A sigmoidoscopy is a medical procedure that allows a physician to visually examine the lining of the lower part of the large intestine, specifically the rectum and the sigmoid colon. The doctor uses a flexible tube equipped with a camera, called a sigmoidoscope, to look for issues like polyps, inflammation, or the cause of symptoms such as bleeding. For this examination to be successful and yield accurate diagnostic results, the bowel must be completely empty of stool. This mandatory cleansing process, known as preparation, is necessary to ensure a clear view of the intestinal wall.
Pre-Examination Dietary Requirements
The preparation for a sigmoidoscopy begins with dietary changes, typically starting two to three days before the scheduled procedure. This involves transitioning to a low-fiber or low-residue diet to reduce the bulk of material passing through the digestive tract. Foods to strictly avoid during this initial phase include high-fiber items like nuts, seeds, popcorn, whole grains, and raw fruits and vegetables. Instead, the diet should consist of easily digestible options such as white bread, white rice, eggs, fish, and clear juices without pulp.
The day before the exam, all solid food consumption must stop, and the diet shifts strictly to clear liquids. A clear liquid is defined as any fluid you can see through, ensuring no residue is left in the colon. Acceptable liquids include water, clear fruit juices like white grape or apple, plain gelatin, clear broth or bouillon, and sports drinks. It is important to avoid any liquids with red or purple dyes, as these colors can be mistaken for blood during the examination.
Bowel Cleansing Procedures and Timing
The physical cleansing of the lower bowel is usually achieved through the use of enemas, which are designed to flush out the sigmoid colon and rectum. Patients are often instructed to purchase two over-the-counter sodium phosphate enema kits, such as a Fleet enema, for administration at home on the day of the procedure. In some cases, a mild oral laxative like Magnesium Citrate may also be prescribed for the evening before the exam.
The timing of the enema is highly prescriptive and is directly related to the appointment time, typically occurring one to three hours before arrival. The first enema is administered, and the fluid should be retained for as long as possible before being expelled. The second enema is administered a short time after the first, often about 10 to 30 minutes later, to ensure a thorough clean. The goal is for the final output to be clear or a slightly pale yellow liquid, indicating a clean colon and a successful preparation.
Frequent bowel movements can cause skin irritation around the anal area. To manage this discomfort, patients may find relief by using a soft cloth instead of toilet paper. Applying a barrier cream or petroleum jelly to the irritated area beforehand can also help protect the skin from further friction and moisture. Following the precise timing and steps provided by the healthcare team is necessary, as inadequate cleansing will result in the procedure being incomplete or needing to be rescheduled.
Medication Adjustments and Hydration Protocol
Managing regular medications is a necessary safety component of the preparation process, and all adjustments must be discussed with the prescribing doctor beforehand. Specific medications that require careful review include blood thinners, such as Warfarin or Plavix, which may need to be temporarily stopped several days prior to reduce the risk of bleeding during the procedure. Iron supplements and multivitamins containing iron should also be discontinued up to a week before, as they can leave dark residue that obscures the visual field.
Patients with diabetes must consult their physician for specific instructions on adjusting insulin or oral diabetes medications, since the clear liquid diet significantly alters blood sugar levels. Often, the dose of long-acting insulin is reduced, and oral medications are held on the morning of the exam to prevent hypoglycemia.
Throughout the preparation, maintaining proper hydration is important to counteract the fluid loss from the bowel cleansing. Consuming clear liquids that contain electrolytes, such as sports drinks and broths, helps to maintain the body’s balance. All liquid consumption must cease at a final cut-off time, typically two to four hours before the procedure, to ensure an empty stomach for the exam.