Introduction
Rectal bleeding describes any sort of blood or bleeding from the anus. It is also sometimes referred to as anal or anorectal bleeding.
Symptoms
Any rectal bleeding is most often noticed in the toilet bowl, on toilet paper or on the stools in the toilet bowl after a bowel movement. The colour of the blood can give some indication of the source of the bleed – bright red blood is most likely to be coming from somewhere near the anal opening, whereas darker blood or black and sometimes tarry stools indicate bleeding higher in the gastrointestinal tract or in the stomach.
Certain types of medication or foods can give a red colouration to the faeces (for example some iron supplements and beetroot can do this), however it is always a good idea to have this checked by your doctor. Severe blood loss can cause cramping in the stomach and weakness and dizziness – if you experience any of these symptoms it is important to get medical assistance as soon as possible.
If there is any associated pain with rectal bleeding this indicates that the condition is very likely close to the anal opening. Although more commonly caused by an anal fissure, it is again important to have this checked by a doctor.
Causes
Although rectal bleeding is not uncommon and generally is not associated with serious conditions, it is important to make sure that the bleeding is not a symptom of a more serious condition. For this reason it is important to have any incident of rectal bleeding checked by your doctor.
The most common reasons for rectal bleeding are:
Other possible causes include:
- Malformed blood vessels (angiodysplasia)
- Crohn's disease.
- Ulcerative colitis.
- Diverticular disease.
- Colorectal polyps.
- Bowel cancer.
Tests & Diagnosis
The first step in diagnosing the cause of rectal bleeding is a physical examination and a review of medical history. Any changes in bowel habits, or the way the bowel motions look, are important. The following tests may be needed to reach a diagnosis:
- Blood tests – this will detect whether there is anaemia caused by blood loss somewhere in the gastrointestinal tract.
- Anoscopy or sigmoidoscopy – a device that is used to conduct a visual examination of the lower rectum and anus.
- Colonoscopy.
