Rectal Bleeding

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is rectal bleeding?

Rectal bleeding indicates the passage of blood from the anus. The bleeding may arise from any part of the gastrointestinal tract, including the rectum. Therefore, rectal bleeding can be caused by any number of gastrointestinal difficulties. 

Typically, bleeding from the upper gastrointestinal tract manifests as black or tarry stool known as melena. The black color develops because of chemical changes that occur as the blood passes through the digestive tract. Certain over-the-counter medications such as iron supplements and heartburn remedies containing bismuth can also turn the stool black. The passage of bright red blood from the anus is known as hematochezia and usually results from bleeding from sources that are closer to the anus and rectum

Common causes of rectal bleeding are hemorrhoids, anal fissures, and diverticulosis. The severity of rectal bleeding varies among individuals depending on the cause. Most often, people experience rectal bleeding that is mild, is caused by minor problems such as hemorrhoids, and resolves on its own. People who have severe bleeding may see a large amount of blood after a single bowel movement, which, if it continues, can result in significant blood loss. Symptoms of blood loss include lightheadedness, dizziness, fainting, and difficulty breathing.

While rectal bleeding can be minor, it can also result from severe conditions that are characterized by prolonged bleeding. In these cases, serious complications such as shock can develop. Rectal bleeding can also occur from cancers in the digestive tract.

Left untreated, severe rectal bleeding can result in a life-threatening loss of blood. Seek immediate medical care (call 911) for serious symptoms, such as pale skin or pallor and difficulty breathing, severe abdominal pain, vomiting blood or black material, or change in level of consciousness.

What are the symptoms of rectal bleeding?

Rectal bleeding is a symptom of a disease originating in the digestive tract. A number of different conditions can cause bleeding. Many causes of bleeding are related to conditions that can be cured or controlled, such as ulcers or hemorrhoids. Some causes of bleeding may be life threatening.

Symptoms of rectal bleeding

You may experience rectal bleeding symptoms daily or just once in a while. Symptoms that may occur with rectal bleeding include:

Serious symptoms that might indicate a life-threatening condition

In some cases, rectal bleeding can be life threatening. Seek immediate medical care (call 911) if you, or someone you are with, have rectal bleeding along with any of these life-threatening symptoms including:

  • Change in level of consciousness or alertness such as passing out or unresponsiveness

  • Dizziness

  • Respiratory or breathing problems such as shortness of breath, difficulty breathing, labored breathing, wheezing, not breathing, or choking

  • Severe abdominal pain

  • Vomiting blood or black material resembling coffee grounds

  • Weakness (loss of strength)

What causes rectal bleeding?

Rectal bleeding can be the result of any condition of the digestive tract, particularly the lower gastrointestinal organs. The rectum itself may bleed due to hemorrhoids or anal fissures. Other common causes for rectal bleeding include inflammation or infection of the colon or weakening of the intestinal blood vessels.

Common causes of rectal bleeding

Common causes of rectal bleeding include:

Serious or life threatening causes of rectal bleeding

Serious or life threatening causes of rectal bleeding can include:

  • Cancers of the digestive tract

  • Perforated peptic ulcer

  • Perforation of the intestine

What are the risk factors for rectal bleeding?

A number of factors increase the risk of developing rectal bleeding. Not all people with risk factors will get rectal bleeding. Risk factors for rectal bleeding include:

  • Abdominal gas, which increases pressure on the rectum and may cause bleeding hemorrhoids

  • Alcoholism or heavy alcohol ingestion, which is associated with esophageal varices (swollen veins in the esophagus that have the potential to rupture)

  • Constipation, which may cause straining and dry hard stools, which can abrade the rectum

  • Family history of gastrointestinal diseases such as ulcerative colitis and Crohn’s disease, which is known to cause bleeding

  • Older age, which may result in weakened intestinal blood vessels

How is rectal bleeding treated?

Treatment for rectal bleeding begins with seeking medical care from your health care provider. Diagnostic procedures, such as endoscopy, colonoscopy or angiography, may be done to pinpoint the source of the bleeding.

In endoscopy, a flexible tube with a camera is inserted into your digestive tract. The tube may be inserted by way of the mouth, or, in the case of colonoscopy or sigmoidoscopy, through the anus. Another technique to locate the origin of the bleeding is angiography, in which a dye is inserted into a vein to show the area of blood leakage. In many cases, once the source is located, these same tools and techniques can be used to stop the bleeding, for example, by delivering chemicals, laser energy, or electricity through the tube or into the vein. If these procedures do not stop the bleeding, surgery may be required.

In cases of severe bleeding, other measures may also be used including:

  • Blood transfusions
  • Drainage of the stomach contents
  • Intravenous fluid replacement

If the bleeding was caused by an underlying disease, treatment of that condition may help to prevent further episodes of bleeding. Depending on the cause, treatment may include antibiotics, antacids, or anti-gas medications; or, in cases of cancer, radiation and chemotherapy.

What are the potential complications of rectal bleeding?

You can help minimize your risk of serious complications of rectal bleeding by following the treatment plan that you and your health care professional design specifically for you. Complications of rectal bleeding include:

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Nov 10
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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