Rectal bleeding, also known as blood in the stool, refers to the passage of fresh, bright red blood through the anus. The amount of blood may be small or large.
In any case of bleeding in the stool, it is important to monitor the bleeding, its duration, frequency, and severity. When the bleeding is prolonged and involves significant blood loss, this may be life-threatening and you should contact your physician for evaluation and appropriate treatment.
The blood may be visible in the stool, in the toilet bowl, or on toilet paper. Mild bleeding typically appears as a few drops of fresh, red blood.
When bleeding is accompanied by pain, it often indicates that the source of the problem is at the anus.
Symptoms include the passage from the anus of red or reddish-brown blood and blood clots.
The color of the blood in the stool depends mainly on the location of the bleeding within the digestive tract. The closer the bleeding site is to the anus, the brighter red the blood will be. Therefore, bleeding from the rectum, anus, and lower part of the colon tends to be bright red, while bleeding originating from the upper parts of the colon - the right or transverse colon - is usually darker red or brown. In upper gastrointestinal bleeding, the stool color will be brown or black.
The common causes of this type of bleeding can be grouped as follows:
• Diseases of the anus and rectum, such as anal fissures, hemorrhoids, and ulcers.
• Rectal bleeding may be mild and result from constipation and the passage of hard stool through the anus.
• Anatomical (structural) problems - mainly the presence of "pockets" (known as diverticula or diverticulosis) in the colon, which can cause problems with blood supply to the bowel (ischemia).
• Tumors such as colorectal cancer.
• Inflammation of the bowel - for example, due to infection or radiation exposure - as well as inflammatory diseases such as Crohn's disease and ulcerative colitis.
• Following invasive procedures such as colonoscopy during which polyps were removed or a biopsy was taken.
• Abnormal superficial blood vessels in the bowel wall (angiodysplasia).
• After pelvic radiation therapy for malignancy, for example in the prostate gland.
