What is a colonoscopy?

A colonoscopy is a useful procedure to help doctors diagnose and prevent problems in your lower intestine. And you are not alone; hundreds of thousands of Canadians have colonoscopies every year.

During a colonoscopy, a flexible tube called a colonoscope is carefully fed through your rectum and into your colon. This special scope is rigged with a light and video camera, allowing the doctor to take a good look at your insides. It may sound a little overwhelming, but rest assured that your doctor will make every effort to make it easy on you.

Why do I have to have one?
Your doctor may recommend this test if you have any of these unexplained symptoms:

  • abdominal pain
  • chronic diarrhea
  • bloody bowel movements
  • iron-deficiency anemia
  • a change in bowel habits

A colonoscopy can help with a diagnosis by ruling out various gastrointestinal conditions or confirming others.

Studies show many people just aren't having their insides examined often enough. Yet if your colon is checked over, it can actually reduce your risk of death from colorectal cancer.

A screening tool for colorectal cancer
Importantly, a colonoscopy is also considered the gold standard when it comes to screening for colorectal cancer. When your doctor takes a close look inside your colon, it's an opportunity to check out any abnormal-looking tissue, like tumours or polyps. Polyps are small growths that can sometimes develop into cancer.

Did you know that colorectal cancer (cancer that grows in the colon or rectum) is the third most common cancer in Canada? It's also the second leading cause of death from cancer. Every year, about 23,000 Canadians are diagnosed with colorectal cancer.

People at greater risk include those with a family history of colorectal cancer, or those with polyps (small growths on the colon and rectum) or inflammatory bowel disease. Smoking, being obese, and eating a diet high in red meat, high in fat, or low in fibre are all factors that increase your risk.

This cancer usually affects people over the age of 50. If you're in a high-risk group for colorectal cancer, ask your doctor how often you should have a colonoscopy. If you're in an average-risk group and have no troublesome symptoms, once you hit that half-century mark, ask your doctor if you should get a colonoscopy. Your doctor will advise you on how often you will need to have a colonoscopy.

Preparing for your colonoscopy

Well before the appointed date, your doctor will give you instructions on how to prepare yourself for your colonoscopy. You may need to start doing your homework a few days before your exam.

The main goal of all this groundwork is to make sure you'll present your doctor with a properly cleansed colon. Otherwise, the colonoscopy may end up taking longer, and it will certainly be more difficult for your doctor to take a look around and give you accurate results.

Tasks to take care of
You can expect to be given several guidelines by your doctor before your colonoscopy. It's important that you follow them carefully. Here are a few examples of what your doctor may instruct you to do:

  • You may be asked to avoid solid food for one to three days, dining on nothing more than clear liquids (broth, tea, coffee, and clear juice). Avoid alcoholic drinks as you prepare for your colonoscopy.
  • You may be told to drink plenty of water. This is extremely important. Water will keep your body hydrated as your bowel empties.
  • You may need to stop certain medications or vitamins, sometimes as early as a week before the procedure. Make sure you discuss what you're taking with your doctor.
  • You may also be advised not to take anything at all by mouth for a few hours before your appointment.

Clearing out your colon
The housekeeping isn't finished yet. A critical task will be to thoroughly sweep out your system with a bowel-cleansing product, usually based on either sodium phosphate or polyethylene glycol (PEG). Each works in a different way. Sodium phosphate helps your bowels absorb water and flush themselves out. PEG is a non-absorbable electrolyte solution that helps move your colon contents along to be evacuated.

Whatever the product, get ready to guzzle. When taking a sodium phosphate product, you must be sure to keep drinking lots of fluids to make up for all the water that's leaving your body. When taking a PEG product, it's important to drink the full volume required, 4 litres (a gallon) in total, so it can work to its full potential. Both sodium phosphate products and PEG preparations are effective and are known to be relatively safe when used as directed.

To keep things simple, we have described two common types of bowel cleansing products. Your doctor may instruct you to use other bowel cleansing products not listed here.

As the bowel cleansing product goes to work, you can expect to have lots of loose stool or diarrhea. Make plans to be home while you prepare for your procedure, because you'll likely find yourself bolting for the bathroom fairly frequently.

What will happen during the colonoscopy?

It's normal to be a bit nervous before a new procedure, even a routine one. But believe it or not, a colonoscopy is not as bad as you might think.

The entire procedure usually takes 20 to 60 minutes, but time will seem to pass quickly. That's because the doctor will sedate you and give you pain medication to help you relax. The medications are given to you through an intravenous, or IV, line in your arm. You'll soon begin to feel drowsy, and you may not even remember much of the procedure later.

The colonoscope will gently be inserted and passed through your rectum and colon. You might feel the urge to go to the bathroom at the beginning. Try to take deep breaths and allow the tension to leave your body. This will make it easier for the doctor to advance the scope.

Air is blown out of the scope to inflate the bowel and clear the way in front, so you may also experience a bit of cramping or a feeling of fullness. While the test is going on, an image of the inside of your rectum and colon is transmitted to a monitor. Your doctor looks for irritated patches of skin, signs of damage to the colon or polyps. If any of these are visible, your doctor may take tissue samples or remove the polyps. This process is usually completely painless.

All finished! Thanks to the sedation you've been given, the entire colonoscopy may seem to be over in the blink of an eye.

What happens after the colonoscopy?

Now is the time to take it easy. The most challenging part of the procedure is over and done with. Still, there are a few things to know about as you get back on your feet.

Right after the procedure
Immediately after your colonoscopy you'll still feel sleepy. You'll be taken to a recovery area and given time to rest and regain your senses as the sedative begins to wear off, which can take one or two hours. You may be feeling crampy or gassy as a result of the air that was used during the procedure.

You'll also receive instructions about aftercare. You'll be told when you can eat and drink normally, which is often immediately but may depend on whether or not you did have any polyps removed. You might be asked to refrain from taking certain medications for a short time afterwards. You will also be told when you can expect the results of any biopsies that are done.

After you're home
Since the sedative may linger in your system for 24 hours, you shouldn't drive or operate machinery during that time. Make sure a family member or friend is with you to take you home. Then give yourself permission to lay low for the rest of the day.

Keep drinking lots of liquids to replace what you've lost, but do continue to avoid alcohol. Any leftover cramping or bloating should not be extreme and should disappear within a day.

Serious complications from colonoscopies are very rare, affecting fewer than 1 in 1,000 cases. Red flags to watch for are fever, severe stomach pain, significant amounts of blood in your stool, and weakness or dizziness. Call your doctor or head for an emergency room right away if you have any of these symptoms.

Colonoscopy is a valuable tool to help detect colon problems – it can even help reduce your risk of death from colorectal cancer. That's why it's so important to have regular colonoscopies as recommended by your doctor.