P0988 RECTAL FUNCTION IN FUNCTIONAL NON-RETENTIVE FECAL SOILING (FNRFS)

Introduction: To date children with FNRFS are believed to suffer from a mental disturbance. To what extent abnormalities in rectal function may be involved, has not been evaluated. We evaluated rectal sensation and compliance in these patients using the barostat. Methods: Rectal sensation (first sensation, urge to defecate and pain), and compliance were determined using a barostat (pressure controlled, intermittent distension procedure). Results: Rectal function was evaluated in 19 children with FNRFS (15 M, mean age 10.0 ± 1.9 yrs) and compared with 22 healthy volunteers (11 M, mean age 12.7 ± 2.6 yrs) (HV). Mean sensation thresholds (first sensation, urge to defecate and pain) were not significantly different from HV. Moreover, mean rectal compliance in FNRFS (14 ± 4.0 ml/mmHg) was not significantly different from HV (16 ± 2 ml/mmHg). A subgroup (4/19) of FNRFS patients showed an abnormal rectal function: 2 patients (11%) showed disturbed rectal sensation for urge (cutoff: mean of HV + 2SD). Additionally, another 2 patients (11%) had an abnormal rectal compliance (cutoff: mean of HV + 2SD). Conclusion: Rectal function is normal in the majority of patients with FNRFS underscoring that fecal retention does not play a role in the symptomatology in this patient group. However, in a subgroup, increased compliance (11%) or decreased sensation (11%) can be demonstrated suggesting impaired rectal function as possible underlying pathophysiological mechanism.