Barium Enema

Test Overview

A barium enema, or lower gastrointestinal (GI) examination, is an X-ray examination of the large intestine (colon and rectum). The test is used to help diagnose diseases and other problems that affect the large intestine. To make the intestine visible on an X-ray picture, the colon is filled with a contrast material containing barium. This is done by pouring the contrast material through a tube inserted into the anus. The barium blocks X-rays, causing the barium-filled colon to show up clearly on the X-ray picture.

There are two types of barium enemas.

• In a single-contrast study , the colon is filled with barium, which outlines the intestine and reveals large abnormalities.
• In a double-contrast or air-contrast study , the colon is first filled with barium and then the barium is drained out, leaving only a thin layer of barium on the wall of the colon. The colon is then filled with air. This provides a detailed view of the inner surface of the colon, making it easier to see colon polyps, colorectal cancer, or inflammation.

In some cases, the single-contrast study may be preferred for specific medical reasons or for older people who may not be able to tolerate the time-consuming and somewhat more uncomfortable double-contrast study. However, if the results are not clear or there is a strong suspicion of colorectal cancer, a double-contrast study may also be done.

Why It Is Done

A barium enema is done to:

• Screen for colon polyps or colon cancer. Most medical experts recommend colon cancer screening beginning at age 50 for people who do not have an increased risk of colon cancer. Earlier screening is recommended for people who have an increased risk of colon cancer, such as those with a family history of colon cancer.
• Identify inflammation of the intestinal wall that occurs in inflammatory bowel diseases, such as ulcerative colitis or Crohn's disease. A barium enema also may be used to monitor the progress of these diseases.
• Detect problems with the structure of the large intestine, such as narrowed areas (strictures) or pockets or sacs (diverticula) in the intestinal wall.
• Help correct a condition called ileocolic intussusception , in which the end of a child's small intestine protrudes into the large intestine.
• Evaluate abdominal symptoms such as altered bowel habits, anemia, or unexplained weight loss.

How To Prepare

Before a barium enema, tell your health professional if you:

• Are or might be pregnant.
• Are allergic to latex. Latex products are commonly used to administer the contrast material. If you have a latex allergy, different products will be used.
• Know that you are allergic to barium.
• Have had an upper digestive barium test (upper GI or barium swallow) recently.

The preparation for a barium enema usually involves a very thorough cleansing of the large intestine, because the colon must be completely clear of stool and gas. Even a small amount of stool can affect the accuracy of the test.

• For 1 to 3 days before the test, you will usually be on a clear liquid diet.
• On the day before the test:
  • You should drink very large amounts of noncarbonated clear liquids, unless your health professional has advised you not to.
  • You will then take a combination of laxatives (such as castor oil, magnesium citrate, or bisacodyl) to empty your intestines.
  • You may be asked to take a tap water enema to clean any remaining stool from your colon.
• On the day of the test, you may need to repeat the enema until the liquid that passes is free of any stool particles. Sometimes a rectal suppository or a commercially prepared enema, such as a Fleet enema, is used instead of a tap water enema.

Talk to your health professional about any concerns you have regarding the need for this test, its risks, how it will be done, or what the results will indicate. To help you understand the importance of this test, fill out the medical test information form (What is a PDF document?) .

How It Is Done

To make the intestine visible on an X-ray picture, the colon is filled with a contrast material containing barium. This is done by pouring the contrast material through a tube inserted into the anus. The barium blocks X-rays, causing the barium-filled colon to show up clearly on the X-ray picture.

• You will lie on the X-ray table while a preliminary X-ray film is taken.
• While you are lying on your side , a well-lubricated enema tube will be inserted gently into your rectum. The barium contrast material is then allowed to flow slowly into your colon.
• A small balloon on the enema tip may be inflated to help you hold in the barium. Tightening your anal sphincter muscle (as if you were trying to hold back a bowel movement) against the tube and taking slow, deep breaths may also help.
• Occasionally, you may be given an injection of medicine to relieve the cramping.

Your health professional will observe the flow of the barium through your colon on an X-ray fluoroscope monitor that is similar to a television screen.

• You will be asked to turn to different positions, and the table may be tilted slightly to help the barium flow through your colon and to take X-rays from different directions (sides, front, and back).
• Your health professional may also press gently on your abdomen with his or her hand or a plastic paddle to help move the barium through your intestines.
• If a double-contrast study is being done, the barium will be drained out and your colon will be filled with air.

When the test is finished:

• The enema tube is then removed.
• You will be given a bedpan or be taken to the toilet to get rid of as much of the barium as you can.
• One or two additional X-ray pictures (post-evacuation films) will then be taken.

A single-contrast study usually takes 30 to 45 minutes, although the actual time the barium is held inside is only 10 to 15 minutes. A double- or air-contrast study may take up to an hour.

After the test, you may resume your regular diet unless otherwise instructed. Be sure to drink plenty of liquids to replace those you have lost and to help flush the remaining barium out of your system. Your bowel movements may look white or pinkish for 1 to 2 days after the test.

How It Feels

A barium enema procedure can be uncomfortable and tiring, but usually it does not last very long.

Many people report that the preparation and bowel cleaning are the most difficult parts of the test. The castor oil has an unpleasant taste, and the frequent bowel movements can be tiring. Also, the anal area can become quite sore during the process. Warm sitz baths or a local anesthetic salve, such as Preparation H, can help ease this discomfort.

You may be embarrassed by the test. You may worry that you won't be able to hold the barium and that it will leak onto you or onto the table. The health professionals who perform this procedure are accustomed to this and will be able to help you.

The X-ray table is hard and sometimes cold because air-conditioning is used to keep the equipment cool. When the barium first flows into your colon, it may feel a bit cool. As your colon fills, you may feel a sensation of fullness, moderate cramping, and a strong urge to have a bowel movement. If an air-contrast study is performed, you may feel increased cramping or gas pains from having gas pumped into your large intestine. Taking slow, deep breaths through your mouth can help you relax.

You may feel tired for a day or so after the test. You should arrange for someone to drive you home after the test. This test can be exhausting.

Risks

There is very little risk of complications from having a barium enema.

• Occasionally the barium remaining in the colon hardens, causing severe constipation (impaction) or obstruction. To decrease the risk of impaction, drink extra fluids following the procedure and, if necessary, take an enema or mild laxative after the test.
• In rare cases, barium can cause inflamed areas in the colon called barium granulomas.
• Perforation of the bowel is a more serious, but very rare complication. Under the pressure from the barium or air, a weakened section of the colon may break open, allowing the intestinal contents to spill into the abdominal cavity. It may occur in people whose bowel wall has been weakened by intestinal problems, such as inflammatory bowel diseases, ulcerative colitis, or Crohn's disease.

Call your health professional immediately if you:

• Have rectal bleeding.
• Have severe abdominal pain.
• Develop a fever.
• Do not have a bowel movement within 2 days after the test.

Results

A barium enema, or lower gastrointestinal (GI) examination, is an X-ray examination of the large intestine (colon and rectum).

The results of a barium enema are usually available immediately after the test or within a few days.

Many conditions can change barium enema test results. Your health professional will discuss any significant abnormal results with you in relation to your symptoms and past health.

What Affects the Test

Factors that can interfere with your test or the accuracy of the results include:

• Stool or gas in the colon.
• Muscle spasms in the colon wall.
• Inability to remain still or to cooperate during the test.
• Extreme obesity.

What To Think About

• A barium enema is less expensive and has fewer risks than colonoscopy and sigmoidoscopy. It does not require sedation. However, small colon polyps are more likely to be missed during a barium enema. For more information, see the medical tests Colonoscopy and Sigmoidoscopy.
• Polyps cannot be removed during a barium enema. Further evaluation with a colonoscopy is generally recommended if abnormal results are found during a barium enema.
• If your health professional suspects you have an abdominal mass, other tests may be needed before or after a barium enema. These include abdominal X-rays, ultrasound studies, and computed tomography (CT) scans.
• A flexible sigmoidoscopy provides a more direct view of the rectum and sigmoid colon, where more than half of colon polyps are usually found. For more information, see the medical test Sigmoidoscopy.
• If an upper gastrointestinal series is planned, it should be performed after the barium enema. The barium swallowed during an upper GI series may take several days to pass through the intestine and thus can interfere with the results of a barium enema.
• A barium enema should not be done if you have a rapid, irregular heartbeat (tachycardia), severe ulcerative colitis, toxic megacolon, acute diverticulitis, or if a perforation of the intestine is suspected. If a contrast enema is necessary but there is an increased risk of an intestinal perforation, a water-soluble contrast material (Gastrografin) may be used instead of barium. Gastrografin decreases the risk for problems that could result if the bowel is perforated.
• Because a developing baby (fetus) is very sensitive to radiation, such as from X-rays, this test is not done during pregnancy.

References

Other Works Consulted

• Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed. Philadelphia: Saunders.

• Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.

• Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.

• Pagana KD, Pagana TJ (2002). Mosby's Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis: Mosby.

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