Gallstones can lead to recurrent cholecystitis. Due to the anatomical proximity of the gallbladder and small bowel, the recurrent inflammation can lead to the formation of fistula. The gallstone then passes through the fistula into the intestine where it leads to obstruction. The most common site of obstruction is the terminal ileum, but the obstruction can occur anywhere along the intestine.

The classical radiological finding in gallstone ileus is the Rigler triad consisting of pneumobilia, small bowel obstruction and ectopic gallstone, two of which are present in our case.