Manometry is a way of measuring how well the muscles and nerves in the digestive system are working. Anorectal manometry looks at the muscles and nerves in the rectum and anus (bottom). This page from Great Ormond Street Hospital (GOSH) explains about the anorectal manometry test and what to expect when your child has one.The digestive system is a hollow tube from the mouth to the anus. The walls of the tube contain muscles and nerves that squeeze food rhythmically through the system – this action is called peristalsis. If the muscles and/or nerves are not working properly, food cannot pass through the digestive system.
What happens before the test?
You will already have received information about how to prepare your child for the test in your admission letter.
The person bringing your child to the test should have ‘Parental Responsibility’ for them. Parental Responsibility refers to the individual who has legal rights, responsibilities, duties, power and authority to make decisions for a child. If the person bringing your child does not have Parental Responsibility, we may have to cancel the test.
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 medicines your child is currently taking and show these to the doctor.
If your child normally takes any laxative medications please continue to give these in the lead up to the test.
This investigation is done while your child is awake. This means that your child can continue to eat and drink up until the test. You will be able to stay with your child the entire time.
It is a good idea to bring something your child likes to distract them for parts of the test, like a tablet or phone, as your child will need to stay quite still for most of the test.
On the morning of the test, your child will be given an enema – a liquid medicine will be flushed into their bottom and rectum so that it is empty of faeces (poo) for the test. If your child normally uses a trans anal irrigation system such as Peristeen®, please bring the equipment with you to hospital, as it can be used as an alternative to an enema, which your child may prefer.
If your child is having other tests in the same week that require the large bowel to be empty your child may not require an enema as they will have had bowel preparation already.
What does the test involve?
You and your child will be taken to the Gastroenterology Investigation Suite where the test is done. A nurse will stay with your child throughout.
The doctor will insert a catheter (flexible plastic tube) into your child’s bottom, the other end is attached to a machine which measures how well the muscles and nerves are working. The catheter contains lots of sensors that can record nerve and muscle reactions.
The end of the catheter is then inflated gradually, which mimics poo in the rectum. The machine will record the reaction of the nerves and muscles in your child’s rectum and anus when this happens. We will ask your child to tell us when they can feel like they need to poo.
Your child will be asked to do things like cough, squeeze their bottom and push like they are trying to do a poo.
At the end of the test your child will be asked to try to push the catheter out by themselves as if trying to do a poo. If they cannot fully push it out by themselves (many children can’t) the doctor will remove the catheter.
Are there any risks?
There is a very small risk that the catheter could damage your child’s anus and rectum. However, this is very unlikely as the catheter is flexible and the doctors and nurses who do the test are very experienced.
What happens afterwards?
After the test, the doctor will remove the catheter so that your child can return to the ward.
Your child will be able to go straight home after the test unless they have any other tests or appointments planned.
When you are at home
Your child can continue with their usual activities after the test.
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. 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.