Effect of rectal distention on lower urinary tract function in children.

PURPOSE: We investigated the effect of rectal distention on lower urinary tract function. MATERIALS AND METHODS: Children were assigned to a constipation and lower urinary tract symptoms group or to a lower urinary tract symptoms only group. The definition of constipation was based on pediatric Rome III criteria. Standard urodynamics were done initially and repeated during simultaneous barostat pressure controlled rectal balloon distention and after balloon deflation. We evaluated the effects of rectal balloon inflation and deflation on urodynamic parameters. Colonic transit time measurement, anorectal manometry and the Parenting Rating Scale of child behavior were also used. RESULTS: We studied 7 boys and 13 girls with a median age of 7.5 years who had constipation and lower urinary tract symptoms, and 3 boys and 3 girls with a median age of 7.5 years who had lower urinary tract symptoms only. Urodynamic patterns of response to rectal distention were inhibitory in 6 children and stimulatory in 12, and did not change in 8. In 54% of the cases balloon deflation reversed balloon inflation changes while in 46% balloon inflation changes persisted or progressed. No significant differences were noted in children with vs without constipation and no clinical symptom or diagnostic study predicted the occurrence, direction or degree of bladder responses. CONCLUSIONS: In almost 70% of children with lower urinary tract symptoms rectal distention significantly but unpredictably affected bladder capacity, sensation and overactivity regardless of whether the children had constipation, and independent of clinical features and baseline urodynamic findings. Urodynamics and management protocols for lower urinary tract symptoms that fail to recognize the effects of rectal distention may lead to unpredictable outcomes.