Neuropathic-Like Properties Identified in Setting of Endometriosis-Associated Pain

A substantial proportion of women with endometriosis-associated pain were found to have a neuropathic-like component. These findings were published in Frontiers in Pain Research.

For this study, women (N=1417) with endometriosis-associated pain living in the United Kingdom were recruited through patient support websites. Participants responded to an online survey comprising questions about medical history, pain symptoms, psychological symptoms, and the painDETECT screening tool to assess for neuropathic pain. PainDETECT is a patient-completed screening questionnaire developed to measure neuropathic pain in a ranger of contexts. Responses were evaluated using a cluster analysis and patients were categorized into groups on the basis of their pain symptomology.

Study participants had a median age of 33 years (range, 18-59), had been experiencing pain for 18 years (range, 1-47), had 2 past abdominal surgeries (range, 1-23). The study population scored the following on the 10-point numerical rating scale (NRS): Dysmenorrhea pain, 8 points (range, 0-10), dyspareunia, 7 points (range, 0-10), noncyclical pain, 8 points (range, 0-10) points, dysuria pain points, 4 (range, 0-10), and dyschezia pain, 7 points (range, 0-10).

Among participants who completed the survey (n=1401), 40% were found to have neuropathic pain, 25% had nociceptive pain, and 35% had mixed nociceptive/neuropathic pain.

Stratified by pain type, the 3 groups differed significantly by age, dysmenorrhea, dyspareunia, dyschezia, dysuria, depression, noncyclical pain, the duration of noncyclical pain, anxiety, fatigue, trouble thinking or remembering, and waking up feeling tired (all P <.001).

PainDETECT scores were significantly correlated with Beck Depression Inventory (r, 0.33; P <.001), State-Trait Anxiety Inventory (r, 0.24; P <.001), fatigue (r, 0.26; P <.001), waking up tired (r, 0.24; P <.001), and trouble thinking or remembering (r, 0.26; P <.001).

Stratified by number of surgeries, more of the patients who had ≥5 procedures (n=272) had neuropathic pain (P <.001) compared with patients who had 1 procedure (n=403).

Among the neuropathic or mixed pain groups, 79.3% reported painful attacks, 28.2% burning, 25.4% prickling, 23.3% mechanical allodynia, 15.2% pressure-evoked pain, 14.1% numbness, and 8.9% thermal hyperalgesia.

Using neuropathic pain symptomology, a cluster analysis found that 56.3% of patients were in cluster 1 and 43.7% in cluster 2. The symptoms which best discriminated between groups were prickling, tingling, and burning. Patients in cluster 1 had higher Fibromyalgia Symptom Scale scores (P <.001).

This study was limited by the inability to clinically verify the diagnosis of endometriosis, reported symptoms, or number of surgeries.

This study found that a substantial proportion of women with endometriosis have a neuropathic-like pain component. These findings challenge the current conceptualization of endometriosis-associated pain, suggesting that additional study and reevaluation of pain and pain management in endometriosis may be warranted.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.

Reference

Coxon L, Wiech K, Vincent K. Is there a neuropathic-like component to endometriosis-associated pain? Results from a large cohort questionnaire study. Front Pain Res. 2021;2:743812. doi:10.3389/fpain.2021.743812