Suspect constipation in kids with UTIs, incontinence

"Constipation is a very common problem in children," said Yves Homsy, MD, clinical professor of surgery and pediatrics at the University of South Florida, Tampa. "Constipation is the cause of about 3% of visits to pediatricians and 25% of visits to pediatric gastroenterologists. It is also frequently detected in the course of evaluation for wetting disorders and urinary tract infections."

Causes of constipation include a diet poor in fiber, inadequate fluid intake, irregular feeding schedules, irregular timing of bowel movements, poor posture on the toilet seat, certain medications such as anticholinergic drugs and codeine derivatives, and insufficient exercise. These situations usually can be addressed with diet and lifestyle changes, but children face other, more insidious causes of constipation at schools that have toilets that are unsanitary or that have no doors as "security measures," giving children little privacy to develop normal voiding habits, Dr. Homsy pointed out.

'Holding it' multiplies problems

Failure to properly defecate in a timely manner has its own cascade of problems, he noted. If defecation circumstances are inconvenient, urge is consciously repressed by voluntary contraction of the external anal sphincter, and subconscious reflex inhibition, by contraction of the puborectalis. If delayed, defecation becomes more difficult as stool becomes harder, and pain and discomfort may cause further withholding. The rectum distends and enlarges to accommodate a growing fecal mass and gradually loses its propulsive ability.

From there it is a short step to dysfunctional elimination syndrome, a term coined in 1998 by Stephen Koff, MD, professor of surgery and chief of pediatric urology at the Ohio State University and Children's Hospital, Columbus, to describe functional bladder and/or bowel problems that influence the natural history or treatment of urinary tract infections and reflux.

"The precise relationship between constipation and the pathophysiology of dysfunctional elimination syndrome is still unclear," said Dr. Homsy, who acted as co-chairman of the course, co-sponsored by the ICCS and USF Health at the University of South Florida.

Fecal retention may allow greater numbers of pathogenic bacteria to persist, causing perineal and vaginal colonization, he said. In addition, it may affect bladder function by pressure effects on bladder wall or pelvic neural and vascular structures, leading to incontinence from bladder overactivity or incomplete voiding.

For example, Dr. Homsy said that during uninhibited bladder contractions found in the overactive bladder, turbulent flow may occur in the urethra, creating a retrograde flow from the urethra into the bladder, leading to urinary tract infections, especially in girls. The mechanism may be accentuated with non-relaxation of pelvic floor.