An MCU is an x-ray test of the bladder as it fills and empties. It checks to see if the urine is flowing backwards from the bladder up towards the kidneys.
Your baby or child is having a micturating cysto-urethrogram (MCU) to find out if they have urinary reflux (backflow of urine from the bladder to the kidneys).
Check some diagrams showing the different grades of urinary reflux [1]
See this KidsHealth page to find out more about urinary reflux [2]
If your child is a boy, they may also have an MCU to check for an obstruction of the urethra.
The urinary tract is the kidneys, ureters, bladder, and urethra.
The kidneys filter and remove waste and water from the blood to produce urine. The urine travels from the kidneys down 2 narrow tubes called the ureters. The urine is then stored in the bladder.
When your child does a wee, urine flows out of the body through the urethra, a tube at the bottom of the bladder. The opening of the urethra is at the end of the penis in boys and in front of the vagina in girls.
Front and side view of the female urinary tract
Front and side view of the male urinary tract
The test will take place in the radiology department of your hospital, or at another radiology centre.
Some radiology departments may recommend antibiotics around the time of the test to prevent urinary infection. You will get instructions about this from your radiology department, or from the doctor who referred your child for the test.
Your radiology centre might give medicine to make your child sleepy. If healthcare staff do offer this medicine to your child, they will give you instructions about when your child needs to stop eating and drinking before the test.
Some radiology centres will give a medicine to make your child sleepy before the procedure. Or, they might use a medicine your child breathes (nitrous oxide) during the procedure.
Putting in the catheter can be uncomfortable, more so for boys because of their longer urethra. The doctor or nurse will use a lubricating gel to make it easier to put the catheter in. In older boys, local anaesthetic jelly can make the procedure easier.
Although having the catheter put in is uncomfortable, the x-ray is painless. Children do find having a full bladder uncomfortable, but this goes away when they empty their bladder.
Many medical procedures or tests can be frightening for children. To help your child feel more comfortable or reassured you can try the following.
A dummy (pacifier) for babies (if they normally suck on one) can be very soothing.
It is also helpful to bring something that will catch your child's interest and help them to focus on something else during the procedure. This could be a book that has an element of surprise or requires your child's concentration such as:
See some other suggestions for helping your child manage their treatment or procedure [3]
Many hospitals have play specialists. Their job it is to help explain these tests to your child. Play specialists use play to show your child what is going to happen and ways to help them cope.
If your child is old enough, ask if your hospital's x-ray or children's department has a video explaining MCUs. It may help your child to watch this. Your local branch of Kidney Kids may also be able to help with this.
You will be able to stay with your child for the test. Your presence can help reassure your child.
Pregnant mothers cannot stay during the test, and in this case fathers or someone else familiar to your child can be there.
There are usually no side effects from this test. Some children feel a mild burning while weeing for a short time afterwards (sometimes a day or two). Encourage your child to drink plenty of fluids and this will pass quickly.
In rare cases, children can have difficulty emptying their bladder. If your child has this problem, get them to wee while sitting in a warm bath.
Very rarely, your child may develop a UTI after an MCU.
Check the information about UTIs [4]
The x-ray doctor (radiologist) will examine and interpret the x-ray films and send a written report to your doctor. This usually takes several days. Sometimes the radiologist will be able to discuss the results with you at the time of the examination.
Urinary tract anatomy illustrations and urinary reflux illustration by Dr Greta File. Property of KidsHealth.
This page last reviewed 31 October 2021.
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Links
[1] https://kidshealth.org.nz/urinary-reflux-diagrams
[2] https://kidshealth.org.nz/urinary-reflux
[3] https://kidshealth.org.nz/helping-your-child-manage-their-treatment
[4] https://kidshealth.org.nz/urinary-tract-infection
[5] https://kidshealth.org.nz/tags/x-rays-scans
[6] https://kidshealth.org.nz/node/1663?language=zh-hant
[7] https://kidshealth.org.nz/node/1853?language=zh-hant
[8] https://kidshealth.org.nz/contact?from=http%3A%2F%2Fkidshealth.org.nz%2Fprint%2F251%3Flanguage%3Dzh-hant