What is blood in stool?
Blood in stool refers to the blood that is passed out of the anus. Sometimes, they show up as blood stains on toilet paper when wiping. Or, for more severe cases, blood would cover the toilet bowl. The blood may or may not be mixed with the stool, i.e. sometimes there may be bleeding without stool. Usually, the bleeding is not life-threatening but it may be severe enough to cause other problems like low blood pressure and giddiness.
The colour of the blood can indicate where the bleeding is from. Fresh blood that is brighter red in colour usually comes from the area nearer the anus. Bleeding from a deeper part of the colon would appear darker, whereas a bleed from the stomach would turn the stool completely black, appearing like tar with a fishy smell.
Sometimes, there may be small traces of blood that are too little to be seen with the naked eye. A stool test called a faecal occult test would then reveal the presence of this blood. In Singapore, there are test kits for blood in stools that are distributed for free to eligible Singaporeans by organisations like the Singapore Cancer Society.
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What causes blood in stool?
Blood in stool usually means there is bleeding somewhere along the digestive tract. It could be a sign of an underlying medical condition such as:
This is the most common cause of blood in stool. It happens when blood vessels near the anus become swollen, causing a lump at the anus. The blood tends to be bright red in colour but the amount of bleeding could vary.
Other symptoms of piles include:
- Itching
- Pain
- Mucus discharge
If there is severe pain in the anus, the cause is most likely to be an anal fissure that occurs after passing very hard or large stools. An anal fissure is when there is a small tear in the mucus layer that lines the anus, causing bleeding.
Sometimes, blood in the stool may be the only symptom of colon cancer. Other symptoms of colon cancer may appear in the later stages and include:
- Abdominal pain
- Change in bowel habits
- Weight loss
- Shortness of breath (from lack of blood)
Or, it might be because of polyps which are precursors to cancerous tumours. It usually does not cause symptoms but can sometimes cause bleeding.
Bacterial infection can cause colitis leading to diarrhoea with blood, also called dysentery.
Other symptoms of dysentery include:
- Painful stomach cramps
- Feeling sick or being sick and vomiting
- High fever
Varicose veins, which are swollen and twisted, or tears in the oesophagus can result in severe blood loss.
Diverticula are small pouches that project from the colon wall. They usually don’t cause problems but could bleed or become infected.
These are open sores in the lining of the stomach or duodenum, the first part of the small intestine. These peptic ulcers may be caused by an infection with a bacterium called Helicobacter pylori (H. pylori).
In other cases, long-term use or high doses of anti-inflammatory drugs such as aspirin, ibuprofen or naproxen may also cause peptic ulcers.
This happens when there are abnormal, tortuous and dilated blood vessels in the mucus layer of the gastrointestinal (GI) tract that cause blood loss.
What are the symptoms accompanying blood in stool?
Symptoms that often occur in conjunction with blood in stool include:
- Abdominal pain
- Fatigue or Weakness
- Shortness of breath
- Pale skin
Most of these symptoms are due to extensive blood loss. Seek help from the doctor if you notice these symptoms.
What are the risk factors for blood in stool?
You could be at higher risk of having blood in stool if you have the following:
- A history of stomach bleeding or haemorrhoids
- Previous peptic ulcers
- Undiagnosed or diagnosed inflammatory bowel disease
- A genetic predisposition for colorectal or upper GI cancers
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What is the diagnosis like for blood in stool?
This is a simple stool test to detect small amounts of blood in the stool, but cannot be used to identify the source or cause of bleeding.
A tube is placed down the nose (naso-) to suck away the stomach contents (gastric lavage) in order to determine if the stomach is bleeding.
A tube with a camera, called a scope, is inserted into the rectum from your bottom to view the colon and collect tissue samples for biopsies.
This is to check the small intestine using a tube with a camera, called a scope, to take images to diagnose the location of the bleeding.
Barium is swallowed or inserted into the rectum such that the digestive tract shows up more clearly on the X-ray.
A radioactive dye is injected into your vein such that the blood vessels show up on the images taken by an X-ray or CT scan to determine where the bleeding is.
What is the treatment for blood in stool?
Your doctor will recommend the appropriate treatment based on your diagnosis.
Your doctor would normally want to stop the bleeding first. This can be done via endoscopy or angiography.
- Endoscopy
Endoscopy may be used to inject chemicals into the bleeding site. Alternatively, the bleeding site may be treated with an electric current, or a band or a clip may be used to close the bleeding vessel.
- Angiography
If endoscopy doesn’t work, then angiography may be needed to inject medicines into the blood vessels to get the bleeding under control.
The cause of the bleeding needs to be treated to prevent the bleed from occurring again. Treatment depends on the cause and can include:
- Antibiotics to treat H. pylori
- Medicines to suppress stomach acid production
- Anti-inflammatory drugs to treat colitis
You might need surgery to remove polyps or parts of the colon that are damaged by cancer, diverticulitis or inflammatory bowel disease.
You may be able to carry out simple lifestyle modifications to relieve blood in stools, such as by eating a high-fibre diet to prevent constipation which can cause or aggravate haemorrhoids and anal fissures.
Another technique you can carry out on your own includes taking a Sitz bath where you sit in warm water to relieve the fissures and haemorrhoids.
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