Gallstone ileus is an uncommon cause of a mechanical small bowel obstruction. It is a rare complication of chronic cholecystitis 7 and occurs when a gallstone passes through a fistula between the gallbladder and small bowel before becoming impacted at the ileocaecal valve.
Although overall gallstone ileus is an uncommon cause of small bowel obstruction (1-4% in general adult population 9), 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 7.
Typically patients have a long history of recurrent right upper quadrant pain, in keeping with chronic cholecystitis with repeated inflammatory events 6. Gallstone ileus can acutely present as colicky abdominal pain and abdominal distension in the course of small bowel obstruction.
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. The most common site of entry 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 ileocaecal valve 6. As such, gallstone ileus is a mechanical small bowel obstruction. Ileus is a misnomer as the term ileus is usually used to describe a functional, rather than, mechanical obstruction.
Most frequently, stones become impacted in the distal ileum, although they may become lodged at other locations 5:
- terminal ileum: most common
- proximal ileum
- duodenum/stomach: leading to gastric outlet obstruction (Bouveret syndrome)
Classically the findings on abdominal radiographs are a small bowel obstruction, gas within the biliary tree, and a gallstone (usually in the right iliac fossa): Rigler triad.
The overall sensitivity, specificity and accuracy of CT in diagnosing gallstone ileus is around 93%, 100%; and 99%, respectively 11.
Appearances are those of Rigler triad, better seen than on plain radiograph. Since only the minority of gallstones calcify (12.5%), and their density is similar to regular bowel content, it is easy to overlook the offending gallstone 1. There may be bulging of the bowel just before the transition point which may be helpful in locating the gallstone. Typically, stones are large and measure several centimetres (2-3 cm).
Additionally, the site of fistulisation 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 the removal of the stone (enterolithotomy) and repair of the choledochoenteric fistula, accompanied by a cholecystectomy.
History and etymology
The first descriptions of gallstone ileus occurred in 1654 by Thomas Bartholin (1616-1680), a Danish physician, naturalist, physiologist, and anatomist 3,4.
The differential is that of each component of Rigler triad:
- 1. Lassandro F, Romano S, Ragozzino A et-al. Role of helical CT in diagnosis of gallstone ileus and related conditions. AJR Am J Roentgenol. 2005;185 (5): 1159-65. doi:10.2214/AJR.04.1371 - Pubmed citation
- 2. Reisner RM, Cohen JR. Gallstone ileus: a review of 1001 reported cases. Am Surg. 1994;60 (6): 441-6. Pubmed citation
- 3. Thomas Bartholin from whonamedit.com, the dictionary of medical eponyms. Thomas Bartholin
- 4. Raiford TS. Intestinal obstruction due to gallstones. (Gallstone ileus). Ann. Surg. 1961;153 : 830-8. Free text at pubmed - Pubmed citation
- 5. Singh AK, Shirkhoda A, Lal N et-al. Bouveret's syndrome: appearance on CT and upper gastrointestinal radiography before and after stone obturation. AJR Am J Roentgenol. 2003;181 (3): 828-30. AJR Am J Roentgenol (full text) - Pubmed citation
- 6. Britt LD, Trunkey DD, Feliciano DV. Acute Care Surgery, Principles and Practice. Springer Verlag. (2007) ISBN:0387344705. Read it at Google Books - Find it at Amazon
- 7. Summerton SL, Hollander AC, Stassi J et-al. US case of the day. Gallstone ileus. Radiographics. 1995;15 (2): 493-5. Radiographics (citation) - Pubmed citation
- 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
- 9. Zinkin EB, Brammer WM, Colombo CA. Case of the day. General. Gallstone perforation of the terminal ileum with abscess formation. Radiographics. 1990;10 (6): 1108-10. Radiographics (citation) - Pubmed citation
- 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
- 12. Lorén I, Lasson A, Nilsson A et-al. Gallstone ileus demonstrated by CT. J Comput Assist Tomogr. 1994;18 (2): 262-5. Pubmed citation