Phenotyping Sexual Pain in Endometriosis Using the Central Sensitization Inventory

Deep dyspareunia, a common symptom in endometriosis, has previously been associated with bladder and/or pelvic floor tenderness (BPFT), which suggests a role for central nervous system sensitization. The Central Sensitization Inventory (CSI, 0-100) is a validated self-reported scale for patients with central sensitization.

The objective of this study was to phenotype deep dyspareunia using BPFT and the CSI.

The methods included cross-sectional analysis from a prospective registry from January 2018 to June 2018 at a tertiary center for endometriosis (ClinicalTrials.gov #NCT02911090). Included were women aged 18-50 years with endometriosis (previously surgically diagnosed, current visualized endometrioma on ultrasound, or current palpable or visualized nodule on ultrasound), who were newly or re-referred to the center. Severity of deep dyspareunia was self-reported using an 11-point numeric rating scale (0 = no pain; 10 = worst pain imaginable), categorized as no or low deep dyspareunia (0-4) and high deep dyspareunia (5-10). We identified the subgroup with high deep dyspareunia and presence of BPFT, where we hypothesized a central component of the sexual pain. This subgroup was compared with 2 other subgroups: no or low deep dyspareunia and high deep dyspareunia but no BPFT. The CSI was compared between the groups using analysis of variance, followed by post hoc testing (P < .05).

The main outcome measure was the CSI score ranging from 0 to 100.

Data from 163 women with endometriosis were analyzed. The mean age of this cohort was 36.4 ± 6.8 years, and the mean CSI score was 41.0 ± 18.6. 37 percent (61/163) had high deep dyspareunia and BPFT; 29% (47/163) had high deep dyspareunia and no BPFT; and 34% (55/163) had no or low deep dyspareunia. The CSI significantly differed between the 3 groups (analysis of variance: F = 22.4, P < .001). In post hoc testing, the CSI was higher in women with high deep dyspareunia and BPFT (51.3 ± 16.9), compared with women with no or low deep dyspareunia (30.9 ± 15.4, P < .001) and compared with women with high deep dyspareunia but no BPFT (39.4 ± 17.2, P = .001).

The CSI could be used to classify and phenotype patients with endometriosis-associated sexual pain.

Strengths include a prospective registry with integrated pain scores, validated questionnaires, and physical examination findings. Limitations include the lack of quantitative sensory testing for central sensitization.

In women with endometriosis, the subgroup with high deep dyspareunia and bladder and/or pelvic floor tenderness had a significantly higher score on the CSI than other subgroups, suggesting that this group may have a central component to their sexual pain. Orr NL, Wahl KJ,Noga H, et al. Phenotyping Sexual Pain in Endometriosis Using the Central Sensitization Inventory. J Sex Med 2020;17:761-770.