Gallstone ileus is a misnomer: this condition is not a physiologic ileus at all, but a mechanical obstruction of the intestinal lumen (most commonly the small bowel) by a large gallstone that has passed through a cholecystoenteric fistula. Cholecystoenteric fistulae may occur from the gallbladder to the adjacent luminal viscera-duodenum (most common), stomach, or colon. Gallstone obstruction of the stomach at the pylorus is known as Bouveret’s syndrome. Cholecystocolic fistula is less common. Colonic obstruction in this situation typically occurs at the sigmoid colon. Most common is cholecystoduodenal fistula, with a large (usually >2 cm) gallstone passing through the small bowel and becoming lodged in the terminal ileum. Cholecystoenteric fistula is felt to be caused by a combination of pressure, necrosis, and inflammation with chronic longstanding gallstone disease. Up to 25% of patients who develop gallstone ileus will harbor multiple stones in the alimentary tract; therefore, a close inspection of the entire intestine is important at the time of operation.
Over the past few years, however, the incidence of gallstone ileus has been shown to be greater than previously thought. Several recent large population-based series have found that gallstone ileus accounts for approximately 0.1% of all small bowel obstructions. The disease usually affects women (70%) and those in the seventh or eighth decade of life. Most patients present with bloating, crampy abdominal pain, and vomiting, symptoms typical of mechanical small bowel obstruction. A careful history may reveal earlier episodic colicky right upper quadrant abdominal pain consistent with gallstone disease. The classic finding on plain abdominal radiograph is that of Rigler’s triad (pneumobilia, dilated small bowel loops with air-fluid levels, and a large, calcified gallstone in the lumen of the small bowel). Currently, computed tomography (CT) is used ubiquitously. CT has 99% accuracy for diagnosing gallstone ileus. Typical CT findings include pneumobilia, dilated loops of small bowel with air-fluid levels consistent with small bowel obstruction, and transition point with the ectopic stone always visible radiologically.
Operation is required for all patients with gallstone ileus, as spontaneous passage of these large stones is rare once the patient has become symptomatic. It is crucial to optimize the patient physiologically as much as possible in this semi urgent situation, with the understanding that most gallstone ileus patients are elderly and commonly have numerous medical comorbidities. Two contemporary series of registry data have expanded our understanding of gallstone ileus. This condition was once thought to be relatively rare; however, the National Inpatient Sample study identified 3268 gallstone ileus patients, which accounts for approximately 0.1% of all patients admitted to the hospital with mechanical small bowel obstruction during this time period. In this series, overall hospital mortality was substantial at 6.7%. Mortality was significantly higher in patients who underwent cholecystectomy and closure of the biliary fistula compared to those who simply had small bowel obstruction addressed by cholecystolithotomy. Overall, 77% of the 3268 patients had small bowel obstruction pathology treated and the remaining 23% had biliary fistula closed and cholecystectomy at the same operation. An interesting finding was the substantial incidence of postoperative renal insufficiency, or approximately 30% in the entire group of patients. The latter finding highlights the need for preoperative resuscitation and close attention to postoperative fluid management. The surgeon must consider carefully feasibility of same operation intervention to repair biliary pathology: It is safe to defer biliary operation to a later date with a second staged operation. When this strategy of two stage operation is selected, surgeons should consider and counsel their patient regarding the substantial incidence of recurrent biliary symptoms.