Gallstone ileus

Clinical History

An 80 year old female presented to the emergency room with diffuse colicky abdominal pain, nausea and vomiting during the last three days. The patient had a history of cholelithiasis. The clinical examination and blood tests were followed by plain abdominal radiograph and abdominal CT examination.

Imaging Findings

The patient presented complaining of diffuse colicky abdominal pain, nausea and vomiting for the last 3 days. She had a history of cholelithiasis while she had undergone ERCP examination several weeks ago. The clinical examination did not show abdominal distention or pathological bowel sounds but there was diffuse tenderness during palpation. Murphy sign was negative. WBCs was 14,300; bilirubin was 1.57; conjugated bilirubin 0.71 and CRP 6.86. All these values were rising with time. The plain abdominal radiograph was normal. During her staying in hospital, the patient presented bile vomiting. A nasogastric tube was placed and bile fluid came out. The patient underwent abdominal CT examination, which revealed distention of the small intestine, air in the gallbladder, thickening of the gallbladder wall with unclear borders and in close proximity to duodenum and fat strading around it. Also a rim-calcified gallstone in the distal ileum was noticed (Fig. 1a-c). The final diagnosis was that of gallstone ileus after cholecystoduodenal fistula formation. The patient was treated surgically and the follow up was uneventfull.

Discussion

Gallstone ileus is defined as a mechanical obstruction of the gastrointestinal tract caused by the presence of a gallstone in its lumen. Bouveret syndrome is caused by the impact of a gallstone in the duodenum producing gastric outlet obstruction.
Gallstone ileus is the result of a fistula formation between gallbladder and small intestine and is usually preceded by recurrent attacks of cholecystitis that cause inflammation and adhesions in the area of the gallbladder bed. The pressure effect of the gallstone leads to erosion of the gallbladder wall and favours the fistula-formation. Gallbladder carcinoma is an extremely rare condition that may also lead to gallstone ileus.
The commonest fistula is between the gallbladder and the duodenum in 60% of cases, but cholecystocolic, cholecystojejunal and cholecystogastric fistulae have also been described. The terminal ileum is the most frequent site of obstruction. However, the gallstone may also be found in jejunum (30%), colon (2.5%) or in duodenum causing Bouveret's syndrome.
Gallstone ileus occurs almost exclusively in the elderly (peak 65-75 years). It is 3-5 times more frequent in women. The incidence is 0.3-0.5% of all gallstone cases and it accounts for 1-2% of mechanical small bowel obstruction, though in geriatric population the incidence may reach 25%. There is a high morbidity and mortality rate (12-18%) probably due to delayed diagnosis, senile patient, and coexisting morbid illness.
Patients present with signs of intestinal obstruction, usually preceded by biliary complaints. There is crampy abdominal pain, nausea, vomiting, increased bowel sounds with tympanic sound on percussion and abdominal tenderness with or without distention. Rarely, haematemesis has been reported. The presentation may also be of intermittent obstruction that improves and reappears later. This is the “tumbling phenomenon” in which the impacted stone intermittently passes and lodges in the intestinal lumen while migrating distally. It may pass through the gastrointestinal tract if it is less than 2-2.5 cm.
Abdominal X-ray findings of gallstone ileus are the Rigler’s triad a) intestinal obstruction, b) pneumobilia or contrast in the biliary tree and c) ectopic gallstone. A fourth and a fifth sign was added: d) change of the position of the previously observed stone and e) two air fluid levels in the right upper quadrant on abdominal X-ray secondary to air in the gallbladder. Though diagnostic, only 36% of patients match the full criteria of Rigler's triad. Possible aetiology is that air collection within the gall bladder can be easily misdiagnosed and misinterpreted as colon gas and ectopic gallstone may be superimposed by bony structures or fluid-filled bowel, obscured by obesity, or lack identifiable calcification.
The diagnostic criteria of gallstone ileus on CT include: (a) small bowel obstruction, (b) ectopic gallstone; either rim-calcified or total-calcified (c) abnormal gall bladder with complete air collection, presence of air-fluid level, or fluid accumulation with irregular wall. False negative results may be due to poor rim-calcification of the ectopic gallstone.
Endoscopic retrieval or lithotripsy, if it is within reach of an endoscope, otherwise open surgery or laparoscopic-assisted enterolithotomy may be done.

Differential Diagnosis List

Final Diagnosis

Gallstone ileus

URL:	https://www.eurorad.org/case/8578
DOI:	10.1594/EURORAD/CASE.8578
ISSN:	1563-4086