Cholecystocolonic Fistula

Cholecystocolonic fistula is an abnormal communication between the gallbladder and the colon, most often the hepatic flexure or transverse colon. It is the second commonest cholecystoenteric fistula, accounting for about 10 to 20% of the group, and arises in less than 1% of patients with gallstone disease. It is more common in older women and patients with chronic cholecystitis of long standing.

Causes

• Gallstone disease with pressure necrosis from a large stone and inflammatory adhesion (the cause in over 90% of cases)
• Gallbladder carcinoma invading the colon
• Perforated duodenal ulcer, colon carcinoma, diverticulitis, trauma and instrumentation (ERCP or biliary stenting)

Bile flows into the colon, which causes bile acid diarrhea. Colonic bacteria enter the biliary tree and cause ascending cholangitis. A gallstone that passes into the colon may obstruct at the sigmoid colon, which is a rare cause of large bowel obstruction. Complications: cholangitis, sepsis, colonic obstruction by a stone, recurrent infection and cancer of the gallbladder in about 5%.

• Often asymptomatic, found at operation or on imaging
• Chronic diarrhea and steatorrhea, with malabsorption of fat-soluble vitamins
• Recurrent right upper quadrant pain, fever and jaundice from cholangitis
• Fecal vomiting is rare, and bowel obstruction from a large stone may occur
• Red flags: cholangitis with rigors, jaundice, sepsis and signs of large bowel obstruction

1. CT of the abdomen with intravenous contrast: air in the biliary tree (pneumobilia), a thickened gallbladder wall contracted around stones, a track between the gallbladder and the colon, and possible stone in the colon.
2. Ultrasound: air in the gallbladder or biliary tree and a contracted gallbladder with stones.
3. Barium enema or colonoscopy: contrast or fecal matter enters the gallbladder, and colonoscopy may show the fistula opening with bile.
4. ERCP or MRCP to define the biliary anatomy and exclude stones in the bile duct.
5. Laboratory tests: liver function, C-reactive protein, white cell count, and CA 19-9 if carcinoma is suspected.

Differentials: gallstone ileus, cholecystoduodenal fistula, colon carcinoma, diverticular disease, Crohn disease, gallbladder carcinoma.

1. Asymptomatic or unfit patients: observation may be reasonable when the fistula is found incidentally, with treatment of symptoms. Use cholestyramine 4 g orally once to twice daily for bile acid diarrhea.
2. Cholangitis or sepsis: piperacillin-tazobactam 4.5 g IV every 6 hours for 5 to 7 days, with biliary decompression by ERCP if there is a common duct stone or obstruction.
3. Definitive surgery:
   • Cholecystectomy with takedown of the fistula and repair of the colon: primary two-layer closure for a small defect with healthy bowel.
   • Segmental colectomy with primary anastomosis for a large or unhealthy defect, or when malignancy is suspected.
   • Intraoperative cholangiography and common bile duct exploration if stones are present.
   • Frozen section of the gallbladder, because of the risk of carcinoma, with an oncologic resection if cancer is found.
   • Open or laparoscopic approach, with conversion to open surgery when the dissection is difficult.
4. Perioperative prophylaxis: cefazolin 2 g IV with metronidazole 500 mg IV before incision, continued for 24 hours (longer if infection is present), and enoxaparin 40 mg SC once daily for 7 days.
5. Complications: bile leak (5 to 10%), colonic leak, bile duct injury, abscess, wound infection and recurrence.

Follow-up at 2 weeks, 6 weeks and 3 months. Counsel on dietary fat restriction at first and on early return for fever, jaundice or recurrent pain.