By Steve Hodges, M.D.
The other day, a fortuitous mistake at my pediatric urology clinic sparked a “Wow!” moment for me.
The patient, referred to me by her pediatrician, was an 11-year-old girl with daily bedwetting, daytime accidents, and severe belly pain. The pediatrician reasonably assumed constipation was causing the girl’s symptoms and prescribed the regimen most doctors favor: Miralax. And more Miralax.
When that didn’t work — as it usually doesn’t! — he sent her to me.
But here’s the interesting part: Before referring the girl, the pediatrician ordered a CT scan of her abdomen. Apparently, he was seeking to rule out appendicitis as a cause of the belly pain.
In my clinic we generally don't do CT scans; instead, as a matter of practice, we do a plain X-ray of all enuresis (wetting) patients. The radiation dose is reasonable, much lower than with a CT scan, and the images are sufficient for showing families what’s really going on: the child’s rectum is so stuffed with stool that it’s encroaching upon, even flattening, the bladder. Parents are usually blown away by the giant, hardened mass of stool in the rectum, as depicted on the X-ray.
Following our clinic’s procedure, my staff scheduled an X-ray for the 11-year-old. No one realized she’d already had an abdominal CT scan, which — offering more detail than an X-ray — would have made the X-ray redundant.
By the time I met with the patient, I had two images in front of me: a CT scan and an X-ray. Remarkably, they told different stories.
The X-ray looked normal; the rectum did not appear to be terribly stretched by stool, a surprising finding given the child’s symptoms.
But the CT scan — wow. It showed a huge stool impaction in the girl’s rectum, exactly what I would have expected the X-ray to show.
What I learned from this: a child can be constipated even when a plain X-ray suggests otherwise.
The experience only reinforced two observations that drive my practice:
•Childhood bedwetting and daytime accidents are rarely caused by anything other than chronic constipation.
•If treatment for constipation does not resolve the bedwetting, this does not mean the cause is something other than a stool-impacted rectum; it usually means the treatment isn’t aggressive enough.
Many families come to my clinic believing their child’s accidents are caused by “deep sleep,” anxiety, a behavioral issue, a hormonal problem, or heredity. (All wrong!) Parents may not know that constipation causes enuresis or may not suspect their child is constipated. (“But she poops every day!”) Or, the pediatrician — using inadequate diagnostic methods, such as feeling a child’s belly — may have declared the child “not constipated.”
Other families, like the parents of my 11-year-old patient, may believe constipation is the issue but are baffled when typical constipation treatment — oral laxatives such as Miralax — does nothing to relieve the symptoms. At that point they suspect “something else” must be going on.
The X-ray almost always prove otherwise, highlighting the mass of impacted stool the pediatrician missed when feeling the child’s belly.
Except now I know X-rays can miss the boat, too.
What’s my message here? Should every enuresis patient have a CT scan? No!
When a Contrast Enema for Constipation is Warranted
I still believe radiation levels with a CT scan are too high to make them standard practice (not to mention the issues of cost and convenience). And in the vast majority of cases, a plain X-ray adequately showcases the problem.
However, if your child has been on an aggressive regimen such as the Modified O’Regan Protocol (M.O.P.) for several months without improvement and you want evidence your child is (or isn’t) still constipated, you may want to request a contrast enema instead of a plain X-ray.
A contrast enema uses a water-soluble fluid that shows up on an X-ray, and it’s generally as accurate as a CT scan for detecting constipation, but without subjecting the child to excessive radiation.
This test is a fair amount of trouble: It’s done at a radiology clinic and requires the child to consume nothing but clear fluids for 24 hours prior to the exam. You can read more about the procedure on the websites of Cincinnati Children’s Hospital or Children’s Hospital of Philadelphia.
I continue to believe plain X-rays should be standard medical practice for enuresis. They are sufficient to detect most cases of constipation, provide a helpful baseline picture (especially if you take a rectal diameter measurement, and are important for determining the direction of treatment in tough cases.
A recent conversation with pediatric GI surgeon Mark Levitt, M.D. — my guru for the most challenging constipation cases — confirmed my strong opinion on this issue.
Levitt told me: “If you don’t get an X-ray, you can’t check your work. The X-ray is the decider between which direction to go with the next plan.”
For example, if a patient has made no progress on M.O.P.+ — daily large-volume enemas plus osmotic laxatives — and an X-ray shows the child’s rectum is still full of stool, I may recommend, for example, changing the enema solution, adding Double M.O.P. (overnight olive-oil enemas), and/or replacing Miralax with Ex-Lax. There are many options — as I detail in The M.O.P. Book: Anthology Edition — and the X-ray can help guide the treatment.
And if the X-ray does not show an impacted rectum, I would order a contrast enema, to test my hunch that the child is still constipated.
As Dr. Levitt told me, if you have bedwetting patient, you have to assume constipation is causing the symptoms “until you absolutely eliminate the colon as the problem.”
Sometimes, the only way to “absolutely” eliminate the colon is to get a picture more precise than a plain X-ray.