Mirizzi Syndrome

Gallstone ileus is mechanical intestinal obstruction caused by migration of a gallstone into the gastrointestinal tract through a biliary enteric fistula.

The usual fistula is cholecystoduodenal. Less commonly, stones enter through cholecystogastric or cholecystocolonic fistulas.

Most stones impact in the terminal ileum because it is the narrowest segment of small bowel. Proximal impaction in the duodenum causing gastric outlet obstruction is termed Bouveret syndrome.

Patients are usually older and physiologically vulnerable. The immediate priority is relief of bowel obstruction rather than a complex definitive biliary operation.

Presentation resembles intermittent or complete small bowel obstruction:

• Colicky abdominal pain
• Vomiting
• Distension
• Reduced stool or flatus

Symptoms may fluctuate as the stone migrates before finally impacting.

Continuous pain, guarding, fever or systemic deterioration suggests pressure necrosis, bowel ischaemia or perforation.

A previous history of gallstones may be absent.

CT abdomen with IV contrast: identify an ectopic gallstone at the transition point with associated bowel obstruction and evidence of a biliary enteric fistula or pneumobilia.

Inspect the entire bowel on imaging for additional large stones because a second retained stone can cause recurrent obstruction.

Resuscitate as for small bowel obstruction with fasting, IV crystalloid, correction of electrolyte deficits and nasogastric decompression when vomiting or major gastric distension is present.

Definitive treatment is usually operative.

Enterolithotomy

In most older or physiologically compromised patients, perform enterolithotomy alone.

Identify the obstructing stone, make a longitudinal enterotomy on healthy bowel proximal to the impaction, extract the stone and close the enterotomy transversely to minimise luminal narrowing.

Palpate the entire small bowel for additional stones before closure.

Resect bowel rather than performing simple enterolithotomy if the impaction has caused necrosis or perforation.

One stage surgery

Enterolithotomy combined with cholecystectomy and fistula closure is substantially more extensive and should be reserved for carefully selected fit patients with favourable anatomy, ongoing gallbladder sepsis or another compelling biliary indication.

Most elderly patients do not require immediate fistula repair because the operative priority is relief of obstruction.

Persistent biliary symptoms after recovery justify later reassessment for elective fistula and gallbladder management.