Learn the basics of this lifesaving test
If it’s time for your colonoscopy, don’t worry. On average, most recommendations advise people start getting screened at age 50, and then they only need it done once every decade from there. However, there are certain groups of people who are at a higher risk, and should start getting screened earlier. And for some, the screening is a genuine lifesaver.
Introduced in 1969, the same year man first walked on the moon, the test is now a mainstay of preventive medicine, credited with detecting or averting countless cases of colorectal cancer.
But anxiety about the rigorous pretest preparation—a regimen of laxatives and fasting—still keeps many people away. Their fears are greatly exaggerated, says Yale Medicine gastroenterologist Xavier Llor, M.D., Ph.D., medical director of the Colorectal Cancer Prevention Program.
Since the test requires a totally clean, empty colon, patients must fast and take powerful laxatives beforehand.
“Afterward, people always wonder what they were so worried about,”Dr. Llor says. “They always feel the test was worth having.”
What’s a Colonoscopy?
A colonoscopy is an approximately 20-minute screening that examines the entire five-foot length of the large intestine with a camera embedded in a long flexible tube (10 minutes to the end of the colon and 10 minutes back, if no polyps are found). Usually performed while you’re sedated, the painless test can uncover hidden problems in the intestine and often instantly remove polyps. And if nothing is found, a follow-up isn’t required for 10 years.
But to ensure success, the test requires that no waste products remain in your colon to obstruct the view. And that’s where the infamous test preparation comes in. Instructions differ among physicians, but you’ll be expected to pick up special supplies and carefully follow the doctor’s guidelines and timetable.
“The only way you can have a high-quality colonoscopy is with a clean intestine, so if you don’t finish the prep, a huge effort is wasted,” warns Dr. Llor.
Preparing for the Prep
A few days before the colonoscopy, you’ll stop eating high-fiber foods that are tough to cleanse from the bowel. Those include nuts, seeds, certain fruits with edible seeds or skins (like strawberries and apples), and deep red or purple foods that can leave a stain that looks like blood.
You’ll replace those with the low-fiber foods your doctor recommends.
The Big Prep
The exact timetable varies, but anywhere from a day to several hours before you transition to consuming a full pretest preparation diet, you’ll stop eating solid foods and switch to a liquid diet.
Many doctors favor GoLYTELY powder, which you mix with water at home. “Its larger volume ensures better cleansing, especially when people have hard stools or constipation,” explains Northwell Health gastroenterologist Maurice Cerulli, M.D.Other preparations may be used depending upon kidney function and bowel habits prior to the screening.
In most cases, you’ll consume half the formula the night before, chased with lots of clear liquids. Pulp-free juices, flavored or plain water, sodas, seltzer, Jell-O, popsicles, and bouillon soup are all acceptable.
Then comes the not-so-enjoyable part: diarrhea. It usually begins roughly an hour after you’ve finished the first half of the prep liquid, and it can be urgent. You may not enjoy drinking additional liquid, but it helps keep you hydrated. Diarrhea depletes the body’s natural salts.
The Day of the Test
Roughly six hours before the colonoscopy, you’ll polish off the laxative drink. When your output is clear or slightly yellow and completely free of solids, you’re done. You won’t be allowed to drink anything else after that.
Before you head in for the test, be sure you know who will meet you there afterward. You won’t be released unless you’re accompanied by a “designated driver.”
At the Test Center
When you arrive, you’ll don a hospital gown, hop onto a surgical bed, and be transported into the examining room. You’ll be asked to turn on your side with your knees drawn up, and the anesthesiologist will prepare your sedation.
Propofol is one of the more popular types of anesthesia for colonoscopies because it is fast-acting, safe in small amounts, and rapidly cleared from the body. If you’re anxious about sedation, talk to your doctors.
“The most common concern is that you’ll get too much sedation or won’t be able to wake up easily, but that really doesn’t happen,” says Dr. Llor. “People wake up fine and they usually feel great.”
During the Colonoscopy Itself
Once you’re safely dozing, the colonoscope is inserted into the rectum and threaded through the colon, making some sharp turns along the way. The journey ends where the large and small intestines meet, although some doctors may travel further if they suspect potential damage.
Then, the real work of the colonoscopy begins. As the tube is slowly withdrawn, the camera inspects every inch of the colon. If a growth or polyp is found, a special device in the scope can snip it off, seal the wound, and remove it for testing.
“In an uncomplicated case, it takes a minimum of seven minutes to draw the scope through the whole intestine,” says Dr. Llor.
When the screening is over, the scope is removed, the sedation ends, and you awaken.
What to Expect Afterward
After a colonoscopy, most people emerge alert and happy. In rare cases there can be exceptions.
“If you have a history of irritable bowel and sensitive colon, the bloating from the remaining carbon dioxide gas may make you feel uncomfortable for a few hours, sometimes days,” explains Dr. Llor.
And if a polyp was removed, there can be some bleeding in the stool. “Most of the time, though, it’s limited and doesn’t require any follow-up,” he adds.
Chances are, you’ll leave the screening feeling seriously hungry. But you should regard your time in the testing center as well spent, stresses Dr. Cerulli.
“Think of it this way: In the time it would take to play bridge or hit a golf ball, you may save your life.”
