Gallstone Ileus

Expansion

The sequence:

1. Chronic cholecystitis causes the gallbladder to adhere to the duodenum
2. A large stone erodes through, creating a cholecystoduodenal fistula
3. The stone passes into the bowel and travels distally
4. It impacts at the terminal ileum, the narrowest part of the small bowel

Rigler’s triad on imaging:

• Pneumobilia - air in the biliary tree, entering through the fistula
• Small bowel obstruction
• An ectopic gallstone, usually in the right iliac fossa

A stone must generally be over 2.5 cm to obstruct. If it impacts in the duodenum instead, causing gastric outlet obstruction, that is Bouveret’s syndrome.

It is a disease of elderly women, and carries high mortality because of the comorbidity and late presentation. Treatment is enterolithotomy; the fistula is often left alone.