Bladder-bowel interactions

AIMS: Mounting evidence from experimental animal and human studies suggests that cross-sensitization exists between different organs. Lower urinary tract (LUT) and bowel dysfunction commonly overlap, and the role of cross-sensitization between pelvic visceral organs is uncertain.METHODS: At the International Consultation on Incontinence Research Society (ICI-RS) meeting in 2018, a panel of clinicians participated in a discussion on bladder and bowel interactions in the context of pelvic organ cross-sensitization.RESULTS: Bladder and bowel problems commonly co-occur in adults and children across different disorders, and the mechanism responsible for overlapping dysfunction is uncertain in most instances. At a neuronal level, cross-sensitization occurs as a result of afferent signaling from the LUT and lower bowel through different central and peripheral mechanisms. Studies in animals and humans have demonstrated evidence for cross-organ sensitization following experimental inflammation or distension of the lower bowel, affecting the LUT. Nerve stimulation is an effective treatment for different functional LUT and bowel disorders, and whether this treatment may influence cross-organ sensitization remains uncertain. The role of physiologically dormant C-fibers, the bladder-gut-brain axis, and gut microbiome in cross-sensitization are speculative.CONCLUSION: Recommendations for research were made to explore the role of cross-organ sensitization in the pathogenesis of co-occurring LUT and bowel dysfunction in humans.