Rectal bleeding is always serious and always requires investigation.
What are the common causes of rectal bleeding?
The commonest causes of rectal bleeding are problems around the anal canal such as haemorrhoids and anal fissures. More serious causes are bowel cancer, diverticular disease, inflammation of the bowel, infection of the bowel and other colonic abnormalities.
Does the colour of the bleeding mean anything?
Generally the closer the source of bleeding to anal canal the fresher the bleeding (brighter red). The longer the blood spends in the colon the more altered it becomes darker. If there is large volume bleeding there may be less time for the blood to get altered.
Is the amount of blood loss important?
Obviously if there is very large amounts of bleeding urgent admission to hospital is required. Do not hesitate to go to hospital if there is any question about how much blood loss is important. Dangerous symptoms are feeling lightheaded or if there is any pain or diarrhoea associated with the bleeding.
Most bleeding, even if large amounts initially, will stop without treatment.
What if the bleeding does not stop?
Urgent admission to hospital is required. Urgent investigations and treatment are required. Sometimes surgery is required.
What other symptoms are important?
Any recent or associated changes in bowel habit such as diarrhoea or abdominal pain are worrying symptoms. Local anal symptoms such as pain or a lump are common with anorectal causes.
What investigations are required?
Sometimes urgent investigations are required if the bleeding does not stop. In such situations admission is required and tests such as CT scanning and angiography are required.
Usually the bleeding stops and the best investigation is a colonoscopy.
What is the treatment?
Most bleeding stops without treatment and the patient is investigated for the cause. The treatment is then aimed at the specific cause. Surgery is often required.