An anal fissure is a small tear or open sore in the anus. It can cause pain and bleeding when you…
Rectal bleeding (blood in stools)
What is rectal bleeding?
Rectal bleeding is very common and can have numerous causes. It is often due to less serious causes; however, occasionally it can be due to a life-threatening condition. All cases of rectal bleeding should be assessed by a doctor.
Rectal bleeding can vary in its colour, duration and frequency. Bright red blood usually indicates bleeding from somewhere close to the anus, such as from the rectum or anus. Darker, sticky blood generally means bleeding is higher up in the digestive system, such as in the stomach or small intestine. Other associated symptoms can include rectal or abdominal pain, itching and irritation around the anus, or a mass around the anus.
Potential causes of rectal bleeding include:
Haemorrhoids, commonly known as piles, are swollen, potentially painful varicose veins bulging from the rectal wall. They can look like small grapes and sometimes protrude outside your anus. They are usually caused by straining to pass hardened stools (constipation), obesity, heavy lifting or pregnancy. Although they are not life-threatening, they can cause great discomfort, itching and irritation. Bleeding is usually bright red and characteristically seen on the toilet paper. They are a common cause of rectal bleeding.
An anal fissure is either a small tear or open sore in the lining of your anal passage. It can be quite painful, especially when passing a bowel movement. The bleeding is usually bright red, but does not typically last long. It is commonly caused by constipation. Treatment comprises pain relief and medication to reduce constipation. They usually heal themselves over a few weeks, but some need further medical care, especially if severely painful or not healing after six weeks.
Diverticular disease is a very common disorder of the bowel in which small, abnormal pouches (diverticula) form in the wall of the large bowel. Having diverticular disease without any symptoms is known as diverticulosis. However, if these pouches become inflamed or infected, it is called diverticulitis. The pouches sometimes have weak blood vessels in them that can burst, causing painless but heavy bleeding. The blood is usually bright red and warrants prompt medical attention as there can be significant blood loss. Diverticulitis can rarely cause bleeding.
Angiodysplasia is a condition in which blood vessels abnormally develop in the bowel. These blood vessels are prone to bleeding, which is often painless, heavy and sudden. The blood is usually bright red. It is one of the leading causes of rectal bleeding in people over the age of 60.
Polyps are non-cancerous growths, although a few may develop into bowel cancers, which grow from the lining of the bowel wall. Large polyps can occasionally bleed, but are variable in the type and frequency of bleeding.
Bowel cancer is one of the leading causes of cancer in Australia. Symptoms depend on which area of the large bowel the cancer develops in. Rectal bleeding may be a symptom of bowel cancer, particularly it the cancer is closer to the anus. The bleeding can vary from bright red to dark blood. For this reason, rectal bleeding needs to be assessed by a doctor, especially if you are over 50 years old or have a family history of bowel cancer.
Other causes of rectal bleeding include:
- Inflammatory bowel disease, such as Crohn's disease or ulcerative colitis, can cause bloody diarrhoea. Often mucus is also present in the stools;
- Gastroenteritis is usually a short-term condition causing inflammation of the lining of the digestive system. It can cause fevers, vomiting, cramps and diarrhoea that can contain blood or mucus, and;
- Gastritis and stomach ulcers can occasionally cause rectal bleeding. The bleeding typically results in dark and sticky stools (melaena), but rarely it can be bright red blood if bleeding is heavy.
Risk factors for rectal bleeding include:
- Age - as you get older, blood vessels within the digestive system can weaken and become prone to bleeding;
- Constipation - many cases of rectal bleeding can be linked to damage and pressure caused by constipation;
- Blood-thinning medications, such as aspirin or warfarin can worsen rectal bleeding, and;
- Family history - if you have a family history of conditions such as haemorrhoids, inflammatory bowel disease, polyps or bowel cancer.
Methods for diagnosis
Rectal bleeding warrants medical assessment to rule out any serious cause. Do not be embarrassed about discussing this with your doctor as it is a very common condition. The method of diagnosis will depend on your age and symptoms and may include all or a few of the following tests:
Digital rectal examination
This common procedure involves insertion of a thin, hollow lubricated instrument (proctoscope) into your rectum. The instrument has a tiny light and allows your rectum to be examined closely. If your doctor suspects that you are bleeding further up your colon, other tests, such as colonoscopy, may be suggested.
A colonoscopy involves inserting a thin, flexible, lit tube (endoscope) into the rectum to examine your colon and lower bowels. You will be given a mild sedative to help you relax during the procedure and often will be asked not to eat for 12 hours prior to the test. The endoscope can take video, photos and tissues samples, providing your doctor with a highly detailed view of your intestines.
Gastroscopy is similar to colonoscopy, but the tube enters via the mouth and is used to examine the upper digestive tract, including the oesophagus, stomach and first part of the small intestine. Your doctor may organise this test if you have had melaena, to help in the diagnosis of conditions such as bleeding stomach ulcers.
Computer tomography (CT) or nuclear scans
Special scans of the abdomen, including CT or nuclear scans, may be performed to help visualise abdominal structures and/or the source of bleeding. These tests are generally used to assess for more serious causes of rectal bleeding.
Types of treatment
The type of treatment you are offered will depend on the cause of your rectal bleeding.
Haemorrhoids and anal fissure
Many cases of haemorrhoids and anal fissure can be resolved with simple lifestyle changes and home treatments. In certain cases, haemorrhoids may need surgery, which can involve stapling, banding procedures, injection or infrared treatment. Anal fissures that fail to heal can also be treated using surgery. Changing your diet to reduce constipation may be the first step you are advised to take towards resolving these conditions.
Bleeding related to angiodysplasia (a condition in which blood vessels abnormally form in the bowel) is initially managed in a hospital, so a person can be closely monitored and supported with intravenous fluids and blood transfusions until the bleeding resolves. In severe cases, or where bleeding does not cease, a variety of surgical procedures can be used.
In rare cases, haemorrhaging (uncontrolled bleeding) may occur and require immediate surgery to prevent further blood loss. Bowel resection (surgical removal of the bleeding part of the bowel) may need to be done as an emergency procedure. Less severe or slower bleeds may be able to be managed via colonoscopy rather than surgery.
Polyps that are found at the time of colonoscopy can generally be removed at the same time using small biopsy or snaring devices. Often the removed polyps are sent to be examined by a pathologist to ensure no cancerous growths are detected.
If you have been diagnosed with bowel cancer, you may need to undergo surgery, chemotherapy, radiotherapy, biological therapy or a combination of all of these. Please refer to our report on bowel cancer for full details.
Complications associated with rectal bleeding are as follows:
Loss of blood will eventually lead to anaemia, which can cause pale skin, breathlessness, weakness, dizziness and fatigue.
If you lose a large volume of blood, your body may go into shock if untreated. This can be potentially fatal, but can be managed with the prompt medical care.
The outcome for rectal bleeding depends on your diagnosis and individual circumstances. Rectal bleeding generally needs medical assessment to rule out serious conditions.
Steps to help prevent rectal bleeding depend on the cause, but include the following:
- Eat a healthy diet high in fibre, fruits, vegetables, cereals and wholegrain products;
- Drink more water. Drinking water throughout the day will help keep your stools soft and keep your digestive system moving, and;
- Get active. Try to avoid sitting for long periods of time and exercise as often as you can.
Get regularly screened for bowel cancer if you are over 50 years of age or have a family history of bowel cancer. Discuss screening options with your doctor.