What causes rectal bleeding?

Although rectal bleeding is common, only about one-third of those affected seek treatment. Rectal bleeding can be caused by:

What are hemorrhoids?

Hemorrhoids, the most common cause of rectal bleeding, are swollen veins in the rectum (internal hemorrhoids) or the anus (external hemorrhoids). Hemorrhoids, also called piles, can develop because of chronic (long-term) constipation or straining at stools, pregnancy, work strain (heavy lifting), obesity, or anal intercourse.

Hemorrhoid treatment includes addressing the underlying causes, such as treating the constipation or straining habits, or changing work habits if necessary. Sometimes surgery is necessary if the hemorrhoids are large or when conservative treatment like dietary changes and increasing water intake fail to control the symptoms. Surgical treatments may include one of the following methods:

  • Rubber band ligation: A rubber band placed around the base of the hemorrhoid cuts off circulation to the bulk of the hemorrhoid and causes it to wither away.
  • Sclerotherapy: The injection of a chemical solution around the blood vessel shrinks the hemorrhoid.
  • Laser/infrared: A precise laser beam or infrared device is used to burn away small hemorrhoids.
  • HET procedure: This is a minimally invasive procedure that uses a bipolar device to burn small hemorrhoids under vision in the office or in an endoscopy suite.
  • Hemorrhoidal arterial ligation: Uses a Doppler probe to locate and tie the blood vessels feeding the hemorrhoid in order to shrink it.
  • Procedure for prolapsed hemorrhoids (PPH): Puts hemorrhoids that have come out of the anal canal back in their original positions.
  • Hemorrhoidectomy: Surgical removal of the hemorrhoid.

What is an anal fissure?

An anal fissure is a split or tear in the lining of the anus, causes bleeding and burning pain after bowel movements. The usual cause is passing a very hard stool. The pain is caused by a spasm of the sphincter muscle. This happens as a protective measure by the body as stool passes through the anal canal and expands the tear. Bleeding is caused by trauma to the existing tear.

Fissures may be mistaken for and misdiagnosed as hemorrhoids. Fissures often improve by themselves, but if they don't, an ointment or medication applied directly to the fissure to relax the muscle can relieve the pain. Surgery may be needed for a chronic or recurrent (returning) fissure or if excessive sphincter spasms prevent the tear from healing on its own. Chronic anal fissures are those that do not heal within three months.

What is a perianal abscess?

There are small glands that open inside the anus and are believed to help with passing stool. An infection can occur when one of these glands becomes blocked. The pocket of pus caused by the blockage is an abscess. The abscess can be drained under local anesthesia in the doctor's office. Large abscesses need to be drained while the patient is under anesthesia. About a third of all perianal abscesses will develop into an anal fistula.

What is an anal fistula?

A fistula is a connection between two spaces. An anal fistula is a connection between the anus or rectum to the skin around the anus. Fistulas usually start as infections in the anal gland that is naturally present in the anus.

An anal fistula is caused by an infection in the perianal area, or by inflammatory bowel disease, tuberculosis, or radiation. Others can result from surgery in that area.

Anal fistulas require surgery in order to heal.

What are diverticulosis and diverticulitis?

Diverticulosis develops when small pouches (diverticuli) form in weakened sections of intestine lining and protrude through the bowel wall, usually in the sigmoid colon. Diverticuli are a common finding among older people in Western societies, and are diagnosed during a colonoscopy or sigmoidoscopy.

Diverticulosis is a benign (noncancerous) disorder, but bleeding and infection can occur. Diverticuli generally occur without symptoms, unless they become blocked and infected and cause diverticulitis. Symptoms of diverticulitis include abdominal pain, fever and a sudden change in bowel habits. Treatment may include a special diet, antibiotics or surgery.

What is inflammatory bowel disease (IBD)?

Inflammatory bowel disease (IBD) is an inflammation (swelling) of the small or large intestine. There are two types of IBD:

  • Crohn's disease: This condition is marked by patches of inflammation occurring anywhere in the digestive tract.
  • Colitis: This condition is characterized by inflammation in the large bowel.

There are several other types of colitis, including:

  • Infectious colitis: This can be caused by an infection that attacks the large bowel.
  • Ischemic colitis: This is the result of a poor blood supply to the colon.
  • Radiation colitis: This type can happen following radiotherapy, usually for prostate, rectal or gynecological cancer).
  • Ulcerative colitis: This type is characterized by ulcers/sores in the large intestine lining.

IBD symptoms may include:

  • Fever.
  • Rectal bleeding.
  • Diarrhea.
  • Abdominal pain and/or cramping.
  • Intestinal blockage.

Treatment of inflammatory bowel disease is critical and may involve a special diet, medication to eliminate or reduce inflammation, and/or surgery.

What are ulcers?

Ulcers are sores in the stomach lining or in the first section of the small intestine (the duodenum) caused by an imbalance of digestive fluids in the stomach and the duodenum. Abdominal pain is the most common symptom of ulcers, though many ulcers produce no obvious symptoms. Ulcers that bleed into the gastrointestinal tract may cause black stool, sometimes with a tar-like appearance.

Ulcers are usually successfully treated without surgery, and successful treatment may also prevent new ulcers from forming. Treatment methods may include:

  • Special diet.
  • Antibiotics.
  • Medications that neutralize gastric acid, or reduce the secretion of gastric acid.
  • Medications that strengthen gastric acid resistance in the stomach and the duodenum.

What are polyps?

The main reason rectal bleeding should not be ignored is that it can sometimes be a symptom of colorectal cancer (cancer of the colon or rectum). Colorectal cancer is a common form of cancer that can usually be cured if diagnosed and treated early enough.

Colorectal cancer occurs when the normal growth and division of the cells lining the large bowel go out of control, leading to the formation of a polyp or polyps. A polyp, which looks like a small mushroom, attaches to the lining of the large bowel. Polyps that grow large can bleed.

While there are many types of polyps that are not cancerous, certain polyps are considered precancerous and can develop into cancer if left untreated. Therefore, removing polyps before they develop such severe changes can prevent cancer.

The early stages of colorectal cancer may have no apparent symptoms. Regular screening is important—particularly for individuals who are at increased risk.

Colonoscopy is the procedure to locate and remove polyps to prevent colorectal cancer. People who have an increased risk of colorectal cancer include those who have a family history of colorectal cancer, and people who have previously had cancer or polyps. Treatment for colorectal cancer may include surgery, chemotherapy and radiation.

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