Anorectal Manometry

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Important! This exam requires that you have an empty stomach. You should not consume any food for or fluids (including clear liquids and water) 4 hrs before the exam (minimal sips are allowed only to take your usual medications). Avoid gum and hard candy. 

What is an anorectal manometry test?

Anorectal manometry is a test to evaluate your anal and rectal muscles. These muscles work together with your brain to control your bowel movements. If you’ve been having difficulties with bowel movements, it could be related to how these muscles function. Anorectal manometry is a way of measuring your muscle strength and tone to determine if they’re activating and coordinating correctly.

Why would you need an anorectal manometry test​?

Your Huron Gastro provider might recommend an anorectal manometry test if you've been having trouble having a bowel movement when and where you want to. It’s one step in the process of evaluating symptoms like:

Your Huron Gastro provider may also use the test to evaluate your muscle function after an injury or surgery, or to check whether a chronic disease has begun to affect your anorectal motility (motor function).

Test Details

How does anorectal manometry work?

A manometer is a pressure transducer. It measures the pressure in your muscle contractions to determine whether they’re too strong, too weak or not triggering at the right time. Our trained Nurse places the transducer inside your anus and rectum. It sends data to a machine that reads it.
The transducer is a long, flexible tube (catheter) with pressure sensors on it. On the inside end, it’s attached to a deflated balloon. When the Nurse inflates the balloon inside your rectum, it activates the nerves that trigger the urge to defecate. This should stimulate your natural muscle reflexes.

What supplies do I need and how do I prepare for an anorectal manometry?

  1. You will purchase 2 Fleet Enemas ahead of your testing date. These can be found at any pharmacy.
  2. 3 hours before you leave home to come to HG for the test, you will use one enema per box instructions.
  3. 1 hour before you leave home to come to HG for the test, you will use the 2nd enema.
  4. We will ask you to not eat any food or drinks for 4 hours before your test.

What happens during the anorectal manometry procedure?

  1. When you arrive for the test, the entire test process will be explained to you. Then you will undress from the waist down and be covered by a drape or change into a gown. You’ll lie on a table on your left side with your knees up.
  2. The Nurse will perform a brief digital rectal exam before inserting the catheter. That means inserting a gloved finger to check for anything abnormal in your anus or rectum. The catheter that is used for the test is a small tube with a small balloon at one end and several connecting cords at the other end. These cords are attached to the unit that records the measurements the Nurse is taking.
  3. They’ll lubricate the end of the catheter to help it go in smoothly, then gently advance it through your anus into your rectum.
  4. They’ll take pressure readings at different depths inside your rectum to establish your baseline internal pressure. Then, they’ll inflate the balloon.
  5. The Nurse will take pressure readings with the balloon inflated to different sizes and in different positions inside your rectum. They’ll ask if you can feel these changes or if you feel the urge to have a bowel movement.
  6. They’ll ask you to squeeze, relax, push and cough at different intervals. The software unit will record your voluntary and involuntary muscle responses.
  7. The last test is the balloon expulsion test. You will be asked to expel the balloon into a commode toilet in the testing room. Keep in mind that the balloon is still attached to the measuring devices, but the staff will help you navigate this process. Staff will step out for privacy.

How long does anorectal manometry take?

It takes an average of 30 to 45 minutes. 

Informed Consent for the test

Before the test starts, a member of our team will review the process with you and ask you to sign an informed consent form which indicates that you understand the testing process, and its benefits and risks.

Is anorectal manometry painful?

You might find it mildly uncomfortable, particularly if you’re sore inside your rectum or anus, but it shouldn’t be painful. The catheter and the balloon only produce as much pressure as a normal bowel movement would.

Are there risks or side effects to anorectal manometry?

There aren’t any significant risks or side effects to this test. If your anus or rectum was inflamed or irritated, you might feel a little soreness or have mild bleeding afterward.

What will the results of my anorectal manometry show?

The results will show whether the muscles and nerves involved in bowel movements are functioning correctly, and where the problem is if they aren’t. Normal results will show:

  • Stool entering your rectum causes it to relax and stretch to accommodate it (rectal compliance).
  • Stretch receptors (nerves) in the wall of your rectum trigger the urge to have a bowel movement (rectal sensation).
  • Your internal anal sphincter automatically relaxes in response (rectoanal inhibitory reflex).
  • Your external anal sphincter contracts when your internal one relaxes to hold on to your stool until you’re ready (rectoanal contractile reflex). It tightens if you cough (cough reflex).
  • Your external anal sphincter responds to your voluntary commands to squeeze, relax or push.
  • Attempting to have a bowel movement increases pressure in your rectum while causing your external anal sphincter to relax to allow stool to pass (coordinated anorectal pressure changes).

If any of these functions don’t work as they should, you might have an abnormal test result. Abnormal results might show:

  • Stool in your rectum doesn’t trigger the urge to defecate. Your rectum doesn’t stretch enough, or the stretch receptors aren’t transmitting signals to your brain.
  • You feel the urge to have a bowel movement, but your automatic muscle reflexes aren’t responding.
  • Your muscles respond incorrectly. For example, they tighten when they should relax or relax when they should tighten.
  • Your muscles do the right thing but at the wrong time, or they aren’t coordinating together.
  • Your muscle contractions are weak and ineffective.
  • Your muscles are too tight, even when they try to relax.

Next Steps:

Your HG Provider will read the results of your test. A Care Team Registered Nurse will call you with the results and the Provider’s recommendations. A letter will also be sent to you via email or portal.

Can anorectal manometry lead to effective diagnosis and treatment?

Yes. Once your Huron Gastro provider determines if any muscles are malfunctioning and how, they can employ different techniques to help retrain the muscles. Typical therapies include:

 

Please feel free to ask any questions on the day of your test or before your test by calling 734-318-1457.