Gallstone ileus

An abdominal CT scan (Figure 2; Figure 1 also viewable) revealed distended small bowel proximal to a 3-cm intraluminal density (white arrow), with collapsed small bowel distal to this. Cholecystitis leads to cholecystoenteric fistula with passage of the gallstone into the duodenum or, less often, the colon.1 The gallstone may either pass in the faeces, or cause obstruction at the mid terminal ileum or, less commonly, the sigmoid colon.