In True Obscure GI Bleeding, What Should I Do if a Capsule Endoscopy and Upper and Lower Endoscopies Are Unrevealing?
Identifying the etiology of obscure gastrointestinal (GI) bleeding can be time intensive and frustrating for both clinician and patient. Obscure GI bleeding should be further designated as obscure-overt or obscure-occult before embarking on a diagnostic plan. Obscure-overt bleeding manifests as visible blood (ie, hematochezia or melena) while obscure-occult bleeding may manifest as a positive fecal occult blood test or iron deficiency anemia. This chapter will only consider the former condition.
The first step after negative esophagogastroduodenoscopy (EGD), colonoscopy, and video capsule endoscopy (VCE) is to repeat the colonoscopy and upper endoscopy with or without push enteroscopy. This is particularly true if the patient is referred to you from a source that is not familiar to you. Factors such as the referring endoscopist’s experience, different endoscopes with different handling characteristics, and the patient’s condition can all affect diagnostic capabilities. The culprit lesion that may have been overlooked at initial EGD and colonoscopy include Cameron’s syndrome, ulcers in the duodenal fornices, angioectasias, and Dieulafoy’s lesions. The entire VCE should be read by an experienced reader, particularly if the patient is referred.
If the cause of bleeding remains elusive, we would then recommend a repeat VCE to evaluate the small bowel. Two recent studies employing capsules given on the same day1 and within 4 days of each other2 noted observer variation of 25% and 27% between the two VCE examinations. This difference in findings is not surprising given the intermittent nature of GI bleeding and the fact that the capsule tumbles. It is likely that only about 70% of the mucosa is seen on any single capsule study. In certain anatomic sites, much less mucosa is seen (eg, the duodenum, where the papilla is seen only a few percent of the time). The data from a second VCE study can aid in planning subsequent therapeutic approaches such as double balloon endoscopy (DBE) or intraoperative enteroscopy.
If a second capsule fails, then DBE can be considered if available. This enteroscope employs the inflation and deflation of two balloons and an overtube for pleating of the small bowel over a 200-cm enteroscope. The entire small bowel can sometimes be examined using a combination of per oral and per rectal approaches although this requires two procedures and cannot be accomplished in all cases. Unfortunately, DBE is not widely available at the present time, is labor intensive, and is technically challenging. The major advantage of DBE over VCE is the potential for therapeutic intervention. A new single balloon enteroscope has recently become available, but there are no comparative data.
A recent series compared the yield of DBE following VCE in 130 patients with obscure GI bleeding. The study reported a DBE miss-rate of 27.8% and a VCE miss-rate of 20.3% for detecting a potential bleeding source. DBE allowed for a variety of interventions, including 35 cases in which argon plasma coagulation or cautery was applied to an arteriovenous malformation (AVM) and 33 cases in which biopsies were taken.3
In most cases, we would recommend VCE to identify a treatable lesion prior to undertaking DBE. However, in cases with ongoing obscure-overt bleeding, a decision has to be made as to whether DBE should be performed before VCE given the therapeutic intervention capability of the device or whether to use a technetium bleeding scan followed by angiography and embolization. Angiography will only localize the bleeding lesion if the rate of bleeding is at least 0.5 mL/minute. Angiography can offer therapy with vasopressin infusion or coil embolization. The latter approach is more generally available at present than DBE and is probably safer in the hemodynamically unstable patient since sedation is not needed.
Intraoperative enteroscopy had been used as a method of last resort before the advent of wireless capsule endoscopy for the diagnosis and therapy of obscure GI bleeding. In this procedure, a surgeon sleeves the small bowel over the endoscope while the endoscopist examines the mucosa. While some endoscopists use a per-oral approach, we would advocate introducing the endoscope via a small bowel enterotomy using a sterilized enteroscope sheathed in a plastic sleeve to maintain a sterile operative field. In a large case series published before VCE was widely available, 74% of lesions were identified and treated with intraoperative enteroscopy (IOE).4 One significant drawback of IOE is mucosal trauma and bleeding caused by pleating of the bowel over the endoscope, thus making differentiation of artifact versus culprit lesions difficult. Also, given the inherent higher risk of IOE complications, including mesenteric tears, perforation, hematoma, infection, and ileus, we would typically recommend IOE in cases where other diagnostic and therapeutic measures had already been attempted and failed.
Small bowel follow-through examination and enteroclysis have very low diagnostic yields for obscure GI bleeding. We do not recommend these tests in the work-up of obscure GI bleeding. However, in cases of suspected small bowel stricturing due to Crohn’s disease or non-steroidal anti-inflammatory drugs (NSAIDs) causing possible capsule retention, one should obtain a small bowel follow-through or patency capsule examination prior to VCE.
1. Cave DR, Fleisher DE, Gostout CJ, et al. A multi-center randomized comparison of the endocapsule: Olympus Inc and the Pillcam SB: given imaging in patients with obscure GI bleeding. Gastrointest Endosc. 2007;65:AB 125.
2. Kimble J, Chak A, Isenberg G, et al. Variation in diagnostic yield back-to-back capsule endoscopy in obscure GI bleeding: final results. Gastrointest Endoscop. 2007;65:AB 185.
3. Mehdizadeh S, Ross A, Leighton J, et al. Double balloon enteroscopy (DBE) compared to capsule endoscopy (CE) among patients with obscure gastrointestinal bleeding (OGIB): a multicenter U.S. experience. Gastrointest Endosc. 2006;63:AB 91.
4. Kendrick M, Buttar N, Anderson M, et al. Contribution of intraoperative enteroscopy in the management of obscure gastrointestinal bleeding. J Gastrointest Surg. 2001;5:162-167.