatively more frequently in this type of colitis. The haustral thickening sometimes leads to a finding known as the accordion sign.
The C. difficile toxin tests were subsequently found to be positive.