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Cholecystocolic fistulas comprise between 10% and 20% of all biliary intestinal fistulas. In the majority of cases they are a sequel of cholecystitis but are reported to complicate only 0.13% of cases.1
A 72 year old man was admitted in our hospital for evaluation of unexplained pneumobilia demonstrated on a routine ultrasound examination of the abdomen. The patient admitted that in previous years he had recurrent episodes of biliary-type pain accompanied by low grade fever, but in the previous nine months he had been free of symptoms from the biliary tract. Barium enema was normal and blood examination showed no abnormalities. Endoscopic retrograde cholangiopancreatography (ERCP) revealed a cholecystocolic fistula (fig 1). The patient underwent cholecystectomy, excision of the fistula, bile duct exploration, and intraoperative cholangiography.
In most patients with cholecystocolic fistula, a long history of biliary tract disease is obtainable. A sequence of events occur in acute obstructive cholecystitis, resulting in the formation of the fistula.2 During these attacks, the adjacent serosal surface becomes inflamed and adherent to the gallbladder. The ischaemic area in the wall of the gallbladder becomes gangrenous, and the increased pressure within results in its contents penetrating its own necrotic wall at first and then the wall of the adjacent viscus, forming a cholecystocolic fistula.2 Recurrent episodes of jaundice and cholangitis along with small amounts of air seen within the biliary tree should raise the possibility of a cholecystocolic fistula. The most useful techniques for diagnosis are plain film of the abdomen, barium studies, and biliary scintigraphy. ERCP can identify cholecystocolic fistulas by visualisation of the colon after injection of contrast medium in the common bile duct. The recommended treatment for these fistulas is cholecystectomy, excision of the fistula, common bile duct exploration, and intraoperative cholangiography.
Although diagnosis of cholecystocolic fistula is rarely suspected clinically, it should be considered in elderly patients with unexplained biliary pneumobilia or unexplained persistent diarrhoea. ERCP can be helpful in establishing diagnosis, especially if barium studies are negative.