Gallstone ileus is an uncommon cause of mechanical bowel obstruction.
However,
it is associated with high morbidity and mortality (8-30%) [1-3],
and usually affects elderly patients,
who often had other concomitant medical-surgical diseases.
It is crucial an early and precise preoperative diagnosis,
where different imaging tests play an important role.
We will review the most important aspects of this entity,
particularly the main radiological findings,
and illustrate it with a series of 5 cases of our center.
PATHOGENESIS
The gallstone ileus is defined as the intestinal impaction of a gallstone passing through a bilioenteric fistula mainly cholecystoduodenal (60%) [1,4,5].
There may be other fistulous communications (cholecysto-colonic,
cholecysto-jejunal,
cholecysto-gastric,
and more rarely,
choledocus-duodenal [6].
The 1-15% of bileoenteric fistulas produce gallstone ileus [6,7].
Probably the responsible process for most cases of fistula formation is due to the impaction of a large stone in the gallbladder,
causing pressure,
ischemia and necrosis of the wall of it that leads to the development of a inflammatory adhesion between gallbladder and intestine,
and then an erosion of gallstones on adjacent structures,
causing a cholecystoenteric fistula,
with the subsequent evacuation of the stone to the intestinal tract.
The entrance to the small gallstone may also occur by natural pass through the bile duct due to Oddi’s sphincter disorders,
especially after surgical enlargement of it.
Usually,
the gallstone that go into the digestive tract are expelled in the feces [7],
but if the stone size exceeds the diameter of the bowel segment,
it could impact and cause obstruction.
Most of the obstructing stones are bigger than 2.5 cm. diameter [1-8] unless there is some preexisting intestinal pathology that alters the dynamics or causes stenosis,
where a smaller size gallstone can locked it.
The most gallstones impact at the terminal ileum (50-70%) [4-7],
due to its relative minor diameter and peristaltic activity [6],
followed by jejunum (15-31% of cases) [6,7],
stomach (14%) [6],
duodenum (3 - 5%,
[6,7] which is known as Bouveret's syndrome) and colon (2.5 - 8% of cases [6,7].
Usually as a result of a preexisting pathology).
We can find multiple gallstones along obstructed bowel,
that is an important fact to keep in mind in surgery of this entity,
to prevent future recurrences.
INCIDENCE
Gallstone ileus is a rare complication of cholelithiasis (less than 0.5% of patients) [2-4,6,7],
and involve a 1-4% of mechanical intestinal obstruction [1,4,6,7,9,10],
increasing to 25% over 65 years [1,3,4,6,7,10].
Usually affects elderly patients,
between 65 and 75 years of age [2,4,5,7,8],
with a higher prevalence in females (ratio 5:1) [3,6,8] (4 of 5 cases from our center),
attributed to the higher frequency of gallbladder disease (cholelithiasis or cholecystitis) [7]
PREOPERATIVE DIAGNOSIS
The classic clinical presentation is a elderly woman with prior biliary disease,
that presents a episodic subacute intestinal occlusion ("tumbling obstruction") as a result of continued stone migration.
The gallstone impaction produces transient abdominal pain and vomiting,
disappearing when the stone moves in the intestinal lumen,
and reappear with a new obstruction.
Intermittent symptoms may be present several days prior to the medical evaluation (median 4-8 days) [4,6,8].
Hematemesis is an occasional complication due to bleeding at the site of biliary enteric fistula formation.
It is important to have a high clinical suspicion of this entity,
being able to suggest it as a preoperative diagnosis based on a plain abdominal film.
Other imaging modalities used are ultrasound and CT being this the most important because it allows a more accurate and early diagnosis,
that helps in the therapeutic approach.
Only 50-77 % of cases had a correct preoperative diagnosis [4,6].
In other cases the diagnosis is performed by laparotomy [4].
TREATMENT
The main therapeutic goal is to solve the obstruction [3,6],
mainly through a surgical procedure: enterolithotomy and stone extraction (4 of our 5 cases).
A one-stage procedure may be considered in patients at low surgical risk [3,4,6].
Consisting in surgical resolution of the obstruction,
surgical treatment of biliary-enteric fistula and cholecystectomy.
In patients in a high surgical risk,
most of the patients,
the main goal is to treat first the intestinal obstruction.
The gallbladder can be removed in a two-stage procedure if there is a recurrence or symptoms of cholecystitis [4,6].
Biliary-enteric fistulas may close or shrink spontaneously,
especially if the cystic duct is patent or there are no residual stones [4].
The risk of recurrence is 4.7-10% [3-6,9].
The surgeon must inspect the entire intestine in order to rule out further gallstones,
which can be found in a proportion of 3-44% [3].
Bowel resection may be needed,
when there is a perforation,
ischemia,
or a gallstone that can not be detached.
Sometimes the entity may resolve spontaneously (7%) [6],
as happened in one of our cases.