A colonoscopy is a type of exam that your doctor uses to check the lining of your large intestine (colon) for signs of cancer, abnormal areas that could turn into cancer, or causes of gastrointestinal problems. To see inside your colon, your doctor (typically, a gastroenterologist who specializes in the gastrointestinal system) will place a thin flexible tube into your anus and slowly move the tube into the rectum and colon. This instrument, called a colonoscope, has a lens and light attached to it that sends images of your colon to a video screen.
Why You’re Getting a Colonoscopy
Your doctor may recommend colonoscopy as a screening test for colorectal cancer or if you’re experiencing gastrointestinal problems or symptoms, such as bleeding, diarrhea, or abdominal pain. Many physicians recommend an annual colonoscopy for patients over age 50 to screen for colorectal cancer. Common problems detected by colonoscopy include irritable bowel syndrome and inflammatory bowel disease (or ulcerative colitis).
How to Prepare for a Colonoscopy
You can help your doctor get the best results from a colonoscopy by preparing for it the way your doctor recommends. By following preparation instructions, you can help your doctor view your colon clearly. You’ll be asked to follow a clear liquid diet for 24 to hours 72 (one to three days) before the procedure and take a form of laxative in scheduled doses. Your doctor will tell you what type of laxative to take and when to it.
On a clear liquid diet, you can only consume:
If you don’t follow your doctor’s preparation instructions, your colonoscopy results may not be accurate. This may cause your doctor to miss early warning signs of colon cancer or other conditions, and you may have to undergo a repeat colonoscopy.
You’ll go to hospital or clinic for a colonoscopy. When you make your appointment, be sure to ask what time you need to arrive the day of the procedure. You’ll need to get there early enough to check in and be ready. Colonoscopy is an outpatient procedure, so you’ll plan to go home afterwards.
Before you have your colonoscopy, your doctor will want to discuss your medical history and any medical conditions you may have. He or she will also want a list of all the medications you are taking, including prescriptions and any over-the-counter medications, supplements, or herbal remedies you are taking. Also tell your doctor if you have any allergies.
What Happens the Day of a Colonoscopy
After you check in at the hospital or clinic, you’ll be taken to room to prepare for the colonoscopy. You’ll be given an intravenous (IV) line. A doctor will use this IV line to give you medications to help you relax during the procedure. He or she can also use the IV line to give you fluids, if needed, during the procedure.
Before the colonoscopy you’ll also be fitted with tools to monitor your vital signs during the procedure. These tools include patches for an electrocardiogram, or EKG, which are placed on your chest, arms, or legs. An EKG records the electrical activity of your heart. You’ll also be fitted with an automatic blood pressure cuff on your arm and a pulse oximeter on your finger. The pulse oximeter checks the oxygen levels in your blood.
What Happens During a Colonoscopy
In general, most people tolerate colonoscopy well and don’t experience much pain. You may feel pressure, bloating, or cramping during the procedure. Typically, your doctor will give you a sedative or painkiller to help you relax and better tolerate the examination. You will lie on your side or back while your doctor slowly moves the colonoscope along your large intestine to examine the lining. Your doctor will examine the lining again as he or she slowly removes the colonoscope. To help guide the colonoscope, healthcare providers might gently press on your abdomen or have you change position to your back or your other side for a short time during the procedure.
The procedure itself usually takes less than 45 minutes, but you should plan on a total of two to three hours for waiting, preparation, and recovery.
In some cases, the doctor cannot pass the colonoscope through the entire colon to where it meets the small intestine. Your doctor will tell you if this happens and whether any additional testing is necessary.
If the Colonoscopy Shows Something Abnormal
If your doctor thinks an area needs to be examined more, he or she might pass an instrument through the colonoscope to get a biopsy (a small sample of the colon lining) to be analyzed. Biopsies are used to identify many conditions, and your doctor will often take a biopsy even if he or she doesn’t suspect cancer. If colonoscopy is being performed to identify sites of bleeding, your doctor might control the bleeding through the colonoscope by injecting medications or by cauterization (sealing off bleeding vessels with heat treatment) or with small clips.
Your doctor might also find polyps (abnormal growths; see next section) during colonoscopy, and he or she will most likely remove the polyps during the examination. These procedures are called polypectomies and don’t usually cause any pain. There are many ways that a polyp can be removed, depending on its size and shape. Your doctor may destroy tiny polyps with a process called fulguration (burning) or by removing them with wire loops called snares or with biopsy instruments. Your doctor will use a technique called snare polypectomy to remove larger polyps. With this technique, he or she will pass a wire loop through the colonoscope and remove the polyp from the intestinal wall using an electrical current. This should not cause any pain.
After the polyp is removed, it is passed through the colonoscope and sent to the laboratory for examination.
After any treatments are finished, the doctor will slowly pull out the colonoscope through your rectum.
Polyps: What They Are and Why Are They Removed
Polyps are abnormal growths in the colon lining that are usually benign (noncancerous), but can turn into cancer. They vary in size from a tiny dot to several inches. Your doctor can’t always tell if a polyp is cancerous or not by its outer appearance. He or she will usually remove the polyps to examine them more closely. Because cancer begins in polyps, removing them during colonoscopy is an important step in preventing colorectal cancer.
After the Colonoscopy
You will be looked after in the hospital or clinic until most of the effects of the sedatives have worn off. You might have some cramping or bloating because of the air that’s gets into the colon during the examination. This should disappear quickly when you pass gas. Your physician will explain the results of the examination to you, although you’ll probably have to wait for the results of any biopsies performed. If you have been given sedatives during the procedure, someone must drive you home and stay with you. Even if you feel alert after the procedure, your judgment and reflexes could be impaired for the rest of the day.
After the colonoscopy your doctor might tell you to restrict your diet, your home medications, or your activities. If you’ve had polyps removed, your doctor may recommend even more restrictions and that you alter your activities for seven days after the colonoscopy. Recommendations when polyps have been removed include: avoid blood thinners, limit travel, don’t lift more than five pounds, and don’t run or do other high-impact activity.
Recommendations are different for each patient, so make sure you carefully follow your doctor’s instructions. You’ll probably be told not to drive (or operate heavy machinery) until the day after your colonoscopy. Then, unless otherwise instructed, you should be able to return to normal activity. This includes eating and drinking like normal. However, you may be asked to avoid drinking alcohol until 24 hours after the colonoscopy.
There are certain symptoms you need to watch for after a colonoscopy. Call your doctor immediately if you experience any of the following symptoms during the 24 hours following a colonoscopy:
Possible Complications of Colonoscopy
Colonoscopy and polypectomy are generally safe when performed by doctors who have been specially trained and are experienced in these procedures. One possible complication is a perforation, or tear, through the bowel wall. Perforation can require surgery. Sometimes there’s minor bleeding at the site of biopsy or polypectomy. Bleeding can stop naturally or be controlled through the colonoscope; it rarely requires follow-up treatment. Some patients might have a reaction to the sedatives or complications from heart or lung disease. Although complications after colonoscopy are uncommon, it’s important to recognize early signs of possible complications. Contact your doctor if you notice severe abdominal pain, fever and chills, or rectal bleeding. Note that bleeding can occur several days after the procedure.