Definition and Overview
The gastrointestinal tract is responsible for digestion and expelling of wastes from the body. It is divided into two sections, namely, the upper and the lower tract. The upper tract is composed of the mouth, esophagus, stomach, and the first section of the small intestine. The lower tract, on the other hand, includes the rest of the small intestine, all of the large intestine, the anus and the rectum.
In a typical digestive process, the food goes into the mouth then passes through the esophagus and into the stomach, which secretes acids so small pieces of food are further broken down into tiny molecules. The food then proceeds to the small intestine and the nutrients produced in the process is absorbed by their walls and delivered to the bloodstream so they can be distributed to various cells.
Meanwhile, the undigested food goes to the large intestine, which contains the body wastes. The muscles that make up the large intestine will then push the wastes out of the body through the rectum.
There are, however, cases when some parts of the GI tract are damaged that may lead to bleeding. This bleeding may then interfere with the normal digestive process and in turn, prevent the body from receiving the right nutrition. Moreover, as the body part experiences blood loss, the tissue can die, making the organ non-functional. This may also lead to death depending on the severity of the bleeding.
Causes of Condition
GI bleeding may be because of:
Trauma and injury - There are many ways on how the GI tract can be injured. For example, a sharp object may go through the intestine and puncture the lining, or acid burns the throat and esophagus.
Polyps – Polyps are overgrowths that are found in the lining of the bowel or the large intestine. They cause bleeding when they burst. Depending on how many polyps there are, the bleeding may be quite severe or occult (or not easily seen).
Bowel cancer – One of the most common symptoms of colon cancer is bleeding because, like polyps, these tumors can also bleed.
Hemorrhoids – Hemorrhoids form when the veins near the anus and the rectum bulge or swell. They are classified as either internal, wherein they are found deep in the rectum area, or external, where they prolapse especially when a person exerts more force and pressure when passing out stool. Either way, they can bleed when they get irritated.
Esophageal varices – This refers to the swelling of the veins found in the lower part of the esophagus. This is normally due to a blockage problem in the liver, which causes the obstructed blood to flow elsewhere such as in the veins of the esophagus. As the pressure builds up, the veins may burst, which may then lead to massive bleeding. This condition is considered an emergency.
Other conditions that can cause GI bleeding include:
- Esophagitis (inflammation of the esophagus)
- Angiodysplasia (the formation of unusual blood vessels on the digestive tract lining; these blood vessels may rupture, leaking blood in the process)
- Ulcers in the stomach
- Crohn’s disease
Certain conditions affecting other related organs such as the liver may also cause bleeding in the GI tract. These include liver cirrhosis or the scarring of the liver's tissue.
- Black, tarry stools
- Vomiting or coughing up blood
- Abdominal pain
- Pale skin
- Shortness of breath
The bleeding may be described as overt if it can be seen, such as when the patient is throwing up or passing out blood through the rectum. Meanwhile, it is referred to as occult when it can only be seen through a microscope.
Who to See and Types of Treatments Available
Problems affecting the GI tract are usually handled by gastroenterologists who diagnose GI bleeding through the following procedures:
Scope exams – These include endoscopy for the upper GI tract, esophagogastroduodenoscopy to also cover the duodenum (which belongs to the first section of the small intestine), and colonoscopy, which is used to inspect the colon. All these use flexible thin tubes that have a small camera and a light that illuminates the area of concern. The GI tract is then observed in real time through the images fed to the screen.
Occult test – A fecal occult blood test (FOBT) is a common diagnostic exam that analyzes the stool’s components. It is also used to determine the presence of bacteria and blood that may not be visible to the human eye.
Imaging scans like CT or MRI scans
Complete blood count
When it comes to GI bleeding, the usual course of action is finding the source, stopping the bleeding, and identifying the cause. The bleeding can be stopped with procedures like endoscopic band ligation or endoscopic clips. If necessary, the patient may receive blood transfusion to increase red blood cell count and avoid possible organ damage.
Treating the root cause may also stop the bleeding. For instance, with Crohn’s disease, the patient may have to take steroids or immune-suppressing drugs to control the inflammation that may be causing the bleeding. On the other hand, if the cause of the condition is hemorrhoid, eating a diet high in fiber may help.
Jensen DM. GI hemorrhage and occult GI bleeding. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 137.
Savides TJ, Jensen DM. Gastrointestinal bleeding. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, PA: Elsevier Saunders; 2010:chap 19.