Central sensitization in patients with deep endometriosis

Multidimensional Evaluation of Myofascial Pelvic Pain and Other Comorbidities in Endometriosis Patients

Background/Objectives: Pain associated with endometriosis is complex and influenced by multiple factors. The presence of myofascial pelvic pain (MPP), associated comorbidities, and overlapping symptoms may play a role in endometriosis-associated pain. The aim of this study was to evaluate MPP in patients with endometriosis and correlate it with other self-reported comorbidities and symptoms, health-related quality of life, and mental health. Methods: A cross-sectional study was carried out at a tertiary hospital referral center on 175 women with endometriosis. MPP was evaluated by clinical examination; if present, the patient was allocated to the MPP group (n = 84), and if absent, the patient was allocated to the non-MPP group (n = 91). Other comorbidities and symptoms frequently found in patients with chronic pain were also recorded. The Short Form 36-Item health questionnaire (SF-36) and the Hospital Anxiety and Depression Scale (HADS) were administered. Central sensitization-related symptoms were assessed using the Central Sensitization Inventory (CSI). Results: Patients with MPP showed significantly higher scores related to endometriosis-associated pain, reported lower scores in all domains of the SF-36, and higher scores in the HADS questionnaire. This group also reported more comorbid symptoms and showed higher scores in the CSI questionnaire. In the multivariate analysis, severe non-cyclic pelvic pain, abdominal bloating, and CSI ≥ 40 remained significantly associated with the presence of MPP. Conclusions: Endometriosis patients with MPP presented more pain comorbidities and general symptoms. Moreover, they reported more endometriosis-associated pain and worse health-related quality of life, and they may be at higher risk of depression and anxiety.

The connection between endometriosis and secondary dysmenorrhea

Endometriosis (EMS) is a prevalent gynecological condition characterized by the presence of endometrial tissue outside the uterus, often leading to secondary dysmenorrhea (SD), chronic pelvic pain and infertility. This review explores the intricate connection between EMS- associated pain and SD, focusing on the pathophysiological mechanisms underlying dysmenorrhea in EMS. Key contributors to pain include inflammation, aberrant immune responses, neurogenic inflammation, peritoneal irritation, peripheral sensitization, central sensitization and cross-organ sensitization. Understanding the pain pathways in EMS highlights the complexity of symptom manifestation and underscores the necessity for a multidisciplinary approach to management. Clinical manifestations, including chronic pelvic pain, dyspareunia, infertility, gastrointestinal and bladder symptoms, fatigue and malaise, are discussed, emphasizing the diverse impact of EMS on women's health. Various treatment modalities, ranging from pharmacological interventions to surgical and complementary approaches, are outlined to provide comprehensive management strategies for EMS-related menstrual pain/SD. This review aims to enhance understanding and facilitate the effective management of EMS-associated SD, ultimately improving the quality of life for affected individuals.

A Multimodal Approach to Symptomatic Endometriosis: A Proposed Algorithm for Clinical Management

Recent research has proven that peripheral (PS) and central sensitization (CS), mental health, and myofascial dysfunction all play a role, alongside nociception, in the genesis and in the perpetuation of endometriosis' symptoms. However, such components of pain are still largely ignored in clinical practice, although not considering such contributors may entail serious consequences on women's health, including the choice of unnecessary surgery and leaving the real causes of pain untreated. At the present time, we are facing a paradox by which 25-40% of women who undergo laparoscopic surgery for pelvic pain do not have an obvious diagnosis, while the percentage of women with endometriosis who have signs of CS, of depressive or anxiety disorders, or who have an increased pelvic muscle tone ammounts to 41-55%, 15-88% and 28-73%, respectively. Moving from the widely-accepted stepwise approach suggested for endometriosis management, which consists in the initial prescription of low-dose combined oral contraceptives (COCs) or of a progestin monotherapy, followed by GnRH analogues and, ultimately, by surgery, when COCs and progestins have proven ineffective or are not tolerated or contraindicated, we propose an integration of such model which takes into account the identification and the simultaneous treatment of all pain contributors. Our objective is to encourage physicians' awareness of the need of a multidisciplinary, multimodal approach to endometriosis-related pain, and ultimately to promote a reduction in the number of unnecessary surgeries.

Prevalence of anhedonia in women with deep endometriosis

Anhedonia, characterized by diminished motivation and pleasure sensitivity, is increasingly recognized as prevalent among patients with chronic pain. Deep Endometriosis (DE), the most severe endophenotype of the disease, is commonly presented with chronic pelvic pain. This cross-sectional study reports, for the first time, the prevalence of anhedonia in a sample comprised by 212 premenopausal women with suspected DE referred to a tertiary hospital. Our findings show that 27,8% [95% CI 22.1, 26.5] of DE patients experience abnormal hedonic tone. Severity of DE pain-related symptoms significantly correlated with anhedonia, consistent with previous findings. Chronic pelvic pain emerged as a significant predictor of anhedonia (OR 1.5, 95% CI 1.0-1.22, p < 0.05) with the odds increasing to 2.28 [95% CI 1.12, 4.23] when pain was severe. The most affected areas in DE patients were interests, social interaction and food pleasure. The present results are representative of DE patients under multimodal treatment, limiting generalizability. Overall, our study highlights the impact of chronic pain on hedonic functioning in DE. Therapeutic approaches targeting hedonic capacity in DE patients are crucial for restoring health and well-being.

Nociplastic Pain in Endometriosis: A Scoping Review

Endometriosis is an inflammatory chronic condition associated with nociceptive, neuropathic, and nociplastic pain. Central sensitization (CS) is the primary nociplastic pain mechanism. However, there are currently no standardized methods for detecting CS or nociplastic pain. This review aims to identify available tools for characterizing CS/nociplastic pain in endometriosis-related chronic pelvic pain. Following the PRISMA-P protocol, MEDLINE, Embase, Scopus, and PsychINFO databases were searched on 23 April 2024, for the terms "endometriosis", "central sensitization", "nociplastic pain", "widespread pain", and "assessment tools". Publications were selected if they mentioned tool(s) for detecting nociplastic pain or CS in endometriosis patients. Information was extracted on study demographics, assessment types, and the tools used for detection. Of the 379 citations retrieved, 30 papers met the inclusion criteria. When working to identify CS and nociplastic pain, fourteen studies exclusively used patient-reported questionnaires, six used quantitative sensory testing (QST), two used clinical assessments, and eight used multiple approaches combining patient-reported questionnaires and clinical assessment. This review illustrates the diversity of tools currently used to identify CS and nociplastic pain in endometriosis patients. Further research is needed to evaluate their validity and to standardize methods in order to improve the accuracy of nociplastic pain identification and guide treatment.

Bidirectional causality between the levels of blood lipids and endometriosis: a two-sample mendelian randomization study

BACKGROUND

Observational studies have found a correlation between the levels of blood lipids and the development and progression of endometriosis (EM). However, the causality and direction of this correlation is unclear. This study aimed to examine the bidirectional connection between lipid profiles and the risk of EM using publicly available genome-wide association study (GWAS) summary statistics.

METHODS

Eligible exposure variables such as levels of triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) were selected using a two-sample Mendelian randomization (MR) analysis method following a series of quality control procedures. Data on EM were obtained from the publicly available Finnish database of European patients. Inverse variance weighted (IVW), MR Egger, weighted median, and weighted mode methods were used to analyze the causal relationship between lipid exposure and EM, exclude confounders, perform sensitivity analyses, and assess the stability of the results. Reverse MR analyses were performed with EM as exposure and lipid results as study outcomes.

RESULTS

IVW analysis results identified HDL as a protective factor for EM, while TG was shown to be a risk factor for EM. Subgroup analyses based on the site of the EM lesion identified HDL as a protective factor for EM of the uterus, while TG was identified a risk factor for the EM of the fallopian tube, ovary, and pelvic peritoneum. Reverse analysis did not reveal any effect of EM on the levels of lipids.

CONCLUSION

Blood lipids, such as HDL and TG, may play an important role in the development and progression of EM. However, EM does not lead to dyslipidemia.

Questionnaires for the Assessment of Central Sensitization in Endometriosis: What Is the Available Evidence? A Systematic Review with a Narrative Synthesis

It has been suggested that central sensitization (CS) may be involved in the failure of standard medical and surgical treatment to relieve endometriosis-related pain. However, there is no gold standard for the diagnosis of CS, and self-reported questionnaires are used as diagnostic surrogates. The main objective of this review was to identify all CS questionnaires used in clinical endometriosis studies. The secondary objective was to qualitatively analyze strengths and weaknesses of each questionnaire. A PubMed and EMBASE systematic literature search conducted in April 2023 using the terms "endometriosis; central pain; central sensitization; questionnaire; patient-reported outcome measure; screening tool" identified 122 publications: six articles were included in the review. The Central Sensitization Inventory (CSI) is the most frequently used questionnaire for the detection of CS in patients with endometriosis. It has been validated in patients with endometriosis, in whom it appears to have good psychometric proprieties. The Fibromyalgia Survey Questionnaire (FSQ) has also been used, although it has not been specifically validated in endometriosis patients. The debate regarding these questionnaires' construct validity is still open and will be so until a gold standard diagnostic tool for CS is found. In fact, some authors argue these questionnaires are measuring psychological vulnerability and a hypervigilant state that is associated with pain, rather than CS itself. However, their use should not be discouraged as they are able to identify chronic pain patients which warrant further attention and who may benefit from broader treatment strategies.

Endometriosis-Related Chronic Pelvic Pain

Endometriosis, which is the presence of endometrial stroma and glands outside the uterus, is one of the most frequently diagnosed gynecologic diseases in reproductive women. Patients with endometriosis suffer from various pain symptoms such as dysmenorrhea, dyspareunia, and chronic pelvic pain. The pathophysiology for chronic pain in patients with endometriosis has not been fully understood. Altered inflammatory responses have been shown to contribute to pain symptoms. Increased secretion of cytokines, angiogenic factors, and nerve growth factors has been suggested to increase pain. Also, altered distribution of nerve fibers may also contribute to chronic pain. Aside from local contributing factors, sensitization of the nervous system is also important in understanding persistent pain in endometriosis. Peripheral sensitization as well as central sensitization have been identified in patients with endometriosis. These sensitizations of the nervous system can also explain increased incidence of comorbidities related to pain such as irritable bowel disease, bladder pain syndrome, and vulvodynia in patients with endometriosis. In conclusion, there are various possible mechanisms behind pain in patients with endometriosis, and understanding these mechanisms can help clinicians understand the nature of the pain symptoms and decide on treatments for endometriosis-related pain symptoms.