Gallstone ileus is an uncommon cause ( 1-4% of cases9) of a mechanical small bowel obstruction (SBO). It is rare complication of chronic cholecystitis 7 and occurs when a gallstone passes into the small bowel and usually impacts at the iliocaecal valve.
Although overall gallstone ileus is an uncommon cause of small bowel obstruction, in the elderly is not uncommon, and accounts for up to 25% of non-strangulated bowel obstructions 1. As is the case with cholelithiasis, women are more frequently affected. There is a recognised increased female predilcation 7.
Typically patients have a long history of recurrent right upper quadrant pain, in keeping with chronic cholecystitis with repeated inflammatory events 6. The acute presentation of gallstone ileus is that of a small bowel obstruction, with colicky abdominal pain and abdominal distension.
Repeated bouts of cholecystitis result in adhesion of the gallbladder to the small bowel (usually duodenum) with eventual fistula formation and passage of gallstones into the lumen of the bowel. The commonest site of enrty by erosion is thought to be to the duodenum 7. Small stones presumably pass without incidence, however large cholesterol stones can become impacted typically at the ileocecal valve 6. As such gallstone ileus is a mechanical small bowel obstruction.
Most frequently, stones impact in the distal ileum, although other locations are also encountered 5:
- terminal ileum : most common
- proximal ileum
- duodenum / stomach : leading to gastric outlet obstruction (Bouveret's syndrome)
Classically the findings on abdominal xrays are a small bowel obstruction, gas within the biliary tree and a gallstone (usually in the right iliac fossa). This is known as Rigler's triad.
The overall sensitivity, specificity and accuracy of CT in diagnosing gallstone ileus is reported at around 93%, 100%; and 99%, respectively 11.
Appearances are those of Rigler's triad, better seen than on plain film. Care must be taken in finding the gallstone, as only a minority (12.5%) are calcified, and density may be very similar to bowel content 1. The presence of bulging of the bowel just prior to the transition point is often seen. Typically stones are a number of centimetres across (2 - 3cm).
Additionally, the site of fistulization is often visible.
Treatment and prognosis
Due to the demographics of the population affected (elderly) this condition continues to have a high mortality (12 - 30%) 1-2,7
Surgery is definitive, with removal of the stone (enterolithotomy) and repair of the choledochoenteric fistula, accompanied by a cholecystectomy.
The differential is essentially that of each component of Rigler's triad.
The entity was first described in 1654 3,4 by : Bartholin (1616 - 1680), a Danish physician, naturalist, physiologist and anatomist
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- 8. Hanbidge AE, Buckler PM, O'Malley ME et-al. From the RSNA refresher courses: imaging evaluation for acute pain in the right upper quadrant. Radiographics. 2004;24 (4): 1117-35. Radiographics (full text) - doi:10.1148/rg.244035149 - Pubmed citation
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- 10 . Chou JW, Hsu CH, Liao KF et-al. Gallstone ileus: report of two cases and review of the literature. World J. Gastroenterol. 2007;13 (8): 1295-8. Pubmed citation
- 11. Yu CY, Lin CC, Shyu RY et-al. Value of CT in the diagnosis and management of gallstone ileus. World J. Gastroenterol. 2005;11 (14): 2142-7. Pubmed citation