Although the etiology of conjugated hyperbilirubinemia in the pediatric population can be similar to adults, one must have a higher consideration for congenital biliary anomalies, such as choledochal cyst , accessory bile duct, and biliary atresia , when evaluating the neonatal or pediatric patient. Although malignancy of the bile duct is rare in the pediatric population, botryoid rhabdomyosarcoma can present with obstructive biliary disease, and a hepatic infiltrative process can resemble biliary obstruction in laboratory values. When evaluating the pediatric patient, the differential diagnosis must also include diseases seen in adults, such as choledocholithiasis, primary sclerosing cholangitis , and infectious etiologies (Table 20.2).

US is usually the first radiographic tool to evaluate the biliary system for obstructing stones or lesions and the gallbladder for cholelithiasis. US sensitivity for detecting bile duct stones ranges from 45 to 55 % [33, 34]. In addition, US may not be able to evaluate the entire bile duct due to anatomy and bowel gas that can obstruct the sonographic signals.

Computed tomography (CT), which is readily available, can provide valuable anatomical details of the pancreaticobiliary system in children with biliary obstruction. There are concerns that children are more radiosensitive than adults, and that increased exposure to ionizing radiation can potentially raise malignancy risk [35, 36]. Therefore, MRCP is usually recommended instead of an abdominal CT in the pediatric population for detailed imaging of the pancreaticobiliary system.

MRCP is the diagnostic study of choice after abdominal ultrasonography due to its ability to define the pancreaticobiliary anatomy well in a non-invasive manner. MRCP with and without contrast can evaluate for the presence of a choledochal cyst and for filling defects concerning obstructing lesions such as choledocholithiasis, or biliary neoplasms such as rhabdomyosarcoma. MRCP correlates highly with ERCP in the pediatric population [37]. Practically, one must consider whether the child can lay motionless for an MRCP over an extended period of time. Therefore, with infants and young children, sedation is usually required to ensure optimal MRCP image quality.

Endoscopic ultrasound (EUS) can image the entire pancreaticobiliary anatomy in detail while providing the opportunity to perform fine-needle aspiration and needle biopsy of concerning lesions. EUS is technically feasible and safe while adding valuable diagnostic information in the care of children [38–40]. Similar to ERCP, EUS can be limited in children mainly due to the relatively large outer diameters of the echoendoscopes. Currently, echoendoscope diameters range from 11.8 to 12.8 mm, which precludes its use in infants and small children. The variation in size of duodenoscopes makes ERCP easier than EUS in some cases as EUS can be difficult in small children and infants due to the relatively large outer diameter and stiffness of the tip of the echoendoscope.

The patient was admitted from the emergency department and rehydrated. Repeat laboratory values showed persistent conjugated hyperbilirubinemia and elevated markers of liver inflammation. The obtained MRCP confirmed a dilated biliary tree of the patient’s left and right intrahepatic bile ducts to the mid common bile duct with the largest diameter of up to 1 cm. The MRCP also revealed a filling defect in the distal bile duct, suggestive of a bile duct stone.

As the patient had persistent obstructive jaundice and radiographic findings suggestive of obstructing biliary stone, ERCP is a treatment option that can both further confirm the diagnosis and treat the biliary obstruction. ERCP with sphincterotomy and stone extraction can relieve the acute obstruction, treat potential ascending cholangitis , and reestablish bile flow. Larger stones may require more advanced techniques including mechanical, electrohydraulic, or laser lithotripsy . The latter two are performed under direct endoscopic visualization via a choledochoscope advanced into the bile duct (Video 20.1). As stated earlier, therapeutic ERCP in the pediatric population has been shown to be safe and effective for pancreaticobiliary diseases [8–12]. In cases of potential choledochal cyst , ERCP has an established role to better define the biliary anatomy, assess for the presence of an anomalous pancreaticobiliary junction, and aid the surgical planning for cyst resection [19, 41–46].

Due to persistent hyperbilirubinemia and high suspicion for obstructive jaundice suggested by MRCP, the patient underwent ERCP. Cholangiogram was consistent with MRCP showing dilated common hepatic, left, and right intrahepatic bile ducts. A 5 mm-filling defect was seen in the distal bile duct. Biliary sphincterotomy was performed and balloon sweep retrieved a bile duct stone. The patient recovered from the ERCP without complications and his laboratory values normalized. Repeat imaging 6 months post-ERCP and sphincterotomy showed persistent dilation of the common hepatic duct and intrahepatic ducts with normal liver laboratory values. As the biliary system remained dilated despite adequate drainage of his biliary system, the patient was diagnosed with a choledochal cyst and referred for surgical resection. After multidisciplinary discussion, it was decided that the patient complete all stages of his planned cardiac surgeries prior to the biliary cyst resection to optimize his cardiopulmonary status. There would also be little immediate risk of biliary complications, such as biliary obstruction with his biliary sphincterotomy providing adequate bile flow, and his risk of biliary malignancy was not immediate given his young age.

ERCP, EUS, and choledochoscopy are utilized for both, diagnosis and treatment in children after orthotopic liver transplant (OLT) and other abdominal organ transplants [47]. ERCP may be performed in the first days of transplant, although ideally after two weeks in patients with choledochocholedochostomy (duct-to-duct) or related anastomoses. Although the most common reason for transplant is biliary atresia (which requires Roux-en-Y anastomoses), in other infants and children, duct-to-duct anastomoses may be performed. Most commonly, ERCP is used in this population to diagnose and treat strictures or leaks at the anastomosis or vascular insufficiency leading to ischemic strictures (Figs. 20.10 and 20.11, Chap. 9) [48]. Cast-syndrome and other stone and sludge formations can occur in the setting of a stricture and should be treated at the same session. Balloon dilation of anastomotic or ischemic-induced strictures (using 4–8 mm diameter balloons) with or without stent placement (5F–10F with upsizing as appropriate) is frequently performed. Sphincterotomy with removal of stone and debris from the biliary tree can also be safely performed [47]. Direct visualization with choledochoscopy may be used to improve diagnostic yield in pediatric liver transplant patients [49, 50]. During ERCP, choledochoscopy has been used for a variety of indications to provide direct visualization and offer therapeutic options with subsequent change in management in over 60 % of the patients [50]. Percutaneous transhepatic cholangiography should be considered if ERCP is unsuccessful, and is usually the first option in children with Roux-en-Y anastomoses.

Traumatic leaks from blunt or penetrating injury as well as postoperative leaks are treated with combined sphincterotomy and stent or stent therapy alone (Fig. 20.12) [48]. Spontaneous bile duct perforation has been reported in an infant and ERCP with stent placement was used successfully [51]. Sphincter of Oddi manometry can also be performed to evaluate and treat patients with either suspected abnormal biliary or pancreatic types of sphincter of Oddi dysfunction . There is limited published data on normal pediatric sphincter pressure values, and larger pediatric series are usually grouped with other therapeutic ERCP procedures [52–54].

A 4-year-old boy with autism presented to the emergency department with acute onset of vomiting and abdominal pain and laboratory investigation notable for a lipase of 19,000 U/L. These symptoms had been ongoing for 2 years, but pancreatic enzymes were normal during a prior clinic visit. He was hospitalized for the first time with pancreatitis , and MRCP demonstrated normal pancreatic anatomy without strictures, dilation, or stones. He then had several additional episodes of documented pancreatitis. Genetic analysis confirmed a mutation encoding cationic trypsinogen (PRSS1).

It is generally accepted that ERCP is not necessary for the first episode of pancreatitis in a child, unless therapy is indicated from an auxiliary study, such as CT or MRCP. Improved imaging modalities have shifted the indications for ERCP from diagnostic to mainly therapeutic. The evaluation of recurrent pancreatitis typically involves a battery of labs, transabdominal ultrasound, and usually an MRCP (Table 20.3) [55]. ERCP is often considered at this point and recurrent pancreatitis is the most common indication for pancreatic ERCP in children (Table 20.4). While gallbladder or stone-related disease can be identified in patients of all ages, an anatomic cause is more likely in younger children. Multiple centers have reported their experience with pancreatic ERCP in children with recurrent pancreatitis, but there are limited recommendations to guide patient selection regarding pediatric-specific endotherapies [53, 54, 56–58].