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To Help Bedwetting Children, We Need a New Definition of Constipation

By Steve Hodges, M.D.


Recently I appeared as a guest on The Hamilton Review, a podcast hosted by Dr. Bob Hamilton, the affable pediatrician who created the “Hamilton Hold” method for soothing crying babies.


During our enjoyable half hour, Dr. Hamilton and I chatted about enuresis (bedwetting and daytime wetting) and encopresis (poop accidents), common symptoms of chronic constipation. At one point, he asked, “Are you saying there’s a lot of constipation that’s going unrecognized by parents and doctors?”


Yes! That’s what I have been saying for two decades!


In fact, when it comes to patients with enuresis, my guiding principle is constipated until proven otherwise. In other words, if you want me to believe the child is not constipated, you’ll need to show me an x-ray of an empty rectum. (To clarify: there will always be some stool in the colon, but the rectum, the end of the colon, should remain empty.)


Yes, there are medical conditions that can cause enuresis in the absence of constipation, and I discuss these exceptions in the M.O.P. Anthology. However, they are super rare.


Enuresis is almost always caused by chronic constipation, and encopresis has no other cause. Yet when children develop these conditions, their constipation is often overlooked, allowing their accidents — and distress — to persist.


How can this be? Why are so many cases of constipation missed? Because the traditional definition of “constipation” doesn’t fit the actual condition. We have a serious semantic problem.


Parents of my enuresis patients often tell me, “My kid’s an awesome pooper. She poops every day! There’s no way her bedwetting is related to constipation. It’s got to be something else.”


That’s when I send the child off for an abdominal x-ray. You can’t argue with a film. Inevitably, the x-ray shows a rectum full of poop. But nobody noticed, because most folks define constipation as “infrequent pooping” or “straining to poop.” Even the Rome IV Criteria, a list of symptoms many doctors rely on to diagnose constipation, doesn’t cut it.


A far more accurate definition of chronic constipation is, simply, “incomplete evacuation of the rectum."


That’s the definition proposed back in the 1980s by pediatric kidney specialist Dr. Sean O’Regan for whom the Modified O’Regan Protocol (M.O.P.) is named. Truly, Dr. O’Regan’s observation was brilliant.


In a 1987 paper, Dr. O’Regan summarized his studies, demonstrating that a clogged rectum is the root cause of most enuresis. He also lamented that awareness of this fact “has been hampered by the lack of a standard definition of constipation.”


Back then, just as today, doctors and parents alike equated constipation with infrequent pooping.


Unsatisfied with the conventional wisdom, Dr. O’Regan crafted his own definition. Sure, he said, a child who goes 3 days without pooping is constipated, and so is any child with encopresis. But those criteria capture only the most obvious cases. A more reliable definition of chronic constipation considers less visible criteria: “poor emptying” and “dilation” of the rectum.


In other words, a clogged, stretched rectum.


How can you prove a child’s rectum is stuffed with stool and has gone floppy?


To remove the guesswork, Dr. Hodges had his patients undergo anorectal manometry. With this test, a balloon is inserted rectally and inflated to the point where the child feels discomfort. A child with a healthy rectum will feel discomfort with minimal inflation. By contrast, a child with a rectum stretched by a stool pile-up can tolerate a fully inflated balloon.


Dr. O’Regan reported that his enuresis patients were able to withstand maximal inflation without discomfort, proof these kids lacked rectal tone.


While Dr. O’Regan preferred anorectal manometry, he did note in his studies that x-ray, the method I use, can reliably identify a clogged rectum.


In his published papers, Dr. O’Regan emphasized the importance of objective measures and the unreliability of a patient’s pooping history.


He wrote that in many of his enuresis patients, “a history of constipation was denied” by the child’s parents,” and “normal bowel habits were perceived by parents.” In fact, he noted, some parents insisted their children were not constipated even when anorectal manometry demonstrated otherwise!


That’s how tightly our culture clings to an inadequate definition of constipation.


Dr. O’Regan's definition not only is more accurate but also underscores how exactly a clogged rectum causes enuresis.


In his papers, Dr. O’Regan posited that “in chronically constipated children, the rectum is never empty,” and over time, the rectum stretches to accommodate the stool pile-up. The enlarged rectum, in turn, encroaches upon the bladder, decreasing bladder capacity and triggering “uninhibited bladder contractions.” (Indeed, additional testing on Dr. O’Regan’s enuresis patients showed they all had an unstable bladder.) In children with sensitive bladders, these contractions trigger accidents.

Dr. O'Regan reported that about 40% of his enuresis patients also had encopresis, consistent with what I see in m my clinic. In these kids, so much stool piles up that it just falls out of the child's bottom, without the child noticing.

When Dr. Hamilton and I discussed this on his podcast, he asked two good follow-up questions: 1.) Why are constipated children unable to empty completely, and 2.) How do you get the rectum back in shape to do its job?


To answer the first question: As stool accumulates, the rectum stretches, much like your stomach might expand if you consistently overeat. With an expanded stomach, you may require more food to feel full.


Similarly, a chronically expanded rectum requires extra stool to trigger the nerve impulse that signals it’s time to poop. Under normal circumstances, the mere arrival of stool in the rectum triggers that urge. But in a stretched rectum, the sensing mechanism is compromised. Depending on how stretched the rectum is, the child might not sense the urge at all.


Compounding the problem, the enlarged rectum loses its elasticity, like an old, stretched-out sock. The rectum just can’t squeeze enough to shovel out the latest load of poop. So, even more poop piles up, creating a vicious cycle.


Fortunately, this cycle can be stopped.


In nearly all cases, a stretched rectum, even one expanded for years, can shrink back to size. Which brings me to Dr. Hamilton’s second question: how to make that happen.


As Dr. O’Regan reported, “aggressive” treatment — that is, a daily enema regimen, followed by gradual tapering — allows for the “return of normal rectal tone.”  


Dr. O’Regan did not compare enemas with oral laxatives such as PEG 3350 (Miralax), today’s go-to treatment for constipated children. Back then, Miralax didn’t exist, and enemas, a remedy that’s been around for centuries, were readily accepted by doctors and parents alike.


However, I have compared the two treatment approaches, in my practice and my research, and know that Dr. O’Regan’s instincts were correct: enemas are the ticket to emptying and healing a floppy rectum.


Half-measures such as Miralax are far less effective and often fail altogether. Often, the freshly softened stool just oozes around the hardened mass, rather than dislodging it. Even when accidents stop initially, the results tend to be short lived. The floppy rectum fills right back up.

What the pro- Miralax doctors don't realize: It takes a good three months for the rectum, once emptied, to regain its tone and sensation, and during the time, the rectum must be fully evacuated daily. The cookbook approach I was taught in medical school — a high-dose Miralax clean-out followed by a a daily "maintenance" dose — typically does not accomplish that. All that is "maintained" is a clogged rectum.


When accidents recur on a Miralax regimen, parents often think: Well, it must not have been the constipation that was causing the wetting accidents. My kid isn’t constipated anymore but is still having accidents.


Yes, with the help of Miralax, the child might be pooping more often and with less straining. But you can’t assume the child’s constipation has been resolved. As Dr. O'Regan discovered, that requires weeks and weeks of complete evacuation.






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