It is a rare complication of cholelithiasis .
It is defined as a mechanical intestinal obstruction due to the presence of one or more gallstones in the intestinal lumen.
The term “ileus” is a misnomer, as obstruction is a true mechanical phenomenon. Gastrointestinal obstruction from gallstones would be an appropriate term.
This entity was first described by the Danish physician Thomas Bartholin in 1654 during an autopsy.
This was the first preoperative diagnosis of Bouveret’s syndrome .
Gallstone ileus accounts for 1–2% of all causes of mechanical bowel obstruction, but it should always be considered whenever small bowel obstruction is found in an elderly patient.
Causes of biliary ileum
Gallstone ileus is frequently preceded by an initial episode of acute cholecystitis.
Inflammation in the gallbladder and surrounding structures leads to the formation of adhesions.
Inflammation and the pressure effect of the offending gallstone cause erosion through the gallbladder wall, leading to fistula formation between the gallbladder and the adjacent, attached portion of the gastrointestinal tract.
The size of the gallstone, the site of fistula formation, and the intestinal lumen will determine whether an impaction will occur.
The site of impact can be almost anywhere in the gastrointestinal tract.
If the gallstone enters the duodenum, the most common intestinal obstruction will be the terminal ileum and ileocecal valve due to their relatively narrow lumen and potentially less active peristalsis.
Less commonly, the gallstone may impact the proximal ileum or jejunum, especially if the gallstone is large enough.
Gallstone ileus has been reported at anastomotic sites after partial gastrectomy and Billroth II reconstruction and after biliointestinal bypass.
Some factors that can increase the risk of ileus include:
- According to the predominance of female patients in gallstone disease, the majority of patients with gallstone ileus correspond to the female gender.
- Gallstone ileus has been observed more frequently among the elderly.
- The presentation of gallstone ileus may be preceded by a history of previous biliary symptoms.
Symptoms of gallstone ileus
Biliary symptoms may be absent. But gallstone ileus can manifest as acute, intermittent, or chronic episodes of gastrointestinal obstruction.
Nausea, vomiting, acute abdominal pain, and variable bloating are common.
The intermittent nature of the pain and vomiting of the proximal gastrointestinal material, which later turns dark and starchy, is due to the advancement of the stones.
Thus, there may be intermittent partial or complete intestinal obstruction, with temporary progression of the gallstone and relief of symptoms, until the gallstone passes through the gastrointestinal tract or is permanently impacted and complete intestinal obstruction occurs.
Recent weight loss, anorexia, early satiety, and constipation may be referred symptoms.
Signs of dehydration, abdominal distention, and tenderness are seen with high-pitched bowel sounds and obstructive jaundice .
Other symptoms such as fever, toxicity, and physical signs of peritonitis may occur if a perforation of the intestinal wall occurs.
The symptoms and signs of gallstone ileus are mostly nonspecific.
The intermittence of symptoms could also interfere with a correct diagnosis, if the clinical manifestations at this time correspond to a partial obstruction or distal migration of the gallstone.
Imaging tests help locate an ileus by highlighting abnormalities in the intestine, such as gas accumulation or an enlarged intestine.
The tests used include:
Plain X-ray of the abdomen
Plain radiographs of the abdomen are of great importance in establishing the diagnosis. It can show signs like:
- Partial or complete intestinal obstruction.
- Pneumobilia or contrast material in the biliary tree.
- Aberrant gallstone and two levels of air fluid in the right upper quadrant on an abdominal radiograph.
A CT scan provides more detail than standard X-ray images.
These scans are more likely to highlight an ileus because they show the intestines from different angles.
Three diagnostic criteria can be identified, first an obstruction of the small intestine, second an ectopic gallstone, either calcified at the edge or calcified in total, and third an abnormal gallbladder with complete air collection, presence of air fluid level or buildup of fluid with irregular wall.
Doctors often diagnose children with suspected ileus by ultrasound.
When the diagnosis is still in doubt, an abdominal ultrasound will be indicated for gallbladder stones, fistula, and visualization of impacted gallstones.
The presence of choledocholithiasis can also be confirmed.
Magnetic resonance cholangiopancreatography
Magnetic resonance cholangiopancreatography may be useful in selected cases where the diagnosis is unclear after computed tomography.
Treatment of gallstone ileus
The main therapeutic objective is the relief of intestinal obstruction by removing the offending gallstone.
Fluid and electrolyte imbalances and metabolic disorders due to intestinal obstruction, late presentation, and pre-existing comorbidities are common and require treatment before surgery.
Enterolithotomy has been the most commonly performed surgical procedure.
Through an exploratory laparotomy, the site of gastrointestinal obstruction is located.
A longitudinal incision is made on the antimesenteric border proximal to the gallstone impaction site.
Laparoscopy can be performed on the affected ileum segment, removed from the abdominal cavity through a small incision, and the gallstone can be removed through enterotomy.
Gallstones that cause gastroduodenal or colonic obstruction may be amenable to endoscopic detection and, in certain cases, endoscopic removal.