Gallstone Ileus

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 2.5cm 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 2.5cm in diameter may traverse the alimentary canal without causing obstruction. When the gallstone lodges in the duodenum and causes gastric outlet obstruction, it is called Bouveret's syndrome.

It accounts for only about 4% of causes of intestinal obstruction but up to 25% of cases of intestinal obstruction over the age of 65. It is commoner in women than in men and the incidence reflects the prevalence of gallstones with age and sex. It is regarded as "rare and controversial".¹
The commonest site of impaction of gallstones is in the distal ileum, followed by jejunum and stomach.

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 non-specific tenderness of the abdomen is common.
• Auscultation will reveal rushes, gurgling and tinkling sounds at times of pain
• Features of dehydration will develop.

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.

• Plain abdominal x-ray with 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 (US). Computed tomography (CT) 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. From the practical perspective, plain abdominal films demonstrate small bowel obstruction, ultrasound shows biliary tract pathology and CT makes the final diagnosis.² Helical CT can be especially useful.³
• Blood tests should include FBC, U&E and creatinine, LFTs.
• In an elderly person, routine CXR and ECG before anticipated surgery is wise.
• In view of anticipated surgery, blood should be group and cross-matched.

Patients with gallstone ileus are often old and frail. They often have other pathology too.

• An intravenous infusion is required to correct dehydration and to reduce the risk of surgery.
• A nasogastric tube will decompress the stomach an 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.⁴ Some authors say that definitive treatment of biliary pathology at the initial operation is the management of choice.⁵ Others disagree as it is a longer operation in a high risk group and so the risk of complications is increased.⁶
• Some surgeons manage to achieve this by a laparoscopic technique.⁷

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

Because the condition tends to affect the old and frail, there is a 20% mortality.