To investigate the clinical and urodynamic characteristics of female bladder outlet obstruction (BOO) accompanied with interstitial cystitis/bladder painful syndrome (IC/BPS).

The electronic charts from 192 consecutive women with BOO underwent transurethral surgery in our hospital were retrospectively reviewed. The BOO was diagnosed by the history, voiding cysto-urethrography, and cystoscopy performed by same experienced surgeon. Of those, 37 were diagnosed as IC/BPS due to the presence of glomerulations. After excluding 11 because of incomplete data, a total of 26 patients were included in this study. Another 26 patients without IC/BPS, matched age and the length of symptoms, were set as control. The clinical and urodynamic characteristics including volume at first desire to void (FDV), strong desire to void (SDV), maximal cystometric capacity (MMC), post void residual (PVR), maximum flow rate (Qmax), and detrusor pressure at maximum flow (PdetQmax) were collected and compared in two groups. In addition, the bladder outlet obstruction Index (BOOI), obstruction coefficient (OCO), and bladder contractility index (BCI) were also calculated and compared. Continuous variables were expressed as means ± standard deviation or median (interquartile range) while categorical variables were expressed as percentage and frequency. Difference between two groups was compared by two sample t-test, Mann-Whitney U test or Chi-square test. All reported P-values were two-sided, and P<0.05 was considered statistically significant.

As shown in Table 1, no significant difference in age and the length of symptoms was found between the two groups (𝑃 > 0.05). The patients in BOO accompanied with IC/BPS had a significant higher proportion to experience frequency and bladder pain, so did the nocturia, compared to controls. By contrast, the presence of urgency between two groups was not significant. In terms of the urodynamic characteristics, the patients with BOO accompanied with IC/BPS had significant higher bladder oversensitivity with a lower FDV, SDV and MCC in comparison with controls. However, there were no significant difference between two groups in the Qmax and PdetQmax. The patients with pure BOO seem to have a higher BOOI, OCO, BCI, but no significant compared to those with IC/BPS. (Table 2)

It is reported that the presence of BOO in patients with IC/BPS is associated with more severe symptoms and higher voiding pressure (1). In this study, we found the presence of IC/BPS might be associated with more severe storage symptoms and higher bladder oversensitivity, which may mainly stem from the reduction of bladder compliance secondary to IC/BPS. Moreover, although no significant difference was detected between two groups, patients with pure BOO seems to have a higher BOOI, OCO, BCI, which indicates these patients might have more severe obstruction, but the small sample size may weaken the significance of difference. In other words, the presences of IC/BPS symptoms may contribute to the diagnosis of BOO even with less severe obstruction.

Our study suggests that the presence of IC/BPS in patients with BOO may cause a more severe storage symptoms and higher bladder sensitivity. In addition, the presence of IC/BPS might be helpful for patients to detect their BOO. Future study with larger sample size is needed to provide sufficient evidence.

Cameron AP, Gajewski JB. Bladder outlet obstruction in painful bladder syndrome/interstitial cystitis. Neurourol Urodyn. 2009;28(8):944-8.