Pelvic floor, abdominal and uterine tenderness in relation to pressure pain sensitivity among women with endometriosis and chronic pelvic pain

World Endometriosis Research Foundation Endometriosis Phenome and Biobanking Harmonization Project: V. Physical examination standards in endometriosis research

OBJECTIVE

The World Endometriosis Research Foundation established the Endometriosis Phenome and Biobanking Harmonisation Project (EPHect) to create standardized documentation tools (with common data elements) to facilitate the comparison and combination of data across different research sites and studies. In 2014, 4 data research standards were published: clinician-reported surgical data, patient-reported clinical data, and fluid and tissue biospecimen collection. Our current objective is to create an EPHect standard for the clinician-reported physical examination (EPHect-PE) for research studies.

DESIGN

An international consortium involving 26 clinical and academic experts and patient partners from 11 countries representing 25 institutions and organizations. Two virtual workshops, followed by the development of the physical examination standards underwent multiple rounds of iterations and revisions.

SUBJECTS

N/A MAIN OUTCOME MEASURE(S): N/A RESULT(S): The EPHect-PE tool provides standardized assessment of physical examination characteristics and pain phenotyping. Data elements involve examination of back and pelvic girdle; abdomen including allodynia and trigger points; vulva including provoked vestibulodynia; pelvic floor muscle tone and tenderness; tenderness on unidigital pelvic examination; presence of pelvic nodularity; uterine size and mobility; presence of adnexal masses; presence of incisional masses; speculum examination; tenderness and allodynia at an extra-pelvic site (e.g., forearm); and recording of anthropometrics.

CONCLUSION(S)

The EPHect-PE standards will facilitate the standardized documentation of the physical examination, including the assessment and documentation of examination phenotyping of endometriosis-associated pelvic pain.

Quantitative somatosensory testing of the abdomen: establishing initial reference values across developmental age and biological sex

ABSTRACT

Abdominal pain is a common symptom of several debilitating conditions (eg, inflammatory bowel disease, irritable bowel syndrome, and endometriosis) and affects individuals throughout their lifespan. Quantitative sensory testing (QST) reference values exist for many body sites but not the abdomen. Using a QST battery adapted from the German Research Network on Neuropathic Pain, we collected QST data on the upper and lower abdomen in 181 pain-free participants, ages 12 to 50 years, to establish reference values by age and biological sex. The normative values are presented as medians for each QST measure by sex (male, n = 63; female, n = 118) and across 3 age categories (adolescents: 12-19 years, n = 48; young adults: 20-30 years, n = 87; and adults: 31-50 years, n = 46). Evaluating the sensory functioning of the abdomen and characterizing ranges of QST measures is an essential first step in understanding and monitoring the clinical course of sensory abnormalities in patients with underlying diseases affecting the abdomen and pelvis. The impact of age and development on sensory functioning is necessary, given age-related changes in pain perception and modulation.

Presence of endometriosis and chronic overlapping pain conditions negatively impacts the pain experience in women with chronic pelvic-abdominal pain: A cross-sectional survey

BACKGROUND

Evidence of overlap between endometriosis and chronic pain conditions is emerging; however, little is known about how the pain experience differs based on the presence or absence of endometriosis.

OBJECTIVES

In a sample of women reporting chronic pelvic-abdominal pain (CPP), the aim of this study was to characterize differences in pain symptomatology between women with and without endometriosis and to examine the influence of chronic overlapping pain conditions (COPCs) on pain among these two groups.

DESIGN

This was a cross-sectional study, based on an online survey.

METHODS

Participants (aged 18+ years) completed a survey collecting pain diagnoses and symptoms assessing pelvic pain severity, pain interference, and pain impact. Independent sample t-tests, chi-square, and multiple linear regression models were employed to analyze group differences in pain symptomatology and COPCs.

RESULTS

Of the 525 respondents with CPP, 25% (n = 133) reported having endometriosis. Women with endometriosis were younger at the onset of pelvic pain, relative to women without endometriosis (p = 0.04). There were no differences in age, race, ethnicity, or duration of pelvic pain between women with and without endometriosis. Women with endometriosis reported higher pelvic pain severity (+0.8, 95% CI = 0.4-1.1), pain interference (+5.9, 95% CI = 2.4-9.3), and pain impact (+1.9, 95% CI = 0.8-2.9). Endometriosis was associated with a higher number of COPCs (p = 0.003), with 25% (n = 33) of women reporting ⩾3 overlapping pain conditions compared with 12% (n = 45) of those without endometriosis. Women with endometriosis had a higher frequency of fibromyalgia (p < 0.001), chronic fatigue syndrome (p < 0.001), and temporomandibular disorder (p = 0.001). The number of COPCs was associated with higher pain severity, interference, and impact, independently of endometriosis.

CONCLUSION

Women with endometriosis experienced higher levels of pain-related burden and COPCs compared with those without endometriosis. Pain intensity, interference, and impact increased with a higher number of pain conditions regardless of endometriosis presence.

Guideline No. 445: Management of Chronic Pelvic Pain

OBJECTIVE

To provide evidence-based recommendations for the management of chronic pelvic pain in females.

TARGET POPULATION

This guideline is specific to pelvic pain in adolescent and adult females and excluded literature that looked at pelvic pain in males. It also did not address genital pain.

BENEFITS, HARMS, AND COSTS

The intent is to benefit patients with chronic pelvic pain by providing an evidence-based approach to management. Access to certain interventions such as physiotherapy and psychological treatments, and to interdisciplinary care overall, may be limited by costs and service availability.

EVIDENCE

Medline and the Cochrane Database from 1990 to 2020 were searched for articles in English on subjects related to chronic pelvic pain, including diagnosis, overlapping pain conditions, central sensitization, management, medications, surgery, physiotherapy, psychological therapies, alternative and complementary therapies, and multidisciplinary and interdisciplinary care. The committee reviewed the literature and available data and used a consensus approach to develop recommendations. Only articles in English and pertaining to female subjects were included.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and conditional [weak] recommendations).

INTENDED AUDIENCE

Family physicians, gynaecologists, urologists, pain specialists, physiotherapists, and mental health professionals.

TWEETABLE ABSTRACT

Management of chronic pelvic pain should consider multifactorial contributors, including underlying central sensitization/nociplastic pain, and employ an interdisciplinary biopsychosocial approach that includes pain education, physiotherapy, and psychological & medical treatments.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Ligustrazine inhibits inflammatory response of human endometrial stromal cells through the STAT3/IGF2BP1/RELA axis

CONTEXT

Endometriosis (EMs) is a gynecological disorder. Ligustrazine has been reported to exert an anti-inflammatory effect on EMs. However, the underlying mechanisms are not completely understood.

OBJECTIVE

To investigate the effects of ligustrazine on the progression of EMs and the underlying regulatory mechanisms.

MATERIALS AND METHODS

Human endometrial stromal cells (HESCs) were isolated from patients with EMs or control subjects. HESCs were treated with 25, 50, 100, or 200 μM ligustrazine for 1, 3, 6, or 12 h. Western blot and enzyme-linked immunosorbent assays were performed to determine the levels of proteins and inflammatory cytokines, respectively. The binding between STAT3 and insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) was assessed by chromatin immunoprecipitation and dual-luciferase reporter assays. The relationship between IGF2BP1 and RELA was assessed by RNA immunoprecipitation and RNA pull-down assay.

RESULTS

Phosphorylated STAT3, IGF2BP1, RELA, TNF-α, IL-6, and IL-1β were upregulated in EMs tissues compared with control tissues (by 1.79-, 2.55-, 1.58-, 3.01-, 2.55-, and 3.34-fold, respectively). Ligustrazine inhibited the expression of p-STAT3, IGF2BP1, RELA, IL-6, TNF-α, and IL-1β. Overexpression of STAT3 promoted RELA-mediated inflammatory responses, while ligustrazine (100 µM) notably reversed this phenomenon. Ligustrazine also alleviated RELA-induced inflammation via downregulating IGF2BP1. STAT3 bound to the promoter of IGF2BP1, and IGF2BP1 bound to the RELA mRNA.

DISCUSSION AND CONCLUSION

Ligustrazine inhibited inflammation in EMs via regulating the STAT3/IGF2BP1/RELA axis. These findings propose a new agent against EMs and support the development of ligustrazine-based treatment strategies for EMs.

Comprehensive quantitative sensory testing shows altered sensory function in women with chronic pelvic pain: results from the Translational Research in Pelvic Pain (TRiPP) Study

ABSTRACT

Chronic pelvic pain (CPP), despite its high prevalence, is still relatively poorly understood mechanistically. This study, as part of the Translational Research in Pelvic Pain (TRiPP) project, has used a full quantitative sensory testing (QST) paradigm to profile n = 85 women with and without CPP (endometriosis or bladder pain specifically). We used the foot as a control site and abdomen as the test site. Across 5 diagnostically determined subgroups, we found features which are common across different aetiologies, eg, gain of function in pressure pain threshold (PPT) when assessing responses from the lower abdomen or pelvis (referred pain site). However, disease-specific phenotypes were also identified, eg, greater mechanical allodynia in endometriosis, despite there being large heterogeneities within diagnostic groups. The most common QST sensory phenotype was mechanical hyperalgesia (>50% across all the groups). A "healthy' sensory phenotype was seen in <7% of CPP participants. Specific QST measures correlated with sensory symptoms assessed by the painDETECT questionnaire (pressure-evoked pain [painDETECT] and PPT [QST] [ r = 0.47, P < 0.001]; mechanical hyperalgesia (painDETECT) and mechanical pain sensitivity [MPS from QST] [ r = 0.38, P = 0.009]). The data suggest that participants with CPP are sensitive to both deep tissue and cutaneous inputs, suggesting that central mechanisms may be important in this cohort. We also see phenotypes such as thermal hyperalgesia, which may be the result of peripheral mechanisms, such as irritable nociceptors. This highlights the importance of stratifying patients into clinically meaningful phenotypes, which may have implications for the development of better therapeutic strategies for CPP.

Evaluation of a scoring system for the detection of central sensitization among women with chronic pelvic pain

BACKGROUND

Central sensitization is frequently associated with chronic pelvic pain and requires specific management. The pain is described as hypersensitivity to an innocuous stimulus that is both widespread and persistent. However, no study has evaluated if central sensitization can be measured objectively with neurophysiological tests in the pelvic and perineal area to prove this concept in women with chronic pelvic pain.

OBJECTIVE

This study aimed to evaluate nociceptive thresholds (primary objective) and spatial and temporal diffusion of pain among women with chronic pelvic pain and high or low scores of central sensitization.

STUDY DESIGN

This prospective, assessor-blinded, comparative study compared a cohort of women with chronic pelvic pain and a high (>5/10; n=29) vs low (<5/10; n=24) score of sensitization according to the Convergences PP criteria. Participants underwent a noninvasive bladder sensory test, a rectal barostat test, and a muscular (algometer) and a vulvar (vulvagesiometer) sensory test. Poststimulation pain (minutes), quality of life (Medical Outcomes Study 36-Item Short Form Survey), and psychological state, comprising anxiety (State-Trait Anxiety Inventory), depression (Beck Depression Inventory Short Form), and catastrophizing (Pain Catastrophizing Scale), were assessed.

RESULTS

The participants mostly suffered from endometriosis (35.8%), irritable bowel syndrome (35.8%), bladder pain syndrome (32.1%), and vestibulodynia (28.3%). Baseline characteristics were similar. Women with a high sensitization score had more painful diseases diagnosed (2.7±1.3 vs 1.6±0.8; P=.002) and suffered for longer (11±8 vs 6±5 years; P=.028) than participants with a low score. The bladder maximum capacity was equivalent between participants (399±168 vs 465±164 mL; P=.18). However, the pain felt at each cystometric threshold was significantly increased in women with a high sensitization score. No difference was identified for the rectal pain pressure step (29.3±5.5 vs 30.7±6.5 mm Hg; P=.38). Rectal compliance was decreased in women with a high sensitization score with a considerable increase in pain felt. The average of pain pressure thresholds at the 5 vulvar sites tested was decreased in these participants (162.5±90.5 vs 358.7±196.5 g; P=.0003). Similar results were found for the average of the pain pressure thresholds at 6 muscles tested (1.34±0.41 vs 2.63±1.52 kg/m2; P=.0002). A longer period was needed for patients with high sensitization score to obtain a VAS <3 out of 10 after the stimulation of the bladder (4.52±5.26 vs 1.27±2.96 minutes; P=.01), the rectum (3.75±3.81 vs 1.19±1.23 minutes; P=.009), and the muscles (1.46±1.69 vs 0.64±0.40 minutes; P=.002). The psychological state was equivalent between groups. No association was found between the sensory thresholds and the psychological state results. The physical component of the quality of life score was reduced in women with high sensitization score (P=.0005), with no difference in the mental component.

CONCLUSION

Using neurophysiological tests, this study showed that there are objective elements to assess for the presence of central sensitization, independently of psychological factors.

Association Between Nociplastic Pain and Pain Severity and Impact in Women With Chronic Pelvic Pain

Exploring the relationship between nociplastic pain and the severity and impact of pelvic pain symptoms could lend insight into the heterogeneous symptom presentation and treatment response that complicates management of chronic pelvic pain. In this prospective cross-sectional study, we sought to evaluate relationships between degree of nociplastic pain, measured by the Fibromyalgia (FM) Survey Score, and multiple aspects of the chronic pelvic pain (CPP) experience, including severity, frequency, tenderness during pelvic myofascial exam, interference with daily life, and high-impact pain. The study included 303 women who presented to a tertiary referral clinic for chronic pelvic pain and endometriosis. Multiple measures of pelvic pain, including pain severity, frequency, interference, pelvic myofascial pain, and high-impact pain were examined in General Linear Models with FM Survey Score as the primary predictor of interest in models controlling for endometriosis, surgical history, use of opioids, body mass index, and patient age. Higher level of nociplastic pain was associated with greater pelvic pain severity, frequency, interference, and pelvic myofascial pain (all P < .05). For all models, degree of nociplastic pain was more strongly associated with pain outcomes than the presence of endometriosis, and use of opioids was the only stronger predictor of worse pain outcomes. The likelihood of high impact pain increased 7% for each additional point on the FM Survey Score. Degree of nociplastic pain was robustly associated with severity, frequency, and impact of pelvic pain, and was independent of the presence of endometriosis, history of surgical procedures for pelvic pain, age, and BMI. Trial registration: not applicable PERSPECTIVE: This article evaluates the impact of nociplastic pain on symptoms and functional status in chronic pelvic pain. These findings raise the possibility that a simple screening tool for nociplastic pain might provide clinically actionable information without the need for deep neurobiological phenotyping and may inform development of personalized management strategies.

What Do We Know about Nociplastic Pain?

Nociplastic pain is a recently distinguished type of pain, distinct from neuropathic and nociceptive pain, and is well described in the literature. It is often mistaken for central sensitization. Pathophysiology has not been clearly established with regard to alteration of the concentration of spinal fluid elements, the structure of the white and gray matter of the brain, and psychological aspects. Many different diagnostic tools, i.e., the painDETECT and Douleur Neuropathique 4 questionnaires, have been developed to diagnose neuropathic pain, but they can also be applied for nociplastic pain; however, more standardized instruments are still needed in order to assess its occurrence and clinical presentation. Numerous studies have shown that nociplastic pain is present in many different diseases such as fibromyalgia, complex regional pain syndrome type 1, and irritable bowel syndrome. Current pharmacological and nonpharmacological treatments for nociceptive and neuropathic pain are not entirely suitable for treating nociplastic pain. There is an ongoing effort to establish the most efficient way to manage it. The significance of this field has led to several clinical trials being carried out in a short time. The aim of this narrative review was to discuss the currently available evidence on pathophysiology, associated diseases, treatment possibilities, and clinical trials. It is important that physicians widely discuss and acknowledge this relatively new concept in order to provide optimized pain control for patients.

Targeting Oxidative Stress Involved in Endometriosis and Its Pain

Endometriosis is a common gynecological disorder seen in women and is characterized by chronic pelvic pain and infertility. This disorder is becoming more prevalent with increased morbidity. The etiology of endometriosis remains to be fully elucidated, which will lead to improved therapeutic options. In this review, we will evaluate the biochemical mechanisms leading to oxidative stress and their implication in the pathophysiology of endometriosis, as well as potential treatments that target these processes. A comprehensive exploration of previous research revealed that endometriosis is associated with elevated reactive oxygen species and oxidation products, decreased antioxidants and detoxification enzymes, and dysregulated iron metabolism. High levels of oxidative stress contributed to inflammation, extracellular matrix degradation, angiogenesis, and cell proliferation, which may explain its role in endometriosis. Endometriosis-associated pain was attributed to neurogenic inflammation and a feed-forward mechanism involving macrophages, pro-inflammatory cytokines, and pain-inducing prostaglandins. N-acetylcysteine, curcumin, melatonin, and combined vitamin C and E supplementation displayed promising results for the treatment of endometriosis, but further research is needed for their use in this population.

Current Challenges in the Management of Chronic Pelvic Pain in Women: From Bench to Bedside

Chronic pelvic pain (CPP) affects a significant proportion of women worldwide And has a negative impact on several aspects of these women’s lives including mental health, work, relationships and sexual function, among others. This set of factors ultimately reflects negatively on quality Of life. The physiopathology of CPP is complex and remains to be fully clarified; however, recent advances have increased understanding of the mechanisms involved in chronic pain in general, and more specifically, CPP. Nonetheless, even when a detailed clinical history is obtained, meticulous physical examination is performed and imaging resources are appropriately used, the organic cause of the pain may still fail to be identified in a substantial number of women with CPP. Management of CPP may therefore be challenging. This narrative review was aimed at adding to the available literature on the subject, presenting and discussing the principal characteristics of CPP in women. The paper highlights gaps in the literature while providing the most up-to-date evidence associated with the physiopathology and classification of pain, its diagnosis and treatment. In addition, current challenges in the management of women with CPP are discussed.