Esophagogastroduodenoscopy and Related Techniques

Personnel

Specially trained pediatric endoscopy assistants are an important component of the endoscopy team. Procedure anxiety can be diminished by an assistant who has previously met the child and parent(s), explained the procedure, and greeted them in the endoscopy suite. The same person can hold and reassure the child throughout the procedure if the procedure is performed under conscious sedation. A second assistant is typically needed to help obtain and process tissue during the procedure and assist with other equipment. Specially trained child life personnel can also be utilized to reduce procedure-related anxiety. Psychologic preparation before endoscopy has been shown to reduce procedure-related anxiety, improve patient cooperation, decrease autonomic nervous system stimulation during the procedure, and reduce the amount of medication required. Physicians performing endoscopy on infants and children should have completed a pediatric gastroenterology fellowship or have experience with pediatric gastrointestinal diseases and adequate training in pediatric endoscopy. Guidelines for the minimal number of procedures to establish competency have been established by the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) and the American Society for Gastrointestinal Endoscopy (ASGE). ^, Intravenous (IV) sedation should be used only by physicians competent in the administration of drugs and resuscitation in children. Levels of sedation must be carefully and continuously assessed. There is a continuum from conscious sedation to deep sedation to general anesthesia. Physicians administering sedation should be familiar with the definitions of these three levels of sedation and appropriately credentialed for sedation administration, with appropriate equipment and personnel available for monitoring and resuscitation.

Facilities

Routine endoscopy in infants and children is typically performed in an outpatient setting using parenteral sedation or general anesthesia. Large series have reported on the efficacy and safety of parenteral sedation with combined minor and major complication rates of less than 0.5% to 9% for both EGD and colonoscopy and major complication rates usually less than 0.5%, depending on the series and how adverse events were defined. Occasionally it is necessary to perform endoscopy at the hospital bedside or in an operating room, based on the severity and complexity of the case. In many institutions, anesthesiologists are utilized to administer sedation for more invasive or therapeutic procedures, such as foreign body removal, placement of percutaneous tubes (gastrostomy or cecostomy), dilation of strictures and pneumatic dilation, variceal band ligation, and therapeutic endoscopy for gastrointestinal bleeding. Some endoscopists may also prefer the assistance of an anesthesiologist for younger patients or those in whom cooperation may be impaired. Some pediatric centers utilize pediatric anesthesiologists to provide sedation for the majority of their procedures. To date, an advantage of one form of sedation over another has not been demonstrated.

The endoscopy suite should be equipped with instruments to monitor blood pressure, pulse rate, and oxygen saturation. Pediatric resuscitation equipment including emergency medications, reversal agents, IV fluids, appropriately sized endotracheal tubes, laryngoscopes, oxygen, and resuscitation bags should be available. Newer methods of noninvasive monitoring such as capnography have been shown to be useful in pediatric patients undergoing upper endoscopy or colonoscopy while under deep sedation. Capnography allows for earlier detection of alveolar hypoventilation in nonintubated pediatric patients, leading to reduced frequency of hypoxemia events as a result of earlier intervention. Recent literature suggests the integration of capnography as the new standard of care in patient monitoring to help minimize respiratory compromise during procedural sedation.

Equipment

Almost all endoscopes currently used are video endoscopes. Upper gastrointestinal endoscopes may also be divided based on their angle of viewing: either forward or side viewing. Currently, side-viewing endoscopes are used primarily for endoscopic retrograde cholangiopancreatography (ERCP) and will be discussed in that context. In some cases, side-viewing endoscopes are used in older adolescent and young adult patients undergoing surveillance of the ampullary region in patients with familial adenomatous polyposis (FAP).

The video endoscope, an adaptation of the earlier fiberoptic instrument, is composed of a control handle that is attached to an insertion tube with a charge coupled device (CCD) located at its distal tip behind the objective lens. The objective lens focuses a miniature picture on the surface of the CCD. The pattern of light falling on the CCD is converted to an array of electrical charges, transforming the optical image into an electronic representation. The charges developed in the CCD are “read” and processed to reproduce the image ultimately being transmitted to a video processor for display on a television monitor. Images are “colorized” by different color imaging systems such as a RGB (red, green, blue) sequential imaging system or color chip imaging technology. Each of the systems has advantages, descriptions of which are beyond the scope of this text. Differential color imaging systems are currently being used in adults as an alternative to chromoendoscopy. These are discussed later in the chapter, in the section on special endoscopic techniques.

The control section of the endoscope is attached via a universal cord to a light, water, suction, and electrical source. On the control handle, dials control the up-down and right-left angulation of the instrument tip. Lateral to each dial is a locking mechanism that increases the resistance to turning the dial. On the proximal shaft of the endoscope, there are two valves. The more proximal valve is for suction, and the distal valve controls air and water. Air is insufflated through the endoscope by lightly occluding the distal button. Firmly pushing down on the button provides a stream of water for irrigation through the endoscope. The endoscope was designed in such a way that accidental overinsufflation should not occur, as there is not a way for the air channel to get stuck in the “on” position. The only way for air to enter the lumen is for the physician to cover the distal button. Otherwise, when not occluded, air exits the vent hole, decompressing the system. Another important safety feature is that removal of all the valves will lead to decompression of the gastrointestinal (GI) tract and halt all supply of air and water. This is useful in the situation where the suction system becomes obstructed, leading to overinsufflation of the GI tract. The control handle contains additional buttons to freeze or alter the image on the video screen as well as buttons to employ differential color imaging systems. Parts or all of the procedure can be recorded for image storage or later review on digital video recorders.

Further down the endoscope is a channel with a biopsy valve, through which can be passed various instruments, including biopsy forceps, cytology brushes, needles for sclerotherapy or injection, balloon dilators, clips, guidewires, coagulation probes, heater probes, polypectomy snares, and other instruments. The endoscopic field can be irrigated manually by using a blunt-ended needle attached to a syringe and manually flushing the channel. The rate of irrigation that can be achieved by this method is greater than the rate achieved by occluding the button on the endoscope. Irrigation pumps are also available but are more frequently used for colonoscopy. If the air button does not function properly during endoscopy and the issue is not resolved with button replacement and checking all the connections, air can also be injected with a syringe via this channel to avoid switching endoscopes in midprocedure. At the endoscope tip are various openings: an air-water outlet (for lens cleaning), the objective lens, a light guide, and an instrument channel for suction and biopsy forceps. Large-diameter therapeutic instruments may contain an auxiliary water channel or a second suction/instrument channel, or both. The tip of the endoscope has a certain degree of angulation possible in an up or down, right or left direction. The flexible portion of the endoscope is the “working length” of the instrument. Equipment such as a friction fit adaptor and endoscopic cap and hoods have been developed to attach to the endoscope tip. The friction fit adaptor is used primarily to deploy bands for esophageal variceal ligation but can also be used in the removal of esophageal meat impactions. Endoscopic caps and hoods are used primarily to assist with endoscopic mucosal resection (EMR), a newer technique that has been developed primarily in adult patients for resection of large mucosal lesions including dysplastic epithelium or carcinomas, but the caps can also be used for food bolus removal. Endoscopic hoods are used primarily for sharp foreign body removal. There have been significant advances in the gastroenterologist’s ability to visualize and examine the small bowel distal to the ligament of Treitz with the development of balloon-assisted enteroscopy. Previously utilized Sonde endoscopes are rarely utilized, although despite advent of the new devices, push enteroscopy utilizing pediatric colonoscopes is still employed.

Single- and double-balloon endoscopes allow for examination and treatment of lesions identified in the more distal small bowel and are the instruments most commonly used for distal small bowel examination in pediatric patients in cases in which therapy is anticipated. Both push-type endoscopes and balloon enteroscopes have a working channel to perform therapeutic procedures such as polypectomy, biopsy, injection, clipping, or coagulation. The balloon enteroscopes allow for more distal small bowel examination. A new approach is spiral enteroscopy, which is a two-person procedure and utilizes rotational force to allow for advancement of the endoscope. This novel approach is promising, allowing for improved diagnostic yield with overall decreased procedure time compared with balloon-assisted enteroscopy. Recently the use of a motorized spiral enteroscope, which would allow performance by a single operator, has been reported. There have been no reports in the literature of spiral endoscopy being performed in the pediatric population. Small bowel enteroscopy is discussed more in Chapter 63 .

Video capsule endoscopy (VCE) is U.S. Food and Drug Administration (FDA) approved for patients 2 years of age and older. ^, VCE is another technique that competes with small bowel enteroscopy as a method for examining the small bowel distal to the ligament of Treitz. Although capsules are not currently able to be read in real time and do not allow for tissue sampling or endoscopic therapy, future modifications of this technology may allow for these types of advancement, thereby increasing the utility of this technology. At this time the major limitation of VCE is the inability of a patient to swallow the capsule based on age, size, or other patient risk factors. The youngest reported patient who voluntarily swallowed the capsule was a 4-year-old. ^, VCE is discussed in more detail in Chapter 63 .

The most important issues related to pediatric endoscopy equipment are the diameter and length of the insertion tube, degree of tip angulation, and depth of field. In term infants, the esophagus measures only 4 to 6 mm in diameter and 8 to 10 cm in length. ^, Some of the earliest EGDs were performed using small-diameter bronchoscopes with an insertion tube diameter of 5 mm. However, the tubes were too short to allow adequate visualization of the small bowel. Despite theoretical concerns of trauma, perforation, or airway compression, early pediatric endoscopists found that they could safely and effectively examine a neonate’s digestive tract with an instrument 7 mm in diameter without complication, because of the distensibility of the esophagus. Newer gastrointestinal endoscopes have a 4.9- to 12.6-mm outer diameter with a 2- to 3.7-mm instrument channel, and side-viewing endoscopes have variable outer diameters in the range of 7.5 to 12.1 mm. Endoscopes of a larger diameter are primarily used in adults for therapeutic procedures. Standard upper endoscopes have an external diameter in the range of 8.0 to 9.8 mm with a 2- to 2.8-mm channel. Therapeutic channel scopes have an outer diameter in the range of 11.3 to 12.6 mm with instrument channel(s) of up to 3.7 mm.

Endoscopic reprocessing and disinfection are vital to prevent infection transmission between patients. The Spaulding classification system is utilized by multiple professional organizations including the Centers for Disease Control and Prevention (CDC) and the FDA to categorize medical devices based on infectious risk and to guide the level of disinfection required for a variety of medical devices. Endoscopes are categorized as semicritical and require high-level disinfection (HLD). It is imperative to follow established recommendations by the manufacturer and established societal guidelines to avoid pathogen transmission from medical devices. ^, Recent reports of transmission of multidrug-resistant organisms have involved duodenoscopes with mechanical elevators, which is secondary to the design of the mechanical parts resulting in continual contamination. This issue has been reported with endoscopes from all major manufacturers. The FDA highlighted the importance of reprocessing and optimal cleaning methods of duodenoscopes in 2015 with an emphasis on ensuring strict adherence to the manufacturer’s instructions at all levels. Overall, transmission of pathogens by GI endoscopes is a rare occurrence and secondary to deviations from established protocols and guidelines. If a reprocessing error is identified, it is important to inform not only the patient but additional parties including infection control, public health agencies, the FDA, the CDC, and the equipment manufacturer.

Indications

The indications for gastrointestinal endoscopy vary with the age of the patient. The need for upper endoscopy in neonates and infants is usually suggested by physical signs reported by parents or other observers, which include dysphagia, vomiting, hematemesis, melena, hypotension, respiratory distress, abnormal posturing, or anemia. With toddlers and older children, the history is of greater importance in identifying gastrointestinal disorders. The sensitivity of gastrointestinal endoscopy in establishing a diagnosis varies with the indication for the procedure ( Box 60.1 ). The yield of upper endoscopic examination in pediatric patients differs with the age of the child and the indication for the procedure. Younger patients with specific complaints, such as failure to thrive and weight loss, appear to have an increased incidence of pathology on endoscopic examination compared with older children with nonspecific abdominal pain. In addition, endoscopies performed for gastrointestinal bleeding are more likely to identify a cause than procedures performed for nonspecific complaints. Endoscopy can be performed for diagnosis of gastroesophageal reflux (GER), eosinophilic esophagitis (EoE), gastroenteritis, celiac disease, and small bowel enteropathy, evaluation of graft-versus-host disease and surveillance for Barrett esophagus, polyposis syndromes, or following transplantation including evaluation for posttransplantation lymphoproliferative disease (PTLD); therapy, as in stricture dilation, foreign body removal, percutaneous endoscopic gastrostomy (PEG) insertion, pyloric dilation, pneumatic dilation, catheter placement, stent insertion, or gastroplication; or a combination of diagnosis and therapy, such as evaluation and treatment of gastrointestinal bleeding, including that from acid peptic disease and variceal sources, or in evaluation of injury following a caustic ingestion and for capsule (VCE) or Bravo (Medtronic, Minneapolis, MN) placement. Current guidelines and standards of practice should be followed in terms of the yield of endoscopy. ^{, , ,} New endoscopic techniques continue to be developed, will be applied increasingly to pediatric patients, and are discussed at the end of this chapter.

Contraindications

Absolute contraindications to gastrointestinal endoscopy include suspected perforation of the intestine and peritonitis in a toxic patient. There are several relative contraindications, including patients who are severely neutropenic or have bleeding disorders and children with a recent history of bowel surgery. In addition, patients with connective tissue disease, especially Ehlers-Danlos syndrome type 4 and Marfan syndrome, are at increased risk of perforation during endoscopy. ^, Other relative contraindications include partial or complete bowel obstruction and aneurysm of the abdominal and iliac aorta. In all endoscopic procedures, the clinician and endoscopist must determine whether the potential information or therapeutic intervention outweighs the risk of the procedure ( Box 60.2 ).

Antibiotic Prophylaxis

The incidence of bacteremia after gastrointestinal endoscopy varies according to the patient’s underlying medical problem and the procedure performed: EGD 0% to 8% (mean 4.4%), colonoscopy 0% to 25% (mean 4.4%), sclerotherapy 0% to 52% (mean 14.6%), endoscopic variceal ligation (EVL) 1% to 25% (mean 8.8%), esophageal dilation 12% to 22%, ERCP 6.4% without associated bile duct obstruction and up to 18% with biliary obstruction, and endoscopic ultrasound (EUS) guided fine-needle aspiration (FNA) 4% to 5.8%. In regard to single- and double-balloon enteroscopy, the risk of bacteremia is unknown but is thought to be comparable to routine upper and lower endoscopy. In general, the risk of bacteremia following routine endoscopy is lower than the risk of transient bacteremia associated with some of our daily activities. For example, the rate of transient bacteremia associated with brushing and flossing of teeth ranges from 28% to 60%. The highest risk of bacteremia is associated with the following procedures: esophageal dilation, sclerotherapy of varices, and ERCP. Certain bacteria are more likely to be the cause of bacteremia after a procedure. These include Escherichia coli , Bacteroides , Pseudomonas , Veillonella , and Peptostreptococcus , especially after a lower gastrointestinal procedure. However, other bacteria may be more virulent and more likely to cause endocarditis, especially Streptococcus viridans and Enterococcus . Prophylaxis is directed by the frequency and virulence of the anticipated organisms that may be encountered during the procedure.

The actual incidence of bacterial endocarditis following gastrointestinal procedures is quite low, with fewer than 20 cases reported. Antibiotic recommendations are based on a combination of procedure-related risk of bacteremia and patient risk and should be reassessed periodically as new data and guidelines become available. ^{, ,}

Patients at high risk for infective endocarditis are those with prosthetic heart valves, including bioprosthetic and homograft valves; a previous history of bacterial endocarditis; a surgically constructed systemic pulmonary shunt or conduit; those who have had a cardiac transplant with cardiac valvulopathy; and those with complex cyanotic congenital cardiac malformations, including single-ventricle states, transposition of the great arteries, and tetralogy of Fallot. If indicated, prophylaxis is usually given as a single dose 30 to 60 minutes prior to the procedure unless otherwise specified for other special procedures as indicated in current guidelines.

Intermediate-risk patients include most other congenital cardiac malformations, acquired valvular dysfunction (e.g., rheumatic heart disease), hypertrophic cardiomyopathy, mitral valve prolapse with valvular regurgitation, and/or thickened leaflets.

The most current recommendations are that antibiotic prophylaxis solely to prevent infective endocarditis is no longer recommended before endoscopic procedures, except as specified elsewhere in this chapter. For patients with established GI tract infection in which enterococci may be part of the infecting bacterial flora, such as in cases of cholangitis and with one of the previously listed cardiac conditions associated with highest risk of adverse outcome from endocarditis, amoxicillin or ampicillin should be included in the antibiotic regimen for enterococcal coverage. Clindamycin may be substituted for patients who are allergic or unable to tolerate amoxicillin or ampicillin ( Box 60.3 ). ^,

Antibiotic prophylaxis may be useful for prevention of infection related to some endoscopic procedures, before placement of prosthetic devices and in specific clinical scenarios. The current guidelines are complex and subject to continual update and revision and should be reviewed.

Antibiotic prophylaxis is recommended for all patients before PEG placement. Thirty minutes before PEG placement, parenteral coverage with cefazolin or an equivalent antibiotic is indicated. Additional doses of antibiotics are required following PEG placement.

Antibiotic prophylaxis should be considered for all patients undergoing ERCP for known or suspected biliary obstruction in which there is a possibility of incomplete biliary drainage, and antibiotics should be continued following the procedure. In the case of ERCP, antibiotics should be directed against biliary flora including enteric gram-negative organisms, enterococci, and possibly Pseudomonas species. Antibiotics should also be continued postprocedure, even if complete biliary drainage is achieved in cases of posttransplantation biliary strictures. Antibiotic prophylaxis is also recommended before ERCP in patients with communicating cysts or pseudocysts and before transpapillary drainage of pseudocysts.

Although infrequently performed in pediatrics, antibiotic prophylaxis is recommended before EUS with FNA of cystic lesions along the GI tract. Due to the risk of cyst infection, antibiotics are also continued for 3 to 5 days following the procedure. Prophylaxis is not recommended for EUS FNA of solid lesions in the upper GI tract, and there is no recommendation for EUS FNA of lower GI tract solid lesions. Other special patient populations include those with a prosthetic joint or orthopedic prosthesis; those with synthetic vascular grafts or other nonvalvular cardiac devices, in whom antibiotics are not recommended; and those with acute gastrointestinal hemorrhage, in whom antibiotics are generally recommended. In patients with cirrhosis, especially those with ascites or with gastrointestinal bleeding, antibiotics are strongly recommended starting at admission (IV ceftriaxone or oral norfloxacin in adults if allergic or intolerant to ceftriaxone). In patients following transplantation or other immunocompromised patients undergoing high-risk procedures, prophylaxis should be considered on a case-by-case basis except as otherwise specified.

Preparation

Sedation and Monitoring

Sedation is used in most pediatric patients not only to minimize discomfort but also to provide amnesia for the procedure. This helps prevent the child from becoming fearful of contact with the physician, which is especially important in pediatric patients with chronic conditions that may require repeated procedures. The pendulum continues to shift for most pediatric endoscopists between conscious sedation delivered by the proceduralist and monitored anesthesia care provided by a pediatric anesthesiologist for routine endoscopic procedures; preferences for one type of sedation over another are largely based on training and available local resources. Many pediatric endoscopists utilize IV sedation for routine upper and lower endoscopy. General anesthesia may be required for therapeutic procedures such as foreign body removal, dilation, PEG placement, or in patients in whom cooperation is not anticipated, including very young patients or those for whom procedure time is likely to be prolonged, such as ERCP or balloon enteroscopy. A variety of regimens have been tried in pediatric patients, although there are few comparative trials. Most pediatric endoscopists use a combination of a benzodiazepine, such as midazolam, and a narcotic, such as meperidine, for conscious sedation. A variety of other regimens, such as fentanyl, ketamine-midazolam, and, more recently, propofol administered by an anesthesiologist and considered a sedative anesthetic, have been used in pediatric patients. ^, Oral midazolam premedication before conscious sedation with a combination of a benzodiazepine and a narcotic has also been reported to be beneficial in improving both patient and parent satisfaction, although administration may prolong postprocedure recovery time. In selected highly motivated pediatric patients, unsedated or transnasal endoscopy has been successful, especially for evaluation of EoE.

When used together, meperidine 1 to 2 mg/kg body weight to a maximum of 100 mg is administered by slow infusion followed by midazolam 0.1 to 0.2 mg/kg body weight. The dose of midazolam is titrated according to the patient’s level of consciousness but rarely exceeds 5 mg as a total dose. Meperidine is usually given first to decrease the discomfort at the site of injection associated with IV midazolam. Younger children may require more midazolam per kilogram of body weight. Occasionally, it may be necessary to administer additional amounts of these medications during the procedure.

Transient reactions at the site of medication administration are not unusual and include cutaneous erythema distal to the site of injection not associated with clinically significant thrombophlebitis. Other reactions include coughing and a characteristic taste with meperidine infusion. In a prospective evaluation of this method of sedation in 100 pediatric endoscopic procedures at the Cleveland Clinic, approximately 50% of the patients had generalized cutaneous flushing, and urticaria without audible wheezing developed in 12 children. Rechallenge with the same sedative in two patients did not result in a more severe reaction. Endoscopy in neonates may be performed with or without sedation, depending on the indication for the procedure. Sedation is helpful if the procedure will last more than a few minutes or interventional endoscopy is anticipated.

General anesthesia is necessary when a patient is uncooperative, requires a lengthy or complicated procedure, or has extenuating medical problems. Increasingly, propofol (2,6-diisopropylphenol) has been administered primarily by pediatric anesthesiologists for sedation for pediatric procedures. It is classified as an ultrashort-acting hypnotic agent that provides sedative, amnestic, and hypnotic effects with no analgesic properties. It rapidly crosses the blood-brain barrier and causes a depression in consciousness likely related to potentiation of the γ-aminobutyric acid A receptor in the brain. It is contraindicated in patients with propofol allergy or hypersensitivity to eggs or soybeans. It is metabolized primarily in the liver. Dose reduction is required in patients with cardiac dysfunction and in those with decreased clearance of the drug. Onset of action is rapid following injection. It is highly effective at inducing sedation and provides excellent amnesia for the procedure. In addition, the pharmacokinetics of this agent allow for rapid patient awakening once the agent is turned off. There are limited pediatric trials that compare this agent with standard endoscopist-administered sedation of a narcotic and benzodiazepine. A nonrandomized pediatric trial suggests that there is no advantage of this agent in terms of procedure time or time to patient discharge, especially in healthy patients undergoing diagnostic upper endoscopy. Propofol administration in some series appears to be associated with a higher likelihood of endotracheal intubation during or before the endoscopic procedure. A review of pediatric procedural sedation for gastrointestinal endoscopy suggests that propofol-based regimens may be more efficacious compared with more traditionally based opioid and benzodiazepine combinations.

During the endoscopic procedure, arterial oxygen saturation and electrocardiographic tracings are routinely monitored. Patients younger than 1 year, compared with patients more than 1 year of age and those with underlying cardiopulmonary disease, have a greater tendency for decreased mean oxygen saturation with endoscopy.

Oxygen desaturation during sedation may occur without clinically apparent signs and symptoms. For this reason, pulse oximetry should be monitored during endoscopy. Neurologically impaired patients often have gastrointestinal problems that require endoscopy. Sedation in these patients can be unpredictable, and respiratory depression is more common. In this patient population, dose reduction and slow titration of medications are implemented to avoid adverse events. Careful and attentive monitoring of the cardiopulmonary status is essential. Medication dosages are also reduced in patients who have undergone a recent weight loss where the volume of distribution may be altered. These include patients with inflammatory bowel disease, malignancy, and anorexia nervosa. A number of other adverse effects, including respiratory depression, pulmonary edema, allergic reactions, arrhythmias, hypotension, paradoxical reactions, and hallucinations, have been reported following a variety of sedation regimens. ^, Endoscopists should counsel patients and their families based on the specific known risks associated with their preferred sedation regimen.

Naloxone is indicated only for narcotic-induced respiratory depression, because its use is usually associated with marked irritability in infants and young children. Flumazenil (Romazicon, Roche) is an IV benzodiazepine antagonist that competitively blocks the effects of benzodiazepines on γ-aminobutyric acid pathway–mediated inhibition in the central nervous system. Side effects with administration include facial erythema, dizziness, hyperexcitability, seizures, and serious cardiac arrhythmias. Because the half-life of Flumazenil is shorter than that of benzodiazepines, resedation after reversal of benzodiazepine sedation may occur, and patients should be monitored accordingly. Routine administration after endoscopy appears to be of questionable benefit in pediatric patients. Recommended doses for IV sedation medications and reversal agents are indicated in Table 60.1 .

Anatomy

The esophagus is located posterior to the trachea in the neck. It ranges in diameter from 4 to 6 mm and in length from 9 to 10 cm in the term infant, to a length of approximately 25 cm in the adult. It begins distal to the cricoid cartilage and ends at the cardiac orifice of the stomach.

The esophagus opens with swallowing, unlike the trachea, which is always open except with vocal cord movement. The esophageal opening appears lateral and posterior to each side of the trachea with swallowing. The trachea is easily distinguished from the esophagus by the presence of bilateral vocal cords on its anterolateral aspects and, if intubated, by the circular tracheal rings along its length.

The esophagus is narrowed at four locations: (1) at the level of the cricopharyngeus, (2) where the esophagus is crossed by the aortic arch, (3) where it is crossed by the left mainstem bronchus, and (4) at the lower esophageal sphincter. Of these, the regions just below the cricopharyngeus and just above the lower esophageal sphincter are often the sites where foreign bodies lodge after ingestion. The lower esophageal sphincter plays an important role in certain diseases, such as achalasia and GER.

The stomach is usually located beneath the diaphragm and, in an adult, is approximately 40 cm distal to the incisors. The right aspect of the esophagus is in continuity with the lesser curvature of the stomach, whereas the left margin of the esophagus joins the greater curvature ( Fig. 60.1 ). The gastric rugae are most prominent along the greater curvature. The area of the stomach where the esophagus enters is known as the gastric cardia. The portion of the stomach above the junction of the esophagus and stomach is known as the fundus; it is also the most posterior aspect of the stomach. The majority of the stomach is known as the body of the stomach. On occasion, the esophagogastric junction is located above the diaphragm, representing a hiatal hernia. Along the lesser curvature of the stomach is the incisura. This notch divides the body of the stomach from the gastric antrum. The pylorus is the muscular junction between the stomach and the small intestine. The pyloric canal is 2 to 3 cm in length in the adult. The diameter of the pyloric opening may vary according to patient age and size and may be affected or altered in certain disease states.

The most proximal portion of the small intestine is the duodenum. The average duodenal length in a full-term infant is 5 cm. ^, The duodenal bulb is an expanded region immediately distal to the pylorus. The duodenum then forms a C -shaped loop and, from the endoscopist’s point of view, turns posteriorly and to the right for 2.5 cm in the older child and adult, then inferiorly for 7.5 to 10 cm (descending portion), then anteriorly and to the left for approximately 2.5 cm, finally connecting to the jejunum at the level of the ligament of Treitz. When it joins the jejunum, it turns abruptly forward. The duodenum ranges from 25 to 30 cm in length in the adult.

The common bile duct and pancreatic duct enter the duodenal wall obliquely and join in the ampulla of Vater, which opens into the descending portion of the duodenum via the duodenal papilla. The papilla is usually located approximately 8 to 10 cm distal to the pylorus in adults. The pancreatic duct may also empty via an accessory pancreatic duct, which is usually located proximal to the major duodenal papilla ( Fig. 60.2 ). The duodenum, unlike the jejunum or ileum, does not have a mesentery.

The jejunum and ileum form a series of loops attached to the posterior abdominal wall via a mesentery. In a newborn, the average small intestinal length is 266 ± 56 cm. In adults, the jejunum represents the proximal 2.5 m and the ileum represents the distal 3.5 m of the small bowel. Although the point of transition is often unclear, the jejunum is initially located in the left upper and left lower quadrants. Intraluminally, the jejunum is characterized by large thick folds, large villi, and a luminal diameter of approximately 4 cm. The ileum is thinner walled than the jejunum, with an inner diameter of 3.5 cm, smaller villi, and an increased amount of lymphoid tissue compared with the jejunum.

Technique

The endoscope is usually held in the left hand. The thumb is used to turn the large dial; the index finger and sometimes the middle finger are used to control the suction, air, and water valves; and the remaining fingers hold the control handle. The insertion tube is held in the right hand. The lateral wheel, which controls right and left tip deflection, is usually manipulated with the right hand by endoscopists with smaller hands, but may be controlled by either the left hand or the right hand in endoscopists with larger hands. The instruments used via the biopsy channel include needles for injection, biopsy forceps, cytology brushes, foreign-body retrieval instruments, balloons, clips, polypectomy snares, probes for cautery, and syringes for irrigation and are usually inserted with the right hand. Before initiating a procedure, the suction and air channels should be checked to ensure proper functioning and the endoscope should be “white balanced.”

Upper Endoscopy

The endoscopist usually stands on the patient’s left during performance of EGD. After sedation in the supine position, the patient is turned to the left lateral decubitus position with the neck flexed downward in preparation for the procedure. For ease of airway management, patients undergoing endoscopy under general anesthesia are usually left in the supine position rather than being placed in the lateral decubitus position. Before insertion of the endoscope into the oral cavity, a bite block is placed in the mouth of the nonintubated patient. The endoscope dials are placed in a neutral position. Some operators prefer to lock the right-left dial during esophageal intubation. The endoscope is guided through the bite block over the tongue to the back of the oropharynx by directing the endoscope tip posteriorly and somewhat laterally to the trachea; lateral motion is usually obtained by gentle right and left torque on the shaft rather than by turning the dial. Some individuals use their forefinger to direct the tip and blindly advance the instrument. As the patient swallows, the cricopharyngeus relaxes and the esophagus, located posteriorly to the trachea and between the pyriform sinuses, can be intubated under direct vision. If the patient is unwilling or unable to swallow after the tip of the instrument is positioned at the esophageal inlet, gentle pressure will usually ease the tip through the cricopharyngeus into the proximal esophagus. The position of the endoscope during this procedure usually makes the patient gag if under conscious sedation, and if the instrument cannot be passed expeditiously, it should be withdrawn.

After intubating the esophagus, the instrument is advanced down the esophageal lumen while simultaneously examining the mucosa for any lesions. The mucosa is examined as the instrument is inserted to avoid misinterpreting mucosal changes caused by passage of the endoscope. The esophagus is examined for evidence of inflammation, ulcerations, furrowing, varices, hernias, narrowing, and strictures. The location of the lower esophageal sphincter should be noted. The transition between squamous esophageal and gastric columnar mucosa is called the “Z line.” At this point, the mucosa changes from a pale pink to a deep red. The diaphragmatic constriction of the lumen should be noted within 2 cm of the squamocolumnar junction unless a hiatal hernia or Barrett esophagus is present.

When the stomach is entered, suction is utilized to remove any residual gastric secretions. After the gastric secretions are removed, air is insufflated to separate the gastric rugae. The endoscope is then advanced while torquing to the right. This can be accomplished by applying pressure to the shaft or by the endoscopist twisting to the right; torque can also be achieved by dropping the handle to the right or left, depending on the desired direction of torque. The endoscope is advanced along the lesser curve toward the pylorus, but it is usually necessary to fill the greater curvature with the endoscope before cannulating the pyloric canal ( Fig. 60.3 ).

The pylorus appears as a small opening with radiating folds around it. Periodic antral waves may pass to the pylorus, changing its location and the size of the canal opening. The pylorus is entered by nudging the tip of the endoscope up to the opening and then directly cannulating the pyloric canal.

The duodenal bulb should be examined on endoscope insertion rather than during withdrawal because of possible mucosal changes caused by passage of the instrument. After examination of all four quadrants, the scope is advanced to the posterior aspect of the bulb, where the duodenum takes a sharp right and downward turn. The instrument is advanced using the dials and shaft torque, usually down and to the right followed by an upward spin of the dial, bringing the tip into the descending duodenum. Once the lumen of the descending duodenum is seen, a straightening maneuver is performed. This consists of pulling the endoscope slowly backward while maintaining the lumen in view. This reduces the loop along the greater curvature of the stomach and usually, paradoxically, advances the endoscope into the distal duodenum ( Fig. 60.4 ). The duodenal mucosa, including ampulla of Vater, is examined while withdrawing the endoscope.

After adequate examination of the antrum, pylorus, and duodenum, the endoscope is retroflexed to look for lesions in the gastric cardia and fundus ( Fig. 60.5 ). With the instrument looking toward the pylorus and located proximal to the incisura, the tip is deflected until the proximal stomach comes into view. The endoscope is then progressively withdrawn, bringing the cardia closer to the instrument tip while distending the cardia and fundus with air ( Fig. 60.6 ). Patients often burp during this maneuver, and cooperative children under conscious sedation may be instructed to try to hold the air in the stomach. The endoscope is then rotated 180 degrees in each direction by torquing the insertion tube in a clockwise or counterclockwise manner. Any residual gastric liquid in the cardia should be suctioned out at this time. The instrument is then straightened, the remainder of the gastric mucosa is examined, and biopsies, if necessary, are performed. The endoscope is then withdrawn. Immediately before removing the endoscope from the stomach, air is aspirated from the stomach. The esophageal mucosa is once again examined and biopsied as indicated. To increase patient comfort and diminish gagging, the endoscope is usually withdrawn smoothly but rapidly in children when the level of the larynx is reached.

Biopsy Technique

Histopathologic evaluation of the GI tract is helpful in differentiating infectious, inflammatory, and malignant processes. Tissue biopsy is routinely obtained from suspicious lesions during endoscopic examination, and in many centers, routine endoscopic biopsy is performed at designated sites, because clinically significant disease may be present with macroscopically normal appearing mucosa. Advances in our understanding of the pathogenesis of disease, such as the relationship of Helicobacter pylori and peptic ulcer disease, indicate that tissue biopsy may be indicated even when the source of gastrointestinal bleeding, from a duodenal ulcer for example, is apparent. Numerous techniques and devices have been designed to obtain tissue samples. A variety of pinch biopsy forceps are available that are coordinated in size with endoscopic channel diameter. Standard-size biopsy forceps are fenestrated with a needle so that two sequential biopsies may be performed without removing the forceps from the endoscope. “Spiked” forceps that fit through a 2.0-mm channel are not yet available. Fine-needle biopsy may have an advantage when biopsy material from submucosal lesions is sought. Suction biopsy, which has been adapted to the endoscope, is designed to obtain deeper samples, and jumbo biopsy forceps or large-capacity forceps are also available. Large-capacity forceps require an endoscopic channel diameter of 3.6 mm or larger. They have the ability to sample a larger surface area but do not necessarily procure deeper specimens. Larger biopsy specimens may also be obtained with a turn and suction technique. Multiple biopsy specimens improve the diagnostic yield, but the size and location of the biopsies are probably more important. Brush cytology or other combinations of techniques can increase diagnostic yield. Snare excision is usually reserved for large polyps. For a more detailed discussion, see Chapter 65 .

The technique of biopsy varies according to the lesion to be biopsied. To perform a routine biopsy, the closed pinch biopsy forceps are advanced through the biopsy channel to a point just past the tip of the endoscope; they are then opened immediately adjacent and perpendicular to the lesion if possible. This angulation may be difficult to achieve in the esophagus, small bowel, and terminal ileum. The open forceps are then advanced and closed, and the tissue is removed through the endoscope. The depth of biopsy is determined by the lesion being sought and the application force of the forceps. There is an ideal distance at which to obtain endoscopic biopsies. Biopsies obtained too close or too far away may be of insufficient size, or associated with mucosal trauma or shear injury.

Esophagus

Reflux esophagitis is traditionally diagnosed with use of clinical criteria. Endoscopy and biopsy are indicated in patients who are refractory to therapy. Biopsy increases the diagnostic yield compared with visual examination alone. There is a high rate of interobserver variability in the diagnosis of milder forms of esophagitis when “erythema and edema” are the only diagnostic findings. There is a greater uniformity of diagnosis when esophageal erosions are present. Prolonged pH probe and impedance monitoring appear to be the current “gold standard” for the diagnosis of GER and are discussed elsewhere in the text. ^, Numerous eosinophils found in the esophagus can be caused by reflux esophagitis or EoE ( Fig. 60.7 ). The two conditions are distinguished by histologic findings including the absolute number of eosinophils per high power field (eos/hpf), clinical course, and response to therapy. ^, EoE is a clinicopathologic diagnosis with a varying clinical presentation from vague abdominal complaints to dysphagia and esophageal food impaction. The diagnosis is established by upper endoscopy with biopsies obtained from two different locations in the proximal or mid and distal esophagus. Histologic findings of 15 or more eos/hpf in the proximal or midesophagus are diagnostic with sensitivity of 100% and specificity of 96% while distal eosinophilia alone may represent GER. Histology of EoE is discussed in more detail in the chapter on GI pathology. ^,

The finding of the highly specialized columnar epithelium of Barrett esophagus on EGD necessitates multiple four-quadrant biopsies obtained in a serial and directed manner to screen for dysplasia or adenocarcinoma according to current guidelines. The frequency and location of biopsies are guided by findings on prior endoscopy of no dysplasia, low-grade dysplasia, or high-grade dysplasia.

A rare but dramatic endoscopic appearance is found in patients with esophagitis dissecans superficialis, also sometimes known as sloughing esophagitis. This condition of unknown etiology is characterized by a stripped off mucosal lining with or without bleeding, long linear mucosal breaks, vertical fissures, and circumferential cracks ( Fig. 60.8 ). Biopsy may demonstrate flaking of the superficial squamous epithelium with occasional separation of mucosal layers, parakeratosis, and inflammation. The natural history of this condition appears benign, and it has been associated with celiac disease, autoimmune bullous dermatoses, chemical irritants, intake of hot beverages, and medications, including nonsteroidal antiinflammatory agents and bisphosphonates.

Fungal and viral (cytomegalovirus, herpes simplex virus) esophagitis occurs in both immunocompromised and immunocompetent hosts. Biopsy, cytology, and cultures aid in the diagnosis.

Esophageal polyps are rare in pediatric patients, with only a limited number of case reports or small case series reports in the literature. Esophageal polyps occur in less than 1% of endoscopies performed in pediatric patients. One case series reports the estimated frequency at 0.14%, which is consistent with the current literature. Polyps are typically located near the gastroesophageal junction in the majority of cases and are typically inflammatory on histology or occasionally squamous papillomas. In those patients who undergo follow-up endoscopy, persistence of polyps without progression is not uncommon.

Malignant primary and metastatic tumors of the esophagus that are rare in childhood are diagnosed by biopsy in the majority of cases ( Fig. 60.9A and B ). The addition of brush cytology and FNA increases the diagnostic yield in cancerous lesions, and EUS is frequently used to stage lesions. Although exceedingly uncommon, adenocarcinoma of the esophagus has been reported in adolescent patients.

Stomach

The base of gastric ulcers is not routinely biopsied because ulcerating gastric malignancies are rare in pediatric patients. Biopsies should be obtained from the edge rather than the base of the ulcer lesion to look for H. pylori , but biopsies may be relatively contraindicated if a visible vessel is present. Complications include perforation and bleeding. If a gastric malignancy is suspected, endoscopic biopsies of the lesion, if they can be safely obtained, may aid in the diagnosis.

Gastritis secondary to drug administration does not usually require biopsy. Gastritis and duodenitis due to nonsteroidal inflammatory drug use may be significant, even in otherwise healthy patients, and can be associated with the presence of gastric or duodenal erosions ( Fig. 60.10 ). ^, Generalized gastritis, especially in the setting of a nodular-appearing mucosa, may suggest the diagnosis of H. pylori infection, confirmed by Giemsa staining or urease testing of antral biopsies. ^, Gastric biopsy may also aid in the diagnosis of idiopathic granulomatous gastritis, Crohn disease, eosinophilic gastroenteritis, sarcoidosis, and Ménétrier disease.

Gastric neoplasia, although uncommon in pediatric patients, may appear as an ulcerative, polypoid, or submucosal deformity or as thickened gastric folds. Gastric malignancies presenting in the pediatric age group include gastrointestinal stromal tumors (GISTs), which may present with gastrointestinal bleeding, and PTLD, which may present with bleeding in addition to a variety of other presentations discussed in detail in Chapter 47 . ^, PTLD lesions can be single or multiple, have a characteristic umbilicated appearance, and can be found in the stomach, small bowel, or colon ( Fig. 60.11 ).

Pinch biopsy is the preferred technique for ulcerative or small polypoid lesions. Adenomas or hyperplastic polyps of 1.0 cm or larger should be removed, if feasible. Snare polypectomy in the stomach is associated with an increased risk of gastric perforation. Submucosal saline injection may be an important adjuvant technique in this circumstance and is discussed in Chapter 61 . Gastric polypectomy should only be performed by practitioners with adequate experience in this technique, and polypectomy should not be performed if submucosal extension of the lesion is suspected. Submucosal deformities may be evaluated by deep biopsies from a single site, with or without FNA. EUS examination may assist with evaluation of the submucosal extent of disease in worrisome lesions such as GISTs.

Therapeutic Endoscopy

During the early years of gastrointestinal endoscopy, endoscopic examination was primarily a diagnostic tool. As technology advanced and procedural skills developed, the endoscope became a therapeutic instrument. Endoscopes have been used in children to remove foreign bodies and polyps; to insert tubes, catheters, capsules, and stents into various organs; to dilate areas of narrowing; to stop bleeding lesions; and to administer medications directly into the mucosa and submucosa.

Acute gastrointestinal hemorrhage is an indication for therapeutic endoscopic intervention, but emergent gastrointestinal endoscopy is associated with an increased risk of complications. ^, This includes a risk of aspiration of gastric contents and a higher risk associated with sedating an actively bleeding patient or a patient with decompensated cardiopulmonary or hepatic function. Scoring systems are utilized in the adult population to aid in identifying high-risk patients, which ultimately aids the clinician in determining the timing of the endoscopy. In pediatrics, Thomson and colleagues developed the Sheffield Scoring System to help predict which patients may require endoscopic intervention for acute upper GI bleeding. Important predictors of the need for endoscopic hemostatic intervention include the presence of liver disease, portal hypertension, requirement for volume support or blood products, tachycardia (heart rate >20 bpm above mean for age), increased capillary refill time of greater than 2 seconds, the presence of significant hematemesis or melena, and a decline in hemoglobin greater than 20 g/L from baseline.

Upper gastrointestinal lesions that may be amenable to endoscopic therapy include ulcers with evidence of active bleeding, oozing from beneath a clot overlying an ulcer (sentinel clot), or an ulcer with a visible vessel at its base that is not actively bleeding but appears as a red, blue, or white plug known as a pigmented protuberance. These lesions have a high rate of rebleeding, approximately 50%, compared with an incidence of 10% or less of rebleeding with low-risk lesions, including ulcers with an overlying clot without oozing or flat spots. These high-risk lesions also frequently require surgery for control of bleeding in those patients who do not undergo endoscopic therapy. At this time, there is a need for validation of pediatric-specific guidelines to the approach and management of variceal and nonvariceal acute upper GI bleeding.

Bleeding from esophageal varices can also be treated with endoscopic sclerotherapy, band ligation, or a combination of the techniques. Ongoing therapy to ablate distal esophageal varices is usually undertaken after the initial bleeding episode has resolved, but in some cases prophylactic endoscopic band ligation is performed in patients who cannot tolerate, have a contraindication to, or fail to respond to β-blockade; in patients with large varices and high-risk stigmata of potential bleed (red wale marks); and in those who may not be able to tolerate the initial bleeding episode (see Chapter 76 ). ^{, ,}

Diffuse mucosal bleeding from duodenitis or gastritis is usually not responsive to endoscopic interventions. There are two exceptions to this, the first of which is gastric antral vascular ectasia (GAVE), which is amenable to treatment with the argon plasma coagulator. The second is application of hemostatic powder, as discussed later in this chapter.

Other lesions that may be treatable with endoscopic therapy include bleeding lesions, angiomata, and polyps.

There are five well-established types of therapeutic intervention for acute gastrointestinal bleeding: injection; coagulation or thermal therapy, including argon plasma coagulation (APC); laser therapy; endoscopic hemostatic devices; and ligation therapy, as well as the newer technique of application of hemostatic powder. The specific techniques used depend on equipment availability and experience of the endoscopist. The more commonly used techniques appear to have roughly equivalent efficacy, but some lesions are more amenable to a particular type of therapy.

Therapeutic endoscopy is most easily accomplished using a two-channeled therapeutic scope so that therapy (e.g., injection and coagulation) may be accomplished via one channel, and simultaneous suction or irrigation may be performed using the second channel to keep the field in view. Unfortunately, therapeutic endoscopes are of a large diameter compared with standard pediatric endoscopes and often cannot be used in the pediatric patient. Therapeutic endoscopy may still be performed using a single-channel scope, but depending on the modality used, this may be technically more difficult.