- What is barium enema?
- How is barium enema conducted?
- How to prepare for a barium enema procedure
- What the results show
A barium enema procedure inserts a radio-opaque contrast material (barium sulfate) into the rectum. This is a chalky mixture that can be visulaised with X-ray machinery and allows investigation of the inner surface of the large intestine (also called the colon). Barium enema is a common diagnostic investigation that provides structural information about the colon. It is used in the investigation of gastrointestinal symptoms such as diarrhoea and constipation which are common patient presentations. Barium enema can help in the diagnosis of conditions such as inflammatory bowel disease, colorectal cancer and other structural abnormalities, such as stenosis and strictures (narrowing of the lumen). It is considered a relatively safe procedure with few complications.
For a barium enema, you will wear a hospital gown and be secured to a special tilting X-ray examination table. Prior to the procedure a baseline x-ray is taken. The physician will then insert a lubricated tube a few centimeters into your rectum. You may be given a drug to relax your bowel during the procedure and prevent spasm.
The barium sulfate (a chalky mixture) is then trickled through the tube into the empty bowel, whilst the physician carefully watches a television monitor. The table may be tilted to provide optimal filling and you will be instructed to contract your anal muscles around the tube to hold it is place and to avoid leakage of fluid (which can interfere with the examination). A small balloon may be inflated at the end of the tube to hold it in place.
As the contrast material fills the intestine, several X-ray photographs are taken so they can be examined to detect any abnormalities. You may have to move into different positions so different angles can be examined and may need to hold your breath at times to avoid blurry images.
Sometimes, a double contrast or ‘air contrast’ enema is performed. For this you may need to expel the fluid from the bowel and then air is slowly injected to inflate the bowel. The thin lining of barium left on the wall can give more detailed information. The injection of air can produce mild discomfort and a feeling of fullness. Following the barium enema procedures, the tube is removed and the patient is helped to the toilet to try to expel as much of the contrast as possible. Further X-rays may be taken after.
The entire procedure usually takes 30-45 minutes. Barium can lead to constipation for a few days following the procedure. You should drink plenty of fluid to prevent dehydration and to relieve constipation. Enemas or laxatives may be given to help clean out the remaining barium.
Prior to booking your procedure, your doctor will thoroughly explain the procedure and possible risks and get you to sign an informed consent form. In the lead up to the procedure, preparation mainly focuses on cleaning out the bowel to allow better visualisation (as waste materials can interfere with images).
Prior to the examination, you will have a special low fibre diet for three days. You will also receive medications and laxatives to clean out the bowel contents. Sometimes the procedure is performed with no preparation but this is mainly in the event of an emergency. Other examinations such as rectal examination (insertion of the index finger into the back passage) and rigid sigmoidoscopy (insertion of a special tube into the S-shaped segment of the colon) will also be performed prior to the procedure.
In normal subjects, the barium will fill uniformly throughout the colon. Barium enema is thus able to detect any structural abnormalities, defects in the wall and sections of narrowing. Abnormalities show up on the X-ray images and can help to diagnose several conditions such as:
- Colorectal cancer: However, most colon cancers occur in the rectosigmoid region so are better detected via other examination methods. Colonoscopy is considered a more accurate method of screening for colon cancer.
- Polyps: Benign mucosal growths that can predispose to carcinoma.
- Inflammatory bowel disease, in particular Crohn’s disease has specific characteristics.
- Diverticular disease: Characterised by out-pouchings of the colon wall.
- Numerous other structural changes such as obstruction, stenosis, intusseption (protrusion of a section of bowel forward into another section of bowel).
- Acute appendicitis may be evident on X-ray.
Barium enema is considered a safe screening procedure and complications are rare. The following however may occur:
- Perforation of the bowel (rupture of the colon wall)
- Air entering the circulation can very rarely cause heart attack or stroke.
- Heart rate may increase due to the injection. This may precipitate angina attacks. If you have a very rapid heart rate, you may be considered inappropriate for this examination.
- The contrast can impair near vision for about half an hour. You should not drive until this effect has gone.
- Allergic reactions to the contrast.
- A small radiation dose is received during the procedure. However, this is a similar dose to the level of background radiation everyone receives after living in a city for three years. The increased risk of cancer is low. Pregnant women and children may be more sensitive to the radiation.
- Many patients find the procedure unpleasant. Cramping pains, feelings of fullness, urges to defaecate and general discomfort can occur during the procedure. As mentioned, constipation can occur for a few days after the procedure.
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