Endoscopy of the Small Intestine

Abstract

For the patient and the clinician, it is well that small-bowel diseases are unusual, as our ability to access this area remains limited. Frequently, all of the diagnostic and therapeutic modalities of radiology, endoscopy, and surgery are required for successful resolution of a given problem. Because management of bleeding from a small-bowel source usually will involve the surgeon at some point, it is mandatory that the best "road map" be obtained prior to exploration. If a small-bowel source is suspected after a negative endoscopic evaluation of the esophagus, stomach, duodenum, and colon, then the clinician must decide which radiographic and endoscopic examination is most appropriate. If bleeding is slow or intermittent, push-type enteroscopy to evaluate the proximal jejunum will have an expected diagnostic discovery rate of about 30 per cent. A stiffening over-tube or internal cable should result in deeper passage of the instrument and a potentially greater yield. Retrograde ileoscopy should be a part of every colonoscopy done for occult bleeding. If endoscopy does not identify a bleeding source, then a detailed barium study of the small bowel using an enteroclysis double-contrast technique will discover more pathology than a standard small-bowel-follow-through. Because sonde-type enteroscopes are not readily available, the clinician must decide at this point whether to refer the patient to an enteroscopist or consider surgery and intraoperative endoscopy. If a bleeding source has been found, then intraoperative endoscopy can localize lesions for specific resection. If the pathology remains obscure, intraoperative endoscopy will have a discovery rate of about 70 per cent. For more active hemorrhage, a bleeding scan with 99mTc-labeled red blood cells can confirm that blood loss is continuing and also will guide the angiographer toward a more directed study, thus decreasing the contrast material load for the patient. If a bleeding source can be identified angiographically, a short course of vasopressin infusion to convert the need for surgical intervention to a more elective situation would be beneficial to the patient. Intraoperative endoscopy under urgent conditions is more difficult, because luminal blood must be lavaged or cleared for a proper examination. Many times, however, intraoperative endoscopy can "surround" a segment of intestine by identifying areas that are clearly normal.