Patient education: Colonoscopy (The Basics)

What is a colonoscopy? — 

This is a test that lets the doctor look at the inner lining of the large intestine (figure 1). The large intestine is also called the colon.

People usually have a colonoscopy 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. This 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

●Anemia, which is a condition that can make you feel tired and weak

●Long-term belly or rectal pain you cannot explain

●Abnormal results from a different type of colon test

●A history of colon cancer or colon polyps

How do I prepare for a colonoscopy? — 

Your doctor will give you instructions about what to do.

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. 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. 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 1). The tube has a camera and light on the end. They will gently move the tube up into your rectum and colon.

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

●They might do a test called a biopsy. This involves taking 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.

●They might also remove polyps (growths) from your colon.

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

What happens after a colonoscopy? — 

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 procedure.

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

What else should I know? — 

Before you go home, make sure that you know what problems to look out for and when you should call the doctor. Make sure that you understand your doctor's or nurse's instructions. Ask questions about anything you do not understand.

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