Biology and therapy of fibromyalgia: pain in fibromyalgia syndrome

Study of Rates and Factors Associated to Psychosomatic Syndromes Assessed Using the Diagnostic Criteria for Psychosomatic Research across Different Clinical Settings

INTRODUCTION

Diagnostic Criteria for Psychosomatic Research (DCPR) serve as an instrument for identifying and classifying specific psychosomatic syndromes that are not adequately encompassed in standard nosography. The present study aimed at measuring the prevalence of DCPR syndromes in different clinical settings and exploring factors associated to such diagnoses.

METHODS

A cross-sectional and nationwide study recruited 6,647 patients in different clinical settings: 306 were diagnosed with fibromyalgia (FM), 333 with irritable bowel syndrome, 1,109 with migraine, 2,550 with coronary heart disease (CHD), and 2,349 with type 2 diabetes (T2D). Participants underwent DCPR diagnostic interview and were assessed for depression (Patient Health Questionnaire-9), anxiety (Generalized Anxiety Disorder 7-Item Scale), and subjective well-being (World Health Organization-5 Well-Being Index). The PsychoSocial Index was used to evaluate global well-being, stress, and abnormal illness behavior. The prevalence of DCPR diagnoses was calculated, and factors associated to such diagnoses were analyzed by logistic regression.

RESULTS

Alexithymia (64.47%), irritable mood (20.55%), and demoralization (15.60%) were the most prevalent psychosomatic syndromes, with demoralization being most common in FM (49.02%). The factors associated to DCPR diagnoses encompassed high anxiety or abnormal illness behavior, and poor well-being. Notably, stress was found to be associated specifically to FM and T2D, with OR of 1.24 (95% CI: 1.06-1.46) and 1.26 (95% CI: 1.18-1.36), respectively.

CONCLUSION

DCPR is a clinically helpful complementary assessment tool in need of being widely implemented in clinical settings in order to have a comprehensive picture of the patients.

Feasibility, Safety, and Effects of an Aerobic Training Program with Blood Flow Restriction on Functional Capacity, and Symptomatology in Women with Fibromyalgia: A Pilot Study

BACKGROUND

Evidence suggests that aerobic training with blood flow restriction is beneficial for treating fibromyalgia. This study evaluated the feasibility, safety, and effects of an aerobic training program with blood flow restriction for women with fibromyalgia.

METHODS

Thirty-seven women with fibromyalgia were included, and thirteen with an average age of 59 ± 3, a BMI of 26 ± 3, and who were polymedicated started the intervention period. The intervention group performed aerobic exercise with blood flow restriction using occlusive bands placed in the upper part of the rectus femoris, with a total duration of 14 min of restriction divided into two periods of 7 min with a rest period of 3 min and a total session duration of 17 min. Pressure intensity was measured using the visual pain scale (VAS), scoring 7 out of 10 (n = 7). The non-intervention group performed aerobic exercise without restriction of blood flow for the same periods, rest periods, and total duration of the session (n = 6). The intervention included 2 weekly sessions with 72 h between aerobic walking for 9 weeks. Walking was measured individually using the rating of perceived exertion scale (RPE) with an intensity between 6 and 7 out of 10. Visual and verbal support for the VAS and RPE scale was always provided throughout the sessions supervised by the investigator. Functional capacity was assessed using tests (six-minute walk test, incremental shuttle walk test, knee extension and handgrip test by dynamometer, 30 s chair stand test, and timed up-and-go test). Symptomatology was assessed using questionnaires (Widespread Pain Index, Symptom Severity Score, Fibromyalgia Impact Questionnaire, and Multidimensional Fatigue Inventory), and blood samples were collected.

RESULTS

There were no adverse effects, and only one participant in the intervention group withdrew. Between-group and intragroup differences showed that the intervention group obtained improvements in the functional tests; CST p = 0.005; 6MWT p = 0.011; Handgrip p = 0.002; TUGT p = 0.002 with reduced impact of the disease according to the questionnaires; FIQ Stiffness p = 0.027 compared with the nonintervention group. Biochemical results remained within normal ranges in both groups.

CONCLUSIONS

Blood flow-restricted aerobic training may be feasible, safe, and more effective than unrestricted aerobic training as a physical exercise prescription tool to improve cardiorespiratory fitness, strength, balance, and stiffness in women with fibromyalgia.

Oxidative stress may be a contributing factor in fibromyalgia patients' pain mechanisms

OBJECTIVE

The pathophysiology of fibromyalgia (FM), a continuously painful syndrome with no known origin, has been related to mitochondrial dysfunction, oxidative stress, and inflammation. Recent studies have shown that FM may be associated with an oxidative balance disorder. The objective of this study was to measure the levels of oxidative stress in FM patients and try to understand the association between FM and free radicals.

METHODS

This study was performed on 100 volunteers admitted to the University of Health Sciences, Sultan 2, Abdulhamid Han Health Application and Research Center Physical Therapy and Rehabilitation Clinic, including 50 healthy controls and 50 patients with FM. To analyze oxidative stress biomarkers, total oxidant status (TOS) and total antioxidant status (TAS) levels were measured. Total thiol (TT) and native thiol (NT) concentrations were measured to determine the relationship between thiol groups. Disulfide (DIS) and oxidative stress index (OSI) were calculated with mathematical formulas.

RESULTS

While TOS and OSI levels were statistically higher in FM patients, TAS levels were significantly lower compared to the healthy control group (p<0.001). In comparison to the healthy control group, FM patients had considerably decreased TT and NT levels. DIS levels were significantly higher in FM patients than in controls (p<0.001).

CONCLUSIONS

Reactive oxygen species have several negative impacts on the human body. As a result of the measurements we analyzed, the relationship between FM and oxidative stress should be studied in terms of disease progression and may help improve the treatment process.

Expressing emotions, rejection sensitivity, and attachment in patients with fibromyalgia

Objectives

This study aimed to examine emotional awareness, control of emotions, and the childhood attachment process in fibromyalgia patients.

Patients and methods

The observational study was conducted with 117 participants (14 males, 103 females; mean age: 43.9±9.0 years; range, 22 to 64 years) between February 20, 2022, and May 20, 2022. Sixty-one patients and 56 healthy control subjects filled out a form including sociodemographic data, such as age, sex, occupation, and educational status. In addition, the participants answered the Expressing Emotions Scale, Rejection Sensitivity Scale, and Experiences in Close Relationships Scale.

Results

In our study, Expressing Emotions Scale scores are significantly higher in the healthy control group than in the patient group (p<0.05). Rejection Sensitivity Scale scores are significantly higher in the patient group than in the healthy control group (p<0.05). In the Experiences in Close Relationships Scale, a significant difference was determined between the patient and control groups in the avoidant attachment subdimension (p<0.05). Similarly, a significant difference was observed between both groups in terms of the anxiety attachment subdimension (p<0.05).

Conclusion

The ability to express emotions is lower and avoidant and anxious attachment rates are higher in fibromyalgia patients.

Neural indices of multimodal sensory and autonomic hyperexcitability in fibromyalgia

Fibromyalgia (FM) is characterized by chronic widespread musculoskeletal pain and psychological distress. Research suggests people with FM experience increased somatosensory sensitization which generalizes to other sensory modalities and may indicate neural hyperexcitability. However, the available evidence is limited, and studies including measures of neural responsivity across sensory domains and both central and peripheral aspects of the neuraxis are lacking. Thirty-nine participants (51.5 ± 13.6 years of age) with no history of neurological disorders, psychosis, visual, auditory, or learning deficits, were recruited for this study. People with FM (N = 19) and control participants (CNT, N = 20) did not differ on demographic variables and cognitive capacity. Participants completed a task that combined innocuous auditory stimuli with electrocutaneous stimulation (ECS), delivered at individually-selected levels that were uncomfortable but not painful. Event-related potentials (ERPs) and electrodermal activity were analyzed to examine the central and sympathetic indices of neural responsivity. FM participants reported greater sensitivity to ECS and auditory stimulation, as well as higher levels of depression, anxiety, ADHD, and an array of pain-related experiences than CNT. In response to ECS, the P50 deflection was greater in FM than CNT participants, reflecting early somatosensory hyperexcitability. The P50 amplitude was positively correlated with the FM profile factor obtained with a principal component analysis. The N100 to innocuous tones and sympathetic reactivity to ECS were greater in FM participants, except in the subgroup treated with gabapentinoids, which aligns with previous evidence of symptomatic improvement with GABA-mimetic medications. These results support the principal tenet of generalized neural hyperexcitability in FM and provide preliminary mechanistic insight into the impact of GABA-mimetic pharmacological therapy on ameliorating the neural excitation dominance.

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.

Knowledge Mapping of Acupuncture for Fibromyalgia from 1990 to 2022: A Bibliometric Analysis

Background

Fibromyalgia is a rheumatic disease with no specific laboratory markers and is insensitive to hormonal drugs and nonsteroidal anti-inflammatory drugs commonly used to treat rheumatism. Guidelines recommend that non-pharmacological therapy should be the first-line treatment for fibromyalgia. Since the publication of the first diagnostic criteria for fibromyalgia in 1990, studies on acupuncture for fibromyalgia have been reported periodically. This study aims to explore the intellectual landscape of acupuncture for fibromyalgia since 1990, and to identify research trends and fronts in this field.

Methods

The Web of Science Core Collection Database was searched for publications on acupuncture for fibromyalgia from 1990 to 2022. VOSviewer and CiteSpace were used to analyze the annual publication, countries, institutions, authors and cited authors, journals and cited journals, references and keywords.

Results

A total of 280 publications were retrieved, and the number of publications showed an overall upward trend. The United States was the most productive country. China Medical University was the institution with the most publications. Lin Yi-wen was the most prolific author, while Wolfe was the most cited author. Evidence-Based Complementary and Alternative Medicine was the journal in which most of the research was published, while Pain was the most cited journal. An article by Wolfe (1990) had the most citations, but an article by Crofford (2001) had the highest centrality. The four most frequently used keywords in the included articles were mechanism, spinal cord, activation and sensitivity.

Conclusion

Acupuncture can effectively relieve pain in patients with fibromyalgia and improve accompanying symptoms such as anxiety and depression. However, the design of clinical trials still needs to be optimized to better verify the efficacy of acupuncture on various clinical symptoms of fibromyalgia. Exploring the central analgesic mechanism of acupuncture on fibromyalgia is also the focus research direction now and future.

Evaluation of the immediate effects of a single transcranial direct current stimulation session on astrocyte activation, inflammatory response, and pain threshold in naïve rats

Transcranial direct current stimulation (tDCS) has demonstrated clinical benefits such as analgesia, anti-inflammatory, and neuroprotective effects. However, the mechanisms of action of a single tDCS session are poorly characterized. The present study aimed to evaluate the effects of a single tDCS session on pain sensitivity, inflammatory parameters, and astrocyte activity in naive rats. In the first experiment, sixty-day-old male Wistar rats (n=95) were tested for mechanical pain threshold (von Frey test). Afterward, animals were submitted to a single bimodal tDCS (0.5mA, 20minutes) or sham-tDCS session. According to the group, animals were re-tested at different time intervals (30, 60, 120minutes, or 24hours) after the intervention, euthanized, and the cerebral cortex collected for biochemical analysis. A second experiment (n=16) was performed using a similar protocol to test the hypotheses that S100B levels in the cerebrospinal fluid (CSF) are altered by tDCS. Elisa assay quantified the levels of tumor necrosis factor-alfa (TNF-α), interleukin-10 (IL10), S100 calcium-binding protein B (S100B), and Glial fibrillary acidic protein (GFAP). Data were analyzed using ANOVA and independent t-test (P<0.05). Results showed that tDCS decreased pain sensitivity (30 and 60min), cerebral TNF-α and S100B levels (30min). CSF S100B levels increased 30minutes after intervention. There were no differences in IL10 and GFAP levels. TCDS showed analgesic, anti-inflammatory, and neuroprotective effects in naive animals. Therefore, this non-invasive and inexpensive therapy may potentially be a preemptive alternative to reduce pain, inflammation, and neurodegeneration in situations where patients will undergo medical procedures (e.g., surgery).

Enhanced sensory conduction in primary fibromyalgia: a case–control pilot study

Background

This study aimed to test the changes in the conduction properties of peripheral nerves in patients with primary fibromyalgia (FM). Thirty patients with FM and sixteen healthy controls participated in this study. Visual analogue scale (VAS) for pain severity, pain duration, Widespread Pain Index (WPI), Symptom Severity (SS) scale, Hamilton depression rating scale, Taylor’s manifest anxiety scale, and Fibromyalgia Impact Questionnaire (FIQR) were used for measurement of psychiatric comorbidities and quality of life for each patient. Routine motor and sensory nerve conduction studies of both median, ulnar, common peroneal, posterior tibial, and sural nerves were measured for all study participants.

Results

We found statistically significant increase in Sensory Conduction Velocity (SCV), Sensory Nerve Action Potential (SNAP) amplitude, and decrease in Sensory Latency (SL) in patients with FM compared to controls. There were no significant changes in motor nerve conduction between patients and controls. Regression analysis showed a significant relation between WPI and both SCV and SL especially in nerves of upper limbs. However, no significant relation between SCV and SL and other presumed predictors including VAS for pain severity, pain duration, SS scale, FIQR, and psychiatric comorbidities. Patients with FM suffered more depression and anxiety than controls.

Conclusions

We found enhanced conductivity of the sensory rather than the motor nerves in patients with FM. To our knowledge, this is the first study to describe these sensory changes which may add further evidence of peripheral sensitization in patients with FM.

Evaluation of fibromyalgia syndrome in patients with rosacea

Objectives

This study aims to investigate the frequency of fibromyalgia syndrome (FMS) in rosacea patients and the relationship between disease disability score of FMS and quality of life score of rosacea.

Patients and methods

This cross-sectional controlled clinical trial was performed between December 2017 and December 2018. One hundred female rosacea patients (mean age 43.2±10.1; range, 21 to 65 years) and 100 age- and sex-matched control subjects (mean age 41.2±11.1; range, 22 to 68 years) with no history of skin disease and systemic diseases including diabetes, cardiovascular, renal and hepatic diseases were recruited. Dermatology Life Quality Index (DLQI) scores were calculated using a 10-item self-administered questionnaire. The diagnosis of FMS was established according to 2010 American College of Rheumatology diagnostic criteria. Fibromyalgia Impact Questionnaire (FIQ) was used to determine the clinical severity and functional disability, while Visual Analog Scale (VAS) was used to determine pain severity in the patients with FMS.

Results

The frequency of FMS in patient group was significantly higher than control group (p=0.019). The mean duration of FMS in patient group was significantly higher than control group (p=0.001). There was no significant difference in terms of the age of onset of FMS, FIQ and VAS scores between groups (p=0.53, p=0.54, p=0.07, respectively). DLQI scores were significantly correlated with FIQ scores in the patient group (r=0.43, p=0.008).

Conclusion

The frequency of FMS in rosacea patients was significantly higher than control subjects without any skin disease and there was a correlation between disability score of FMS and quality of life score of rosacea. Investigating fibromyalgia symptoms in rosacea patients may be helpful for providing patient-based therapeutic approaches where neurologically based treatments may also be beneficial for rosacea.

Prevalence of Fibromyalgia in Pharmacy Professionals and Students: A Cross-Sectional Study

Background

The prevalence of fibromyalgia (FM) in pharmacy students and professionals is unknown. This study identifies the prevalence of FM in pharmacy students and professionals using three screening tools and factors associated with its development. Furthermore, this study assesses the level of agreement between the tools and the magnitude of the participants’ responses to each item in the screening tools.

Methods

This was a cross-sectional survey conducted on members of the Saudi Pharmaceutical Society using an online questionnaire. The participants were asked to fill three questionnaires: the London Fibromyalgia Epidemiology Study Screening Questionnaire (LFESSQ), Fibromyalgia Rapid Screening Tool (FiRST) and Fibromyalgia Survey Questionnaire (FSQ). Demographic data and factors affecting FM in pharmacy students and professionals were collected and analysed.

Results

Two hundred ninety-three participants accessed the survey: most of them were Saudi (93.5%) and females (78.8%) with a mean (standard deviation) age of 29 (8) years. Furthermore, 52% of the participants had generalised body pain. The prevalence of FM using FiRST, LFESSQ Pain, LFESSQ with fatigue criteria and FSQ was 27.1%, 34.9%, 50.9% and 68.4%, respectively. Fleiss’ kappa coefficient revealed fair agreement among all three screening tools (kappa = 0.350; p < 0.001). After adjusting for significant variables, the resulting adjusted odds ratio of developing FM was 4.86 in people working for 41–45 h weekly (95% confidence interval [CI], 1.32–17.84; p = 0.017), 5.16 in people who frequently wake up during sleep (95% CI, 1.85–14.40; p = 0.002) and 12.99 in people with sleep apnea or other sleeping disorders (95% CI, 2.07–81.68; p = 0.006).

Conclusion

FM was prevalent among pharmacy students and professionals and was much more than data reported on the general population or other healthcare workers. Traditional factors along with higher working hours were identified as significant variables.

Daphnetin, a natural coumarin averts reserpine-induced fibromyalgia in mice: modulation of MAO-A

Fibromyalgia is a common, chronic, and generalized pain syndrome that is often associated with comorbid depression. The etiology of fibromyalgia is complex; most researchers have documented that the hallmark symptoms are due to the central nervous system's abnormal functioning. Neurotransmitters such as serotonin, norepinephrine, and glutamate, have been reported to be key regulators of fibromyalgia syndrome. Daphnetin is a 7, 8 dihydroxy coumarin widely distributed in Thymelaeaceae family plants, possessing various activities such as anti-arthritic, anti-tumor, anti-malarial, and anti-parasitic. The present study was designed to explore the potential of daphnetin against reserpine-induced fibromyalgia in mice. In mice, a fibromyalgia-like state was achieved by injecting reserpine (0.5 mg/kg, s.c) continuously for 3 days. All behavioral tests were conducted on the 4th and 6th day of experimentation. Reserpine administration significantly increased the mechanical hypersensitivity in electronic von Frey (eVF) and pressure application measurement (PAM) tests. It also increased the immobility period and time to reach the platform in force swim test (FST) and Morris water maze (MWM) test, respectively. In the biochemical analysis, reserpine treatment upregulated the monoamine oxidase-A (MAO-A) activity and level of glutamate, tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and thiobarbituric acid reactive substances (TBARS). Whereas, it decreased the level of glutathione (GSH), dopamine, serotonin, and norepinephrine. Daphnetin pretreatment attenuated the behavioral and biochemical changes induced by reserpine. Thus, the current investigation results delineate that daphnetin might exert its protective effect by inhibiting inflammatory stress and MAO-A-mediated neurotransmitter depletion and oxidative stress.

Altered Spinal Excitability in Patients with Primary Fibromyalgia: A Case-Control Study

Background and Purpose

Abnormal excitability of the central nervous system, both spinal and supraspinal, has previously been described as a pathophysiological plastic mechanism for chronic pain syndromes. Primary fibromyalgia (FM) as one extreme of this spectrum of diseases. This case-control study aimed to determine the changes in the spinal excitability by investigating the Hoffman reflex (H-reflex) in patients with FM.

Methods

Thirty-eight patients with FM and 30 healthy controls participated in this case-control study. We measured the H-reflex bilaterally in the upper limbs (flexor carpi radialis) and the lower limbs (gastrocnemius and soleus). Moreover, pain-related variables were measured, including pain severity (using a visual analogue scale), pain duration, Widespread Pain Index, and the score on the Symptom Severity Scale. Various psychiatric comorbidities and quality-of-life parameters were measured for each patient, including scores on the Hamilton Depression Rating Scale, Taylor's Manifest Anxiety Scale, and the Revised Fibromyalgia Impact Questionnaire.

Results

A significant increase in the ratio of the maximum baseline-to-peak amplitudes of H and M waves (H_max/M_max) but not in the H-wave minimum latency was found in patients with FM compared with healthy controls. There were no significant correlations between this ratio in both muscles and the various pain-related measures, psychiatric comorbidity, and quality of life in patients with FM. Patients with FM suffered more depression and anxiety than did the controls.

Conclusions

We found increased spinal excitability in patients with FM, which was not confined to the site of maximum pain. This information may help in the diagnosis of FM and supports the hypothesis of central sensitization.

Effects of fibromyalgia on the disease activity and treatment of patients with axial spondyloarthritis

OBJECTIVES

To investigate whether patients with radiologically positive spondyloarthritis (SpA), suffer from comorbid fibromyalgia (FM), and to explore the impact of FM on the clinical manifestations and blood test results of patients with ankylosing spondylitis (AS).

METHODS

121 patients with spondyloarthritis (SpA) were enrolled in the study. The body function of the patients was evaluated using the Bath Ankylosing Spondylitis Functional Index (BASFI); the mental health was evaluated using the Hospital Anxiety and Depression Scale (HADS).

RESULTS

Out of 121 patients with SpA, 111 patients were with axial spondyloarthritis (axSpA) and 11 patients with FM; 10 patients with peripheral SpA and 1 patient with FM. In axSpA, 107 were radiologically positive axSpA patients, 11 were complicated by FM, and 4 were radiologically negative axSpA (nr-axSpA). Among radiologically positive axSpA, the proportion of female patients in the FM group was higher (63.6%, P<0.05). The ASDAS-C-reactive protein (CRP), ASDAS-erythrocyte sedimentation rate (ESR), BASDAI, BASFI, and HADS-anxiety score, and HADS-depression score of the FM group were all significantly higher than those of the non-FM group.

CONCLUSIONS

When determining the treatment plan for SpA, the possibility of coexistence of FM should be considered, and adjuvant treatment should be given when necessary.

Key Milestones Contributing to the Understanding of the Mechanisms Underlying Fibromyalgia

The promulgation of the American College of Rheumatology (ACR) 1990 criteria for fibromyalgia (FM) classification has significantly contributed to an era of increased research into mechanisms that underlie the disorder. The previous emphasis on putative peripheral nociceptive mechanisms has advanced to identifying of changes in central neural networks that modulate pain and other sensory processes. The influences of psychosocial factors on the dynamic and complex neurobiological mechanisms involved in the fibromyalgia clinical phenotype are now better defined. This review highlights key milestones that have directed knowledge concerning the fundamental mechanisms contributing to fibromyalgia.

Linking Nonrestorative Sleep and Activity Interference Through Pain Catastrophizing and Pain Severity: An Intraday Process Model Among Individuals With Fibromyalgia

Nonrestorative sleep is a key diagnostic feature of the musculoskeletal pain disorder fibromyalgia and is robustly associated with poor physical functioning, including activity interference. However, the mechanisms through which nonrestorative sleep elicits activity interference among individuals with fibromyalgia at the within-person level remain unclear. The present study tested the following 3-path mediation model, using data gathered from a 21-day electronic daily diary in 220 individuals with fibromyalgia: previous night nonrestorative sleep → morning pain catastrophizing → afternoon pain severity → end-of-day activity interference. Results of multilevel structural equation modeling supported the 3-path mediation model. Previous night's nonrestorative sleep and morning pain catastrophizing were also directly related to end-of-day activity interference. Previous night nonrestorative sleep did not significantly predict afternoon pain severity while controlling for the effect of morning pain catastrophizing. Greater nonrestorative sleep during the previous night and a higher level of morning pain catastrophizing appear to serve as risk factors for experiencing greater daily pain and activity interference later in the day. These findings point to the potential utility of targeted interventions that improve both sleep quality and pain catastrophizing to help individuals with chronic pain engage in important daily activities despite experiencing pain. PERSPECTIVE: This study provides a better understanding of how nonrestorative sleep is associated with daily activity interference among individuals with fibromyalgia. An intervention that targets attenuating nonrestorative sleep and pain catastrophizing may help improve daily physical functioning of this population.

Oral Health and Fibromyalgia Syndrome: A Systemic Review

Fibromyalgia is a syndrome currently considered idiopathic and multifactorial rheumatic that causes an increase in muscle tension and is characterized by muscle pain and chronic fibrous tissues-widespread, fluctuating and migrating-associated with stiffness, asthenia, cognitive disorders, insomnia or sleep disorders, alterations in sensitivity to stimuli. In affected patients, there may be anxiety or depressive disorder development. The aim of this study is, with the help of an interdisciplinary team, to evaluate the correlations between this syndrome and oral health. A literature review was conducted, analyzing the most common scientific databases, more than 200 studies were obtained. Subsequently to the application of filters and revision by the authors, only 18 articles were considered eligible for this review. From the results, it is clear that the correlations between fibromyalgia and oral health mainly concern pain in the oro-maxillofacial district, especially in the temporomandibular joint. This certainly could help for faster diagnosis of the syndrome, which is currently difficult to identify.

Association of catechol-O-methyltranferase 472G>A (Val158Met) polymorphism with susceptibility to fibromyalgia syndrome

Background

Several lines of research have suggested that the 472G > A (Val158Met) polymorphism at Catechol-O-methyltranferase (COMT) gene is implicated in the pathophysiology of FMS. Here, we have evaluated the association of COMT 472G > A polymorphism with risk of FMS.

Methods

In this study 250 patients with FMS and 250 healthy controls were evaluated for COMT 472G > A polymorphism by RFLP-PCR assay.

Results

There were no significant differences in the allele and genotype frequencies of COMT 472G > A polymorphism between FMS cases and healthy controls.

Conclusions

Our results suggested that the COMT 472G > A polymorphism may not be risk factor for development of FMS.

Association between pain phenotype and disease activity in rheumatoid arthritis patients: a non-interventional, longitudinal cohort study

BACKGROUND

In well-controlled rheumatoid arthritis (RA) without significant joint damage, a substantial proportion of patients complain of persistent pain. Previous studies have identified different pain phenotypes in RA, in which non-nociceptive pain phenotypes are associated with higher concurrent disease activity scores. In this longitudinal study, we explored associations between pain phenotypes and long-term disease activity outcome in RA patients. Secondly, we explored whether pain phenotype is associated with comorbid conditions.

METHODS

One hundred eighty established RA patients were classified with a nociceptive (61%) or a non-nociceptive (39%) pain phenotype, based on their responses to the painDETECT-questionnaire. Two years of clinical follow-up data on disease activity outcomes were collected. Information on comorbid diseases was derived from electronic patient files.

RESULTS

Patients with a non-nociceptive pain phenotype showed higher mean disease activity scores (DAS28, 2.57; 95% CI, 2.37-2.77 vs. 2.11; 95% CI, 1.94-2.27; p < 0.001) and a twofold lower chance of achieving sustained DAS28 remission (OR = 0.49; 95% CI, 0.26-0.92; p = 0.020). Only the tender joint count and patient global health significantly differed between the pain phenotype groups. Patients with a non-nociceptive pain phenotype had more often been diagnosed with concurrent fibromyalgia (9.9% vs. 0.9%; p = 0.007) and other pain-associated comorbid diseases (52.1% vs. 35.8%; p = 0.030) compared with patients with a nociceptive pain phenotype.

CONCLUSION

This longitudinal study showed consistently worse long-term disease activity outcomes in RA patients with a non-nociceptive pain phenotype which appeared to be mainly due to differences in the subjective components of the disease activity score.

TRIAL REGISTRATION

The DREAM cohort study is registered in the Netherlands Trial Register: NTR578.

Genetic mapping in Diversity Outbred mice identifies a Trpa1 variant influencing late-phase formalin response

Identification of genetic variants that influence susceptibility to pain is key to identifying molecular mechanisms and targets for effective and safe therapeutic alternatives to opioids. To identify genes and variants associated with persistent pain, we measured late-phase response to formalin injection in 275 male and female Diversity Outbred mice genotyped for over 70,000 single nucleotide polymorphisms. One quantitative trait locus reached genome-wide significance on chromosome 1 with a support interval of 3.1 Mb. This locus, Nociq4 (nociceptive sensitivity quantitative trait locus 4; MGI: 5661503), harbors the well-known pain gene Trpa1 (transient receptor potential cation channel, subfamily A, member 1). Trpa1 is a cation channel known to play an important role in acute and chronic pain in both humans and mice. Analysis of Diversity Outbred founder strain allele effects revealed a significant effect of the CAST/EiJ allele at Trpa1, with CAST/EiJ carrier mice showing an early, but not late, response to formalin relative to carriers of the 7 other inbred founder alleles (A/J, C57BL/6J, 129S1/SvImJ, NOD/ShiLtJ, NZO/HlLtJ, PWK/PhJ, and WSB/EiJ). We characterized possible functional consequences of sequence variants in Trpa1 by assessing channel conductance, TRPA1-TRPV1 interactions, and isoform expression. The phenotypic differences observed in CAST/EiJ relative to C57BL/6J carriers were best explained by Trpa1 isoform expression differences, implicating a splice junction variant as the causal functional variant. This study demonstrates the utility of advanced, high-precision genetic mapping populations in resolving specific molecular mechanisms of variation in pain sensitivity.

The treatment of central sensitization in an adolescent using pain neuroscience education and graded exposure to activity: A case report

Chronic pain affects 1.7 million children in the United States, and its effects often linger into adulthood. Unfortunately, chronic pediatric pain is often undertreated. The current case report discusses the use of pain neuroscience education (PNE) combined with progressive exposure to activity to treat persistent pain in a 13-year-old female diagnosed with central sensitization syndrome. Prior to the diagnosis, the patient underwent two unsuccessful episodes of physical therapy that focused on musculoskeletal sources of pain. The patient was then referred to a physical therapist specializing in pain management. Following a detailed evaluation, PNE and graded exposure were used over a 4-week period to address the patient's condition and her behavioral responses to it. Significant decreases were observed in lowest (67%) and usual (50%) pain ratings and the portion of the day her worst pain was felt (67%), while the portion of the day with bearable pain (80%). Significant improvements in her ability to dance (168%), hike (50%), and run (200%) were observed. Reconceptualizing pain and its meaning changed perceptions and behaviors, allowing improvement when other approaches failed. Although effective for this patient, more research is needed into the use of this approach in the treatment of chronic pediatric pain.

Bidirectional association between fibromyalgia and gastroesophageal reflux disease: two population-based retrospective cohort analysis

Fibromyalgia (FM) tends to coexist with gastroesophageal reflux disease (GERD). This retrospective cohort study was conducted to determine the bidirectional association between FM and GERD, using a nationwide database, the National Health Insurance of Taiwan. We established 2 study arms, including 35,117 patients with FM in arm 1 and 34,630 patients with GERD in arm 2, newly diagnosed between 2000 and 2010. For each study arm, we randomly selected 4-fold subjects with neither FM nor GERD from the same database, frequency matched by sex, age, and diagnosis date, as the respective control cohorts. Incidence of GERD in arm 1 and incidence of FM in arm 2 were estimated by the end of 2011. The overall incidence of GERD was 1.6-fold greater in the FM cohort than in the non-FM cohort (12.0 and 7.61 per 1000 person-years, crude hazard ratio [HR] = 1.58, 95% confidence interval [CI] = 1.51-1.66), with an adjusted HR (aHR) of 1.27 (95% CI = 1.22-1.33) after controlling for sex, age, comorbidities, and medications. The GERD cohort ultimately had a 1.5-fold higher incidence of FM than the non-GERD cohort (5.76 vs 3.96 per 1000 person-years), with an aHR of 1.44 (95% CI = 1.29-1.60). The present study suggests a bidirectional relationship between FM and GERD. There is a greater risk of developing GERD for patients with FM than developing FM for patients with GERD.

A narrative review on the difficulties associated with fibromyalgia diagnosis

Fibromyalgia presents a clinical enigma as its pathophysiology is not well understood and its symptoms are nonspecific and overlap with many disorders, making its diagnosis a challenge for clinicians and researchers. Efforts have been made to develop a set of diagnostic criteria for this disorder. However, these criteria rely heavily on expert clinician opinion and produce a large heterogeneity within the diagnosed population. With no present specific technique reflecting the underlying pathophysiology of fibromyalgia, a definitive diagnosis of fibromyalgia remains elusive. This review discusses some problems and challenges associated with fibromyalgia diagnosis and presents some novel findings on the pathophysiological nature of fibromyalgia.

Histological Underpinnings of Grey Matter Changes in Fibromyalgia Investigated Using Multimodal Brain Imaging

Chronic pain patients present with cortical gray matter alterations, observed with anatomical magnetic resonance (MR) imaging. Reduced regional gray matter volumes are often interpreted to reflect neurodegeneration, but studies investigating the cellular origin of gray matter changes are lacking. We used multimodal imaging to compare 26 postmenopausal women with fibromyalgia with 25 healthy controls (age range: 50-75 years) to test whether regional gray matter volume decreases in chronic pain are associated with compromised neuronal integrity. Regional gray matter decreases were largely explained by T1 relaxation times in gray matter, a surrogate measure of water content, and not to any substantial degree by GABA_A receptor concentration, an indirect marker of neuronal integrity measured with [¹⁸F] flumazenil PET. In addition, the MR spectroscopy marker of neuronal viability, N-acetylaspartate, did not differ between patients and controls. These findings suggest that decreased gray matter volumes are not explained by compromised neuronal integrity. Alternatively, a decrease in neuronal matter could be compensated for by an upregulation of GABA_A receptors. The relation between regional gray matter and T1 relaxation times suggests decreased tissue water content underlying regional gray matter decreases. In contrast, regional gray matter increases were explained by GABA_A receptor concentration in addition to T1 relaxation times, indicating perhaps increased neuronal matter or GABA_A receptor upregulation and inflammatory edema. By providing information on the histological origins of cerebral gray matter alterations in fibromyalgia, this study advances the understanding of the neurobiology of chronic widespread pain.

SIGNIFICANCE STATEMENT

Regional gray matter alterations in chronic pain, as detected with voxel-based morphometry of anatomical magnetic resonance images, are commonly interpreted to reflect neurodegeneration, but this assumption has not been tested. We found decreased gray matter in fibromyalgia to be associated with T1 relaxation times, a surrogate marker of water content, but not with GABA_A receptor concentration, a surrogate of neuronal integrity. In contrast, regional gray matter increases were partly explained by GABA_A receptor concentration, indicating some form of neuronal plasticity. The study emphasizes that voxel-based morphometry is an exploratory measure, demonstrating the need to investigate the histological origin of gray matter alterations for every distinct clinical entity, and advances the understanding of the neurobiology of chronic (widespread) pain.

Marked Sexual Dimorphism in the Role of the Ryanodine Receptor in a Model of Pain Chronification in the Rat

Hyperalgesic priming, an estrogen dependent model of the transition to chronic pain, produced by agonists at receptors that activate protein kinase C epsilon (PKCε), occurs in male but not in female rats. However, activation of second messengers downstream of PKCε, such as the ryanodine receptor, induces priming in both sexes. Since estrogen regulates intracellular calcium, we investigated the interaction between estrogen and ryanodine in the susceptibility to develop priming in females. The lowest dose of ryanodine able to induce priming in females (1 pg) is 1/100,000^th that needed in males (100 ng), an effect dependent on the activation of ryanodine receptors. Treatment of female rats with antisense to estrogen receptor alpha (ERα), but not beta (ERβ), mRNA, prevented the induction of priming by low dose ryanodine, and the ERα agonist, PPT, induced ryanodine receptor-dependent priming. In vitro application of ryanodine in low concentration (2 nM) to small DRG neurons cultured from females, significantly potentiated calcium release via ryanodine receptors induced by caffeine. This effect was only observed in IB4+ neurons, cultured in the presence of β-estradiol or PPT. Our results demonstrate a profound regulatory role of ERα in ryanodine receptor-dependent transition to chronic pain.

Relationship of physical distress to dizziness in patients with fibromyalgia

CONCLUSIONS

The feelings of dizziness and unsteadiness of the patients with fibromyalgia supposed specifically amplified by the hypersensitivity mechanism of CSS (central sensitivity syndrome) of them. The severity of subjective pain and physical distress according to the questionnaires were not correlated with the objective body sway on the stabilometer.

OBJECTIVES

Fibromyalgia manifests primarily as chronic pain of the entire body, but is also often associated with a variety of physical symptoms including dizziness and unsteadiness. This study assessed whether objective measures of body sway and unsteadiness of them are associated with their subjective dizziness findings.

METHOD

Subjects were 24 patients diagnosed with fibromyalgia, but one patient who had the past history of sudden deafness was excluded. The 23 patients were assessed by a stabilometer as the objective measures of body sway, and JFIQ (Japanese version of the fibromyalgia impact questionnaire), DHI (dizziness handicap inventory) and ABC (activities-specific balance confidence) as the subjective questionnaires.

RESULTS

The significant correlations were shown between the scores of JFIQ and DHI, JFIQ and ABC, and DHI and ABC. Then, the body sway index of stabilometer environmental area was significantly correlated with DHI score. However, the stabilometer index was not correlated neither with JFIQ or ABC.

Quantitative analysis of nailfold capillary morphology in patients with fibromyalgia

BACKGROUND/AIMS

Nailfold capillaroscopy (NFC) has been used to examine morphological and functional microcirculation changes in connective tissue diseases. It has been demonstrated that NFC patterns reflect abnormal microvascular dynamics, which may play a role in fibromyalgia (FM) syndrome. The aim of this study was to determine NFC patterns in FM, and their association with clinical features of FM.

METHODS

A total of 67 patients with FM, and 30 age- and sex-matched healthy controls, were included. Nailfold capillary patterns were quantitatively analyzed using computerized NFC. The parameters of interest were as follows: number of capillaries within the central 3 mm, deletion score, apical limb width, capillary width, and capillary dimension. Capillary dimension was determined by calculating the number of capillaries using the Adobe Photoshop version 7.0.

RESULTS

FM patients had a lower number of capillaries and higher deletion scores on NFC compared to healthy controls (17.3 ± 1.7 vs. 21.8 ± 2.9, p < 0.05; 2.2 ± 0.9 vs. 0.7 ± 0.6, p < 0.05, respectively). Both apical limb width (µm) and capillary width (µm) were significantly decreased in FM patients (1.1 ± 0.2 vs. 3.7 ± 0.6; 5.4 ± 0.5 vs. 7.5 ± 1.4, respectively), indicating that FM patients have abnormally decreased digital capillary diameter and density. Interestingly, there was no difference in capillary dimension between the two groups, suggesting that the length or tortuosity of capillaries in FM patients is increased to compensate for diminished microcirculation.

CONCLUSIONS

FM patients had altered capillary density and diameter in the digits. Diminished microcirculation on NFC may alter capillary density and increase tortuosity.

Linalool and linalool complexed in β-cyclodextrin produce anti-hyperalgesic activity and increase Fos protein expression in animal model for fibromyalgia

The analgesic activity of (-)-linalool (LIN), a monoterpene present in essential oils of Lamiaceae species, has been previously demonstrated in rodents. However, its possible use in the treatment of fibromyalgia (FM) was never demonstrated. Additionally, as a short half-life is a limitation for the LIN medicinal application, the employment of drug delivery systems has been used to improve pharmaceutical properties of this compound. We investigated the anti-nociceptive effect of LIN, isolated or in β-cyclodextrin complex (LIN-CD), in an animal model of chronic non-inflammatory muscle pain (a FM animal model), as well as its effect on the central nervous system (CNS). Male Swiss mice were subjected to two injections of acidic saline (pH 4; 20 μL/gastrocnemius) and were treated on alternate days, with LIN-CD (25 mg/kg, p.o.), LIN (25 mg/kg, p.o.), tramadol (TRM 4 mg/kg, i.p.), or vehicle (neutral saline). After 60 min, they were screened for mechanical hyperalgesia (von Frey), motor coordination (rotarod), and muscle strength (grip strength meter) for 27 days. The CNS areas involved in the anti-hyperalgesic activity were evaluated by immunofluorescence. LIN or LIN-CD produced a significant reduction (p < 0.001) of mechanical hyperalgesia on chronic non-inflammatory muscle pain model, which remained for 24 h only in LIN-CD, and these compounds significantly (p < 0.05) activated neurons of the locus coeruleus, nucleus raphe magnus, and periaqueductal gray areas. So, our results suggest that LIN-CD improved analgesic profile of LIN, with a probable involvement of descending pain pathways and the anti-nociceptive effect of linalool in an animal model of chronic non-inflammatory muscle pain. So far, only the investigations in animal models of inflammatory pain and supraspinatus were published.

Women with fibromyalgia's experience with three motion-controlled video game consoles and indicators of symptom severity and performance of activities of daily living

PURPOSE

Little is known of Motion-Controlled Video Games (MCVGs) as an intervention for people with chronic pain. The aim of this study was to explore the experience women with fibromyalgia syndrome (FMS) had, using commercially available MCVGs; and to investigate indicators of symptom severity and performance of activities of daily living (ADL).

METHOD

Of 15 female participants diagnosed with FMS, 7 completed a program of five sessions with Nintendo Wii (Wii), five sessions with PlayStation 3 Move (PS3 Move) and five sessions with Microsoft Xbox Kinect (Xbox Kinect). Interviews were conducted at baseline and post-intervention and were supported by data from observation and self-reported assessment.

RESULTS

Participants experienced play with MCVGs as a way to get distraction from pain symptoms while doing fun and manageable exercise. They enjoyed the slow pace and familiarity of Wii, while some considered PS3 Move to be too fast paced. Xbox Kinect was reported as the best console for exercise. There were no indication of general improvement in symptom severity or performance of ADL.

CONCLUSION

This study demonstrated MCVG as an effective healthcare intervention for the women with FMS who completed the program, with regards to temporary pain relief and enjoyable low impact exercise. Implications for Rehabilitation Exercise is recommended in the management of fibromyalgia syndrome (FMS). People with FMS often find it counterintuitive to exercise because of pain exacerbation, which may influence adherence to an exercise program. Motion-controlled video games may offer temporary pain relief and fun low impact exercise for women with FMS.

Efficacy and safety of mirtazapine in fibromyalgia syndrome patients: a randomized placebo-controlled pilot study

BACKGROUND

Data from an open-label trial suggest that mirtazapine might prove useful in treatment of fibromyalgia syndrome (FMS).

OBJECTIVE

To obtain preliminary efficacy data of mirtazapine for estimation of sample size requirements for a Phase 2 clinical trial in FMS.

METHODS

This 13-week randomized controlled trial compared the effects of mirtazapine 15 mg/day, mirtazapine 30 mg/day, and placebo in 40 patients with FMS. The primary outcomes were change in Pain Visual Analog Scale (PVAS) and proportion of pain responders (≥30% PVAS reduction). Secondary outcomes included scores from the Jenkins Sleep Scale (JSS), Patient Global Impression of Change (PGIC), Fibromyalgia Impact Questionnaire (FIQ), Hamilton Depression Rating Scale (HAM-D), Patient Global Assessment, and self-reported adverse events.

RESULTS

Significant within-group PVAS reductions from baseline were observed in all 3 groups, with the greatest improvement in the mirtazapine 30-mg group (p < 0.005); between-group difference was not significant. The proportion of pain responders did not meet significance criteria (66.67% for mirtazapine 30 mg, 50% for mirtazapine 15 mg, 41.67% for placebo). Significant within-group improvement in JSS scores was seen for mirtazapine 30 mg (p < 0.01) and mirtazapine 15 mg (p < 0.05). Between-group comparison achieved significance for JSS item 3, waking several times per night (p < 0.05). On the PGIC, 72.73% felt better with both mirtazapine dosages compared with 50% for placebo. Within-group FIQ responses indicated improvement in only mirtazapine-treated groups, whereas within-group improvement for HAM-D and Patient Global Assessment was observed in all groups. Based on our findings, the sample size requirement (80% power, 5% type I error) should be 83 per group to detect PVAS change difference between mirtazapine 30 mg and placebo. Common mirtazapine-related adverse events were increased appetite and weight gain.

CONCLUSIONS

Patients with FMS taking mirtazapine exhibited within-group significant improvement in most of the measured outcomes. Between-group analysis was predictably compromised by the small sample size. Mirtazapine was well tolerated. Further study with a larger sample size is likely to be useful.

Guided imagery in people with fibromyalgia: A randomized controlled trial of effects on pain, functional status and self-efficacy

Studies on the effects of guided imagery in patients with fibromyalgia show varying results. This randomized controlled trial ( n = 65) aims to give more insight into the effects on pain, functional status, and self-efficacy. Daily pain was assessed with a pain diary using a Visual Analogue Scale. Functional status and self-efficacy were measured at pretest, posttest, and follow-up using the Fibromyalgia Impact Questionnaire and the Chronic Pain Self-Efficacy Scale. No effects of guided imagery could be established. Explanations for the diverging results between studies might be found in the content of the exercises, length of the intervention period, and background of participants.

Fear-learning deficits in subjects with fibromyalgia syndrome?

BACKGROUND

Fibromyalgia syndrome (FMS) is frequently associated with psychiatric conditions, particularly anxiety. Deficits in contingency learning during fear conditioning have been hypothesized to increase anxiety and, consequently, pain sensation in susceptible individuals. The goal of this study was to examine the relationship between contingency learning and pain experience in subjects with FMS and rheumatoid arthritis (RA).

METHODS

Fourteen female FMS subjects, 14 age-matched female RA subjects and 14 age-matched female healthy controls (HCs) were included in a fear-conditioning experiment. The conditioned stimulus (CS) consisted of visual signs, the unconditioned stimulus (US) of thermal stimuli. CS- predicted low-temperature exposure (US), while CS+ was followed by low or high temperature.

RESULTS

In the FMS group, only 50% of the subjects were aware of the US-CS contingency, whereas 86% of the RA subjects and all of the HCs were aware of the contingency. CS+ induced more anxiety than CS- in RA subjects and HCs. As expected, low-temperature exposure was experienced as less painful after CS- than after CS+ in these subjects. FMS subjects did not show such adaptive conditioning. The effects of the type of CS on heart rate changes were significant in the HCs and the aware FMS subjects, but not in the unaware FMS subjects.

CONCLUSIONS

Contingency learning deficits represent a potentially promising and specific, but largely unstudied, psychopathological factor in FMS. Deficits in contingency learning may increase anxiety and, consequently, pain sensation. These findings have the potential to contribute to the development of novel therapeutic approaches for FMS.

Clinical overview of fibromyalgia

Fibromyalgia (FM) is a complex disorder that affects up to 5% of the general population worldwide, more frequently in women than in men. In addition to chronic widespread pain, patients with FM usually experience other characteristic symptoms, including fatigue, disturbed sleep, stiffness, reduced functioning, dyscognition, and depressed mood. Many patients also have comorbid conditions such as depression, irritable bowel syndrome, temporomandibular disorder, or migraine. Although the etiology of FM remains unclear, evidence suggests that biologic, genetic, and environmental factors are involved. The variability of symptoms and the frequency of comorbidities among patients with FM make this a difficult disorder to diagnose. Diagnosis may be further complicated by the stigmatization of this disorder among treatment providers, the health insurance industry, and the general population. Treating chronic pain disorders such as FM can be time consuming and costly, and other issues such as polypharmacy, treatment adherence, and access to treatment often need to be addressed. The aim of this article is to provide physicians with a general overview of FM, including a brief review of the pathophysiology that explains the biologic and genetic bases of this disorder. Also included is a synopsis of new diagnostic criteria and other useful diagnostic tools and a discussion of various treatment challenges and strategies.

Not throwing out the baby with the bathwater: lessons from the Fibromyalgia Impact Questionnaire

The Fibromyalgia Impact Questionnaire (FIQ) is the most frequently used questionnaire in patients with fibromyalgia in the last 20 years. Recently, a revised version of the FIQ has been published. In this study, we examined the factor structure of the original version using explorative and confirmative factor analyses in a representative group of about 500 Dutch and Belgian patients with fibromyalgia, in which the work-related item was excluded. The FIQ consisting of a three-factor structure with a functional domain (ten items), physical symptom domain (six items), and mental symptom domain (two items), which is the most accurate. From the data presented, it is concluded that the FIQ is a solid, worldwide-used questionnaire with a history of 20 years consisting of three domains. When constructing a revised FIQ, the results of this study can be incorporated.

Fibromyalgia syndrome: etiology, pathogenesis, diagnosis, and treatment

Fibromyalgia syndrome is mainly characterized by pain, fatigue, and sleep disruption. The etiology of fibromyalgia is still unclear: if central sensitization is considered to be the main mechanism involved, then many other factors, genetic, immunological, and hormonal, may play an important role. The diagnosis is typically clinical (there are no laboratory abnormalities) and the physician must concentrate on pain and on its features. Additional symptoms (e.g., Raynaud's phenomenon, irritable bowel disease, and heat and cold intolerance) can be associated with this condition. A careful differential diagnosis is mandatory: fibromyalgia is not a diagnosis of exclusion. Since 1990, diagnosis has been principally based on the two major diagnostic criteria defined by the ACR. Recently, new criteria have been proposed. The main goals of the treatment are to alleviate pain, increase restorative sleep, and improve physical function. A multidisciplinary approach is optimal. While most nonsteroidal anti-inflammatory drugs and opioids have limited benefit, an important role is played by antidepressants and neuromodulating antiepileptics: currently duloxetine (NNT for a 30% pain reduction 7.2), milnacipran (NNT 19), and pregabalin (NNT 8.6) are the only drugs approved by the US Food and Drug Administration for the treatment of fibromyalgia. In addition, nonpharmacological treatments should be associated with drug therapy.

Reversal of chronic stress-induced pain by transcranial direct current stimulation (tDCS) in an animal model

Transcranial direct current stimulation (tDCS) has been suggested as a therapeutic tool for pain syndromes. Although initial results in human subjects are encouraging, it still remains unclear whether the effects of tDCS can reverse maladaptive plasticity associated with chronic pain. To investigate this question, we tested whether tDCS can reverse the specific behavioral effects of chronic stress in the pain system, and also those indexed by corticosterone and interleukin-1β levels in serum and TNFα levels in the hippocampus, in a well-controlled rat model of chronic restraint stress (CRS). Forty-one adult male Wistar rats were divided into two groups control and stress. The stress group was exposed to CRS for 11 weeks for the establishment of hyperalgesia and mechanical allodynia as shown by the hot plate and von Frey tests, respectively. Rats were then divided into four groups control, stress, stress+sham tDCS and stress+tDCS. Anodal or sham tDCS was applied for 20min/day over 8 days and the tests were repeated. Then, the animals were killed, blood collected and hippocampus removed for ELISA testing. This model of CRS proved effective to induce chronic pain, as the animals exhibited hyperalgesia and mechanical allodynia. The hot plate test showed an analgesic effect, and the von Frey test, an anti-allodynic effect after the last tDCS session, and there was a significant decrease in hippocampal TNFα levels. These results support the notion that tDCS reverses the detrimental effects of chronic stress on the pain system and decreases TNFα levels in the hippocampus.

Trauma and work-related pain syndromes: risk factors, clinical picture, insurance and law interventions

In the past decade, major progress has been made in our understanding of fibromyalgia syndrome (FMS). Various triggers have been implicated as contributing to symptom development in FMS when genetically susceptible individuals are challenged. A substantial amount of data points towards the association between trauma and chronic widespread pain/fibromyalgia syndrome (CWP/FMS). There is abundant data suggesting that the pathogenesis of CWP/FMS might be related to cervical spine injury. Furthermore, several persistent local pain conditions may progress to CWP/FMS. These conditions may share a common pathogenic mechanism namely, central sensitisation. Physical trauma and emotional trauma co-exist in many traumatic events and may interact in the pathogenesis of CWP/FMS.

Central amplification and fibromyalgia: disorder of pain processing

Fibromyalgia (FM), a complex chronic pain disorder affecting a heterogeneous patient population, is an area of active basic and clinical research. Although diagnostic criteria for FM have been available for 2 decades, there remains no definitive diagnostic and no consensus regarding its etiology. Accumulating evidence suggests the underlying cause of FM pain results from abnormal pain processing particularly in the central nervous system rather than from dysfunction in peripheral tissues where pain is perceived. In this review, we examine recent studies investigating abnormalities in central pain processing as a component of FM in both preclinical models of generalized muscle hypersensitivity and clinical research in patients with FM. We focus our discussion on two areas where strong evidence exists for abnormalities in sensory signaling: the reduction of descending control, including suppression of descending inhibitory pathways and/or enhancement of descending facilitatory pathways, and changes in key neurotransmitters associated with central sensitization. Finally, we discuss currently available pharmacological treatments indicated for the management of pain in FM patients, based on their proposed mechanism of action and efficacy.

IMMPACT recommendations for clinical trials: opportunities for the RDC/TMD

The Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) recommendations for core domains and measures of outcome in clinical trials complement the parallel work completed on Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The overall approach of the RDC/TMD is consistent with the IMMPACT recommendations, although the specific tools used to quantify clinical presentation are appropriately different based on the precedents established in the TMD literature. The IMMPACT recommendations, while directed at clinical trials, have broad utility for all clinical research in TMD. Future TMD studies should consider including a measure of health-related quality of life and tracking participant disposition, as well as tracking adverse events from treatment and assessing the participant's global assessment of change in clinical trials. The RDC/TMD methodology provides a rich basis upon which to develop standards for quantifying the clinical significance of treatment outcomes across multiple domains, an area ripe for development. Axis II may benefit from a shift in conceptualisation in which measurement focuses on screening for depression and somatisation to a new, dimensional approach in which Axis II domains are measured and evaluated on a continuum of symptom severity. Combined with the expansion of Axis II to include measures of catastrophising and sleep disturbance, the resulting approach may provide a powerful method for evaluating risk profiles associated with poor outcomes in TMD.

Primary care physical therapy in people with fibromyalgia: opportunities and boundaries within a monodisciplinary setting

Despite the fact that people with fibromyalgia syndrome (FMS) frequently are seen by primary care physical therapists, guidelines for the management of FMS are based primarily on outcomes from multidisciplinary and tertiary care treatment studies. Few data addressing the treatment of patients with FMS in primary care currently are available. The evidence-based guidelines on the management of FMS are based, in part, on evidence from studies examining physical therapy treatment components alone (eg, aerobic exercise, education). Thus, the recommendations can be applied to primary care physical therapy. Primary care physical therapy for patients with FMS should include education, aerobic exercise, and strengthening exercise. For other treatment components such as passive treatments, activity management, and relaxation, less evidence currently is available to advocate their use in primary care physical therapy. Superior results are to be expected when various treatment components are combined.

Duloxetine for the treatment of fibromyalgia

This article presents a brief review of the physiologic abnormalities seen in fibromyalgia, current theories of widespread pain, and treatment options, including emerging therapeutics, with a focus on the use of duloxetine to manage fibromyalgia symptoms. Major clinical trials that examine the efficacy and effectiveness of duloxetine to date are reviewed, and safety issues are discussed.