A barium enema is a specialized X-ray examination that provides images of the large intestine. The procedure requires the introduction of barium sulfate, a contrast material, into the rectum to coat the bowel lining, allowing clear visualization of the colon’s structure on an X-ray screen. To successfully detect abnormalities, such as polyps or inflammation, the colon must be completely free of residual stool. Therefore, a mandatory preparation process involving strict dietary changes and a comprehensive cleansing regimen ensures accurate diagnostic results.
Dietary Changes Leading Up to the Procedure
Preparation for a barium enema begins days before the procedure with a structured adjustment to your diet. This typically involves starting a low-residue diet one to three days before the scheduled exam. This regimen is designed to significantly reduce indigestible fiber and residue in the digestive tract. Foods that are difficult to digest, such as nuts, seeds, whole grains, and raw fruits and vegetables, must be avoided.
A low-residue diet permits foods that leave minimal residue in the colon, including white bread, refined pasta, plain boiled or baked chicken, and well-cooked vegetables without skins. This restriction prevents solid waste from obscuring the X-ray images. The ultimate dietary restriction occurs the day before the procedure, transitioning to an entirely clear liquid diet.
The clear liquid diet ensures no solid particles remain in the bowel while keeping the body hydrated. Acceptable clear liquids include:
- Water
- Clear broth and fat-free bouillon
- Strained fruit juices without pulp
- Black coffee or tea
- Carbonated drinks
- Plain gelatin
Avoid any liquids with red or purple dyes, as these can be mistaken for blood during the examination.
The Required Bowel Emptying Regimen
The bowel emptying regimen actively flushes the colon clean. This process typically utilizes a combination of oral laxatives and high-volume solutions to induce powerful diarrhea, ensuring all fecal matter is expelled. Cleansing kits often include a polyethylene glycol (PEG) solution, sometimes mixed with an electrolyte-containing drink, or a different type of laxative such as magnesium citrate or bisacodyl tablets.
The timing of taking the cleansing agents is precisely scheduled, often beginning in the late afternoon or evening the day before the procedure. Patients might be instructed to take a stimulant laxative tablet first, followed by drinking several liters of the PEG solution over a few hours. This volume of liquid works as an osmotic agent, drawing water into the bowel to produce multiple, watery bowel movements. The process is considered complete when the bowel movements are entirely clear and watery, with no solid flecks remaining.
Maintaining hydration is crucial, as the laxatives cause significant fluid loss. Patients are strongly encouraged to drink extra clear liquids throughout the day to counteract the risk of dehydration, which can manifest as dizziness or excessive thirst. Some preparation instructions may also include a final cleansing enema, such as a saline enema, on the morning of the exam to remove any last residual material. It is important to remain near a toilet once the regimen begins, as the effects of the purgative agents are rapid and pronounced.
Adjusting Medications and Final Preparations
Managing regular medications must be addressed in advance of the barium enema. Patients on blood-thinning medications, such as warfarin or clopidogrel, must consult their prescribing physician at least a week before the exam, as these drugs may need adjustment to prevent bleeding complications. Individuals with diabetes who take insulin or oral medications require specific dosage instructions from their doctor to manage blood sugar levels while on a restricted diet.
Certain supplements, particularly iron tablets, must be discontinued up to a week before the procedure because they can leave a residue that interferes with the X-ray images. Patients taking diuretics or potassium supplements may also need to consult their physician regarding dose adjustments due to fluid loss from the bowel prep. For all other prescription and over-the-counter medications, confirm with your doctor if they can be taken the morning of the exam, usually with a small sip of water.
Logistical preparations are important for a smooth experience on the day of the procedure. Patients should confirm the appointment time and location, and make arrangements for transportation if they anticipate feeling weak or fatigued after the bowel cleansing. On arrival, bring a photo ID, insurance information, and the physician’s prescription for the exam. Wearing comfortable, loose-fitting clothing and removing all jewelry and metal before the test will help ensure an efficient experience in the radiology department.