The development of wireless capsule endoscopy allows noninvasive, rapid and painless imaging especially of the small intestine as well as the whole GI tract. Its clinical use is not yet well-defined. This paper has three aims. One aim is to summarize what has been written about the clinical efficacy and technical performance of capsule endoscopy and push enteroscopy (manual fiberoptic proximal small bowel endoscopy). The second aim is to alert more clinicians to the availability of this relatively new diagnostic tool. The third is to persuade more clinicians to use capsule endoscopy sooner rather than later when evaluating severe bleeding of the GI tract. The invention of fiberoptic endoscopy has allowed inspection of the esophagus, stomach, proximal small intestine and colon. Flexible endoscopy has been of particular value in the investigation and treatment of patients with GI bleeding, and gas-troscopy and/or colonoscopy can find a bleeding source in more than 90% of these cases. Persistent or recurrent bleeding can lead to multiple investigations, prolonged hospitalization and even surgical interventions, all of which may fail to identify the bleeding source.
Push enteroscopy is a valuable tool in some patients as it allows examination of sections of the proximal jejunum. It can identify bleeding sources from that area and not infrequently may find pathology missed at a previous gastroscopy. Despite substantial improvement to push enteroscopy in the last 10 years with manufacturers producing longer instruments of 240 cm with video and overtubes, these instruments can only examine the upper GI tract to the level of the proximal jejunum. generic cialis 20mg
Sonde enteroscopes, which are approximately 275 cm in length, can reach further into the small intestine. The discomforts experienced by the patient and length of time required for this examination have prevented widespread dissemination of this method, which is rarely performed nowadays.
Indirect methods to visualize the small bowel in patients with small-intestinal bleeding have produced low diagnostic yields of approximately 5-8% for small-bowel follow-through or enteroclysis. Angiography is rarely helpful unless the patient is actively bleeding at the rate of more than 3-5 ml/min, and scintigraphy with technetium labeled red cells is of limited value, particularly in the foregut. Meckel scans are helpful when positive, but if negative do not exclude a Meckel’s diverticulum as a bleeding source.
Development of a new radiotelemetry capsule video endoscope, which is small enough to be swallowed (11 x 27 mm) and has no external wires, fibreoptic bundles or cables, made it possible to acquire images of the whole of the small bowel. The Givens M2A System (wireless capsule endoscopy) is a novel noninvasive technology designed primarily to provide diagnostic imaging of the small intestine, an anatomic site that has proved peculiarly difficult to visualize. Limited views of the esophagus, stomach and cecum may also be acquired. Images acquired are of excellent resolution and have an 8:1 magnification, which is higher than that of conventional endoscopes. This magnification allows visualization of villi.
A study was done by Mylonaki et al. to compare the efficacy and clinical impact of this new wireless capsule endoscopy with push enteroscopy in patients with recurrent bleeding or anemia when gastroscopy and colonoscopy were negative. The wireless capsule examination identified a bleeding source in the small intestine in 34/60 patients (68%). These included angiodysplasia, focal active bleeding, small-bowel tumor both located in the ileum (both carcinoid tumors), apthous ulceration and skip lesions suggestive of Crohn’s disease, Meckel’s diverticulum, ulcerating proximal jejunitis, ileal ulcer and ulcer due to intussusception. The diagnostic yield of push enteroscopy to diagnose a bleeding source in the small bowel was 16/50 (32%).
The technical problems encountered with capsular endoscopy are described below. One capsule remained in the esophagus. Temporary electrical disconnection at the aerial recorder interface was associated with some image loss in three patients. In one patient, the battery power ran out at two hours, and only a short period of small-intestinal imaging was acquired. In seven patients, the capsule passed into the pylorus and then returned to the stomach before passing on down the small intestine at least once. In one patient, this occurred several times. The capsule never reported to have been stuck in the small intestine or colon. None of these technical problems led to severe adverse outcomes, and the investigators were able to appropriately correct the problems.
There have been multiple patients at our institution over the years who have been admitted with severe GI bleeding of undetermined etiology. Until recently, we had nothing new to offer. I practice at a hospital that serves a large percentage of poor and underserved. Because of economic factors, this new technology is not generally available to this patient population. These types of patients may be referred to the nearest facility that has the capability to perform this test, which will be more economical in the long run. Patients like this with recurrent bleeding episodes and hypovolemic shock are often triaged for emergency surgery without a known site of bleeding. The value of wireless capsule endoscopy has not been emphasized strongly for the evaluation of lower GI tract. However, this case illustrates how this technique can be of value for lower GI bleeding, because it ruled out any bleeding above the cecum and, consequently, the surgeon was willing to recommend right colectomy with greater confidence. If this decision had been made after colonoscopy on the second day of admission, blood transfusions, morbidity, financial burden and the possibility of near mortality could have been markedly curtailed.
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The use of wireless capsule endoscopy should be used sooner rather than later in the case of severe GI bleeding when the source of the bleeding has not been made in a timely manner after using the well-known and often-used tools of upper- and lower GI evaluation, such as endoscopies, tagged red blood cell studies and angiography. Capsule endoscopy is superior to push enteroscopy in the diagnosis of recurrent bleeding in patients who have a negative gastroscopy and colonoscopy. It is safe and well-tolerated. As more physicians become aware of this technique, I am sure it will be utilized more, greatly reducing costly transfusion days in the hospital, improving morbidity and mortality in patients with severe GI bleeding.
Tags: capsule endoscopy, colonoscopy, endoscopy, gastrointestinal bleeding