The prevalence and therapeutic effect of constipation in pediatric overactive bladder

Overactive bladder (OAB) is a manifestation of urgency, regardless of urge incontinence, due to involuntary bladder contraction during the storage period. There is a close association between constipation and OAB, but constipation cannot be readily diagnosed. The aims of this study were to evaluate the prevalence of constipation in OAB and the consequent therapeutic effects according to the diagnostic criteria for constipation.

We collected clinical data from 40 children (mean age, 71±22 months) with chief complaints of urgency, frequency, and incontinence. A voiding questionnaire and a 2-day voiding diary were collected, and urinalysis, the Bristol stool scale, and plain abdominal radiography were performed. Constipation was defined as conditions satisfying at least one of the following criteria: Rome III diagnostic criteria, Bristol stool scale types I/II, or a Leech score higher than 8 points as determined by plain radiography. Lower urinary tract symptoms, defecation symptoms, and the bladder volume of patients were examined, and the therapeutic outcomes by constipation diagnostic criteria were evaluated.

Of the 40 OAB patients, 25 had constipation. Among them, 6 had reduced functional bladder capacity (24%; P>0.05). Regarding treatment, in patients who satisfied only one diagnostic criterion, the symptoms improved in 76.9%, 76.9%, and 69.6% of patients meeting the Rome III criteria, Bristol stool scale, and Leech score, respectively (P<0.05). Among the 8 patients satisfying all three criteria, 75% responded to treatment (P<0.05).

The prevalence of constipation in OAB is high. Constipated patients recruited by use of the Rome III criteria, Bristol scale, and Leech score alone and together showed similar outcomes on OAB improvement after the treatment of constipation, which implies that each criterion has the same strength and can be applied comprehensively and generally.