Capsule endoscopy (CE)

Capsule endoscopy was first described in 2000 (see Chapter 15) and since then it has gained wide acceptance as a minimally invasive and safe tool for the evaluation of the small intestine. A systemic review of 22 840 capsule endoscopies revealed that OGIB is the most common indication [10] and the diagnostic yield in detection of the source of OGIB has been reported up to 80%, with a higher diagnostic yield in overt compared to occult bleeding [11–13]. It is also proposed that the diagnostic yield is enhanced when the CE is performed in the early stage of OGIB [14].

There are five different capsules available (Medtronic PillCam, Olympus EndoCapsule, IntroMedic Mirocam, Capsovision CapsoCam, Jinshan Science OMOM capsule), but most studies in OGIB have been performed with the PillCam [4,15].

In 2009, the FDA approved the use of CE for children 2 years of age or older but in our unit, and in the literature, CE has been used safely in selected cases even in younger children [16–18]. Older children are asked to swallow the capsule, whereas in young children it is placed in the duodenum endoscopically.

Capsule endoscopy is superior to other diagnostic modalities and the American College of Gastroenterology clinical guideline recommended that CE should be considered first to determine the source of OGIB [19]. However, it has some limitations, with the main one being the inability to obtain biopsies and perform endoscopic therapies. The rate of capsule retention has been reported as 1.4% for adults with OGIB and the risk of retention is higher post abdominal surgery, abdominal radiation therapy or Crohn’s disease with small bowel involvement [10]. A dissolvable test capsule is available but of limited value in children [20].

To date, there is no consensus as to which agents and bowel preparation improve the visualization quality, diagnostic yield, and completion rate, but one systematic review and metaanalysis showed that the combination of polyethylene glycol and simethicone appears to be the best approach for small bowel preparation before CE [21].

Several adult studies have compared the outcomes of CE with enteroscopies (push, single‐balloon, double‐balloon) (see Chapter 15) in OGIB and the recommended approach is to perform CE first prior to enteroscopy and if CE reveals findings that require biopsy or endoscopic intervention, to proceed with enteroscopy [22–26]. A retrospective study in 36 children comparing the diagnostic accuracy and concordance of CE and double‐balloon endoscopy (DBE) showed that CE has excellent negative predictive value for DBE and histological findings but is limited by its low specificity, whereas both sensitivity and specificity of DBE are good [27]. Overall, CE and enteroscopy should be considered to have complementary roles in the diagnostic and therapeutic management of OGIB.

Double‐balloon enteroscopy

Since the first description of DBE by Yamamoto et al. in 2001 [28], it has become a valuable addition to endoscopic techniques when the GI pathology is beyond the reach of conventional endoscopy both in adult and pediatric populations. DBE requires a longer endoscope that offers the advantage of visualization of the entire small bowel with the combination of an oral and anal approach. Its utility is enhanced by the ability to obtain tissue and undertake endotherapeutic procedures. DBE is performed with a 200 cm long enteroscope and a 145 cm long overtube [28].

Over the past decade, the body of evidence on the safety and efficacy of DBE in pediatric patients has gradually increased [29–32]. In Japan, 10 pediatric patients with OGIB were investigated with DBE, with a diagnostic yield of 70% [33]. We have previously published our experience in 16 pediatric patients with OGIB who underwent 30 DBE procedures that revealed ulcers, polyps, varices, strictures, and angiodysplasias. The endotherapeutic interventions included application of argon plasma coagulation and endoclips, injection of epinephrine, and banding using conventional endoscope. The examination time was 45–275 minutes (median 92.5) based on technical difficulties and therapeutic interventions. The diagnostic yield in OGIB was 50%, with therapeutic utility of 43% [34].

The group of Luo et al. reported the safety and efficacy of single‐balloon endoscopy (SBE) in children with small bowel bleeding. The endoscopic findings in the small bowel included nonspecific inflammation, allergic purpura, Crohn’s disease, Meckel’s diverticulum, and Peutz–Jeghers syndrome [35]. In another study, 22 children with OGIB were investigated with CE followed by SBE that led to a diagnostic yield of 95%, with 82% of the cases achieving complete resolution of the bleeding after therapy [36].

To date, only adult studies have compared SBE versus DBE with contradicting results; some studies favor SBE based on the diagnostic yield and significantly shorter average examination time via an anterograde approach through the mouth for SBE [37,38]; however, a recent metaanalysis has not shown statistically significant differences between the two endoscopic approaches [39].

Push enteroscopy

The depth of insertion into the small bowel can be maximized with the use of an enteroscope with an overtube or a variable stiffness colonoscopy. The existing evidence on the safety and efficacy of push enteroscopy in pediatric patients is limited.

Intraoperative enteroscopy

This endoscopic approach achieves the evaluation of the entire small bowel with a mid small bowel enterotomy through which the scope is advanced anterograde and retrograde. We have reported the case of a 5‐year‐old girl with OGIB who was diagnosed with idiopathic small bowel diaphragm disease who had a successful definitive therapeutic DBE and minimally invasive bowel surgery for her small bowel pathology. She was noted to have multiple strictures throughout the mid‐distal small bowel on wireless CE and the diaphragm‐like strictures in the distal ileum were divided with an endoknife transmurally with the enteroscope and a segment of the terminal ileum was resected surgically. Laparoscopic‐assisted enteroscopy in a pediatric patient has also been successfully performed for endotherapeutic treatment of small bowel lesions in blue rubber bleb nevus syndrome with APC.

Bleeding scans and other modalities

In cases of active GI bleeding, additional imaging modalities can be considered to detect the source of GI bleeding. The use of gastrointestinal bleeding scintigraphy with technetium 99m‐labeled red blood cells has been reported in infants as young as 8 months old [40]. It is preferred in children because of the lower absorbed radiation dose [41], providing that the rate of hemorrhage is greater than 0.1–0.4 mL/min. For nonactively bleeding lesions, angiography can add to the diagnostic work‐up and several studies have shown that CT angiography can be a valuable tool in children with OGIB to decide on an appropriate treatment plan and the need for endovascular interventions [42–44]. Even though MR enterography has been largely replaced by CE in the assessment of the small bowel in OGIB in children, a recent prospective study in 25 children with OGIB showed that CT angiography remains a safe and accurate imaging modality with a sensitivity and specificity of 86% and 100% respectively [45] and should be included in the diagnostic work‐up, especially in centers in which CE is not available. Plain CT may also be useful in detection of lesions such as gastric duplication cysts.