Capsule endoscopy for small bowel bleed: Current update

Small intestine, hitherto an obscure area for endoscopists before 2000, is now easily evaluated non-invasively using capsule endoscopy and invasively by device-assisted enteroscopies. Major advances in understanding the causes and management of small bowel diseases have been in obscure gastrointestinal (GI) bleed, currently re-named as small bowel bleed, after the discovery of capsule endoscopy. The current article is a narrative review of the technology of capsule endoscopy, its advantages and limitations, future perspective and Indian studies on its utility in patients with small bowel bleed. Till date, eight large series reporting 2319 patients with obscure GI bleed (1554 overt and 765 occult) undergoing capsule endoscopy have been reported from India. Overall yield of capsule endoscopy to detect lesions in these studies varied from 43.5% to 90%. The major causes detected in various studies for small bowel bleed include vascular malformation, portal hypertensive enteropathy, ulcer, stricture, tumor, polyps, etc. Hookworm can cause both occult as well as overt small bowel bleed as shown mainly from India. Capsule endoscopy has also been quite safe in patients with small bowel bleed as despite 0.6% to 15% retention of imaging capsule in Indian studies, development of clinically evident small bowel obstruction has rarely been reported. The major limitations of capsule endoscopy include lack of maneuvrability and therapeutic capability. Research is in progress to overcome some of the limitations of the current capsule endoscopy system. It is concluded that discovery of capsule endoscopy has brought a new paradigm in GI endoscopy and explored a hitherto unexplored area of GI tract, i.e. small bowel that continued to be a black box for the endoscopists.