Rectal Bleeding Causes: An Overview
The most common cause of
rectal bleeding is
hemorrhoids. However, more serious causes are possible. Therefore, it is still important to locate the source of the bleeding.
It is important that you see your healthcare provider if you have rectal bleeding and:
- You are older than 50
- You have a family history of colon or rectal cancer
- Bleeding occurs between bowel movements
- The blood is dark red or maroon
- You have tar-like, black stools.
How Anatomy Affects Causes of Rectal Bleeding
The digestive or gastrointestinal (GI) tract includes the:
- Esophagus
- Stomach
- Small intestine
- Large intestine (colon)
- Rectum
- Anus.
Rectal bleeding can come from one or more of these areas. For example, bleeding may come from a small area, such as an ulcer in the lining of the stomach, or from a large surface, such as an inflammation of the colon.
This condition can sometimes occur without the person noticing it. This type of bleeding is called occult, or hidden, bleeding. Fortunately, simple tests can detect occult blood in the stool.
Common Rectal Bleeding Causes
Typical causes of rectal bleeding include:
- Hemorrhoids
- Anal fissures
- Infections
- Inflammation (ulcerative colitis or irritable bowel disease)
- Colorectal polyps
- Colorectal cancer
- Diverticular disease
- Angiodysplasia
- Any upper gastrointestinal (GI) or small bowel lesion, if the bleeding is heavy.
In the lower digestive tract, the large intestine and rectum are frequent sites of gastrointestinal bleeding. Hemorrhoids are 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 then show up in the toilet or on toilet paper. If red blood is seen, however, it is essential to exclude other rectal bleeding causes, since the anal area may also be the site of cuts (fissures), inflammation, or cancer.
Benign (noncancerous) growths or polyps of the colon are common, and are thought to be forerunners of cancer. These growths can cause either bright red blood or occult (hidden) bleeding. Colorectal cancer is the third most common cancer in the United States, and often causes occult bleeding at some point, but not necessarily visible bleeding.
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 GI bleeding. Diverticular disease caused by pouches in the colon wall can result in massive bleeding, too.
Finally, as a person gets older, abnormalities may develop in the blood vessels of the large intestine (a condition called angiodysplasia). This may result in recurrent bleeding.
People who are taking blood-thinning medications, such as
warfarin, may have gastrointestinal bleeding, especially if they also take drugs like aspirin.
