25: Mechanisms underlying nocturia in women with bladder pain syndrome/interstitial cystitis

Abstract

Little is known about mechanisms underlying nocturia in women with bladder pain syndrome/interstitial cystitis (BPS/IC). The thalamus plays a primary role in the organization of the sleep-wake cycle. Our hypothesis was that nocturia is associated with activation of the thalamus in women with BPS/IC as compared to controls. Data from 27 subjects (14 women with BPS/IC and 13 age-matched controls) enrolled in a Multi-Disciplinary Approach to Chronic Pelvic Pain (MAPP) ancillary study through November 30, 2018 were analyzed. All subjects completed the Interstitial Cystitis Symptom and Problem Indices and PROMIS Sleep Disturbance Short Form to assess BPS/IC and sleep quality, respectively. All subjects also underwent arterial spin labeling functional magnetic resonance imaging to quantitatively measure cerebral blood flow (CBF) in the thalamus in the empty-bladder state and after oral bladder fill in low urgency (score 1-3) and high urgency (score > 3) states. Nocturia was defined as ≥2 episodes of nocturnal voiding. CBF in the thalamus at baseline, low urgency, and high urgency states in women with BPS/IC and controls was compared using two-way mixed model ANOVA. Associations between nocturia, CBF, sleep disturbance and BPS/IC scores were analyzed using linear regression. There was no significant difference in the mean age (49 ± 13 vs. 45 ± 12 years, p=0.4) of BPS/IC subjects and controls. The BPS/IC group had a greater number of nocturia episodes (median 3 vs. 1, p <0.01) and greater sleep disturbance (60.7 ± 8.8 vs. 41.2 ± 9.9, p<0.001) than controls. CBF in bilateral thalamus increased as the level of urgency increased in the BPS/IC group but not in controls (p<0.01, Figure 1). Baseline CBF in bilateral thalamus correlated with the number of episodes of nocturia in women with BPS/IC but not in controls (Figure 2). CBF at baseline and in the low urgency state was not significantly associated with sleep disturbance or bladder pain scores. However, CBF in the right thalamus in the high urgency state was significantly associated with sleep disturbance score (r= -0.42, p=0.03). Nocturia and sleep disturbance in women with BPS/IC are likely modulated through the thalamus.View Large Image Figure ViewerDownload Hi-res image Download (PPT)