Spontaneous Pyogenic Choledochal Fistula

Abstract

Spontaneous internal biliary fistulas (IBFs) are quite uncommon (<1%). These fistulas can develop between the gallbladder and bile duct with an internal organ, cavity, or a free surface. IBF is associated with chronic cholelithiasis in 90% of the cases. We report a rare case of choledochal fistula with an intra-abdominal abscess in a patient with chronic pancreatitis and diabetes mellitus, which were successfully managed with combined procedures of endoscopic retrograde cholangiopancreatography biliary stenting and ultrasound-guided drainage of the abscess.

Keywords

biliary fistula - abdominal abscess - chronic pancreatitis - ERCP - diabetes

Introduction

Biliary fistulas are an unusual communication from the biliary system to an organ, cavity, or free surface. They are further classified as external (biliary cutaneous) or internal (biliobiliary, bilioenteric, bronchobiliary).[1] Most internal biliary fistulas (IBFs) are associated with chronic cholelithiasis (90%).[2] These fistulas can develop from any part of the biliary system, like gallbladder, cystic duct, and extra- or intrahepatic bile ducts. The fistula most commonly occurs between the gallbladder and the duodenum, and the next most frequent site is between the bile ducts and the duodenum. Fistulas between the biliary system and the colon, stomach, or other nearby organs are observed less often. In patients with chronic pancreatitis, biliary fistulas can occur with pseudocysts and are extremely rare. Frequently these fistulas cause major complications like cholangitis and hemorrhage that can lead to significant morbidity.[3]

Case Report

A 36-year-old man with a background of alcohol-related chronic calcific pancreatitis presented with a 1-week history of generalized abdominal pain and fever without jaundice. His comorbidity also includes insulin-dependent diabetes mellitus. On general examination, his vitals were normal and abdominal examination revealed tenderness in the epigastric region with no obvious, palpable abdominal swellings. Blood parameters showed evidence of sepsis, neutrophilic leukocytosis (16,000 cells/µL), elevated C-reactive protein (CRP) of 246 mg/dL, and positive serum procalcitonin test. His serum amylase and lipase levels were within normal range. His liver function tests revealed normal total bilirubin, alanine aminotransferase, aspartate aminotransferase levels, and an elevated alkaline phosphatase of 200 (normal <130) U/L. A contrast-enhanced computed tomography (CECT) scan of the abdomen revealed a large collection measuring 17 × 6.6 × 4.5 cm (volume: 350 mL) in the porta hepatis, along the second part of the duodenum extending to the right paracolic gutter, and a 5.8-mm defect is also noted in the lateral wall of proximal common bile duct (CBD) and communication is noted between the collection and CBD ([Fig. 1A]). A magnetic resonance cholangiopancreatography (MRCP) confirmed the presence of a choledochal fistula at the proximal CBD with the intra-abdominal collection; there is no intrahepatic biliary radicle dilatation, and the gallbladder showed a thickened wall with minimal sludge as contents within ([Fig. 1B]). After obtaining consent, the patient was planned for both endoscopic retrograde cholangiopancreatography (ERCP) and sonographic drainage of the collection in the same session. A cholangiogram was done while performing ERCP, which showed a normal caliber left and right biliary system and distal CBD of 7 mm with active contrast leak from the proximal CBD into the collection ([Fig. 2A]). A 10-Fr, 10-cm straight plastic biliary stent was placed into the CBD, traversing the site of the leak. Bile aspirated during ERCP showed a low amylase content of 13 IU/L, and its culture grew Klebsiella species sensitive to antibiotics like levofloxacin, ciprofloxacin, and amikacin. The patient was initiated on culture-sensitive antibiotics, and an ultrasound-guided drainage of the collection was done using a 14-Fr pigtail catheter. Thick and purulent contents were drained from the collection, and its culture yielded the growth of Klebsiella species, which was the same as the bile culture. Further analyses of the collection fluid showed an amylase content of 45 IU/L, bilirubin of 0.3 mg/dL, and polymerase chain reaction test for Mycobacterium tuberculosis was negative. Post-ERCP and drainage of the infected collection, there was a significant improvement in the patient's clinical status: no further fever episodes, resolution of abdominal pain, and no further tachycardia. His blood tests showed normalization of WBC counts and a reduction in CRP. At 3 weeks of follow-up, a repeat CT scan of the abdomen revealed a complete collection resolution. Repeat ERCP was performed, and a cholangiogram demonstrated no leak from the proximal CBD ([Fig. 2B]). The biliary stent and the pigtail drain were removed consequently. The patient has no further symptoms or residual collection at 6 months of follow-up in the outpatient clinic.

Fig. 1 (A) Coronal section of CT of the abdomen demonstrating the site of fistula at proximal common bile duct (CBD; dotted arrow) with the paraduodenal collection (asterisk). (B) Magnetic resonance cholangiopancreatography (MRCP) 3D reconstruction image showing a defect along the lateral wall of the proximal CBD (dotted circle).

Fig. 2 (A) Cholangiogram demonstrating active contrast leak from the proximal common bile duct (CBD; arrow) into the collection (asterisk). (B) Repeat endoscopic retrograde cholangiopancreatography (ERCP) and cholangiogram demonstrating no active leak of contrast from the CBD.

Discussion

The common causes of IBF include cholelithiasis, peptic ulceration, malignant neoplasm (gallbladder, bile duct, duodenum, pancreas, or stomach), Crohn's disease of the duodenum, and paraduodenal abscess. The underlying pathogenesis of IBF development is due to acute inflammation of the gallbladder and adhesions to the adjacent viscus, usually to the duodenum. Recurring episodes of inflammation involve gangrenous alterations of the gallbladder wall and the wall of the neighboring organ, leading to eventual erosion and the development of a fistula.[1] Most IBF patients are asymptomatic and are often diagnosed intraoperatively or during biliary interventions like ERCP. MRCP can demonstrate IBF in selected cases[4]; however, ERCP remains the gold standard. According to the study by Duzgun et al, the incidence of cholecystoduodenal fistula and cholecystocholedochal fistula was 83.3 and 16.6%, respectively.[2] The standard treatment of IBF is cholecystectomy and repair of the fistulous opening[5]; additional procedures include bile duct exploration, T-tube insertion, choledochoduodenostomy, tube duodenostomy, enterolithotomy, and hepaticojejunostomy.

IBF with pancreatic pseudocysts is a rare condition with only limited cases reported in the literature to date. Progressive erosion of the biliary tract wall can occur due to compression of the pseudocyst, similar to the pathogenesis of other internal and arterial fistulas.[6] Complications include abdominal pain, jaundice secondary to biliary compression, and cholangitis. Hemobilia has been rarely reported due to erosion of blood vessels. Surgical treatment includes biliopancreatic bypass, pancreatoduodenectomy, hepaticojejunostomy with bile duct excision and choledochoduodenostomy. Nonsurgical interventions include endoscopic and/or percutaneous biliary/pancreatic drainages. A brief literature review by Al Ali et al on biliary fistulas with pancreatic pseudocysts mentions that most of the cases were resolved with surgical treatment (bypass procedures) and with internal or external biliary drainage.[7]

Compared with the above-mentioned spontaneous IBF with cholelithiasis and biliary fistula with a pancreatic pseudocyst, our case revealed a biliary fistula with an intra-abdominal abscess. Normal amylase levels in the bile aspirated during ERCP and in the percutaneous drain from the collection demonstrate that the collection was not of pancreatic origin. Also, the normal bilirubin levels analyzed from the collection fluid reveal that a spontaneous bile duct rupture causing an intra-abdominal collection was unlikely. Risk factors for the development of intra-abdominal abscess in our patient include diabetes and chronic pancreatitis. Microorganisms causing intra-abdominal abscesses are Burkholderia cepacia, B. pseudomallei, Salmonella, and Klebsiella.[8] Both bile and pus culture from the collection of our patient grew Klebsiella species, suggesting that it could be a possible primary intra-abdominal abscess eroding into the bile duct leading to a fistula formation.

Conclusion

IBF with intra-abdominal abscess is an extremely rare and fatal complication. Early and expedited intervention is essential in preventing septic shock and multi-organ dysfunction syndrome. Appropriate antibiotics and either endoscopic or percutaneous biliary/abscess drainage procedures remain the mainstay of treatment.

Conflict of Interest

None declared.

Acknowledgments

None.

Ethical Statement

Not applicable.

Authors' Contributions

All authors contributed equally to the article.

Data Availability Statement

There are no data associated with this work.

Consent

Informed consent was obtained for this case report.

• References

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• 3 Gustavo N, Alesio L, Lorna RT, Eugenia E, Flavia L. Pancreatic pseudocyst with fistula to the dilated common bile duct: mimmicking choledocal cyst?. Ann Hepatobiliary Pancreat Surg 2021; 25 (01) 155-159
• 4 Pickhardt PJ, Friedland JA, Hruza DS, Fisher AJ. Case report. CT, MR cholangiopancreatography, and endoscopy findings in Bouveret's syndrome. AJR Am J Roentgenol 2003; 180 (04) 1033-1035
• 5 Sapuła R, Skibiński W. Gallstone ileus as a complication of cholecystolithiasis. Surg Endosc 2002; 16 (02) 360
• 6 Sankaran S, Walt AJ. The natural and unnatural history of pancreatic pseudocysts. Br J Surg 1975; 62 (01) 37-44
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• 8 Dhanawat A, Gupta P, Mohanty L, Maheshwari G. Intra-abdominal abscesses by Burkholderia cepacia in poorly controlled diabetes mellitus: a case series. J Clin Diagn Res 2020; 14 (11) OR01-OR04

Publication History

Received: 11 February 2025

Accepted: 18 March 2025

Article published online:
22 May 2025