Anorectal Manometry

What is an anorectal manometry test?

Anorectal manometry (often called “ARM”) is a test to gather information about your child’s condition. It is not a treatment or intervention.

This test studies the nerves and muscles of the anus and rectum by measuring pressure and sensation. This is done with a small tube (catheter) and balloon attached to a computer that records the information.

Why might a child need an anorectal manometry?

Anorectal manometry tests whether children have normal sensation and are using their muscles correctly to hold and pass stool. The test may be used to help understand why your child is having symptoms, such as constipation, fecal incontinence (inability to stop stool from leaking), and abnormalities of the anus or pelvic floor muscles. It may also be done before or after certain surgeries to check the function of the anus and rectum. It also helps diagnose a condition that causes blockage in the large intestine called Hirschsprung’s.

What happens before the anorectal manometry test?

Your doctor will provide specific instructions before the test. Usually an enema is given at home on the day of the test to help clean out stool from the rectum. Your child may also be given instructions about when to stop eating and drinking before the test.

The test should not cause pain. However, it is normal for your child to feel anxious about the test. It is helpful to talk to your healthcare professional about this ahead of time. Child Life Specialists may be available, depending on the institution, to make your child feel more comfortable. Sometimes a small amount of medication is given by the doctor to ease anxiety during the procedure.

How is anorectal manometry performed?

Your child will lie on his or her side while the doctor places a small, flexible tube (catheter) into the rectum. One end of the catheter will have a small, deflated balloon and the other end will be attached to a special computer. Once the balloon is inflated, the computer will record information about pressure and sensation in your child’s rectum.

Your child may be asked to squeeze, cough, and/or try to push the balloon out of the rectum. After the measurements have been taken, the tube is slowly removed. The test may take 15 to 45 minutes to complete.

What happens after the anorectal manometry test?

Most children can return home and resume their daily activities immediately after the test. If sedation (anesthesia) is used, your child may feel sleepy for a few hours after the test. You may receive the results of the test immediately afterwards, or your doctor may review the results and contact you within a few days.

What are the risks of anorectal manometry?

Anorectal manometry is considered a very safe test. Rarely, the equipment can fail or there may be bleeding from the rectum due to irritation from the balloon or catheter. If sedation is used during the test, your child might be very sleepy and, in rare cases, may have a reaction to the medication.

The balloon used for the test usually contains latex. If your child has a latex allergy, please discuss this with your doctor.

What should we watch for after the test and when should we seek medical advice?

In most cases, your child will feel normal after the test. Some children might experience discomfort when passing stool or have bleeding from the rectum. Contact your doctor if your child has persistent pain, passes more than a small amount of blood from the rectum or is experiencing any other unusual symptoms after the procedure.

IMPORTANT REMINDER: This information from the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) is intended only to provide general information and not as a definitive basis for diagnosis or treatment in any particular case. It is very important that you consult your doctor about your specific condition.

Revised April 2019

North American Society for Pediatric Gastroenterology, Hepatology and Nutrition
The Association of Pediatric Gastroenterology and Nutrition Nurses
North American Society for Pediatric Gastroenterology, Hepatology and Nutrition Foundation
The NASPGHAN Council For Pediatric Nutrition Professionals
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