Choledochoduodenal fistula: An unusual cause of recurrent cholangitis in children.

Choledochoduodenal fistula (CDF) is an unusual clinical entity and a diagnostic challenge in children. We herein present CDF as an unusual cause of recurrent cholangitis in a 6-year-old child. To the best of our knowledge, this is the youngest patient reported until date. In this paper, we also highlight possible etiologic factors, presenting symptoms, diagnostic methods, and treatment modalities of CDF.

INTRODUCTION

Choledochoduodenal fistula (CDF) is defined as an abnormal passage between the common bile duct (CBD) and duodenum. It mostly affects patients of older age, and is an unusual clinical entity in children. Only a single case of CDF has been reported in an adolescent patient so far.[1] We herein report the case of a 6-year-old female child with CDF. To our knowledge, our case is the youngest patient reported in the literature.

CASE REPORT

A 6-year-old girl was referred to our hospital due to elevated serum hepatic transaminases. Her medical history revealed that she was suffering from recurrent postprandial vomiting and right upper quadrant pain that remained undiagnosed for two years. On admission, her vital signs were normal, and her physical examination was notable only for moderate right upper quadrant tenderness. Initial laboratory investigations revealed mild leukocytosis (10,500/mm3) and elevated levels of alanine aminotransferase (150 U/L), aspartate aminotransferase (110 U/L), γ-glutamyltransferase (559 U/L), and alkaline phosphatase (594 U/L), along with a normal bilirubin level. Abdominal ultrasonography (USG) showed mildly dilated intrahepatic ducts and a CBD of 7 mm in diameter, and a 5-mm gallstone in the gallbladder. Magnetic resonance cholangiopancreatography (MRCP) showed a normal pancreatic duct, and the distal CBD obstruction with proximal ductal dilatation and a suspicious CDF [Figure 1]. The diagnosis of CDF was confirmed by percutaneous transhepatic cholangiography (PTC) [Figure 2]. Exploratory laparotomy revealed dilated extrahepatic bile ducts due to distal CBD obstruction [Figure 3]. Although there was a 5-mm stone in the gallbladder, we did not observe any stone in the CBD. Surgical exploration did not manifest the choledochoduodenal fistula because the distal CBD passed through the pancreatic parenchyma, and severe adhesions were noted in this area. Eventually, cholecystectomy, CBD excision, and Roux-en-Y hepaticojejunostomy were performed on the patient. The patient's postoperative course was uneventful.

Figure 1

Magnetic resonance cholangiopancreatography shows a suspicious CDF (white arrow)

Figure 2

Percutaneous transhepatic cholangiography shows a distal CBD obstruction with proximal ductal dilatation (white arrow), and a CDF (black arrow)

Figure 3

Peroperative photo shows dilated extrahepatic bile ducts

DISCUSSION

CDF is a rare biliary disease, and its exact incidence is unknown in children. In a study from Argentina, 2,012 adult patients with biliary diseases who underwent endoscopic retrograde cholangiopancreatography (ERCP) were reviewed; of these, 14 (0.7%) patients were found to be having CDF.[2] Another review of 1,200 ERCPs in China found 50 cases (4.2%) of CDF.[3] CDF is a complication secondary to some biliary diseases and conditions such as cholelithiasis, recurrent biliary tract infection, previous biliary surgery, endoscopic sphincterotomy, perforated duodenal ulcer, periampullar tumor invasion, and blunt abdominal trauma.[1456] Among these, cholelithiasis is suspected to be the leading cause. Sheu et al.[4] reported 2.53% incidence of CDF in an area endemic for cholelithiasis, which is greater than that found in non-endemic areas. The exact mechanism of CDF caused by gallstones is still vague. The putative mechanism is that CBD obstruction caused by gallstones or recurrent cholangitis results in increased proximal ductal pressure that may lead to fistula formation.[4] Pressure necrosis caused by calculi in the inflamed biliary tract was also proposed as another mechanism.[7] The presence of cholelithiasis supports both scenarios in our case.

CDF is classified into distal and proximal types.[8] The distal type connects to the duodenum via one or multiple fistula orifices located within 2 cm of the distal CBD, and drains into the peripapillar area. The proximal type drains along the posterior wall of the duodenal bulb via a fistula orifice located elsewhere at a distance of more than 2 cm from the papilla. According to this classification, the present case was classified as the proximal type.

The clinical presentation of CDF is usually non-specific. The most common symptoms include right upper quadrant pain, fever, and jaundice. More than 90% of the patients with CDF have recurrent cholangitis because the fistula offers a route for ascending infection.[34] Although our patient presented with right upper quadrant pain and recurrent cholangitis, she did not suffer from jaundice. This condition may be clarified by lower bilirubin levels in proximal CDF, in which the diameter of the fistula is larger than that in distal CDF.[4] The presence of fistula serves as a compensatory mechanism for obstruction, so these cases disclose less jaundice. Furthermore, our patient presented with recurrent vomiting, which is another gastrointestinal manifestation of CDF.

Although CDF is a difficult to diagnose pathology, recent advances in imaging and endoscopic techniques have led to the increased detection of CDF. Pneumobilia can be seen in biliary enteric fistulas.[5] Although this radiologic finding is suggestive of CDF, it did not manifest in our case. MRCP did not demonstrate the fistula exactly, and revealed only findings suspicious for a CDF in our case. Such a suspicious case requires further evaluation by ERCP. The fistula tract can be visualized by endoscopic retrograde cannulation of the CBD, and the fistula orifice may be directly observed endoscopically. However, a highly skilled and experienced team is required for performing ERCP in children. Due to our limited institutional experience with ERCP in children, the diagnosis was confirmed by PTC.

The management of CDF is still controversial. The choice of treatment depends on the etiology, type of the fistula, and severity of the disease. The patients with untreated CDF have a high recurrence of biliary tract information.[4] To prevent this undesirable complication, correction of CDF is necessary. Although distal CDF can be managed by endoscopic approaches,[2] proximal CDF cannot be corrected by this method as early surgery is indicated. Therefore, biliary enteric anastomosis is considered as an effective treatment in our case.

Herein, we present CDF as an unusual cause of recurrent cholangitis in a child. CDF is a diagnostic challenge in children. If MRCP is non-diagnostic, PTC can be considered as an alternative diagnostic method to ERCP. Biliary enteric anastomosis is an effective treatment method for recurrent cholangitis in children with CDF.