Gastrointestinal (GI) bleeding is a serious sign of trouble within your digestive tract. Your digestive tract consists of the following organs:

  • Oesophagus
  • Stomach
  • Small intestine (including the duodenum)
  • Large intestine or colon
  • Rectum
  • Anus

GI bleeding can occur in any one of these organs. If the bleeding occurs in your oesophagus, stomach, or initial portion of the small intestine, it is considered upper GI bleeding. Gastrointestinal bleeding in the lower small intestine, large intestine, rectum, or anus is called lower GI bleeding. The amount of bleeding you experience can range from a very small amount of blood to a life-threatening haemorrhage. In some cases, the amount of bleeding may be so small that it only shows up on microscopic examination.

What causes GI bleeding?

Different parts of the digestive tract are affected by specific conditions, and there are various causes of bleeding in different regions.

Causes of upper GI bleeding

Peptic ulcers (open sores that develop in the lining of your stomach or duodenum (initial part of the small intestine)) are a common cause of GI bleeding. Peptic ulcers are most commonly caused by a bacterial infection known as H. pylori. Enlarged veins in your oesophagus can tear and bleed as a result of a condition called oesophageal varices. Tears in the walls of your oesophagus can also cause GI bleeding in a condition known as a Mallory-Weiss tear.

Causes of lower GI bleeding

One of the most common causes of lower GI bleeding is colitis. This occurs when your colon becomes inflamed. This could be caused by an infection, food poisoning, parasites, Crohn’s disease, or reduced blood flow in the colon. Haemorrhoids are another common cause of GI or rectal bleeding. A haemorrhoid is an enlarged vein in your rectum or anus. These enlarged veins can rupture and bleed, causing rectal bleeding. A final cause of lower GI bleed is from an anal fissure: this is a tear in the muscular ring that forms the anal sphincter, and is usually caused by constipation or hard stools.

What are the signs of gastrointestinal bleeding?

There are a few things that you can look out for if you suspect that you might have GI or rectal bleeding. Your stool might become darker, like coal tar, if the bleeding is coming from the stomach or upper GI tract. You may pass blood from your rectum during bowel movements, which could cause you to see some blood in your toilet or on your toilet tissue. This blood is usually bright red in colour. Vomiting blood is another sign that there is bleeding somewhere in your GI tract.

If you see any of these symptoms or if you have vomit that looks like coffee grounds, call your doctor immediately. GI bleeding could signal a potentially life-threatening condition, and prompt medical treatment is essential. Seek treatment immediately if you experience paleness, weakness, or shortness of breath. These could be signs of severe bleeding.

How do doctors determine the cause of bleeding?

Diagnosis of the underlying cause of your GI bleeding will usually start with your doctor asking you about the symptoms you’ve been experiencing and your medical history. A stool sample might be taken to check for the presence of blood, and blood tests looking for signs of anaemia (a low amount of healthy red blood cells) might be performed as well.

Upper GI bleeding is most commonly diagnosed by doing an endoscopic examination. Endoscopy is a procedure that involves the use of a small camera located atop a long, flexible endoscopic tube that your doctor places down your throat. The scope is then passed through your upper GI tract. This allows your doctor to see inside your GI tract and potentially locate the source of your bleeding. Because endoscopy is limited to the upper GI tract, an enteroscopy might be performed if the cause of your bleeding can’t be found during endoscopy. Enteroscopy is similar to endoscopy except there is usually a balloon attached to the camera-tipped tube. When inflated, this balloon allows your doctor to open up the intestine and see inside.

To determine the cause of lower GI bleeding, your doctor may perform a colonoscopy. During this test your doctor will insert a small, flexible tube with a camera attached into the rectum to view the entire length of the colon (large intestine). Air will be inserted through the tube to provide a better view. A biopsy (tissue sample) may be taken for additional testing.

What can be done to relieve symptoms?

Endoscopy can be useful, not only in diagnosing GI bleeding, but also for treating it. The use of special scopes with a camera and laser attachment, along with medications, can be used to stop the bleeding. In addition, tools can be used with a scope to apply clips to the bleeding vessels to stop the bleeding.

If haemorrhoids are the cause of your bleeding, over-the-counter treatments might work for you. If you find that store-bought remedies are ineffective, your doctor might use a heat treatment to shrink your haemorrhoids. Infections are usually treated with the use of antibiotics.