Endoscopic examination of the entire small bowel has remained elusive. Standard endoscopic and colonoscopic exams view only small amounts of the proximal and distal ends of the small bowel. Push enteroscopy was the first step in the endoscopic evaluation of the intestine.

An endoscopic capsule (Given Imaging Limited, Yoqneam, Israel) has been developed to obtain images from the entire small bowel. Developed by Dr. Gavriel Idan in 1981, the capsule, which measures 11 x 26 mm, contains 4 LEDs (light emitting diodes), a lens, a colour camera chip, two batteries, a radio frequency transmitter and an antenna. The camera is a CMOS (complementary metal oxide semiconductor) chip. This chip requires less power than present CCD (charged coupled device) chips found on video endoscopes and digital cameras, and it can operate at very low levels of illumination. The capsule obtains two images per second and transmits the data via radio frequency to a recording device worn about a patient’s waist. Once the acquisition time is reached, the recording device is downloaded to a computer workstation whose software provides the images to the computer screen. The capsule is disposable and does not need to be retrieved by the patient. It is passed naturally. An average of 50,000 images are obtained during an eight-hour exam.

The first clinical trial was completed 3 years ago and push enteroscopy was compared to capsule endoscopy in 21 patients with obscure GI bleeding. Capsule endoscopy was superior to push enteroscopy in the evaluation of obscure bleeding. Capsule endoscopy made a diagnosis in 11/20 (55%) and findings included angioectasias, fresh blood, a tumour, and an ileal ulcer. Push enteroscopy made a diagnosis in 6/20 (30%); all findings were angioectasias. No additional diagnoses were made by push enteroscopy and the capsule identified lesions found distally in the small bowel, not reachable by push enteroscopy. 95% confidence intervals were 13.65%.

Thus capsule endoscopy appears to be the answer to the long-standing desire for the complete endoscopic examination of the entire small bowel and it performs this in a non-invasive way. The need for this technology is clear, especially when dealing with patients with obscure gastrointestinal bleeding. Gastroenterologists know how truly difficult it is to care for these patients. Nearly one-third of patients with isolated iron deficiency anaemia rebleed and one-half of patients with known angioectasias of the small bowel rebleed. Improved diagnostic abilities would most likely lead to improved prognosis. This lesson was learnt by using sonde enteroscopy where the deeper one looked into the small bowel the more information was obtained. This improved diagnostic ability is especially true in addressing the primary concern of physicians who see patients with obscure bleeding. That is the concern for an occult malignancy. Cancer of the small bowel is uncommon and unfortunately due to the limitations of previous diagnostic testing, such as small bowel series, cancer of the small bowel historically carries a poor prognosis. Studies have shown that if diagnosed early, historically carries a poor prognosis. Studies have shown that if diagnosed early, prognosis is improved and other studies have shown that approximately 10% of patients with obscure bleeding have a tumour of the small bowel. The second major concern of physicians caring for patients with obscure bleeding is to control the transfusion requirement. Limitations in this regard have included limited enteroscopic intubation thus limiting the knowledge of the extent of disease and limiting the depth to which therapy can be provided, the lack of effective medical therapy outside of transfusion, and the difficulty with present surgical intervention when coupled with intraoperative enteroscopy.

Utilizing capsule endoscopy, the evaluation of patients with GI bleeding in the future will be very different from current practice. Capsule endoscopy may become the third test in the evaluation of patients with GI bleeding, once upper endoscopy and colonoscopy are negative. In the patient with active bleeding, capsule endoscopy can confirm the small bowel as the site of bleeding, providing a location. If the study is negative, the study may indicate that the bleeding is actually colonic in origin. In the patient with active bleeding within the small intestine, the capsule will guide further evaluation and therapy. A patient with a small bowel tumour detected by capsule endoscopy will proceed directly to laparoscopic surgery. If the site of bleeding is identified in the proximal small bowel and there is no mass, push enteroscopy will be used to re-identify the site and cauterize the lesion. In cases where a distal small bowel site is identified, surgical intervention coupled with intraoperative enteroscopy will be necessary. Since the entire small bowel has been examined with the capsule exam. surgery can be targeted and a laparoscopic assisted approach coupled with intraoperative enteroscopy to examine only the suspected area will be performed. This will simplify the surgical option. Indeed, difficulties now encountered in the management of patients with colonic diverticular bleeding will be avoided in the future, since the right colon is easily examined with the capsule. The capsule does not disturb normal processes and thus the present or lack of blood in the right colon during an episode of bleeding can provide guidance superior to that of colonoscopy or bleeding scans when trying to determine a site of blood loss. In patients with isolated iron deficiency or a more occult or intermittent type of bleeding, capsule endoscopy will be used similarly to identify an intestinal bleeding lesions and thereby direct subsequent testing or treatment. The early diagnosis of tumours of the small bowel will be obtained and those with negative exams will be reassured.

I am sure availability of capsule endoscopy will change the practice guidelines to study and treat the small bowel lesions in future.