Chapter 27 ERCP in Children

Endoscopic retrograde cholangiopancreatography (ERCP) was introduced into pediatric medicine in the mid to late 1970s following initial experience in adult patients.¹ It is now routinely used for the diagnosis and treatment of biliary tract and pancreatic diseases in children who are referred to major medical centers worldwide.²^–⁹ Although technical expertise remains concentrated among endoscopists trained in adult medicine, pediatric specialists routinely collaborate closely in patient selection and pre- and postprocedural management.¹⁰ In high volume tertiary pediatric referral centers, ERCP is sometimes performed by expert pediatric endoscopists working alone or in concert with adult medicine endoscopists.

Major differences between adult and pediatric ERCP relate to alternative approaches to patient preparation and sedation, to technical constraints imposed by equipment that is less favorably suited for use in small children and infants, and to a spectrum of biliary and pancreatic pathology that is skewed toward congenital and benign acquired conditions.

Description of Technique (Box 27.1)

Procedure Setting

In modern practice, most patients undergo ERCP with the potential for immediate therapeutic intervention. Therefore the setting in which the procedure is conducted should include appropriate equipment and staff to proceed with available therapies and support for adverse events that might arise. Although interventional ERCP can be performed safely on an ambulatory basis, overnight hospital admission for observation is often advisable since the signs of symptoms of adverse events may not be reliably reported or recognized early in a child. Immediate access to subspecialty consultation by pediatric anesthesiologists, surgeons, and radiologists is essential to provide optimal and comprehensive team management. Ideally, recovery nurses with experience in recognition and initial management of postoperative adverse events that occur in children should be available to expedite supportive interventions.

Box 27.1

Key Points

Pediatric emergency equipment and subspecialists should be immediately available to manage adverse events.

The endoscopist should be familiar with pediatric pathology or consult a pediatric specialist and have technical ability to proceed with therapeutic intervention.

General anesthesia is required for the majority of young children.

Fluoroscopic equipment should be adjusted for children to minimize radiation exposure.

Ultraslim diameter duodenoscope is required for infants <12 months of age.

Endoscopist

Pediatric ERCP requires advanced technical skills and sufficient breadth of clinical experience to achieve an optimal outcome for the child. This may involve the collaborative efforts of adult and pediatric medicine specialists.

Therapeutic ERCP requires that an endoscopist achieve selective deep cannulation of the desired (biliary or pancreatic) duct with greater than 90% success to enable the essential interventions of dilation, stent placement, sphincterotomy, and stone extraction. Since experience with more than 200 cases is required by the average trainee to achieve this rate of technical success ¹¹ and the volume of pediatric cases is relatively small even in tertiary care facilities, pediatric specialists will require either supplemental training with adult patients or a very long training period to achieve initial competence. The volume of cases required to maintain competence remains controversial and will vary by endoscopist and by complexity of procedures.¹² Adverse event rates have been shown to correlate with case volume for both endoscopist and facility.^13,¹⁴ High ERCP volume and advanced endoscopic skills reside most often within adult medicine centers of excellence, and technical success is certainly required for optimal outcomes. Yet children may have limited access to these centers. Endoscopists must consider these factors and the availability of alternative management options before embarking on ERCP in pediatric patients.

Sedation

Most pediatric gastroenterologists prefer general anesthesia or deep sedation for technically challenging procedures in children. There has also been a trend toward more frequent use of deep sedation and anesthesia in adults undergoing particularly uncomfortable or lengthy endoscopic procedures. Although ERCP in children and especially in cooperative adolescents may be performed successfully with intravenous moderate sedation, general anesthesia with endotracheal intubation affords safer airway management with assured analgesia and hypnosis for as much time as is necessary to complete a potentially lengthy or difficult procedure.

Fluoroscopy

Fluoroscopy for pediatric ERCP may be performed using a fixed table in a dedicated fluoroscopy suite or a portable C-arm in a separate procedure room. The advantages of the C-arm device are portability, lower cost, and easier oblique imaging. Modern digital devices provide excellent image quality. The x-ray equipment should be adjusted to accommodate the smaller body of a young child and reduce the radiation dose rate. Shielding of reproductive organs is important and should be performed in all patients. Good fluoroscopic technique by the examiner can minimize radiation exposure to the child and to personnel (see also Chapter 3). The following rules or principles will help advance this goal: (1) Position the child so that the beam takes the shortest distance through the body—i.e., avoid unnecessary oblique projection; (2) position the image intensifier or receptor above the patient; (3) minimize the distance of the intensifier and maximize the distance of the x-ray tube to the child’s body; (4) use the least magnification necessary and use field collimators to focus on areas of interest; (5) avoid the use of a grid; and (6) minimize beam-on time and use the slowest pulse rates that produce acceptable imaging for a given task. The assistance of a radiation technologist with pediatric experience for equipment setup and the availability of a radiologist with pediatric training for consultation can be very important in achieving the goals outlined above. Either low osmolar, nonionic or high osmolar, water-soluble contrast media in the range of 150 to 300 mg/mL may be used.

Supplemental Medications

Drug dosing for children is usually based on units per kilogram body weight ranging up to maximum adult doses. In addition to limited use for endocarditis prophylaxis, antibiotics are used in the setting of high-grade biliary or pancreatic duct obstruction, biliary or pancreatic duct disruption, and pancreatic pseudocyst. Ampicillin/sulbactam (100 to 200 mg/kg/day intravenous [IV] divided every 6 hours, maximum 4 g sulbactam per day), a broad-spectrum cephalosporin such as cefazolin (50 to 100 mg/kg/day IV divided every 8 hours, maximum 6 g/day), or a fluoroquinolone such as ciprofloxacin (20 to 30 mg/kg/day IV divided every 12 hours, maximum 800 mg/day) is usually adequate. Intravenous glucagon can be used to briefly reduce duodenal contractions during cannulation. A dose of 0.5 mg IV is appropriate for most ages and can be repeated. Intravenous secretin 0.2 mcg/kg may be used to facilitate successful cannulation of the minor papilla.

Endoscopic Equipment

Children of all ages and sizes, including full-term neonates, can undergo diagnostic and therapeutic ERCP using duodenoscopes that are commercially available. Standard diagnostic duodenoscopes with insertion tube diameters in the range of 11 to 12 mm can be used effectively in children older than 2 years and with difficulty between 1 and 2 years of age. These endoscopes generally have operating channels that will accommodate catheters and stents up to 7 to 8 Fr, which is adequate for most interventions. While “therapeutic” duodenoscopes containing operating channels in excess of 4 mm are needed to place 10 Fr stents, such large endoprostheses are rarely needed in young children. These larger endoscopes are easily used in adolescents.

Neonates and infants require a small diameter instrument in the range of 7 to 8 mm that will pass easily through the pylorus and allow effective positioning of the tip adjacent to the major papilla. Currently, there is only one commercially available duodenoscope that is suitable for use in small infants, the PJF 160 (Olympus America, Inc., Lehigh Valley, Pa.). This endoscope has a maximum distal tip diameter of 7.5 mm, an operating channel diameter of 2.0 mm, and an elevator. Basic diagnostic and therapeutic maneuvers are possible with this endoscope, although the repertoire of available accessories that will fit through the small operating channel is somewhat limited. Catheter tips that taper to a diameter of 3 to 4 Fr are helpful in order to selectively cannulate biliary and pancreatic ducts in infants. However, deep advancement of catheters into normal ducts is not always possible in young infants due to the fine caliber of these structures at this age (Fig. 27.1). An ultratapered (3.5 Fr) cannula, a retrieval balloon catheter, and a wire basket catheter that will fit the 2.0 mm channel of the PJF 160 duodenoscope are available from Olympus. Other highly tapered cannulas such as the precurved Glo-Tip, GT-5-4-3 (Cook Endoscopy, Winston-Salem, N.C.) may be used. A tapered-tip sphincterotome catheter with a short cutting wire such as the UTS-15 (Cook Endoscopy) can be advanced with some resistance through the operating channel of the PJF 160 endoscope.

Fig. 27.1 Former 28-week gestation neonate, now a 3-month-old, 3 kg infant with severe cholestasis. A, Transabdominal ultrasound showed fusiform distension of the common bile duct containing debris suggestive of choledochal cyst. B and C, Endoscopic views of major and minor papillae. D, E, and F, Initial and completed sphincterotomy and emerging sludge. G, Tiny normal pancreatic duct. H, Wire-guided access for deep bile duct cannulation. I and J, Cholangiogram during and after basket extraction of sludge.

Technique

The techniques for ERCP in children are the same as for adult patients. The procedure can be conducted with the child either prone or supine on the examining table, although prone positioning is most comfortable for the endoscopist. The basic endoscopic maneuvers are more technically challenging in children because side-viewing endoscopes and accessories have not been optimally designed to work in a narrow lumen and through a narrow operating channel, respectively. In small children and infants the endoscope tip is forced into a position in close proximity to the papilla, allowing very little of the cannula to extend out into view and increasing the difficulty of achieving optimal position for selective bile duct cannulation. Although precurved cannulas are available, selective biliary cannulation is most easily achieved using a tapered tip, pull-type sphincterotome with a short cutting wire. Tightening the cutting wire increases angulation of the catheter tip within a short working distance from the papilla. Also, by starting the procedure with a sphincterotome, the endoscopist can proceed directly with therapy when indicated. Wire-guided access, using a soft-tipped, hydrophilic, narrow gauge wire, may be used if free cannulation proves too difficult (Fig. 27.1). Stiff catheters such as those used for stricture dilation or stone retrieval are more likely to require wire-guided entry. Also, in young infants a soft-wire retrieval basket will enter the duct more easily if partially opened since the basket wires are more flexible when extending from the stiffer plastic sheath. Alternatively, the endoscope can be placed in the long position, which may achieve a more favorable position in front of the major papilla, similar to the technique used for cannulation of the minor papilla. However, tip control is not optimal with the endoscope in this position. Sphincterotomy, stone extraction, and temporary stent placement have all been successfully performed in very young infants using small diameter endoscopes (Fig. 27.2).¹⁵^–²⁰

Fig. 27.2 Placement of a nasobiliary stent in a 4-month-old infant following sphincterotomy for an impacted stone.

Although the PJF 160 duodenoscope with a 2.0 mm operating channel will accept accessory catheters of 5 Fr diameter, the catheters tend to bind in the channel when the endoscope tip is angled. In addition, air and fluid cannot be evacuated easily when a catheter is within the channel. The endoscopist must be careful to avoid overdistension of the bowel with air, which can impede movement of the diaphragm and acutely compromise ventilation in an infant. It is also difficult to maintain a stable tip position when using a small diameter endoscope in an infant since much of the long flexible insertion tube remains unanchored outside of the child. Assistance is sometimes needed to maintain torque on the insertion tube.

Another caveat to consider when instrumenting a small child or infant is the fragility of the soft tissues. Repeated impaction of catheters or wire guides against the papilla in a young infant can render the structure unrecognizable due to traumatic edema. Also, a false tract can be created using surprisingly little force while advancing a catheter or wire into the ampulla of Vater or into the minor papilla.

Indications and Contraindications (Box 27.2)

Diagnostic and Therapeutic Indications

While the necessity of diagnostic ERCP has been diminished by advances in magnetic resonance cholangiopancreatography (MRCP), subtle diagnostic findings are still best resolved with direct contrast injection. This is particularly true for young children who cannot cooperate with breath-holding sequences required for magnetic resonance imaging (MRI) and for conditions that may require fine spatial resolution such as early sclerosing cholangitis, bile duct paucity syndromes and neonatal biliary atresia, anomalous junction of the biliary and pancreatic ducts, and pancreas divisum. Continued improvement in noninvasive imaging techniques may eventually remove this limitation.

Box 27. 2

Major Indications

Biliary

Neonatal cholestasis

Choledocholithiasis

Choledochal malformations

Strictures

Leaks

Pancreatic

Acute biliary pancreatitis

Recurrent acute pancreatitis

The main indication for ERCP in children, as in adults, is for potential therapeutic intervention of known or suspected structural abnormalities in order to relieve obstruction, divert leakage, or drain a collection.

Biliary Indications

Neonatal Cholestasis

Neonatal cholestasis is the only biliary condition unique to pediatrics in which purely diagnostic cholangiography has a role. The most common causes of neonatal cholestasis are idiopathic neonatal hepatitis and total parenteral nutrition, both of which are frequently encountered in neonates compromised by premature birth, congenital abnormalities requiring surgical intervention, or other acute illnesses of the newborn. These conditions are characterized by hepatocellular and canalicular dysfunction rather than bile duct obstruction. However, they can sometimes be difficult to distinguish from ductal obstruction due to inspissated bile (seen with cystic fibrosis or idiopathic causes), bile duct paucity (e.g., Alagille syndrome), or obliteration of the duct due to biliary atresia (BA). Of these conditions, the correct diagnosis is most urgently needed for BA since surgical intervention by portoenterostomy (Kasai procedure) substantially reduces long-term morbidity and mortality if undertaken during the early weeks and months of life.^21,²² If left untreated, BA leads to liver failure and organ transplantation or death by 1 to 2 years of age.

The role of ERCP in the diagnosis of BA remains controversial due to variations in clinical practice; interpretation of liver histology; access to high-quality diagnostic ultrasound, MRI, and scintigraphy imaging; and availability of highly skilled biliary endoscopists. Most pediatric gastroenterologists, hepatologists, and surgeons continue to rely on a combination of clinical presentation, serum chemistry profile, ultrasonography, biliary scintigraphy, and liver histology rather than ERCP to identify infants in need of surgical exploration, intraoperative cholangiography, and possible portoenterostomy. However, published series of ERCP in infants with unexplained cholestasis consistently report high positive and negative predictive values exceeding 90% with only rare minor adverse events.²³^–²⁷ A high level of skill and confidence in technical proficiency is required by endoscopists who use ERCP for this indication. The endoscopic findings that suggest BA include absence of visible bile within the duodenum, partial filling of the bile duct with abnormal termination, and failure to fill the bile duct despite filling of the pancreatic duct (Fig. 27.3).²⁸ Complete filling of the bile duct including hepatic branches excludes the diagnosis of BA. ERCP is most helpful when the diagnosis of BA is unlikely but cannot be definitely excluded without cholangiography. In this situation, an unnecessary exploratory laparotomy can be avoided by demonstrating a patent bile duct (Fig. 27.4).

Fig. 27.3 Schematic representation of cholangiographic patterns in infants with biliary atresia. Light green indicates nonopacified or atretic segments.

(Adapted from Guelrud M, Carr-Locke DL, Fox VL. ERCP in pediatric practice: diagnosis and treatment. Oxford: Isis Medical Media; 1997, with permission of Taylor and Francis.)

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