A colonoscopy is a medical procedure that allows a doctor to examine the inside of the large intestine, also known as the colon, and the rectum. This examination uses a long, flexible tube with a camera, called a colonoscope, to visually inspect the lining of the bowel. It serves a dual purpose: diagnosing gastrointestinal issues like unexplained changes in bowel habits or bleeding, and screening for colorectal cancer by detecting and often removing precancerous growths called polyps. Colonoscopies are a recommended screening method, especially for individuals aged 45 and older, as they can detect early-stage colorectal cancer before symptoms develop, improving treatment outcomes.
Getting Ready for Your Colonoscopy
Preparation for a colonoscopy begins several days before the procedure to ensure the colon is completely clear, allowing for a thorough examination. Three days prior, you will start a low-fiber diet, avoiding foods like raw fruits, vegetables, whole grains, and nuts. This dietary adjustment helps reduce solid waste in your digestive system. Fiber supplements or anti-diarrheal medications should also be stopped.
The day before the colonoscopy, your diet transitions to clear liquids only, including water, clear broths, apple juice, gelatin, and sports drinks, excluding anything red or purple colored. Solid foods are prohibited to ensure the bowel is empty. This clear liquid diet is complemented by a bowel cleansing regimen, involving a prescription laxative solution.
The laxative is taken in two split doses: one portion the evening before the procedure and the second several hours before your appointment on the day of the colonoscopy. Drinking the laxative can be challenging due to its taste, but mixing it with a flavored sports drink, chilling it, or using a straw can help. Completing this bowel preparation is important because any remaining solid matter can obscure the view, potentially leading to an incomplete examination or a repeat procedure. Adjustments to medications like blood thinners, diabetes medications, or certain weight management drugs may also be necessary, and your doctor will provide specific instructions.
Inside the Procedure
Upon arrival at the facility, you will change into a gown, and an intravenous (IV) line will be placed in your arm to administer sedation. Most colonoscopies in the United States are performed with some level of sedation, ranging from conscious sedation, which makes you relaxed but not fully unconscious, to deeper sedation where you may sleep through the procedure and have no memory of it. Common sedatives include propofol, which acts quickly and wears off rapidly.
Once the sedation takes effect, you will be positioned on your side, with your knees drawn towards your chest. The doctor will insert the colonoscope into your rectum. This long, flexible tube, equipped with a tiny video camera and a light at its tip, is guided through your rectum and into the entire length of your large intestine, reaching the cecum, the beginning of the colon. The camera transmits real-time images to a monitor, allowing the doctor to thoroughly examine the colon’s lining.
During the procedure, a small amount of air, carbon dioxide, or water may be introduced into the colon through the scope to inflate it. This inflation helps expand the passageway, providing a clearer view of the colon walls and detecting any abnormalities. As the colonoscope is withdrawn, the doctor inspects for any signs of swollen or irritated tissues, inflammation, ulcers, or abnormal growths called polyps. If polyps or suspicious tissue are identified, specialized tools can be passed through the colonoscope’s instrument channel to remove them. This process, called polypectomy, is painless as polyps do not contain nerves. Removed polyps and tissue samples are then sent to a laboratory for analysis to determine if they are cancerous, precancerous, or noncancerous. The procedure itself takes about 20 to 60 minutes, with additional time if polyps are removed.
After Your Colonoscopy and What Results Mean
Following your colonoscopy, you will be moved to a recovery area where medical staff will monitor your vital signs as the effects of the sedation wear off. You may feel groggy or disoriented initially, but this subsides within about an hour. Common sensations include mild abdominal discomfort, bloating, and the urge to pass gas due to the air introduced into your colon during the procedure; walking can help relieve this. It is important to have a responsible adult drive you home, as the sedative effects can last up to 24 hours, making it unsafe to drive or make important decisions.
You can resume your normal diet and activities within 24 hours, unless otherwise instructed by your doctor. If polyps were removed or biopsies taken, you might notice a small amount of blood in your first few bowel movements, which is not a cause for concern. Your doctor will discuss the initial findings with you after the procedure.
Formal results from any removed polyps or biopsies are communicated within a few days to a week after the procedure, once the laboratory analysis is complete. These results will indicate if the findings were normal, if benign polyps were found, or if there were any precancerous or cancerous cells. Based on these findings, your doctor will provide guidance on follow-up care, which may include a schedule for future screenings. While rare, it is important to be aware of potential complications such as severe abdominal pain, persistent or heavy rectal bleeding, fever, or persistent nausea and vomiting, and to contact your doctor immediately if any of these symptoms occur.