Endoscopy – colonoscopy

  • A colonoscopy (coal-on-osk-o-pee) is a procedure during which a gastroenterologist (doctor specialising in the digestive system) looks at the inside of the large bowel (colon). This is done with a colonoscope – a long, flexible tube that has a light and a camera on the end. A gastroscopy is often done at the same time as a colonoscopy. For more information, see our fact sheet Endoscopy – gastroscopy and capsule endoscopy.

    The colonoscope is inserted into the anus (bottom) and then slowly pushed in along the large bowel. These areas are examined and biopsies (small samples) of bowel tissue may be taken.

    Why does my child need a colonoscopy?

    The main reasons children need a colonoscopy are to find a cause for abdominal (stomach) pain, diarrhoea or bleeding from the bowel. If a polyp (an overgrowth of tissue, shaped a bit like a mushroom) is found, a polypectomy (removal) may be done at the same time as the colonoscopy. This involves the removal of the polyp from the inside wall of the bowel, using special tools at the end of the colonoscope.

    Preparing for a colonoscopy

    Special preparation is necessary before a colonoscopy, as your child's bowel needs to be completely empty in order for the procedure to be successful. This can usually be done at home.

    To ensure your child's bowel is completely empty, follow these directions:

    One week before

    • Stop giving your child medicines that have iron in them.
    • Most other medicines can be taken as usual, up until the day of the colonoscopy. Talk to your child's doctor about this before the colonoscopy is scheduled.

    Four days before

    • Stop your child eating foods that have small seeds or pips, such as wholegrain bread, tomato, cucumber or nuts.

    The day before

    • All food and milk must be finished at the time written in your appointment letter.
    • Give your child clear drinks only from the time stated in your appointment letter.

    Clear fluids are drinks you can easily see through, including:

    • water
    • clear (not cloudy) apple juice
    • lemonade
    • cordial
    • jelly (not red or green)
    • lemonade icy poles
    • weak black tea or coffee
    • oral rehydration solutions
    • clear sports drinks.

    Clear fluids do not include fresh fruit juice and milk.

    Contact the hospital if your child is unwell before the colonoscopy (e.g. if they have an infection or a bad cold), or if you have any questions about preparing for the procedure.

    Bowel washout

    Most children need to have a special drink (called a bowel washout or bowel prep) the evening before, and sometimes the morning of, a colonoscopy. The bowel washout empties the bowel, helping the doctor to see through the colonoscope more clearly.

    • Children who have their bowel washout at home should have extra clear drinks beforehand, to avoid becoming dehydrated.
    • The full amount of the bowel washout must be taken for the colonoscopy to be successful.
    • If your child cannot take the bowel washout by mouth, they may need to stay in hospital the night before the colonoscopy so that the bowel washout can be given through a nasogastric tube. A nasogastric tube is a small, thin tube that is inserted through the nose and then passed down into the stomach. The bowel washout is then given through this tube over four to six hours.
    • Your child will have diarrhoea for several hours, so avoid leaving the house during this time. Place extra towels on their bed as accidents may happen overnight.

    What to expect on the day of the colonoscopy

    Your child can continue to have clear drinks only until admission time.

    • All children having a colonoscopy are given a light, general anaesthetic to put them to sleep. This involves medicine being given through a drip into a vein (intravenous or IV therapy).
    • The procedure usually takes around 20 to 30 minutes, but may take longer depending on the doctor's findings.
    • After the colonoscopy, your child will be taken to a recovery bed and you will be able to join them when they wake up.

    Care at home

    Children can usually go home on the same day as the colonoscopy.

    • Your child should rest for the remainder of the day, and should be able to return to their normal activities the next day.
    • Your child can start to eat a light diet such as jelly, soup, pasta and sandwiches as soon as they feel ready. They may return to their usual diet when they feel well enough.
    • Babies can start breastfeeding, or drinking formula or water, when they are awake.
    • Because of the anaesthetic, young adults and adolescents must not drive a car, operate machinery or make important decisions for the rest of the day.

    Your child may have one or more of the following side effects after the colonoscopy. These usually get better without any special treatment.

    • Nausea or vomiting: If your child feels sick, stop them from eating and drinking for half an hour. After this, they can start having sips of clear fluids. You can then increase what they eat and drink slowly.
    • Abdominal pain and bloating: If the pain is mild, rest and have sips of clear fluids until feeling better.
    • Sore throat: Sucking throat lozenges or sipping warm fluids can help.
    • Bleeding: A small amount of blood might be seen in bowel actions (poo). This is usually caused by the biopsies that were taken.

    When to seek medical assistance

    Call the hospital if your child has:

    • vomited more than three times
    • a vomit or bowel action with more than 2–3 mL (half a teaspoon) of bright red blood in it
    • severe tummy pain or bloating
    • a high temperature (above 38ºC)
    • difficulty swallowing.

    Key points to remember

    • The full amount of bowel washout preparation must be taken, as your child's bowel needs to be completely empty for a colonoscopy. 
    • Your child can usually go home the same day.
    • Contact the hospital if your child is unwell after the colonoscopy.

    For more information

    Common questions our doctors are asked

    What are the risks of the colonoscopy procedure?

    A colonoscopy is a very safe procedure; however, your child's doctors (gastroenterologist and anaesthetist) will discuss any possible unexpected outcomes with you when taking consent for the procedures. Make sure you ask any questions you have when you are speaking to the doctors and nurses before the colonoscopy.

    Do all children need a general anaesthetic?

    Although not painful, a colonoscopy is very uncomfortable and children would not tolerate it if they were fully awake. For this reason, a light general anaesthetic is used to keep your child still, comfortable and pain-free during the procedure.

    Developed by The Royal Children's Hospital Gastroenterology, Day Surgery and Anaesthesia and Pain Management departments. We acknowledge the input of RCH consumers and carers. 

    Reviewed May 2018.

    This information is awaiting routine review. Please always seek the most recent advice from a registered and practising clinician.

    Kids Health Info is supported by The Royal Children’s Hospital Foundation. To donate, visit  www.rchfoundation.org.au.


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