Constipation in children with isolated overactive bladders. 
To evaluate the prevalence of constipation in children with isolated overactive bladder (IOAB) and no micturition complaints.  A questionnaire was used to evaluate constipation in 51 children with IOAB, as well as in a control group of 74 children between the ages of 4 and 14 years.  The Rome III criteria for children were used to assess constipation.  IOAB was defined as the presence of symptoms such as urgency with or without daytime incontinence or frequency, a bell-shaped uroflow, and no post-residual urine.  Mean patient ages were 7.94 (±2.8) and 8.28 (±3.4) years in the OAB and control group, respectively (p = 0.54).  Twenty-eight (54.9%) of the OAB group were girls, and 34 (45.9%) were girls in the control group (p = 0.32).  More of the children with IOAB had constipation than those without urinary symptoms (54.9% vs. 29.7%, p = 0.005; or 2.87, 95% CI: 1.3-6.0).  The results were statistically significant regarding the following Rome III criteria: "history of stool retention", "presence of painful or hard bowel movements", "the presence of a large fecal mass in the rectum" and "large diameter stools which may obstruct the toilet".  Within the group with OAB, constipation was more common among males (p = 0.05).  There was no association between the type of OAB symptoms and constipation.  The average dysfunctional voiding symptom score was 9.76 (±4.1).  Eleven children (21.6%) presented alterations on ultrasound.  Girls with OAB presented more frequently with UTI than boys (18 vs. 10, p = 0.13).  This was the first comparative study with respect to constipation in children with IOAB and without urinary symptoms.  Children with IOAB have a greater risk of having constipation compared to those with no urinary symptoms.