What Is Rectal Bleeding?
Rectal bleeding generally refers to blood that passes out of the anus. While it is typically the result of a source of bleeding from the lower colon or rectum (the last few inches of the large intestine), it can also come from the upper GI tract such as stomach or small intestine.
During rectal bleeding, the blood can range in color from bright red to a dark, almost black hue with the consistency of tar (known as melena). The color and consistency depends on where the blood is coming from within the intestines.
Patients should seek immediate medical attention if:
- Bleeding is accompanied by severe abdominal pain or cramps
- Bleeding is accompanied by pain in or around the anus
- Constant or heavy bleeding occurs
- Shortness of breath, dizziness or chest pain occurs with rectal bleeding
What Are the Causes of Rectal Bleeding?
Rectal bleeding may be a symptom of:
- Anal cancer
- Anal fissure (tear in the skin of the anus)
- Angiodysplasia (irregularities in the blood vessels close to the intestines)
- Chronic constipation
- Colorectal cancer
- Crohn’s disease
- Hard stools (in association with hemorrhoids and fissures)
- Ischemic colitis (colon inflammation caused by reduced blood flow)
- Proctitis (inflammation of the rectum and anus)
- Radiation therapy
- Rectal prolapse (a portion of the rectum protrudes through the anus)
- Solitary rectal ulcer syndrome (a sore on the wall of the rectum)
- Ulcerative colitis
Treatment for rectal bleeding depends on the cause of the bleed.
How Is Rectal Bleeding Diagnosed?
Following a physical exam that includes checking vitals and assessing the abdomen and anus, the physician may perform diagnostic tests to determine the source of the bleed.
These tests may include the following:
- Angiography using a dye to find active bleeding sites
- Anoscopy to examine the inside of the rectum (rectal vault)
- Blood test to determine the extent of blood loss, clotting ability and infection
- Colonoscopy to examine the colon using a camera
- Computed tomography (CT) scan to search for any diverticulitis or tumors
- Flexible sigmoidoscopy to view the rectum and lower portions of the colon
- Nasogastric tube to check the stomach for bleeding