How is bleeding in the digestive tract recognized?

Signs of bleeding in the digestive tract vary significantly depending on sites of bleeding, as well as the severity. If blood is coming from the rectum or the lower colon, bright red blood will coat or mix with the stool, but when there is bleeding in the esophagus, stomach, or duodenum, the stool will be black or tarry. This is because blood, while passing through intestine, will be digested.  

When the bleeding is hidden, the patient might not notice any changes in stool color but may feel weak, dizzy, faint, short of breath, or have abdominal pain or diarrhea.  

The main diagnostic problem is to locate the site of the bleeding. That’s why a complete history and physical examination could be essential in order to set the appropriate diagnosis. As mentioned before, bright red bleeding seen on the toilet paper or in the toilet water usually comes from the hemorrhoid area, which means lower colon or anal region. In this case the best thing to do is to perform an endoscopy on the anus, rectum, and lower colon. The problem is that this hidden or occult blood could be coming from anywhere in the gastrointestinal tract. That’s why a professional will always use an endoscopy to check the colon first, and if that is normal, only then should the esophagus and stomach be inspected.

Hemorrhage, or massive bleeding, can be from the stomach and esophagus, or from the small intestine, colon or rectum and in that case, the stool will be black and tarry. Since the intake of iron can give normal stool the same appearance as stool with bleeding from the digestive tract, this should be also taken into consideration.

Endoscopy

Endoscopy is an extremely common diagnostic technique that allows direct viewing of the bleeding site. Although very simple, this is probably the best diagnostic tool because the endoscope can detect lesions and confirm the presence or absence of bleeding directly. The endoscope is a flexible instrument that can be inserted through the mouth or rectum easily, and allows the doctor to see into the esophagus, stomach, duodenum, entire colon, sigmoid colon, and rectum to collect small samples of tissue (biopsies). This could be extremely useful in setting the right histological diagnosis.

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Other procedures

Several other methods are available to locate the source of bleeding.

Barium X-rays: Some doctors prefer the barium x-ray diagnostic tool, less accurate tool than endoscopy in locating bleeding sites, but also extremely effective. The barium is swallowed before the imaging and, if there are no lesions in the GI tract, the contrast will nicely cover all the GI walls. However, barium X-rays may interfere with other diagnostic techniques if used for detecting acute bleeding.

Angiography: Also used to diagnose bleeding, angiography is a special technique that uses dye to highlight blood vessels. It is most useful in situations where the patient is acutely bleeding in a way that allows the dye to leak out of the blood vessel, which identifies the site of bleeding. 

Radionuclide scanning: Some doctors prefer the radionuclide scanning to visualize the bleeding. This technique is also used for locating sites of acute bleeding, and involves an injection of small amounts of radioactive material, after which a special camera produces pictures of organs, allowing the doctor to see the blood escaping.