Laboratory Technique ROLE OF CAPSULE ENDOSCOPY IN OBSCURE GASTROINTESTINAL BLEEDING J. JAIN* ABSTRACT Capsule endoscopy (CE) is a safe, non invasive technique for evaluation of small bowel (SB) lesions. Capsule endoscopy has a very high diagnostic yield especially with ongoing bleeding and appears to be superior to other modalities for the detection of suspected lesions of bleeding. 1 Key words : Capsule endoscopy, Obscure gastrointestinal bleeding, Small bowel study. Introduction Obscure gastrointestinal bleeding (OGB) is bleeding from the gastrointestinal tract (GIT) that persists or recurs after a negative initial evaluation using bidirectional endoscopy and radiologic imaging with SB radiograph. 2 The challenges related to evaluation of OGIB include the high missing rate for lesions on initial assessment with standard endoscopy and limited capacity of older diagnostic modalities to efficiently examine the SB.3 OGIB is divided in either obscureoccult bleeding presenting as persistent iron deficiency anemia or a positive faecal occult blood test, or obscure-overt bleeding when visible blood is found (melaena, hematemesis, hematochezia). 2,4 The underlying etiology may not be evident in 10-20% patients of OGIB in initial evaluation and recurrent or persistent bleeding occurs in approximately half of them. The underlying etiology (Table -1) often remains elusive despite extensive evaluations, thereby resulting in recurrent hospitalizations and multiple transfusions. Table 1 : Etiology of obscure gastrointestinal bleeding Vascular Inflammatory Neoplastic Extraluminal Rare Angioectasias Esophagitis Carcinoid Hemobilia Hereditary hemorrhagic Dieulafoy lesion Peptic ulcer Gastrointestinal Hemosuccus Telangiectasias Gastric antral disese stromal tumor pancreaticus von Willebrand vascular disease ectasia Cameron Lymphoma Aortoenteric Pseudoxanthoma Portal erosions Ampullary fistula elasticum hypertensive gastropathy IBD carcinoma Amyloidosis Varices (SB & colonic) Meckel diverticulum Metastases Adeno Blue rubber bleb nevus syndrome vasculities
Hemorrhoids Radiation enteritis NSAID - related carcinoma enteropathy The introduction of CE, balloon assisted enteroscopy, spiral enteroscopy, and computed tomography enterography have served to overcome the limitations of older diagnostic tests. CE is used to examine parts of the GIT that cannot be seen with other types of endoscopy. CE is currently recommended as the investigation of choice for the evaluation of SB lesions in patients with OGIB, after a negative bidirectional endoscopy. It is also known as M2A (mouth to anus), VCE (video capsule endoscopy) and WCE (wireless capsule endoscopy). The images produced by CE are of good quality, comparable to those from other scopes. 5 Procedure CE is relatively new procedure and capsule endoscope is a tiny camera in shape of a pill and measure 22mm x 11 mm. After swallowing the capsule, it captures images at the rate of 2 frames/second over an 8-hour period inside the GIT. 6 Images are transmitted to a recording device, can be downloaded and viewed on a computer. 5 CE allows noninvasive evaluation of the entire SB in 79-90% of patients, with a high positive (94.4%) in patients with intestinal lesions and negative predictive value (100%) in patients with normal CE findings. 7 Findings on CE may lead to endoscopic or surgical intervention, or a change in medical management in 37-87% of patients. After undergoing CE-directed interventions, 50-66% of patients have been reported to remain transfusion-free without recurrent bleeding at follow-up. Factors influencing the yield of Capsule endoscopy 1. Hemoglobing level of < g/dl, 2. Longer duration of bleeding (>6 months), 3. More than 1 episode of bleeding, 4. Overt (rather than occult) bleeding (60% vs 46%), 5. Use of CE within 2 weeks of the bleeding episode (91% vs 34%). 6. Goods bowel preparation 8 Indications of Capsule endoscopy Evaluation of several SB conditions, including crohn s disease, celiac disease and tumours. 4,8 Primarily used for the evaluation of patients with OGIB. 9 Advantages of Capsule endoscopy- 1. Non-invasive, painless imaging technique with little or no complications. 4,6 2. Higher diagnostic yield compared to other imaging techniques. 3,10
3. It can be performed on an out-patient basis. 2 Limitations and Disadvantages of Capsule endoscopy - 1. Lack of therapeutic opportunities and tissue sampling. 5,11 2. Inability to control its movement through the gastrointestinal tract. 3. High rate of incidental findings in up to 23% of healthy controls. 4. Risk of stagnation (1-13%), disintegration and perforation, which prevent its use in suspected SB obstruction but relatively easy method for capsule retrieval, are available. 8 5. Potential for missing solitary lesions in the SB. (false-negative rate of 11% for all SB findings and 19% for neoplasms) 6. Expensive. 3 Comparison of various modalities for detection of obscure gastrointestinal bleeding WCA is currently the only non-operative method to examine the whole of the small intestine. 3 Results of a meta-analysis in patients (n =396) with OGIB showed that CE is superior to push enteroscopy and SB barium radiography for diagnosing clinically significant SB pathology (yield of CE to push enteroscopy showed 63% and 28%, respectively (Incremental yield (1Y)=35%, p<0.00001, 95% CI=26-43%) with an Number needed to test of 3, primarily due to visualization of additional vascular and inflammatory lesions by CE. 4 Other studies compared the yield of significant findings on CE to intraoperative enteroscopy (n=42, 1Y=0%, p=1.0, 95% CI=16% to 16%), computed tomography enteroclysis (n=8, 1Y=38%, p=0.08, 95% CI=- 4% to 79%), mesenteric angiogram (n=17, 1Y= -6%, p=0.73, 95% CI=-39% to 28%), and small bowel magnetic resonance imaging (n=14, 1Y=36%, p=0.007, 95% CI=10-62%). CE had a 36% and 11% yield for vascular and inflammatory lesions versus 20% and 2% for push enteroscopy. There was no significant difference in the yield of tumors or other findings between CE and push enteroscopy. 4 Table 2 : Comparison of various modalities for detection of OGIB Modality diagnostic yield Complication rate majro complications Traditional Endoscopic Tests Push Enteroscopy 3-70%, looping of the enteroscope, discomfort Sonde Enteroscopy No longer utilized in clinical practice due to discomfort and long procedure duration. 2 Intra-operative Enteroscopy 2 New Endoscopic Tests 58-88% 0-52% Serosal tears, avulsion of mesenterichigh mortality rate of 11%
Video Capsule 38%-83%, (1-13%) Risk of stagnation, disintegration, Endoscopy and perforation 10 Balloon-Assisted 60-80% 0.8% - 4% invasive nature, prolonged Enteroscopy* duration, and (DBE and SBE) need for additional personnel, ileus, pancreatitis, and perforation 10 Spiral Enteroscopy 33% minor complications of sore throat and minimal mucosal trauma * Balloon-assisted enteroscopy has the additional advantage over CE of both diagnosis and endoscopic management of OGIB including biopsies, hemostasis, polypectomy, balloon dilation, and foreign body retrieval (eg. for retained capsules). Cost effectiveness of Capsule endoscopy - Only few studies have addressed the issue of cost effectiveness of CE in OGIB. One study examined the cost effectiveness of several modalities, in patients with OGIB, DBE was found to be the most cost effective strategy; however CE followed by DBE was more cost effective if the probability of angiectasia at DBE was less than 59%. 9 Recent developments - Ongoing research is continuing to improve CE technology. Sayaka Capsule is an advanced capsule with wireless power supply from an external source. The next major development is to enable the capsule to do other functions that are possible with current traditional endoscopes like ultrasound, electrocautery, biopsy, laser, and heat with a retractable arm. A concept of a magnetically guided CE, a potential alternative to esophagogastroduodenoscopy, was recently presented. References 1. Gupta R, Lakhtakia S, Tandan M, et al Capsule endoscopy in obscure gastrointestinal bleding -an Indian experience. Indian J Gastroenterol. 2006; 25 (4): 188-90. 2. Shabana F, Army K. Hara, Jonathan A. Diagnostic Evaluation and Management of Obscure Gastrointestinal Bleeding : A Changing Paradigmet Gastroenterology & Hepatology. 2009; 5(12): 839-850 3. Mylonaki M et al. Wireless capsule endoscopy: a comparison with push enteroscopy in patients with gastroscopy and colonoscopy negative gastrointestinal bleeding. Gut, 2003; 52 : 1122-1126. 4. Triester SL, Leighton JA, Leontiadis GI et al. A meta-analysis of the yield of capsule endoscopy compared to other diagnostic modalities in patients with obscure gastrointestinal bleeding. Am J Gastroenterol. 2005; 100: 2407-18. 5. Sietze T. van Turenhout, Maarten A. J. M. et al. Diagnostic Yield of Capsule Endoscopy in a Tertiary Hospital in Patients with Obscure Gastrointestinal Bleeding. J Gastrointestin Liver Dis. 2010; 19(2): 141-145.
6. Paul Swain. The future of wireless capsule endoscopy. World J Gastroenterol. 2008; 14(26): 4142-4145. 7. Delvaux M, Fassler I, Gay G. Clinical usefulness of the endoscopic video capsule as the initial intestinal investigation in patients with obscure digestive bleeding; validation of a diagnostic strategy based on the patient outcome after 12 months. Endoscopy. 2005; 37(8): 780. 8. Dimitrios C, Gregory H, Umar B. Reproducibility of wireless capsule endoscopy in the investigation of chronic obscure gastrointestinal bleeding. Can J Gastroenterol. 2007; 21: (11). 9. Gupta R, Reddy D. N. Capsule endoscopy: Current status in obscure gastrointestinal Bleeding. World Journal of Gastroenterology. 2007; 14(34); 4551-4553. 10. Tsung-N, Ming-Y, Chen-M, et al. Combined Use of Capsule Endoscopy and Doubleballoon Enteroscopy in Patients with Obscure Gastrointestinal Bleeding. Chang Gung Med J 2008; 31: 450-6. 11. Jonathan A, Ian M, Randel E et al. Capsule endoscopy in suspected small bowel Crohn s disease: Economic impact of disease diagnosis and treatment. World J Gastroenterol. 2009; 7; (15): 5685-5692.