Presentation
Abdominal pain, nausea and vomiting.
Patient Data
High-grade small bowel obstruction with abrupt transition point in the midway though the small bowel in the pelvic midline. Distention of the stomach and proximal small bowel with air-fluid levels up to the transition point.
At the point of transition, there is a difficult-to-perceive oval, lamellated structure, consistent with a gallstone. Distally, the small bowel and colon are collapsed. Mild mesenteric edema.
Pneumobilia involving the common bile duct and left hepatic lobe. Relatively subtle cholecystenteric fistula with shrunken gallbladder containing small amount of air (see annotated coronal images).
Annotated images demonstrate salient findings.
Case Discussion
If you got this case correct in quiz format, then good for you! This is probably as subtle and as difficult as gallstone ileus can be to diagnose.
To make matters worse, we were provided with a history of prior cholecystectomy in this patient, and the cholecystenteric fistula could easily be mistaken for a duodenal diverticulum at first glance. It is rather surprising how non-inflamed the gallbladder appears in this case.
It is very common for a noncalcified gallstone to be difficult to identify in the lumen, as it blends in with the intraluminal contents, as was the case for this patient.