Anorectal Manometry: Solving Bowel Mysteries

I often see folks in my clinic who are, well, frustrated. They’re dealing with ongoing trouble with their bowel movements – maybe it’s a real strain to go (what we sometimes call dyschezia), or they feel like things just aren’t emptying out (obstructed defecation). Perhaps it’s the opposite, and they’re struggling to hold things in (fecal incontinence), or they’re dealing with persistent chronic constipation. It’s a sensitive topic, I know, but it’s so common. When these kinds of issues persist, one of the things we might talk about is a test called anorectal manometry.

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What Exactly is Anorectal Manometry?

It sounds a bit technical, I know, but bear with me. Simply put, anorectal manometry is a special test that helps us understand how the muscles in your rectum and anus are working. Think of these muscles as a team that needs to coordinate perfectly with your brain to manage bowel movements. If that coordination is off, problems can arise. This test measures the pressure and strength of your muscle contractions, so we can see if they’re firing up correctly and at the right times.

Why Might We Suggest This Test?

If you’re having persistent trouble with pooping – when you want to, where you want to, or how it feels – this test can give us valuable clues. We might recommend it to get to the bottom of symptoms like:

Pain or significant straining when you try to have a bowel movement.
That frustrating feeling like your poop just can’t come out, even when you need to go.
Long-term constipation, with hard, infrequent stools.
Difficulty controlling your bowels, leading to accidental leakage.

Sometimes, we also use anorectal manometry to check muscle function after an injury or surgery in that area. Or, if someone has a chronic condition, we might use it to see if it’s started to affect how these muscles work – what we call anorectal motility.

This test can help us diagnose specific conditions that might be causing your constipation, like Anismus (or dyssynergic defecation), where the muscles don’t relax properly, or even rarer conditions like Hirschsprung disease, which is usually found in children but can sometimes be diagnosed in adults. For fecal incontinence, it helps pinpoint what’s going wrong and where. And interestingly, the same kind of technology can sometimes be used later as a treatment to help retrain those muscles!

Getting Ready for Your Anorectal Manometry

To get the clearest picture, it’s best if your anus and rectum are empty for the test. So, we’ll give you some specific instructions. Usually, this involves not eating for a bit before the test and using an enema at home to clear things out. Don’t worry, we’ll walk you through exactly when and how to do this, and what products to use. It’s all pretty straightforward.

What Happens During the Test Itself?

Okay, let’s talk about what the actual anorectal manometry procedure involves. I want you to feel as prepared as possible.

The Nitty-Gritty of the Procedure

When you come in, you’ll likely change into a hospital gown or undress from the waist down. You’ll lie down on an examination table, usually on your side with your knees drawn up a bit.
Sometimes, the person doing the test (often a specialized nurse or technician) might do a quick digital rectal exam first. That just means gently inserting a gloved, lubricated finger to check for anything unusual.
Then, they’ll gently insert a thin, flexible tube – this is the catheter – into your anus and up into your rectum. It’s lubricated to help it slide in as comfortably as possible. This catheter has tiny pressure sensors on it and a small, deflated balloon on the very end.
They’ll take some baseline pressure readings at different spots inside your rectum. Then, they’ll slowly inflate the balloon.
As the balloon inflates to different sizes and is moved to different positions, they’ll ask you if you can feel it, or if you feel the urge to poop. This helps us understand your rectal sensation.
You’ll also be asked to do a few simple things like squeeze your muscles as if you’re trying to hold in gas, relax, bear down or push as if you’re trying to have a bowel movement, and maybe even cough. All the while, the sensors are recording how your muscles respond, both voluntarily and involuntarily.

How Long Does It Take?

It’s usually pretty quick. The whole thing often takes about 30 minutes, though it could range anywhere from 15 to 45 minutes.

Will It Be Uncomfortable?

Now, I get asked this a lot: Is it painful? Most people find it mildly uncomfortable, maybe a bit strange, especially if you’re already a little sore down there. But it really shouldn’t be painful. The pressure from the catheter and the balloon is similar to what you’d feel with a normal bowel movement. If you’re feeling particularly anxious about it, though, please do talk to us beforehand; sometimes, sedation can be an option.

What About a Balloon Expulsion Test?

Sometimes, we might do an extra little test at the end called a balloon expulsion test. It’s just what it sounds like: we see if you can “poop out” the inflated balloon, and how long it takes you. You’ll be able to do this part in private, sitting on a commode. Sensors on the balloon will record the pressure and time. It gives us more information about how effectively you can empty your rectum.

Are There Any Risks I Should Know About?

Honestly, there aren’t any significant risks or side effects with anorectal manometry. The main thing to be aware of is if you have a latex allergy, as some balloons contain latex. If you do, please let us know well in advance so we can use a latex-free option. If your anus or rectum was already a bit inflamed or irritated, you might feel a little sore or notice a tiny bit of bleeding afterward, but this is usually very mild and temporary.

Understanding Your Anorectal Manometry Results

So, what does all this information tell us? Well, quite a lot, actually! The results show us whether the muscles and nerves involved in having a bowel movement are functioning as they should, and if not, where the hiccup might be.

What Do “Normal” Results Look Like?

When everything is working well, we’d expect to see things like:

Your rectum can comfortably stretch and hold stool (rectal compliance).
When stool enters your rectum, special nerves (stretch receptors) send a signal to your brain, giving you the urge to go (rectal sensation).
Your internal anal sphincter (the muscle you don’t consciously control) automatically relaxes when stool is present (this is called the rectoanal inhibitory reflex).
Your external anal sphincter (the one you can control) contracts when the internal one relaxes, to help you hold on until you’re ready. It should also tighten if you cough (the cough reflex).
You can voluntarily squeeze, relax, or push with your external anal sphincter when asked.
When you try to poop, the pressure in your rectum increases, and at the same time, your external anal sphincter relaxes to let the poop pass. It’s all about coordinated anorectal pressure changes.

And If Things Aren’t Quite Right?

If the test results are abnormal, it might mean one or more of these functions aren’t happening correctly. For example:

You might not feel the urge to poop even when your rectum is full. Maybe your rectum isn’t stretching enough, or those nerve signals aren’t getting through.
You feel the urge, but your automatic muscle reflexes aren’t kicking in.
Your muscles might be doing the opposite of what they should – like tightening when they need to relax. Weird, right?
The muscles might be doing the right thing but at the wrong time, or they just aren’t working together as a team.
The muscle contractions could be too weak to be effective.
Or, your muscles might be too tight, even when you’re trying to relax them.

What’s Next? From Test to Treatment

The great thing about anorectal manometry is that it doesn’t just give us a label; it helps us understand the why behind your symptoms. Once we can pinpoint which muscles are misbehaving and how, we can talk about specific ways to help. Often, this involves therapies like:

Biofeedback therapy: This is a really neat technique where you learn to control bodily functions that are normally automatic, like muscle contractions. The manometry equipment can actually be used to help you see, in real-time, how your muscles are working, so you can learn to coordinate them better.
Physical therapy for pelvic floor dysfunction: A specialized physical therapist can teach you exercises and techniques to strengthen or relax your pelvic floor muscles, improving their function.

We’ll discuss all the options and figure out the best path forward for you.

Key Things to Remember About Anorectal Manometry

It can feel a little daunting to think about any medical test, especially one in a sensitive area. But here are the main takeaways:

Anorectal manometry is a safe and valuable test to understand how your rectal and anal muscles are working.
It helps us diagnose the cause of problems like chronic constipation, difficulty pooping, or fecal incontinence.
The procedure involves a small, flexible tube with a balloon and isn’t usually painful, though it can be a bit uncomfortable.
Results can show us exactly where the problem lies in your muscle and nerve function.
This information is key to guiding effective treatments, like biofeedback or physical therapy.

You’re not alone in dealing with these kinds of issues. And finding out more about what’s going on is the first step towards feeling better. We’re here to help you through it.