Fibromyalgia and Associated Disorders: From Pain to Chronic Suffering, From Subjective Hypersensitivity to Hypersensitivity Syndrome

Anterior Cingulate Cortex-Anterior Insular Cortex Circuit Mediates Hyperalgesia in Adolescent Mice Experiencing Early Life Stress

Understanding neurobiological mechanisms underlying changes in behavior and neural activity caused by early life stress (ELS) is essential for improving these adverse outcomes in individuals. ELS incited by exposure to maternal separation (MS) can be defined as a form of social pain, but little is known about the neural mechanism in adolescents with ELS-induced pain sensitization. Employing an MS-induced ELS paradigm in mice, we reported here that both male and female MS mice aged 1-2 months exhibited mechanical and thermal hyperalgesia using paw-withdrawal and hot/cold plate tests. The increased high gamma (γhigh) oscillations accompanied by the activation of parvalbumin-positive interneurons (PVINs) in the anterior insular cortex (AIC), but not the anterior cingulate cortex (ACC), were shown in MS mice. Moreover, ACC-driven AIC connectivity was enhanced in MS mice, characterized by amplified phase coherence in the delta (δ) and theta (θ) bands and an escalation in the coupling of the ACC θ phase and AIC γ amplitude. Chemogenetic inactivation of AIC PVINs relieved hyperalgesia and altered the ACC-AIC connectivity in MS mice. The observed increase in δ-θ synchronization and PVIN activation in the ACC-AIC circuit indicates this pathway is a therapeutic target for ELS-induced hyperalgesia.

Unveiling the link: exploring muscle oxygen saturation in fibromyalgia and its implications for symptomatology and therapeutic strategies

Fibromyalgia, characterized as a complex chronic pain syndrome, presents with symptoms of pervasive musculoskeletal pain, significant fatigue, and pronounced sensitivity at specific anatomical sites. Despite extensive research efforts, the origins of fibromyalgia remain enigmatic. This narrative review explores the intricate relationship between muscle oxygen saturation and fibromyalgia, positing that disruptions in the oxygenation processes within muscle tissues markedly influence the symptom profile of this disorder. Muscle oxygen saturation, crucial for muscle function, has been meticulously investigated in fibromyalgia patients through non-invasive techniques such as near-infrared spectroscopy and magnetic resonance imaging. The body of evidence consistently indicates substantial alterations in oxygen utilization within muscle fibers, manifesting as reduced efficiency in oxygen uptake during both rest and physical activity. These anomalies play a significant role in fibromyalgia's symptomatology, especially in terms of chronic pain and severe fatigue, potentially creating conditions that heighten pain sensitivity and accumulate metabolic byproducts. Hypothesized mechanisms for these findings encompass dysfunctions in microcirculation, mitochondrial irregularities, and autonomic nervous system disturbances, all meriting further research. Understanding the dynamics of muscle oxygen saturation in fibromyalgia is of paramount clinical importance, offering the potential for tailored therapeutic approaches to alleviate symptoms and improve the quality of life for sufferers. This investigation not only opens new avenues for innovative research but also fosters hope for more effective treatment strategies and improved outcomes for individuals with fibromyalgia.

A Comprehensive Analysis of Fibromyalgia and the Role of the Endogenous Opioid System

Fibromyalgia represents a chronic pain disorder characterized by musculoskeletal pain, fatigue, and cognitive impairments. The exact mechanisms underlying fibromyalgia remain undefined; as a result, diagnosis and treatment present considerable challenges. On the other hand, the endogenous opioid system is believed to regulate pain intensity and emotional responses; hence, it might be expected to play a key role in the enhanced sensitivity experienced by fibromyalgia patients. One explanation for the emergence of disrupted pain modulation in individuals with fibromyalgia is a significant reduction in opioid receptor activity or an imbalance in the levels of endogenous opioid peptides. Further research is essential to clarify the complex details of the mechanisms underlying this abnormality. This complexity arises from the notion that an improved understanding could contribute to the development of innovative therapeutic strategies aimed at targeting the endogenous opioid system in the context of fibromyalgia. Although progress is being made, a complete understanding of these complexities remains a significant challenge. This paradigm has the potential to revolutionize the complex management of fibromyalgia, although its implementation may experience challenges. The effectiveness of this approach depends on multiple factors, but the implications could be profound. Despite the challenges involved in this transformation, the potential for improving patient care is considerable, as this condition has long been inadequately treated.

Psychological Features of Fibromyalgia in the Psychological Health Services

Patients with health pathologies may exhibit psychological features in addition to medical symptomatology. A sample of 76 Italian women with an age range between 23 and 78 years old (mean = 50.22 ± 10.47 years) diagnosed with fibromyalgia (a disorder characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, cognitive and mood issues) was examined to identify typical characteristics of their psychological profile. All patients were administered a series of questionnaires, to assess avoidance of physical touch by others; anxiety; depression; risk of developing psychotic disorders; self-criticism and perfectionism; acceptance of chronic pain; general impact of the pathology on their lives, and the predisposition to experience positive emotional states. The scores resulting from this assessment were evaluated against the normative data. Patients with fibromyalgia showed psychological dysfunction in most of the scales administered, with a significantly higher disposition to experience compassion towards others (t = 5.94, df = 75, p < 0.001). A higher risk of psychosis was related with higher levels of depression (B = 0.49, t = 0.20, p = 0.015), poor involvement in daily activities (B = 0.41, t = 0.13, p = 0.002), touch avoidance (especially towards strangers, B = -0.20, t = 0.14, p = 0.01), and overall poor quality of life (B = 0.40, t = 0.16, p = 0.01). This study may broaden the possibility to evaluate psychological features in this clinical population; it may contribute to tailoring psychological care and related treatments in the context of health services.

The effectiveness of stretching exercises in patients with fibromyalgia: A systematic review

Fibromyalgia is one of the most prevalent chronic pain disorders. Fibromyalgia is characterised by generalised pain. In addition, patients with fibromyalgia often have co-morbidity. Since no cure is available, the treatment is based on symptom management, with physical exercise being the recommended first-line treatment. Different exercise modalities have been examined, including the practice of stretching exercises. The aim of the systematic review is to summarise the efficacy of stretching exercises on fibromyalgia symptoms and to study the content and the quality of the current evidence. The review followed the recommendations of the PRISMA statement. The search for articles was performed in April 2023. We searched on MEDLINE, PubMed, CINAHL, Web of Science, SCOPUS, AMED, PEDro, ClinicalTrials.gov and the Cochrane Collaboration Trials Register. The search was updated in March 2024. The protocol was registered in PROSPERO. Risk of Bias was assessed using the Cochrane Risk of Bias tool, and quality assessment was performed using the GRADE approach. In total, 2586 studies were found in the database searches, of which nine were included in the analysis. The primary outcome was pain. Secondary outcomes were self-reported quality of life, fatigue and physical and mental functioning. The available evidence shows that stretching exercises may improve pain, health-related quality of life and physical and mental functioning, but the level of evidence is low. The main limitation is due to issues with the heterogeneity of the interventions and small sample sizes. Trial registration: PROSPERO registration number CRD42023399614. Key Points • Stretching exercises show promise in the treatment of fibromyalgia. They may improve pain, health-related quality of life, physical functioning and mental health, but the level of evidence is low. • This study goes beyond previous research by presenting a more comprehensive and detailed analysis of the content and methodological quality of the current evidence. • Further research with clearly outlined protocols must be carried out to advance our understanding of the benefits of stretching exercises on fibromyalgia symptoms.

Diffuse Pain Revealing Clinically Unapparent Subcutaneous Sarcoidosis

Abstract is missing (Short communication)

Inflammation, Autoimmunity, and Infection in Fibromyalgia: A Narrative Review

Fibromyalgia (FM) is a chronic disease characterized by widespread musculoskeletal pain of unknown etiology. The condition is commonly associated with other symptoms, including fatigue, sleep disturbances, cognitive impairment, and depression. For this reason, FM is also referred to as FM syndrome. The nature of the pain is defined as nociplastic according to the latest international classification and is characterized by altered nervous sensitization both centrally and peripherally. Psychosocial conditions have traditionally been considered critical in the genesis of FM. However, recent studies in animal models and humans have provided new evidence in favor of an inflammatory and/or autoimmune pathogenesis. In support of this hypothesis are epidemiological data of an increased female prevalence, similar to that of autoimmune diseases, and the frequent association with immune-mediated inflammatory disorders. In addition, the observation of an increased incidence of this condition during long COVID revived the hypothesis of an infectious pathogenesis. This narrative review will, therefore, discuss the evidence supporting the immune-mediated pathogenesis of FM in light of the most current data available in the literature.

Hyperbaric oxygen therapy vs. pharmacological intervention in adults with fibromyalgia related to childhood sexual abuse: prospective, randomized clinical trial

Fibromyalgia syndrome (FMS) is a chronic pain syndrome characterized by disruptions in pain processing within the central nervous system. It exhibits a high prevalence among patients with a history of traumatic experiences, notably childhood sexual abuse (CSA). This study compared the efficacy of hyperbaric oxygen therapy (HBOT) to the current pharmacological standard of care for individuals suffering from CSA-related FMS. Forty-eight participants diagnosed with FMS and a history of CSA were randomly assigned to either the HBOT group (60 sessions of 100% oxygen at 2 ATA for 90 min, with air breaks every 5 min) or the medication (MED) group (FDA-approved medications, Pregabalin and Duloxetine). The primary endpoint was the Fibromyalgia impact questionnaire (FIQ) score, while secondary endpoints encompassed emotional status and daily functioning questionnaires, as well as pain thresholds and conditioned pain modulation tests. Brain activity was evaluated through single photon emission computed tomography (SPECT). Results revealed a significant group-by-time interaction for the FIQ score favoring HBOT over MED (p < 0.001), with a large effect size (Cohen's d = - 1.27). Similar findings were observed in emotional symptoms and functional measures. SPECT imaging demonstrated an increase in activity in pre-frontal and temporal brain areas, which correlated with symptoms improvement. In conclusion, HBOT exhibited superior benefits over medications in terms of physical, functional, and emotional improvements among FMS patients with a history of CSA. This associated with increased activity in pre-frontal and temporal brain areas, highlighting the neuroplasticity effect of HBOT.

Translation, cross-cultural adaptation and psychometric properties of the Urdu version of the avoidance endurance behavior questionnaire in patients with chronic musculoskeletal pain

BACKGROUND

The Avoidance Endurance Questionnaire (AEQ) successfully measures the fear-avoidance and endurance-related responses to chronic pain.

OBJECTIVE

The objective of this study was to translate, cross-culturally adapt AEQ into Urdu and assess the reliability and validity of the Urdu version.

METHOD

For the translation and cross-cultural adaptation process, the Beaton Guidelines were followed. A total of 103 participants responded to the Urdu version of the AEQ SF-12, Pain Catastrophizing Scale (PCS) and Numeric Pain Rating Scale (NPRS) at baseline and after 48 hours. The test-retest reliability was assessed using the intraclass correlation coefficient (ICC). Cronbach's alpha was used to measure internal consistency. To measure validity, Pearson's correlation between the subscales of AEQ-Urdu and other outcome measures (SF-12, PCS and NPRS scores) were used (p< 0.05).

RESULTS

The mean age of the total 103 participants was 32.7 ± 10.90 among which 45 (43.6%) were male and 58 (56.3%) were female. The pre-final version of the translated AEQ was tested on 40 Urdu speaking participants and no major changes were made. The Cronbach's alpha for all subscales of the AEQ-Urdu ranged from 0.848-0.990. AEQ-U showed an excellent test-retest reliability with the ICC ranging from 0.775-0.996. The majority of the subscales of AEQ showed significant (p< 0.05) positive correlation with pain scales (PCS and NPRS) and negative correlation with the domains of SF-12.

CONCLUSION

The AEQ-U has reliable and valid construct validity, good internal consistency, and test-retest reliability, indicating that it has adequate psychometric features and can be a useful tool for evaluating pain responses in patients with chronic musculoskeletal pain.

Fibromyalgia - etiology, diagnosis and treatment including perioperative management in patients with fibromyalgia

Fibromyalgia (FM) is considered a multifactorial disorder/syndrome with not fully understood etiology. Chronic generalized pain is the main symptom. A broad spectrum of factors is proposed to explain the etiology. Its multifactorial nature is inherently associated with challenges in diagnosis and therapy. Various evidence of etiology has been evaluated with the aim of establishing a novel therapeutic approach. The main issue in the diagnosis and management is to focus on the evaluation of strict diagnostic criteria to minimize under- and overdiagnosis. Fibromyalgia is a challenge for perioperative management because of the increased risk of possible complications and poorer outcomes, including postoperative pain chronification. The authors have proposed an up-to-date evaluation of perioperative management considering the current guidelines. Multimodal analgesia combined with tailored perioperative care is the most appropriate assessment. Interdisciplinary research with special interest in pain management, including perioperative medicine, seems to be the main theme for the future.

The immunomodulatory effects of ethosuximide and sodium butyrate on experimentally induced fibromyalgia: The interaction between IL-4, synaptophysin, and TGF-β1/NF-κB signaling

BACKGROUND AND AIMS

Fibromyalgia is a widespread chronic pain syndrome associated with several comorbid conditions that affect the quality of patients' life. Its pathogenesis is complex, and the treatment strategies are limited by partial efficacy and potential adverse effects. So, our aim was to investigate the possible ameliorative effects of ethosuximide and sodium butyrate on fibromyalgia and compare their effects to pregabalin.

MATERIALS AND METHODS

In a mouse model of reserpine induced fibromyalgia, the effect of ethosuximide, sodium butyrate, and pregabalin was investigated. Evaluation of mechanical allodynia, cold hypersensitivity, anxiety, cognitive impairment, and depression was performed. Also, the brain and spinal cord tissue serotonin, dopamine and glutamate in addition to the serum levels of interleukin (IL)-4 and transforming growth factor beta 1 (TGF-β1) were assayed. Moreover, the expression of nuclear factor kappa B (NF-κB) synaptophysin was immunoassayed in the hippocampal tissues.

KEY FINDINGS

Ethosuximide and sodium butyrate restored the behavioral tests to the normal values except for the antidepressant effect which was evident only with ethosuximide. Both drugs elevated the levels of the anti-inflammatory cytokines IL-4 and TGF-β1, reduced the hippocampal NF-κB, and increased synaptophysin expression with superiority of sodium butyrate. Ethosuximide reduced only spinal cord and brain glutamate while improved brain dopamine while sodium butyrate elevated spinal cord dopamine and serotonin with no effect on glutamate. Also, sodium butyrate elevated brain serotonin and reduced glutamate with no effect on brain dopamine.

SIGNIFICANCE

Each of sodium butyrate and ethosuximide would serve as a promising therapeutic modality for management of fibromyalgia and its comorbid conditions.

Central and peripheral mechanisms of pain in fibromyalgia: scoping review protocol

Fibromyalgia is characterised by widespread musculoskeletal pain, which may present with fatigue, depression, anxiety, sleep and cognitive disturbances. It is the second most prevalent rheumatic disease. An accurate diagnosis is challenging, since its symptoms may resemble diverse conditions such as carpal tunnel syndrome, Raynaud syndrome, Sjögren syndrome, amongst others. Neuropathic pain and autonomic dysfunction in fibromyalgia suggest the involvement of the nervous system. Ion channels, neurotransmitters and neuromodulators may play a role. Small fibre neuropathy (SFN) may also cause chronic widespread pain. SFN may occur in 50% of fibromyalgia patients, but its role in the disease is unknown. Despite several efforts to synthesise the evidence on the mechanisms for pain in fibromyalgia, there are few studies applying an integrative perspective of neurochemical, immunological, and neuroanatomical characteristics, and their relevance to the disease. This protocol aims to clarify the mechanisms of the central and peripheral nervous system associated with pain in fibromyalgia. We will retrieve published studies from Web of Science, MEDLINE, Scopus, EBSCOhost, Ovid and Google Scholar. All clinical studies or experimental models of fibromyalgia reporting imaging, neurophysiological, anatomical, structural, neurochemical, or immunological characteristics of the central or peripheral nervous systems associated with pain will be included. Exclusion criteria will eliminate studies evaluating pain without a standardised measure, studies written in languages different from Spanish or English that could not be appropriately translated, and studies whose full-text files could not be retrieved after all efforts made. A narrative synthesis will be performed.

Investigation of temporomandibular disorders in patients with fibromyalgia syndrome: A case-control study

INTRODUCTION

The aim of this study is to compare the frequency of temporomandibular disorders and to examine the temporomandibular pain and functionality levels between healthy female participants and female patients diagnosed with fibromyalgia.

MATERIALS AND METHODS

Our study included 300 participants. Patients were evaluated according to the Diagnostic Criteria for Temporomandibular Disorders: Assessment Instruments (DC/TMD). While evaluating the patients using DC/TMD, TMD Pain Screener and Symptom questionnaire were used within the scope of Axis I, and Graded Chronic Pain Scale, Jaw Functional Limitation Scale-8 (JFLS-8), Patient Health Questionnaire (PHQ-4) and Oral Behaviors Checklist were applied.

RESULTS

Bruxism, tooth grinding and masseter hypertrophy were found to be significantly higher in fibromyalgia patients compared to healthy volunteers (p<0.001). The pain screener, JFLS-8, PHQ-4 and OBC scores and GCPS levels were found to be increased in the fibromyalgia group compared to healthy individuals (p<0.001). Considering the post-examination diagnoses of the participants, the diagnoses of myalgia (p=0.022) and disc displacement with reduction (p<0.001) were significantly higher than healthy individuals.

CONCLUSIONS

Fibromyalgia is a common pathology, therefore, TMD symptoms, which are more difficult to diagnose and often missed, should be questioned in fibromyalgia patients and should be kept in mind in the management of fibromyalgia patients.

Personality construct as a biomarker in fibromyalgia: A narrative review from an autonomic rehabilitation perspective

BACKGROUND

The heterogeneity of symptoms and ineffective treatment raise questions about the current diagnostic criteria of fibromyalgia (FM). Misdiagnosis of FM often leads to less than efficacious treatment and poor quality of life.

OBJECTIVE

This article reviews relevant evidence-based literature on personality traits in FM patients with an autonomic dysfunction perspective based on a hierarchical model to explain the utility of considering the personality trait in FM diagnosis.

METHODS

A narrative review of articles concerning chronic pain, FM, and personality traits with respect to autonomic dysfunction in FM was conducted after extensive relevant literature searches.

RESULTS

Reports discussing the predisposing factors, including coping styles, anger, suicide risk, a lack of physical activity and social support, in maintaining persistent pain in FM exist. Relationships between pain duration and severity and personality traits like neuroticism and extraversion have been reported. Coexisting clinical manifestations of FM like sleep disorders, anxiety, and intestinal irritability indicate autonomic dysfunction.

CONCLUSIONS

This article lays out a constructive framework for individualized and personalized medicine for the effective rehabilitation of FM patients. The quest to find a definitive diagnosis of FM should include personality biomarkers that might translate into personalized medicine. An individualistic approach may bank upon artificial intelligence algorithms for both diagnostic as well as prognostic purposes in FM.

The Relationship between Daily Physical Activity, Psychological Factors, and Vegetative Symptoms in Women with Fibromyalgia: A Cross-Sectional Observational Study

Nowadays, there is evidence that relates the amount of physical activity, as well as the impact of psychological factors, to the intensity of symptoms present in patients with fibromyalgia (FM). However, there are no studies which correlate the level of association of physical activity, psychological factors and vegetative symptoms in the FM population. The study has a cross-sectional observational design with 41 participants being recruited from a private clinic and rehabilitation service. The Autonomic Symptom Profile (Compass-31) to assess vegetative symptoms, the GODIN questionnaire to evaluate the level of leisure activity, and the pain catastrophizing scale, Tampa Kinesiophobia Scale and Self-Efficacy Scale to assess psychological factors, were used. A low and significant level of association was found between pain catastrophizing (PCS) and Kinesiophobia (r = 0.398; p < 0.01), as well as with catastrophizing and vegetative symptoms (r = 0.428; p < 0.05). Furthermore, a low and significant level of association was also found between self-efficacy and vegetative symptoms (r = 0.397; p < 0.05). No association was found between the level of daily physical activity (measured by the Godin Leisure questionnaire) and vegetative symptoms, nor with any psychological factor studied. There is an association between vegetative symptoms and psychological factors. Nevertheless, more research which takes other factors into account, such as lifestyle and nutritional, is needed.

Whole-Body Cryostimulation in Fibromyalgia: A Scoping Review

Currently, all available therapies for the control and management of fibromyalgia (FM) are mostly focused on relieving patients’ symptoms and improving their quality of life. The purpose of this review is to provide an up-to-date overview of the evidence supporting the beneficial effects of whole-body cryostimulation (WBC) in patients with FM and evidence-based guidance on the possible adjuvant use of WBC in the treatment of FM. We searched the most recent literature by retrieving 10 eligible studies, 4 of which were abstracts only, from a total of 263 records. Thermal stress caused by cryostimulation induces an analgesic effect, improving pain, redox balance, and inflammatory symptoms in an exercise-mimicking fashion. In addition, it reduces the feeling of fatigue, improves mood, and reduces mental health deterioration with positive consequences on depressive states and improved sleep quality. Although the studies included in this review are not of sufficient quality and quantity to draw definitive conclusions about the effectiveness of WBC in FM, initial evidence indicates WBC as a promising add-on option in the multidisciplinary treatment of FM, due to its rapid action and high patients’ compliance. The application of WBC protocols has the potential to expand therapeutic options for the treatment of FM and related disorders; however, larger, high-quality primary studies are still needed.

Cultural Validation of the Chinese Central Sensitization Inventory in Patients with Chronic Pain and its Predictive Ability of Comorbid Central Sensitivity Syndromes

BACKGROUND

Central sensitization (CS) is frequently reported in chronic pain, and the central sensitization inventory (CSI) is popularly used to assess CS. However, a validated Chinese CSI is lacking and its predictive ability for the comorbidity of central sensitivity syndromes (CSSs) remains unclear. Hence, this study aimed to generate the Chinese CSI (CSI-C) with cultural adaptation and examine its psychometric properties.

METHODS

The CSI-C was formulated through forward and backward translation, panel review and piloting and then validated among patients with chronic pain (n = 235). Its internal consistency, test-retest reliability, and concurrent validity were measured. An exploratory factor analysis (EFA) was performed for the construct validity. Receiver operating characteristic (ROC) analysis was employed to determine the discriminative ability in the presence of comorbidity of CSSs.

RESULTS

About 70% of the participants in the study experienced at least mild CS symptoms. CSI-C demonstrates a high internal consistency (Cronbach's alpha = 0.896) and excellent test-retest reliability (ICC = 0.932). CSI-C scoring was significantly correlated with pain intensity (r = 0.188), EQ-5D index (r = -0.375), anxiety (r=0.525), and depression (r = 0.467). The EFA generated a 5-factor model, including physical symptoms, emotional distress, hypersensitivity syndromes and so on. An CSI cutoff of 42 had a sensitivity of 71.4% and a specificity of 70% for identifying chronic pain patients with ≥2 CSSs.

CONCLUSION

The CS manifestations are prevalent in those with persistent pain. CSI-C is a reliable and valid instrument for measuring CS. A CSI score ≥42 may predict the comorbidity of 2 or above CSSs in patients with chronic pain.