Bleeding per rectum is a common complaint, which can range from a few spots on the tissue to frank blood in the toilet. Blood in stools indicates that the origin of bleeding is related to lower gastrointestinal tract, specifically colon, rectum or anus. One of the most common causes are haemorrhoids classically present with bright red painless bleeding. Fissures and bleeding due to excessive wiping (which causes micro-abrasions) will result in blood on toilet paper. The passage of fresh bright blood with stool is called as hematochezia. Bleeding from the rectum or more proximally will present as altered blood mixed with the stool and mandates colonoscopy. Endoscopy and angiography may offer accurate diagnosis and therapeutic interventions in most cases.

Indications for colonoscopy in patients with rectal bleeding:

  • no local cause identified
  • a patient 50 years or older
  • any alert symptoms (change in bowel habit, loss of weight, iron deficiency, anaemia, family history of colorectal cancer)

Other common causes of rectal bleeding are cancer, colitis (intestinal inflammation), a diverticular bleed or angiodysplasia (vascular malformation). Yet there are many other causes of rectal bleeding such as Crohn's disease ( inflammatory bowel disease), salmonellosis, proctitis (an inflammation of the anus and the lining of the rectum) or aortoenteric fistula (a connection between the aorta and the intestines, stomach, or oesophagus). Rectal bleeding may also arise as a consequence of prostate cancer treatment. The major problem with rectal bleeding is trying to distinguish between those patients who can be safely diagnosed as having bleeding from haemorrhoids or another minor peri-anal complaint, and those with an underlying sinister cause. Unfortunately, both cancer and haemorrhoids are common and can co-exist. All patients with rectal bleeding require a careful history, digital examination and sigmoidoscopy (Pic. 1). 

A bleed originated in lower gastrointestinal tract is estimated to occur in 20 to 30 per 100,000 per year. Risk of bleeding is more common in males and increases with age. Initial treatment focuses on resuscitation which may include intravenous fluids and blood transfusions. Often blood transfusions are not recommended unless the haemoglobin is less than 70 or 80 g/L. A number of medications may improve outcomes depending on the source of the bleeding. 

The growth of endometrial tissue outside of uterus is called endometriosis. It usually affects organs within the pelvic/abdominal area such as reproductive organs or gastrointestinal tract (GIT). The GIT is involved in 3 - 37% of women with endometriosis, and although it can affect any site, the rectosigmoid colon (72%), small intestine (7%), caecum (3.6%) and appendix (3%) are most commonly involved. Usually the disease takes the form of small asymptomatic serosal (serosa is protective tissue on surface of organs) implants, but these can progress and become symptomatic. The symptoms are usually chronic and cyclical; although acute presentation such as rectal bleeding are relatively uncommon, but they still may appear.

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Gastrointestinal bleeding ―sourced from Wikipedia licensed under CC BY-SA 3.0
Prostate cancer ―sourced from Wikipedia licensed under CC BY-SA 3.0
Hematochezia ―sourced from Wikipedia licensed under CC BY-SA 3.0
Lower gastrointestinal bleeding ―sourced from Wikipedia licensed under CC BY-SA 3.0
Proctitis ―sourced from Wikipedia licensed under CC BY-SA 3.0
Aortoenteric fistula ―sourced from Wikipedia licensed under CC BY-SA 3.0
The five common symptoms of anal disease ―by Boutall and Baigrie licensed under CC BY-NC 3.0
Angiodysplasia ―sourced from Wikipedia licensed under CC BY-SA 3.0
Rectal bleeding evaluation ―sourced from Wikispaces licensed under CC BY-SA 3.0
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