The relationship between the urinary tract and the lower gastrointestinal tract impacts urinary tract infections (UTIs) and urinary incontinence in children. It is not enough to treat UTIs with antibiotics and examine for reflux, said Yves Homsy, MD, FRCSC, FAAP, during his presentation "Wet pants, UTIs, and constipation: The relationship between bowel and bladder dysfunction." It is also crucial to investigate whether the child has any constipation issues.
That can be difficult, however, because constipation is somewhat relative. It means different things to different people, few of whom like talking about it. However, some children have a more sensitive urinary tract—a large mass of stool in the rectum pressing on the bladder leads to bladder problems ranging from UTIs to urinary incontinence and reflux, and the damage that can follow.
Key steps for diagnosing constipation include the following:
1. Examine the lower abdomen clinically—Once the child relaxes sufficiently, an empty sigmoid should not be palpable. If full, it feels like a little sausage in the left lower quadrant.
2. Use the Bristol Stool Form Scale (BSFS)—This tool (bit.ly/NIDDK-Bristol-scale) simplifies constipation conversations by assigning 7 numerical grades to corresponding images (grades 1-4 indicate retention). After children are aged 6 or 7 years, parents rarely know what their child’s stool looks like, but children can instantly identify which picture looks like their stool. The BSFS also can help families and caregivers track treatment progress.
3. Request a pelvic sonogram—In children aged younger than 12 years, rectal diameter measuring more than 3 cm indicates constipation or fecal retention.1 An abdominal x-ray, which pediatricians often request, is not a reliable diagnostic tool because it is prone to subjective interpretation with no validated objective parameters.
Together, these tools provide a fairly clear idea of the patient's status. Boosting compliance with treatment requires discussing a delicate subject with parents, who might feel embarrassed, guilty, or even insulted that one suspects their child may be constipated. Here again, the BSFS breaks the ice, eliciting giggles from children to get the discussion started.
Although bowel and bladder dysfunction are common problems pediatricians see, those who can get their patients to appreciate the importance of bowel management and commit to compliance see amazing results. This spares children numerous investigations, which can be painful and expensive, not to mention recurrent UTIs and the embarrassment of wetting because of an overfilled rectum as an unsuspected underlying cause.
1. Joensson IM, Siggaard C, Rittig S, Hagstroem S, Djurhuus JC. Transabdominal ultrasound of rectum as a diagnostic tool in childhood constipation. J Urol. 2008;179(5):1997-2002.
For diagnosing constipation, Dr. Homsy suggests switching from plain film to ultrasound. This is not a major change—pediatricians order ultrasounds all the time. Dr. Homsy's approach mirrors ours, except that when we request a pelvic sonogram, usually we get ultrasound images of both the kidneys and bladder (I want to make sure the kidneys are healthy, and 99% of the time they are), and the technician includes the stool images simultaneously.
Often, we still get an abdominal x-ray as well. On a plain film abdominal x-ray, the radiologist may comment if there is lots of stool or a little. Regarding the reliability of abdominal x-rays, we, as specialists, know what we are looking for. Often, we will get a case that the radiologist pronounces normal, but is not. We also get many ultrasounds in which radiologists generally do not comment on amount of stool present on the images. These providers generally do not look at stool unless asked specifically to do so, and even then, they are not quite sure what to look for.
Reading stool on films is not that difficult. If pediatricians did so, constipation would be easier to objectively diagnose using ultrasound or plain films and not be determined by relying on the family history of stool habits alone. However, often pediatricians are too busy, and families rarely bring the films from the radiologist (as we try to have them do).
Pediatricians can examine the abdomen and use the Bristol scale charts with patients and families in their offices. The scale does break the ice. Parents usually have no clue about the bathroom activities of toilet-trained children, as it is a fairly private matter once the child is no longer in a diaper.
If parents and their regular pediatricians investigate how often their child is having a bowel movement and how it would be measured on the Bristol scale, hopefully the children would not need to be seen by bladder and bowel specialists. But the 20- to 30-minute appointments that our office routinely books for patients with bladder and associated constipation problems are not generally possible in most busy pediatricians' offices.
It would be helpful, however, if pediatricians could find those patients with significant constipation and encopresis that obviously should go to gastroenterology. We see many children with wet pants and voiding symptoms, and it turns out that the child's bladder and kidneys are fine, and that most of these problems can be resolved just by treating the child’s constipation. We can treat many of the children with basic dietary means and a good bowel program that can be instituted by the child’s regular doctor. Most children that we see, we can treat in the same fashion, but in very severe cases, we refer patients to gastroenterologists.
Dr. Homsy's presentation is a good start, because many parents do not know that bladder and bowel function, development, and control are related. They develop at the same time. The nerves and muscles that control evacuation and continence are the same. If we treat the constipation, the voiding symptoms usually improve dramatically.