Introduction & Objective :
Bowel and Bladder Dysfunction (BBD) refers to a heterogenous group of voiding disorders, accounting for an estimated 40% 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.
Methods : The Neuroptics PLR-2000 pupilometer was used to assess 7 pupillary parameters: maximum diameter (MAX), minimum pupil diameter (MIN), change in diameter (DELTA), latency (LAT), average constriction velocity (ACV), maximum constriction velocity (MCV), and average dilation velocity (ADV). Both BBD patients and controls were recruited from the urology clinic at Children’s National. Pupillometry was conducted before and after voiding.
Results : BBD patients showed a significantly larger MAX 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 MAX and ACV. 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 ANS in voiding is well described, with the parasympathetic nervous system (PNS) generally more active during voiding, and the sympathetic nervous system (SNS) more active during the retention phase in healthy patients.
The larger MAX 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. The significantly larger changes in MIN and ACV between pre- and post-voiding conditions among BBD patients could indicate greater variability in ANS activity.