The impact of wireless capsule endoscopy on gastrointestinal diseases.

The M2A video capsule endoscope (Pillcam SB, Given Imaging LTD, Yokneam, Israel) is a wireless capsule (11 mm 27 mm) comprised of a light source, lens, CMOS imager, battery and a wireless transmitter. The capsule moves via peristalsis from the mouth to the anus. The current battery provides 7 to 8 hours of work in which the capsule photographs 2 images per second that are transmitted to a recorder, worn on a belt. The photographs are downloaded into a computer and seen as a continous video film. Since its development, additional support systems have been added: a localization system, a blood detector, a double picture viewer, and, recently, a wider picture angle and better light source, all meant to assist the interpretor. Pillcam SB was invented to address a need for a better diagnostic tool for small bowel pathologies. In this issue of the Southern Medical Journal, Mazzarolo and Brady give a systemic review of small bowel capsule endoscopy (CE). They review the data on bleeding, Crohn disease and chronic abdominal pain. The most obvious and first indication to be tested after the capsule invention was obscure gastrointestinal bleeding (OGIB). Many peer reviewed articles compared Pillcam SB to push enteroscopy and other modalities in patients with OGIB. The added value of enteroscopy in these patients was in the range of 25 to 30%, while that of the capsule was significantly better (50–67%). Two important take-home messages came out of these studies: 1) the closer the study is performed to the time of actual bleeding, the greater the diagnostic yield; and 2) patients with overt bleeding who required transfusions were those who benefited most. Moreover, it was found that a second CE of patients with OGIB and a negative first study increased the diagnostic yield by 20%. We have looked at Pillcam SB in real life by reviewing the charts of the first 160 patients referred for capsule endoscopy by various doctors in 4 centers in Israel and found the capsule to be of value mainly in patients with OGIB (65%). Thus, we and others propose an algorithm in which Pillcam SB will be used early to evaluate the small bowel in a patient with gastrointestinal bleeding with negative gastroscopy and colonoscopy. The outcome of the test will guide the gastroenterologist as to the next invasive step—be it push enteroscopy, ileoscopy, double balloon, or intraoperative enteroscopy. The second most studied indication for CE is Crohn disease. CE seems to be superior to all other modalities for diagnosing nonstricturing small bowel Crohn disease, with a number needed to test of 3 to yield one additional diagnosis over small bowel follow-through and 7 for colonoileoscopy. Other subsets of patients that would probably benefit from CE are patients with undetermined colitis, for assessing relapses and postsurgical recurrences, but all these need to be proven in large-scale, controlled studies. CE has proven to be a valuable tool for the detection of small bowel tumors, follow-up of polyposis syndromes and probably complicated celiac disease. Since its FDA approval 5 years ago for the small bowel, a somewhat different, twosided camera, 14 frames per second capsule (PillCam ESO) has received FDA approval. It was found to be valuable for the detection of esophageal pathologies, mainly Barrett esophagus and esophageal varices, though bigger, multicenter, prospective studies are needed. Recently, the company has developed a new capsule designed to view the colon (PillCam Colon). The first generation of this capsule has been tested in 3 prospective, blinded, controlled studies with promising results. Thus, if 6 years ago we were astonished to see the performance of the SB capsule, thought to be science fiction, the day is not far in my mind when we will see a total bowel capsule (“PillCam Total Body”) that would be given to patients with bleeding, iron deficiency anemia or chronic diarrhea. The major complication with CE is capsule retention, usually proximal to a stricture. This happens many times despite normal small bowel x-rays. NSAID usage, ischemic bowel event or known Crohn disease carry a higher risk for capsule retention, necessitating surgery in less than 1% of From the Department of Gastroenterology, Rambam Health Care Campus, Rappaport School of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.