Treatments and Procedures » Capsule endoscopy
Small Bowel Bleeding and Capsule Endoscopy
What is the Small Bowel?
What is Small Bowel Bleeding?
GI bleeding, including from the small bowel, occurs when an abnormality on the inner lining begins to bleed. The bleeding may be slow, resulting in anemia (a low blood count), or it may be rapid, causing a hemorrhage. Approximately 5% of all GI bleeding comes from the small bowel. In many cases, the abnormalities causing the bleeding to lie within reach of a standard endoscope (see below). However, because of the length of the small bowel and its location between the stomach and colon, finding the source of bleeding can be difficult.
What causes bleeding from the small bowel?
How is the small bowel examined?
What are standard endoscopy and enteroscopy?
The examination begins with the patient receiving a sedative. The doctor then passes the scope through the mouth. A regular endoscope is capable of examining the esophagus, stomach and the first portion of the small bowel, known as the duodenum. In cases where the source of bleeding is thought to be lower down in the small bowel, a longer scope, known as an enteroscope, can be used. This scope is capable of reaching the middle portion of the small bowel, known as the jejunum.
What types of x-ray studies are used to find the source of small bowel bleeding?
The small bowel follow-through test is a series of abdominal x-rays that are taken at different times after a patient drinks a white, chalky fluid called barium, that shows up clearly on x-rays. The test allows the doctor to examine the lining of the intestine for any irregularities. The test is good for large abnormalities, but can miss many smaller ones. However, it is safe and easy to tolerate.
A second x-ray test, the enteroclysis study, is similar to the small bowel follow-through in that it uses barium to visualize the inner wall of the small bowel. It is more invasive because it requires a small tube called a catheter to be slowly advanced from the nose down the esophagus, through the stomach and into the small bowel, to allow for air and barium to be instilled. The advantage of this study is that pictures from enteroclysis have better resolution, so abnormalities missed by the small bowel follow-through test may be detected. A disadvantage of the enteroclysis study is that it can be an uncomfortable examination due to the presence of the catheter and the use of air to distend the small bowel while taking pictures. In some cases a CT scan is used instead of regular x-rays. This allows for even more detail to be seen.
A third test is known as a CT enterography. A CT enterography is performed the same way a normal CT scan is done. The patient drinks an oral contrast solution (often dilute barium) while also receiving intravenous (IV) contrast. Then numerous, very detailed images are obtained. A CT enterography differs from a standard CT scan in that the type of contrast that the patient drinks is designed to allow for a more detailed inspection of the lining of the small bowel.
While none of these tests is perfect at finding abnormalities, the advantage of these tests is that they can sometimes find bleeding sources that are out of reach of a standard enteroscope. The major limitations of these studies are that they cannot detect AVMs, and if an abnormality is seen, there is no way to apply immediate treatment to stop the bleeding, to take biopsies to confirm a diagnosis, or to mark the location of the lesion with a tattoo. In addition, some patients are allergic to the IV contrast that is used as part of the CT scan.
What is capsule endoscopy?
Like x-rays, the capsule is purely diagnostic and cannot be used to take biopsies, apply therapy, or mark abnormalities for surgery. Moreover, the capsule cannot be controlled once it has been ingested, so that once it has passed a suspicious abnormality, its progress cannot be slowed to better visualize the area. Despite these limitations, capsule endoscopy is frequently the test of choice for finding a source of small bowel bleeding if standard endoscopy has failed to do so.