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Rectal Bleeding Medical Author: Dennis Lee, MD Medical Editor: Jay W. Marks, MD
What is rectal bleeding? Definition and description of rectal bleeding Origin of rectal bleeding Occult gastrointestinal bleeding What are the causes of rectal bleeding? Anal fissure Hemorrhoids Diverticulosis Colon cancer and polyps Polypectomy Angiodysplasias Colitis and proctitis Meckel�s diverticulum Rare causes of rectal bleeding How is the cause and site of rectal bleeding determined? History and physical examination Anoscopy Flexible sigmoidoscopy Colonoscopy Radionuclide scans Visceral angiogram Blood tests How is rectal bleeding treated? Correcting low blood volume and anemia Determining the cause and site of bleeding Stopping bleeding and preventing rebleeding Rectal Bleeding At A Glance Related blood in stool articles: Blood in stool - on WebMD
What is rectal bleeding?
Definition and description
Rectal bleeding (known medically as hematochezia) refers to passage of bright red blood from the anus, often mixed with stool and/or blood clots. (It is called rectal bleeding because the rectum lies immediately above the anus. Although the bleeding indeed may be coming from the rectum, as discussed later, it also may be coming from other parts of the gastrointestinal tract.) The severity of rectal bleeding (i.e., the quantity of blood loss) varies widely. Most episodes of rectal bleeding are mild and stop on their own. Many patients report only passing a few drops of fresh blood that turns the toilet water pink or seeing spots of blood on the tissue paper. Others may report brief passage of a spoonful or two of blood. Generally, mild rectal bleeding can be evaluated and treated in the doctor�s office without hospitalization or the need for urgent diagnosis and treatment.
Rectal bleeding also may be moderate or severe. Patients with moderate bleeding will repeatedly pass larger quantities of bright or dark red blood often mixed with blood clots. Patients with severe bleeding may pass several bowel movements or a single bowel movement containing a large amount of blood. Moderate or severe rectal bleeding can quickly deplete a patient�s body of blood, leading to symptoms of weakness, dizziness, near-fainting or fainting, and signs of low blood pressure or orthostatic hypotension (a drop in blood pressure when going from the sitting or lying position to the standing position). Rarely, the bleeding may be so severe as to cause shock from the loss of blood. Moderate or severe rectal bleeding usually is evaluated and treated in the hospital. Patients with signs and symptoms of a reduced volume of blood often require emergency hospitalization, and transfusion of blood.
Origin of rectal bleeding (where the blood comes from)
Most rectal bleeding comes from the colon, rectum, or anus. The colon is the part of the gastrointestinal tract through which food passes after it has been digested in the small intestine. The colon is primarily responsible for removing water from the undigested food and storing it until it is eliminated from the body as stool. The rectum is the last