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When to X-Ray a Child for Constipation

By Steve Hodges, M.D.

​The other day an Aussie mum emailed asking if I’d look at an abdominal X-ray of her 12-year-old son, who has been wetting the bed for years. “The doctor didn’t seem to think there was any blockage,” she wrote.

I looked at the X-ray and saw an abnormally large — and very obvious — mass of stool in the rectum. I felt like drawing a bright red circle around it and asking the doctor: “How do you explain this?”

Actually, the explanation is simple: Many doctors, unfamiliar with the constipation-wetting connection, don’t know what they’re looking for.

Other doctors won’t even agree to X-ray their enuresis patients. As one mom, Shawn Thayer Shumate, posted on the It's No Accident Facebook page: “My son’s first pediatrician said an X-ray ‘wasn’t the standard of care’ and that it would expose my son to radiation that could later cause cancer.”

The use of X-rays for constipation is a charged issue, and misconceptions abound. In this blog post I will cover:

•3 reasons to X-ray a child for constipation

•Why X-rays for constipation are safe

•How to tell via X-ray if a child is constipated

3 Reasons to X-ray a Child For Constipation

Let’s clarify one thing up front: an X-ray isn’t necessary to detect constipation. You can generally can assume a child with wetting problems is constipated and start treatment, ideally with M.O.P. (the Modified O'Regan Protocol). Many families on M.O.P. don’t have access to X-rays, either because their doctor won't order one or because they're already convinced their child is constipated, and they do just fine.

However, in my clinic at Wake Forest Baptist Health, we X-ray virtually every child who comes to us for bedwetting, pee accidents, or recurrent urinary tract infections.

We do this for three reasons:

1.) to provide tangible evidence to the child, parents, and referring pediatrician that the child’s rectum is clogged

2.) to catch the unusual cases where constipation is not the cause of wetting

3.) to establish a baseline for later comparison

We typically don’t X-ray children who present only with encopresis, since any child who poops in his pants is necessarily severely constipated. There’s just no other explanation.

In our clinic, abdominal X-rays — known as KUBs, for kidneys, ureters, and bladder — confirm that well over 90 percent of potty-trained children with wetting problems or recurrent urinary tract infections are severely constipated. Yet only 5 percent of parents even had an inkling their child was backed up. Most of these patients were referred by pediatricians who also did not suspect constipation.

Why do pediatricians routinely miss the boat? Because today’s preferred methods of detecting constipation — feeling the child’s abdomen and asking questions about the child’s pooping history — are worthless.

(This wasn’t always the case; in It’s No Accident, I trace how over the last 35 years detection methods have become less “invasive” — and less accurate.)

A severely constipated child can poop daily and have a belly that looks and feels normal.

If you want reliable, tangible evidence that the rectum is stretched by chronic poop build-up, you’re looking at three options: X-rays, anal manometry, and ultrasound.

Anal manometry is the method used by Dr. Sean O’Regan in his research proving enemas resolve constipation: You insert a balloon in the child’s bottom and see how much you can inflate it before the child notices.

Not many families sign up for this option! However, I’ve had a few parents request it. In cases where the child is still wetting after months of daily enemas and an X-ray shows the child's rectum is clear, parents, understandably, want to know: How can my child still not be dry? Anal manometry may indicate that the rectum, though clear, is still stretched and needs more time to shrink back to size. (Remember: It’s rectal stretching, more than the poop buildup, that causes the wetting.)

An ultrasound of the rectum is as accurate as an X-ray, but it’s the rare ultrasound technician who has the skill and experience to ultrasound for poop.

In my clinic, we have both X-ray and ultrasound machines, but unless parents are opposed, an X-ray is what I choose to detect constipation.

X-rays are much easier to administer than ultrasound or anal manometry, they’re painless for the child, and they make a powerful impression on families. Many parents are blown away when they see the film.

“Until you actually look at the film, it’s hard to understand,” says Bailey Hooten, the mom of one of my patients. “My 7-year-old was so stuffed with poop that his bladder was basically flattened. I could totally see why pee could not stay in there all night.”

Another mom, Katherine Mengardon, posted on our Facebook page: “I thought getting an X-ray was pointless, as I didn't believe constipation could be the problem, but the proof was indeed in the pudding.”

Possibly the greatest benefit of an X-ray is that it hammers home the notion, to both parents and children, that accidents are in no way the child’s fault.

“Seeing the X-ray really decreased our frustration with our 5-year-old son,” Bethany Handsaker posted on our Facebook page. “We thought his accidents were a behavior or anxiety issue.” (This is a common misconception we debunk in "Bedwetting is Not Behavioral.")

Bethany and her husband have stopped rewarding their son for dry underwear, and the boy no longer tries to hide his wet undies from them. “Now he doesn't have to feel disappointment for not earning a reward when he has no control over it. We all have better attitudes, as view the wetting as a medical issue.”

Her son is also more amenable to treatment. “When we remind our son to go to the bathroom more frequently, he doesn't fight it as much because we explain we are trying to help him feel better instead of him feeling that we are frustrated with him.”

When Doctors Need Proof

Sometimes it’s the pediatrician, not the parents, who need convincing that a child is constipated and/or that more aggressive treatment is warranted.

“My 5-year-old son started having pee accidents often, even though he’d been potty trained for a while, and I mentioned to the doctor I thought he was constipated,” Bethany Hilton posted on our Facebook page. “The doctor felt his tummy and said he wasn’t.”

Bethany insisted on an X-ray. The doctor reported to her that her son “had the most poop he’d ever seen in a kid.”

Another mom, Rudra Vandercat, posted that her doctor suspected constipation but felt an enema regimen was excessive. It was Rudra who suggested an X-ray. "After seeing the huge amount of backup, the doctor agreed to our use of enemas and is following us on a weekly basis. I’m so glad we did the X-ray, as it shows the starting point and will be a baseline for any future interventions that may or may not be needed.”

I'm always heartened when a physician is open minded enough to question his assumptions and get on board with enemas!

I don’t routinely order second X-rays, but some parents, after diligently following M.O.P. without results, feel certain their child’s colon is clear and demand to know why their child is still wetting the bed. A follow-up X-ray shows exactly why: the child is still full of poop.

In these cases, the child needs a more type of powerful enema to get the job done. (This is the M.O.P.+ regimen, described in The M.O.P. Book.) Getting a visual of just how clogged the child’s rectum is helps me decide on the next course of treatment.

Virtually all the wetting patients in my clinic turn out to be constipated. But every once in a blue moon, an X-ray shows a patient’s rectum to be normal, and in these cases the X-ray is helpful, too. I know to look for another cause.

For example, in one case — the only one out of thousands of children I’ve X-rayed — a child’s wetting turned out to be due to type 1 diabetes that had already been diagnosed. Another bedwetting patient of mine turned out to have a congenital anatomic blockage of his bladder that had not been noticed.

Yes, X-rays for Constipation are Safe

Despite the benefits of X-rays, many parents worry about exposing their child to radiation for a condition as seemingly harmless as constipation. We’re not talking about a broken leg, after all.

I understand! I have three young children. I’m not interested in putting their health at risk for no good reason.

I am absolutely opposed to the overuse of X-rays in children. You’d have to threaten me with a baseball bat to get me to order a CT scan in a kid. But the amount of good you can do for a child with bladder problems by accurately diagnosing constipation far outweighs the risks of a couple of plain X-rays.

Broken legs heal in six weeks. Constipation can cause years and years of suffering — just ask my teenage bedwetting patients.

The radiation dose of an abdominal X-ray is the same dose you get from simply living for three months. I would argue that for kids with wetting problems and/or recurrent urinary tract infections, getting an accurate diagnosis of constipation is completely warranted.

How to Read an X-ray for Constipation

Some doctors, particularly those who don’t believe constipation causes wetting, will look at constipated child’s X-ray and declare it “normal.”

They may tell parents: “The colon will always contain some poop, so the stool we see here doesn’t mean anything.”

While it’s true that the colon will always contain some poop, the primary place to look for excess stool is the rectum. As I explain in It’s No Accident, the rectum is an organ designed for sensing poop needs to be evacuated; it's not a storage facility! Only when kids ignore the signal does the rectum clog up. 

Based on published research and my own experience, I generally say a rectum wider than 3 cm contains too much poop. But usually it’s not even a close call. Most children with wetting problems have rectums stretched to 6 or 7 cm. This is an indisputable indication of constipation.

Many of these patients also have excess stool in the ascending colon. The rectal clog compromises the colon's ability to move stool through the entire colon, so the part that pushes poop up against gravity tends to accumulate stool.

Make sure your doctor is the one who reads your child’s X-ray, rather than relying on a report from a radiologist. Radiologists don’t always comment on stool burden, so they may miss it.

If your child has daytime and/or nighttime accidents, and your doctor insists your child’s X-ray is normal, ask for a measurement of your child’s rectum.

What if you can’t even get your child X-rayed because your doctor won’t order one? Find another doctor.

That’s what Shawn Thayer Shumate did. She’s the mom whose doctor insisted an X-ray would expose her son to radiation that could later cause cancer. The doctor also refused to discuss an enema protocol for her child.

So, the family switched medical providers. The first thing their new nurse practitioner asked was, "Has he had an X-ray?"

“We got one done that day,” Shawn reports, “and my son was literally full of poop! Since then, we have followed M.O.P., which the referring GI doc told me not to do. My son now has regular, non-painful bowel movements and is no longer wet at night.”

She added: “I would love to see a follow up X-ray just to see the changes.”

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