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What is a colonoscopy?

A colonoscopy is a procedure when a doctor inserts a flexible tube with a lens and a light source, to look at the lining of the lower part of the gastrointestinal (GI) tract. The lower part of the GI tract is called the colon or large intestine. A colonoscopy takes approximately 40-60 minutes.

Why would my child need a colonoscopy?

A colonoscopy is used to look for inflammation (redness, irritation), bleeding, ulcers, and polyps.  It also allows the doctor to perform procedures such as biopsy (tissue sampling) and polypectomy (removing polyps).

Bowel preparation

A good bowel preparation is important for colonoscopy. Good preparation allows a good view of the entire colon and also reduces risks of procedure complications. Passing clear watery stool is a sign of good bowel preparation. It is also important that your child has plenty of additional clear fluid along with the bowel preparation. A specific bowel preparation instruction will be prescribed for your child. If your child has difficulty with bowel preparation at home, please discuss this with your doctor in advance as there are alternatives such as delivery through a nasogastric tube.

How is it done?

  • Your child will need to be asleep for the procedure. This means s/he will need a general anaesthetic. The anaesthetists will review your child before the procedure to make sure s/he is well enough for such a procedure, and will explain anaesthetics procedures to you. You will be informed about your child’s fasting (not eating or drinking) time before the procedure.

  • The colonoscopy procedure normally takes between 30-60 minutes.
  • The colonoscope will be passed through the rectum, gradually advanced into the colon – sigmoid, descending, transverse, and ascending colon and caecum. It will also be advanced then to the end of the small bowel called terminal ileum.
  • During the procedure, the doctor will gently pump air and sterile water through the scope into the colon to inflate it. This will give the doctor a better view of the colon.
  • Pictures will be taken with examination of each part of the colon.
  • In most cases, tissue samples called biopsies are needed, and are taken with small forceps. This is not painful and should not cause pain afterwards. 
  • Additional procedure such as removal of polyps may be performed. Your doctor will speak to you in detail both before and after the procedure.

Potential complications and risks

  • Aspiration (inhaling) of food or fluids in the lungs. This is usually minimised by adequate fasting before procedure.
  • Reaction to sedative medications.
  • Bleeding can occur from biopsies or polypectomy. It is usually minimal and stops quickly on its own or can be easily controlled. If your child or any family member has a known bleeding or haematological disorder, please discuss it with your doctor.
  • The endoscopy can cause a tear or hole in the area being examined. This is a serious complication but fortunately extremely rare. If it occurs, a surgeon will be consulted to manage it.
  • Bacterial infection may occur, which results in fever and abdominal pain. This is usually managed with intravenous antibiotics. Infection risk is low.

What happens after the colonoscopy?

  • Your child can usually go home on the same day once sedation wears off.
  • Your doctor will give you a written report and explain the findings.
  • If biopsies are taken or polyps are removed, further histopathology (microscopic) results will usually be available within one week.
  • The most common discomfort after procedure is bloating as result of air introduced during the examination. It usually settles down quickly.
  • There may be small amount of bleeding from biopsies.

When to contact the doctor after a colonoscopy

The following signs and symptoms should be reported immediately, and your child should be taken to the nearest hospital for assessment:

  • Severe abdominal pain (more than gas cramps)
  • A firm, distended abdomen
  • Vomiting, especially vomiting of green/bilious content
  • Fever
  • Large amount of rectal bleeding


  • Colonoscopy is an invasive investigation.
  • Complications may occur.
  • Contact the on call Gastroenterology staff if you have concerns.
  • The procedure may be cancelled if:

-          bowel preparation is inadequate,

-          fasting time is inadequate,

-          your child is unwell.

The Children's Hospital at Westmead
Sydney Children's Hospital, Randwick
Hunter New England Kids Health

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