Patient education: Colonoscopy (The Basics)

What is a colonoscopy? — A colonoscopy is a test that looks at the inner lining of a person's large intestine. The large intestine is also called the colon (figure 1).

Often, people have a colonoscopy as a way to "screen" for colon cancer. It can also check for polyps in the colon or rectum. Polyps are growths that could turn into cancer. If you have polyps, the doctor can usually take them out during the colonoscopy. Taking polyps out lowers your chances of getting cancer.

Your doctor might also order a colonoscopy if you have:

●Blood in your bowel movements

●A change in your bowel habits

●A condition called anemia that can make you feel tired and weak

●Long-term belly or rectal pain that you cannot explain

●Abnormal results from a different type of colon test

●A history of colon cancer or polyps in your colon

How do I prepare for a colonoscopy? — Your doctor will give you instructions about what to do before a colonoscopy.

Before your procedure, your doctor will do an exam. In some cases, they might also send you to get blood tests or other tests.

Your doctor will also ask you about your "health history." This involves asking you questions about any health problems you have or had in the past, past surgeries, and any medicines you take. Tell them about:

●Any medicines you are taking – This includes any prescription or "over-the-counter" medicines you use, plus any herbal supplements you take. It helps to write down and bring a list of any medicines you take, or bring a bag with all of your medicines with you.

●Any allergies you have

●Any bleeding problems you have – Certain medicines, including some herbs and supplements, can increase the risk of bleeding. Some health conditions also increase this risk.

You will also get information about:

●Eating and drinking before your procedure – You will most likely need to eat a "low-residue" diet for a few days before your colonoscopy. This means avoiding foods that have a lot of fiber and are hard to digest. You might need to switch to only clear liquids for 1 day before the procedure. Your doctor or nurse will tell you what foods you can and cannot eat.

●Bowel prep – Your colon needs to be cleaned out before a colonoscopy. This is also called "bowel prep." Your doctor will give you a special drink that causes watery diarrhea. Drink all of it to make sure that your colon is clean. If your colon is clean, your doctor will get a better look at the inside lining. A clean colon also makes the test easier to do and more comfortable.

●What help you will need when you go home – For example, you might need to have someone else bring you home or stay with you for some time while you recover.

Ask the doctor or nurse if you have questions or if there is anything you do not understand. Tell them if you are having any trouble preparing for your colonoscopy.

What happens during a colonoscopy? — When it is time for the procedure:

●You will get an "IV," which is a thin tube that goes into a vein. This can be used to give you fluids and medicines.

●You will get medicines through the IV to make you feel drowsy and relaxed. In some cases, doctors might use anesthesia to put you to sleep for the procedure.

●The doctor will put a thin, flexible tube, or "scope," into your anus (figure 2). The tube has a camera and light on the end. They will gently move the tube up into your rectum and colon.

●The doctor will use the camera to look at the inside lining of your whole colon.

●The doctor might do a test called a biopsy. For a biopsy, they take a small piece of tissue from your colon or the last part of your small intestine. Then, they look at the tissue under a microscope to check for cancer or inflammation.

●The doctor might also remove any polyps (growths) that they see in your colon.

●You will not feel it if the doctor takes a biopsy or removes a growth.

What happens after a colonoscopy? — After your procedure, you will be taken to a recovery room. The staff will watch you closely as your anesthesia wears off.

As you recover:

●You might feel groggy or confused for a short time.

●Most people can eat as usual.

●Your doctor will probably recommend that you do not drive or go to work for the rest of the day.

●Your doctor will tell you when to start taking any medicines that you had to stop before the test.

What are the risks of colonoscopy? — Your doctor will talk to you about all of the possible risks, and answer your questions. Possible risks include:

●Bleeding after removing polyps

●Injury or tearing of the lining of the colon – If severe, this could require surgery or blood transfusions.

●Infection

When should I call the doctor? — Call your doctor or nurse right away if you have any of the following problems after your colonoscopy:

●Belly pain that is much worse than gas pain or cramps

●Bloated and hard belly

●Vomiting

●Fever

●A lot of bleeding from your anus

More on this topic

Patient education: Colon and rectal cancer screening (The Basics)
Patient education: Colon polyps (The Basics)
Patient education: Cancer screening (The Basics)
Patient education: Bloody stools in adults (The Basics)
Patient education: Gas and bloating (The Basics)
Patient education: Stomach ache and stomach upset (The Basics)
Patient education: Anemia caused by low iron (The Basics)
Patient education: Colon and rectal cancer (The Basics)
Patient education: Clear liquid diet (The Basics)
Patient education: Full liquid diet (The Basics)
Patient education: Diverticulosis (The Basics)
Patient education: Gastrointestinal tract perforation (The Basics)
Patient education: Colitis (The Basics)
Patient education: Endoscopic ultrasound (The Basics)

Patient education: Colonoscopy (Beyond the Basics)
Patient education: Screening for colorectal cancer (Beyond the Basics)
Patient education: Colon polyps (Beyond the Basics)