Gallstone ileus is a rare cause of bowel obstruction. Having a systemic approach and clinical suspicion is important in diagnosis. Gallstone ileus is more common in women since gallstones are more common in women. The stone fistulizes into the duodenum and the site of obstruction is often at the terminal ileum since it is the narrowest portion of the small bowel.

Plain radiography would show a small bowel obstruction and sometimes gas in biliary tree and gallbladder. If radiopaque, the stone may be seen as well. The same findings are present on CT, but the ectopic gallstone is easier to see.