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What Causes Bleeding in the Digestive Tract?
Stomach acid can cause inflammation that may lead to bleeding at the lower end of the esophagus. This condition is called esophagitis or inflammation of the esophagus. Sometimes a muscle between the esophagus and stomach fails to close properly and allows the return of food and stomach juices into the esophagus, which can lead to esophagitis. In addition, enlarged veins (varices) at the lower end of the esophagus may rupture and bleed massively. Cirrhosis of the liver is the most common cause of esophageal varices.

Esophageal bleeding can be caused by Mallory-Weiss syndrome, a tear in the lining of the esophagus. Mallory-Weiss syndrome usually results from prolonged vomiting but may also be caused by increased pressure in the abdomen from coughing, hiatal hernia, or childbirth.

The stomach is a frequent site of bleeding. Alcohol, aspirin, aspirin-containing medicines, and various other medicines (particularly those used for arthritis) can cause stomach ulcers or inflammation (gastritis). The stomach is often the site of ulcer disease. Acute or chronic ulcers may enlarge and erode through a blood vessel, causing bleeding. Also, patients suffering from burns, shock, head injuries, or cancer, or those who have undergone extensive surgery may develop stress ulcers. Bleeding can occur from benign tumors or cancer of the stomach, although these disorders usually do not cause massive bleeding.

The most common source of bleeding from the upper digestive tract is ulcers in the duodenum (the upper small intestine). Researchers now believe that these ulcers are caused by excess stomach acid and infection with Helicobacter pylori bacteria.

In the lower digestive tract, the large intestine and rectum are frequent sites of bleeding. Hemorrhoids are probably the most common cause of visible blood in the digestive tract, especially blood that appears bright red. Hemorrhoids are enlarged veins in the anal area that can rupture and produce bright red blood, which can show up in the toilet or on toilet paper.
If red blood is seen, however, it is essential to exclude other causes of bleeding since the anal area may also be the site of cuts (fissures), inflammation, or tumors.
Benign growths or polyps of the colon are very common and are thought to be forerunners of cancer. These growths can cause either bright red blood or occult bleeding. Colorectal cancer is the second most frequent of all cancers in the United States and usually causes bleeding at some time.

Inflammation from various causes can produce extensive bleeding from the colon. Different intestinal infections can cause inflammation and bloody diarrhea. Ulcerative colitis can produce inflammation and extensive surface bleeding from tiny ulcerations. Crohn's disease of the large intestine can also produce spotty bleeding.

Diverticular disease caused by diverticula—outpouchings of the colon wall—can result in massive bleeding. Finally, as one gets older, abnormalities may develop in the blood vessels of the large intestine, which may result in recurrent bleeding.

What Are the Common Causes of Bleeding in the Digestive Tract?
Esophagus

How Is Bleeding in the Digestive Tract Recognized?
The signs of bleeding in the digestive tract depend upon the site and severity of bleeding. If blood is coming from the rectum or the lower colon, bright red blood will coat or mix with the stool. The stool may be mixed with darker blood if the bleeding is higher up in the colon or at the far end of the small intestine. When there is bleeding in the esophagus, stomach, or duodenum, the stool is usually black or tarry. Vomited material may be bright red or have a coffee-grounds appearance when one is bleeding from those sites. If bleeding is occult, the patient might not notice any changes in stool color.

If sudden massive bleeding occurs, a person may feel weak, dizzy, faint, short of breath, or have crampy abdominal pain or diarrhea. Shock may occur, with a rapid pulse, drop in blood pressure, and difficulty in producing urine. The patient may become very pale. If bleeding is slow and occurs over a long period of time, a gradual onset of fatigue, lethargy, shortness of breath, and pallor from the anemia will result. Anemia is a condition in which the blood's iron-rich substance, hemoglobin, is diminished.

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 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 new procedure using a long endoscope. This endoscope may be introduced during surgery to localize a source of bleeding in the small intestine.

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.

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.

In addition, barium x-rays, angiography, and radionuclide scans can be used to locate sources of chronic occult bleeding. These techniques are especially useful when the small intestine is suspected as the site of bleeding since the small intestine may not be seen easily with endoscopy.

How Is Bleeding in the Digestive Tract Treated?
The use of endoscopy has grown and now allows doctors not only to see bleeding sites but to directly apply therapy as well. A variety of endoscopic therapies are useful to the patient for treating GI tract bleeding.

Active bleeding from the upper GI tract can often be controlled by injecting chemicals directly into a bleeding site with a needle introduced through the endoscope. A physician can also cauterize, or heat treat, a bleeding site and surrounding tissue with a heater probe or electrocoagulation device passed through the endoscope. Laser therapy, although effective, is no longer used regularly by many physicians because it is expensive and cumbersome.

Once bleeding is controlled, medicines are often prescribed to prevent recurrence of bleeding. Medical treatment of ulcers to ensure healing and maintenance therapy to prevent ulcer recurrence can also lessen the chance of recurrent bleeding. Studies are now under way to see if elimination of Helicobacter pylori affects the recurrence of ulcer bleeding.

Removal of polyps with an endoscope can control bleeding from colon polyps. Removal of hemorrhoids by banding or various heat or electrical devices is effective in patients who suffer hemorrhoidal bleeding on a recurrent basis. Endoscopic injection or cautery can be used to treat bleeding sites throughout the lower intestinal tract.

Endoscopic techniques do not always control bleeding. Sometimes angiography may be used. However, surgery is often needed to control active, severe, or recurrent bleeding when endoscopy is not successful.