The large bowel is that portion of the digestive tract that lies between the small intestine above and the anus below. The barium enema examination consists of the infusion of liquid barium into the large bowel via a tube inserted into the rectum followed by distension of the large bowel with appropriate amounts of air (carbon dioxide). X-ray pictures are taken. The test is a very successful way of examining the large bowel.
The barium enema examination of the large bowel may be performed for a number of symptoms including lower abdominal pain, the passage of blood or mucus into the stool, and altered bowel habits. A careful, detailed barium enema may reveal evidence of large bowel narrowing, ulceration, or focal mass lesions such as a polyp or a tumor.
The colon must be clear of all stool and contain as little fluid as possible. There are a variety of preparations available. Generally speaking it is necessary to be on a low fiber diet for 2 days prior to the examination and to undergo some form of bowel cleansing,with laxatives or enemas. Prior to the procedure the technologist will ascertain when the patient last ate or drank, whether there was any previous surgery, or if the patient is taking any medication. In addition, it is necessary for the patient to inform the technologist or radiologist if they are pregnant or they think they may be so. Some patients with artificial heart valves will need to receive antibiotics prior to the procedure to reduce the risk of valve infection.
With the patient lying on the X-ray table on the left side, a small plastic tube is inserted through the anus into the rectum. The tip of the tube is coated with K-Y Jelly to facilitate insertion. The tube is then connected to a bag containing barium which is infused slowly into the large bowel. Along with the barium, small amounts of air (carbon dioxide) are inflated into the colon to produce maximum and adequate distension of the barium coated large bowel. The patient is then asked to move around in different positions in order for the radiologist to obtain the best images using the X-ray unit. During the examination the patient should retain as much of the liquid barium and air as is possible in order to optimize the quality of the study. Once the examination is complete the enema tube is removed, and the patient can visit the bathroom. It may be necessary for some patients to receive an intravenous injection of a muscle relaxant (glucagon) in order to reduce spasm within the large bowel, and to facilitate the passage of sufficient quantities of air in order to distend it appropriately. Glucagon is essentially entirely safe and without risk.
What happens afterwards?
The patient will likely experience some diarrhea and therefore should not resume normal activities or return to work until the following day. It is necessary to drink more water than usual in order to reduce the possibility of any constipation that may occur after this test. The stool may appear white or light for a day or two but this is entirely normal as the barium is removed in the stool.
The barium enema is a remarkably safe examination with few if any complications. One complication is the inadvertent perforation of the large bowel with passage of barium outside of the bowel wall into the abdominal cavity. This however is extremely rare and is most unlikely to occur with a good technique and an appropriately experienced radiologist. There is a small amount of radiation involved in the examination. The potential benefits of this test far outweigh any risks.