How is bleeding in the digestive tract diagnosed?

The site of the bleeding must be located. A complete history and physical examination are essential. Symptoms such as changes in bowel habits, stool color (to black or red) and consistency, and the presence of pain or tenderness may tell the doctor which area of the GI tract is affected. Because the intake of iron, bismuth (Pepto Bismol), or foods such as beets can give the stool the same appearance as bleeding from the digestive tract, a doctor must test the stool for blood before offering a diagnosis. A blood count will indicate whether the patient is anemic and also will give an idea of the extent of the bleeding and how chronic it may be.

Endoscopy

Endoscopy is a common diagnostic technique that allows direct viewing of the bleeding site. Because the endoscope can detect lesions and confirm the presence or absence of bleeding, doctors often choose this method to diagnose patients with acute bleeding. In many cases, the doctor can use the endoscope to treat the cause of bleeding as well.

The endoscope is a flexible instrument that can be inserted through the mouth or rectum. The instrument allows the doctor to see into the esophagus, stomach, duodenum (esophago-duodenoscopy), colon (colonoscopy), and rectum (sigmoidoscopy); to collect small samples of tissue (biopsies); to take photographs; and to stop the bleeding.

Small bowel endoscopy, or enteroscopy, is a procedure using a long endoscope. This endoscope may be used to localize unidentified sources of bleeding in the small intestine.

A new diagnostic instrument called a capsule endoscope is swallowed by the patient. The capsule contains a tiny camera that transmits images to a video monitor. It is used most often to find bleeding in portions of the small intestine that are hard to reach with a conventional endoscope.

Other Procedures

Several other methods are available to locate the source of bleeding. Barium x rays, in general, are less accurate than endoscopy in locating bleeding sites. Some drawbacks of barium x rays are that they may interfere with other diagnostic techniques if used for detecting acute bleeding, they expose the patient to x rays, and they do not offer the capabilities of biopsy or treatment. Another type of x ray is CT scan, particularly useful for inflammatory conditions and cancer.

Angiography is a technique that uses dye to highlight blood vessels. This procedure is most useful in situations when the patient is acutely bleeding such that dye leaks out of the blood vessel and identifies the site of bleeding. In selected situations, angiography allows injection of medicine into arteries that may stop the bleeding.

Radionuclide scanning is a noninvasive screening technique used for locating sites of acute bleeding, especially in the lower GI tract. This technique involves injection of small amounts of radioactive material. Then, a special camera produces pictures of organs, allowing the doctor to detect a bleeding site.

source: http://digestive.niddk.nih.gov/ddiseases/pubs/bleeding/index.htm