Description

Gallstone ileus is obstruction of the bowel due to impaction of one of more gallstones. To achieve this, stones usually have to be at least 2.5 cm in diameter.

A fistula develops between a gangrenous gallbladder and the duodenum or other parts of the gastrointestinal tract, allowing passage of the stone. Occasionally the stone may enter the intestine through a fistulous communication between the bile duct and the gastrointestinal tract. Stones less than 2.5 cm in diameter may traverse the alimentary canal without causing obstruction.^[1] When the gallstone lodges in the duodenum and causes gastric outlet obstruction, it is called Bouveret's syndrome.

Epidemiology

It accounts for only about 1-4% of causes of intestinal obstruction, but up to 25% of cases of intestinal obstruction in those over the age of 65. It is more common in women than in men and the incidence reflects the prevalence of gallstones with age and sex. It is regarded as 'rare and controversial'.^[2][3]

The most common site of impaction of gallstones is in the distal ileum, followed by the jejunum^[4] and the stomach.

Presentation

The presentation is usually that of distal obstruction of the small bowel but the symptoms and signs of gallstone ileus can be vague. It is important to make the diagnosis, as there is a high mortality in the usual age group.

Symptoms

• Abdominal pain is an early sign with vomiting developing later. It tends to become progressively more severe.
• Abdominal pain is colicky in nature, with freedom from pain between spasms. It is periumbilical and is not clearly localised.
• Abdominal distension develops.
• Initially the patient may pass stools or flatus but not later.
• Vomiting occurs some hours after the onset of pain and it may be faeculent.

Signs

• Patients with gallstones are often, but not invariably, obese.
• The patient tends to look unwell.
• The abdomen may be bloated and small bowel peristalsis may be visible.
• Some slight and nonspecific tenderness of the abdomen is common.
• Auscultation will reveal rushes, gurgling and tinkling sounds at times of pain.
• Features of dehydration will develop.

Differential diagnosis

This is between other causes of intestinal obstruction. This may include adhesions from previous surgery. Malignancy almost never occurs in the small intestine. Large bowel malignancy tends to present as chronic blood loss when proximal and obstruction when distal. This is because the contents of the bowel are liquid in the first part and become progressively more solid as they traverse the colon.

Investigations

• Plain abdominal X-ray should show the typical features of small intestinal obstruction. It may be possible to see air in the biliary tract. It may be possible to see a radio-opaque gallstone.
• Rigler's triad of small bowel obstruction, pneumobilia and ectopic gallstones may be occasionally detected by plain radiograph or ultrasound. Computed tomography (CT) scanning invariably demonstrates a fistulous communication, intraluminal gallstone in the small bowel, pneumobilia and any other co-existing pathology contributing to the impaction of the gallstone. The interpretation of subtle signs on CT scanning requires skill but can increase the accuracy of the diagnosis.^[5] From the practical perspective, plain abdominal films demonstrate small bowel obstruction, ultrasound shows biliary tract pathology and CT makes the final diagnosis.^[6][7] Helical CT can be especially useful.^[8]
• Blood tests should include FBC, U&E and creatinine, and LFTs.
• In an elderly person, routine CXR and ECG before anticipated surgery are wise.
• In view of anticipated surgery, blood should be group and cross-matched.

Associated diseases

Patients with gallstone ileus are often old and frail. Cases of gallstone ileus have been reported in patients whose intestines are strictured due to tuberculosis or other disease.^[9]

Management

• An intravenous infusion is required to correct dehydration and to reduce the risk of surgery.
• A nasogastric tube will decompress the stomach and avoid further vomiting.
• Removal of the obstruction at laparotomy should be accompanied by a careful search for other gallstones proximal to the obstruction. It is generally recommended that those with chronic gallstone problems should undergo a later cholecystectomy, but it can be performed concurrently.^[10] Some authors say that definitive treatment of biliary pathology at the initial operation is the management of choice.^[11] Others disagree as it is a longer operation in a high-risk group and so the risk of complications is increased.^[12] One retrospective study concluded that treatment should be individualised and that removal of the stone through the bowel (enterolithotomy) should only be accompanied by cholecystectomy if the patient has good cardiorespiratory reserve and with absolute indications for biliary surgery at the time of presentation (the one-stage procedure).^[7]
• Some surgeons manage to use a laparoscopic technique.^[13]

Complications

Complications are common as this is major surgery, usually in a group who are old and frail.

Prognosis

Because the condition tends to affect the old and frail, there is a 20% mortality. There appears to be no real difference in terms of the operative procedure performed, eg simple enterolithotomy to fistula repair.^[14] [X20023]