It is a rare complication of cholelithiasis that usually presents with signs and symptoms of gastric outlet obstruction.
Bouveret’s syndrome is a rare form of gallstone ileus secondary to an acquired fistula between the gallbladder and the duodenum or stomach.
Through the fistula, a gallstone can enter the enteric system and cause gastric outlet obstruction.
Gallstone ileus is extremely rare, complicating only 0.3% to 10.5% of patients with cholelithiasis.
Bouveret syndrome represents 1% to 3% of cases of gallstone ileus.
Due to the rare nature of this disease, there are no standardized recommendations for the diagnosis and treatment of these patients, including endoscopic, laparoscopic, and open surgery options.
Causes of Bouveret syndrome
Bouveret’s syndrome is the rarest variant of gallstone ileus, with just over 300 cases in the literature since its first description in 1654.
It is the result of a gallstone that enters the intestinal lumen and causes gastric outlet obstruction and occasionally other portions of the intestine as well.
The entry point is usually a fistula between the gallbladder and a portion of the stomach or intestine.
The risk factors for Bouveret syndrome are similar to the risk factors for gallstones, as gallstones play an integral role in the etiology of Bouveret syndrome.
These risk factors for gallstones are: more prevalent in white populations, a body mass index greater than 30, female gender, fertile women (one or more children), and an age greater than 40 years.
Well-studied risk factors for Bouveret syndrome include a history of cholelithiasis, stones larger than 2 to 8 cm, female gender, and age older than 60 years.
Bouveret syndrome symptoms
The presentation of Bouveret’s syndrome is typically nonspecific and often has symptoms of nausea, vomiting, abdominal distention, and pain due to different positions of the gallstone.
The patient may also present with epigastric and right upper quadrant pain, along with signs of dehydration and weight loss.
Less commonly, Bouveret syndrome may present with hematemesis secondary to erosions of the duodenal and celiac arteries or with the expulsion of stones in your vomit.
Symptoms usually begin 5 to 7 days before a doctor’s visit.
Importantly, the intensity of pain often does not correlate with the underlying anatomical abnormality.
A physical exam is also not specific, although dry mucous membranes, abdominal distension, abdominal tenderness, high-pitched bowel sounds, and obstructive jaundice may be seen.
Diagnosis of Bouveret’s syndrome
Unfortunately, laboratory studies are typically nonspecific.
Labs may show jaundice and liver enzyme abnormalities, but this only accounts for a third of patients with Bouveret syndrome.
There may also be leukocytosis, hydroelectrolyte, acid-base disturbances, and renal failure, but the degree depends on comorbidity, the intensity of the inflammatory response, and the individual’s compensatory mechanisms.
Imagingly, the constellation of pneumobilia, intestinal obstruction, and an aberrant gallstone is highly suggestive of Bouveret syndrome, but is only found in 40% to 50% of cases.
Ultrasound may be helpful, as it shows possible cholecystitis, a dilated stomach, pneumobilia, and ectopic location of gallstones, although intestinal gas makes it suboptimal.
Also, when the gallbladder contracts, it can be difficult to detect the exact location of the stone (orthotopic or ectopic) with ultrasound.
Abdominal X-rays can also be used. These may show pneumobilia, intestinal obstruction, an aberrant gallstone, fluid levels in the upper right quadrant due to air in the gallbladder or dilation of the stomach, and a change in the location of a stone seen previously.
However, abdominal radiographs are only diagnostic in 21% of Bouveret syndrome cases.
Computed tomography is the imaging modality of choice, with an overall sensitivity of 93%, a specificity of 100%, and a diagnostic accuracy of 99%.
In addition to its greater accuracy compared to plain radiography or ultrasound, it can also provide important information about the presence of a fistula, the presence of abscesses, the inflammatory status of the lumen and surrounding tissue, the size of gallstones, and the number of gallstones.
Magnetic resonance cholangiopancreatography can be used in patients unable to tolerate oral contrast or with severe emesis, as well as in cases with isoathening stones, as it distinguishes stones from fluids, visualizes the fistula with greater precision, and does not require use of oral contrast material.
The disadvantage is the difficulty in the interpretation as concern and difficult to differentiate.
Esophagogastroduodenoscopy is another option, the advantages of which are the visualization of the stone and the simultaneous removal of the stone with the visualization, but this is only successful in the minority of cases and may be associated with additional complications.
In about 20% to 40% of all cases, the final diagnosis is made intraoperatively when a patient undergoes laparotomy for small bowel obstruction of unknown origin.
This is particularly true for the 15% to 25% of gallstones that are isoattenuating and not visible on CT.
Bouveret syndrome treatment
Given the advanced age and extensive comorbidities of the typical patient with this syndrome, many have initially advocated percutaneous or endoscopic approaches, such as laser or extracorporeal shock wave lithotripsy.
Approximately 91% of patients fail this procedure and require surgical treatment.
Surgical options are the one-stage procedure (enterolithotomy to relieve intestinal obstruction, cholecystectomy, and chole-enteric fistula repair), the two-stage procedure (interval enterolithotomy and cholecystectomy), and enterolithotomy alone.