Changes in Bladder Sensory and Motor Functions in Response to Inflation or Deflation of a Rectal Balloon

Purpose To study the effect of rectal balloon inflation and deflation on bladder function Material and Methods We prospectively studied 26 children 10 M /16F aged 6 to 11 years with symptoms of urinary incontinence (day and night) or infrequent voiding +/- constipation with GI-GU studies including: elimination questionnaires and diaries, psychopathology and behavioral assessments, colonic transit time, anorectal manometery, and simultaneous urodynamic-rectal balloon pressure studies attempted 3X with rectal balloon empty, inflated and then deflated. Results Anorectal manometery was normal in all. Colonic transit was prolonged in 39%. Constipation was diagnosed by Rome III criteria in 16. Constipation did not correlate with symptoms of urinary infrequency or incontinence, presence of uninhibited contractions (UNC) or UTI history. UNC were seen in only 16 of 22 with OAB symptoms. Bladder responses to rectal balloon inflation fell into three categories: Stimulatory effect: decreased functional bladder capacity in 40%, increased bladder sensation in 40% and increased bladder instability in 66%. Inhibitory effect: increased functional bladder capacity in 25%, decreased bladder sensation in 40%, and decreased bladder instability in 34%. No effect: in the remainder. Conclusions Rectal balloon distension significantly altered bladder sensory motor functions in many but not all children with urinary tract dysfunction with or without constipation. Individual responses did not correlate with specific GI-GU symptoms or diagnoses, but the patterns of bladder response were different in different subgroups of children: those with large rectal vaults or small capacity bladders often displayed stimulatory responses while inhibitory responses occurred when bladder capacity was large. These preliminary observations help understand the interrelationships between bladder and bowel functions and clarify the pathophysiology of urinary symptoms in clinical constipation.