Characterization of Pediatric Bowel and Bladder Dysfunction via Pupillometry

Bowel and Bladder Dysfunction (BBD) refers to a heterogenous group of voiding disorders, accounting for an estimated 40 percent of pediatric urology visits.Symptoms of BBD include enuresis, urgency, and urinary retention, often accompanied by constipation. While the role of the autonomic nervous system (ANS) in regulation of voiding is well-characterized, it is not known if children presenting with BBD exhibit distinct patterns of ANS activity that could be measured for diagnosis, or targeted for intervention. Pupillometry allows for assessment of systemic ANS activity, and therefore could elucidate differences in ANS function among BBD patients. This study aimed to determine whether a pupillary response can be characterized for BBD. The goal of this study was to use pupillometry to compare the pupillary responses of BBD patients to controls pre- and post-voiding. Both BBD patients and controls were recruited from the urology clinic at Children’s National. Using scores from the Dysfunctional Voiding and Incontinence Scoring System (DVISS) questionnaire, subjects were identified as BBD patients or control patients. Pupillometry was then conducted before and after voiding. BBD patients showed a significantly larger maximum pupil size in the pre-voiding condition relative to controls. Additionally, several pre- and post-voiding parameters showed near-significant differences. The changes in values pre- and post-voiding were also compared, and BBD patients showed significantly larger changes in both minimum pupil size and in average constriction velocity. These results suggest that BBD patients may have a distinctive profile of ANS activity, and that this profile may be detectable in a clinical setting via pupillometry. The role of the autonomic nervous system in voiding behavior is well described, with the parasympathetic nervous system (PNS) more active during voiding, and the sympathetic nervous system (SNS) more active during the retention phase in healthy patients. The larger maximum pupil size seen in the pre-voiding condition among BBD patients could indicate relatively higher SNS activity during the retention phase. This is consistent with a finding from a study of cardiac autonomic activity among BBD patients, which found higher baseline heart rates relative to controls. Additionally, the significantly larger changes in minimum pupil size and average constriction velocity between pre- and post-voiding conditions among BBD patients could indicate greater variability in ANS activity related to voiding behavior. The results could be applied toward a diagnostic tool for identify patients with BBD dysautonomia, versus patients with behavioral, anatomical, or other causes of urinary symptoms