Rectal bleeding, also called hematochezia, may be found in the stool following a bowel movement, or it may appear on its own. The colour and amount of bleeding helps doctors discover the cause.
Because the rectum is the last section of the large intestine that ends at the anus, it is the site where bleeding from either external or internal sources might be found.
Blood in your stool can originate from many places in your gastrointestinal system. It might, for example, indicate ulcerative colitis or Crohn's disease. Bloody stool is often very dark red or even black. Occasionally it will signify the presence of a tumour in your colon or rectum.
As the source of the bleeding moves closer to the rectum, the blood is usually a brighter red. If rectal bleeding is minor and occurs in the absence of a bowel movement, the most common source is haemorrhoids. These are caused when the veins in your anus become inflamed and swollen. Itching and burning are common symptoms, and bright red blood can be found on toilet tissue after wiping. Haemorrhoids may be labelled as internal or external but are generally treated the same way.
Anal fissures are another common cause of rectal bleeding. These fissures may develop as tissues tear with the strain of expelling hard stools. The blood from these is usually bright red. Anal fissures cause pain that increases substantially during efforts to defecate.
To determine the source of rectal bleeding, your doctor will give you a thorough physical examine. Scrapings of skin cells may be taken from your anal area and sent to a lab to find out if you have an infection. And your doctor may order a colonoscopy to be sure the bleeding isn't associated with a colon tumour or polyp. Your doctor may also order a hemocult, which can identify blood in your stool that is often not visible.
If your doctor suspects an anal fissure, he may order an endoscopic evaluation, so the internal area can be viewed to identify the location of the fissure.
If your rectal bleeding is from haemorrhoids, the treatment is most commonly an over-the-counter ointment or cream, though these mainly treat symptoms, such as itching or burning.
For anal fissures, treatment starts with a high-fibre diet to add bulk to the stool and allow it to pass more easily. Topical anesthetics may be prescribed to numb the anal region during bowel movements, and steroids may be added to help reduce inflammation. A sitz bath is recommended to help relax the spasm of the sphincter muscle, which so often accompanies an anal fissure. Drugs and surgery are options if conservative treatment doesn't work.
If you experience rectal bleeding, make an appointment to see your doctor. You may just have haemorrhoids, but the bleeding may also be a sign of a more serious medical condition.