Colonic manometry

Colonic manometry is a test to measure how well the muscles and nerves in the colon (large intestine) work. These muscles squeeze rhythmically to push faeces (poo) through to the rectum and out of the body.

Diagram showing gastrointestinal tract
Diagram showing gastrointestinal tract

Why is this test needed?

Your child needs this test so that the doctors can check how well the muscles and nerves in their digestive system are working to push out poo.

What happens before the test?

You will need to come to the ward two days before the test so that your child can have some special medicine to clear their large intestine. Following a discussion with the pre-admission nurse a plan to either increase medications at home or to admit to hospital for longer will be made. If your child has severe constipation, they may need to take bowel cleansing medicine for a few days before the test. Your child will need to follow a special diet during the days that the medicine is being taken. A diet sheet will be provided.

The doctors will explain about the test in more detail, discuss any worries you may have and ask you to sign a consent form giving permission for your child to have the test. If your child has any medical problems, particularly allergies, please tell the doctors about these. Please also bring in any medications your child is currently taking. Your child will also need to have a cannula (thin plastic tube) inserted into a vein.

What does the test involve?

You and your child will be taken to the Gastroenterology Investigation Suite where the test will take place. A nurse will stay with your child throughout. While your child is under general anaesthetic, the doctor will carry out a colonoscopy – that is, they will use an endoscope (a tube with a light on the end) to insert a catheter (flexible, plastic tube) into your child’s large intestine via their bottom. Once the catheter is in the correct place, the end outside your child is taped to your child’s buttock to keep it in place. For more information about the colonoscopy, please see our leaflet.

When your child has fully recovered from the anaesthetic, this end of the catheter is attached to a machine which measures how well the muscles and nerves are working. During the test an x-ray will be taken of your child’s tummy to confirm the position of the catheter and a medicine will be put into the catheter to test how the colon contracts. The test could take up to five hours but your child will be able to watch DVDs or read during the test.

What happens afterwards?

After the test, the doctor or nurse will remove the catheter from your child’s bottom and your child will come back to the ward. Once your child has eaten something and have passed urine, and as long as no other tests are planned and there are no complications, the cannula will be removed from their vein and they will be able to go home.

Are there any risks of the test or side-effects of the medicines used?

There is a very small risk that the catheter could damage your child’s rectum and large intestine. However, this is very unlikely as the catheter is flexible and the doctors and nurses who do the test are very experienced.

When your child has a general anaesthetic, they may feel dizzy or sick afterwards. This usually passes quickly but can last for a few days. Keep a close watch on your child until you feel happy that they are fully recovered, and do not leave them alone.

Contact the staff on the Gastroenterology Investigation Suite or take your child to your local Accident and Emergency (A+E) department if you are worried.

How long will it take to get the results?

Your child’s test results will be given to you at your next outpatient appointment at the hospital. The analysis of this test is complicated so may take some time to get the results. However if there is a need to start on new treatment before the appointment, the hospital will contact both you and your family doctor (GP) with details.

When you go home, you should call the ward or your GP if your child:

  • becomes generally unwell

  • refuses to eat or drink

  • is sick

  • is unusually sleepy or it is difficult to wake them up

Compiled by: 
The Gastroenterology Investigation Suite staff in collaboration with the Child and Family Information Group.
Last review date: 
May 2013


Please note this is a generic GOSH information sheet. If you have specific questions about how this relates to your child, please ask your doctor. Please note this information may not necessarily reflect treatment at other hospitals.