Myofascial pain syndrome and its suggested role in the pathogenesis and treatment of fibromyalgia syndrome

Transcranial direct current stimulation is more effective than pregabalin in controlling nociceptive and anxiety-like behaviors in a rat fibromyalgia-like model

OBJECTIVES

Despite the fact that fibromyalgia, a widespread disease of the musculoskeletal system, has no specific treatment, patients have shown improvement after pharmacological intervention. Pregabalin has demonstrated efficacy; however, its adverse effects may reduce treatment adherence. In this context, neuromodulatory techniques such as transcranial direct current stimulation (tDCS) may be employed as a complementary pain-relieving method. Consequently, the purpose of this study was to evaluate the effect of pregabalin and tDCS treatments on the behavioral and biomarker parameters of rats submitted to a fibromyalgia-like model.

METHODS

Forty adult male Wistar rats were divided into two groups: control and reserpine. Five days after the end of the administration of reserpine (1 mg/kg/3 days) to induce a fibromyalgia-like model, rats were randomly assigned to receive either vehicle or pregabalin (30 mg/kg) along with sham or active- tDCS treatments. The evaluated behavioral parameters included mechanical allodynia by von Frey test and anxiety-like behaviors by elevated plus-maze test (time spent in opened and closed arms, number of entries in opened and closed arms, protected head-dipping, unprotected head-dipping [NPHD], grooming, rearing, fecal boluses). The biomarker analysis (brain-derived neurotrophic factor [BDNF] and tumor necrosis factor-α [TNF-α]) was performed in brainstem and cerebral cortex and in serum.

RESULTS

tDCS reversed the reduction in the mechanical nociceptive threshold and the decrease in the serum BDNF levels induced by the model of fibromyalgia; however, there was no effect of pregabalin in the mechanical threshold. There were no effects of pregabalin or tDCS found in TNF-α levels. The pain model induced an increase in grooming time and a decrease in NPHD and rearing; while tDCS reversed the increase in grooming, pregabalin reversed the decrease in NPHD.

CONCLUSIONS

tDCS was more effective than pregabalin in controlling nociception and anxiety-like behavior in a rat model-like fibromyalgia. Considering the translational aspect, our findings suggest that tDCS could be a potential non-pharmacological treatment for fibromyalgia.

Insulin Resistance in Patients with Polycystic Ovary Syndrome is a Predictor of Fibromyalgia

OBJECTIVE

This study aims to investigate the frequency of fibromyalgia and its predictors in women with polycystic ovary syndrome (PCOS) and its relationship with insulin resistance, and to assess the effect of fibromyalgia on the anxiety and depressive symptoms in PCOS patients, and how the quality of life was affected by this combination.

MEASUREMENTS

The study was conducted with 74 women with PCOS according to the Rotterdam criteria, which applied to our tertiary care clinic between January 2021 and January 2022, and 51 controls. Endocrinologic and rheumatologic examinations, biochemical and hormonal analyses, and radiologic imaging are made. Hospital anxiety and depression scale (HADs) and Short Form 36 (SF-36) quality of life scale were applied.

RESULTS

There was no statistical difference between patients (n = 74 (23%)) and controls (n = 51 (13.7%)) in terms of fibromyalgia frequency. This frequency was 41.4% in PCOS patients with insulin resistance. The presence of insulin resistance was significantly higher in patients with PCOS and fibromyalgia (70.4%, 12 of 17 patients with fibromyalgia for the PCOS group; 8.3%, 1 of 7 patients with fibromyalgia for the control group) (χ2 = 9.130, p=0.003). Higher HOMA-IR levels (B = 1.278, p = 0.034) and age (B = 1.134, p = 0.022) were significant predictors of fibromyalgia in PCOS patients. Physical functioning (U = 1.960, P = 0.050), bodily pain subscales (U = 2.765, p = 0.006), and physical health summary measure (U = 2.296, p = 0.022) were significantly lower, VAS pain (U = 5.145, p < 0.0001) and fatigue (U = 5.997, p < 0.0001) scale scores were higher in PCOS patients with fibromyalgia.

CONCLUSIONS

Our results show that fibromyalgia is frequent in PCOS patients with insulin resistance.

Consistency of inconsistency in long-COVID-19 pain symptoms persistency: A systematic review and meta-analysis

INTRODUCTION

Individuals recovering from acute COVID-19 episodes may continue to suffer from various ongoing symptoms, collectively referred to as Long-COVID. Long-term pain symptoms are amongst the most common and clinically significant symptoms to be reported for this post-COVID-19 syndrome.

OBJECTIVES

This systematic review and meta-analysis aimed to evaluate the proportions of persisting pain symptoms experienced by individuals past the acute phase of COVID-19 and to identify their associated functional consequences and inflammatory correlates.

METHODS

Two online databases were systematically searched from their inception until 31 March 2022. We searched primary research articles in English, which evaluated individuals after laboratory-confirmed COVID-19 acute phase resolution and specifically reported on pain symptoms and their inflammatory and/or functional outcomes.

RESULTS

Of the 611 identified articles, 26 were included, used for data extraction, and assessed for their methodological quality and risk of bias by two independent reviewers. Pain symptoms were grouped under one of six major pain domains, serving as our primary co-outcomes. Proportional meta-analyses of pooled logit-transformed values of single proportions were performed using the random-effects-restricted maximum-likelihood model. An estimated 8%, 6%, 18%, 18%, 17%, and 12% of individuals continued to report the persistence of chest, gastrointestinal, musculoskeletal joint, musculoskeletal muscle, general body, and nervous system-related pain symptoms, respectively, for up to one year after acute phase resolution of COVID-19. Considerable levels of heterogeneity were demonstrated across all results. Functional and quality-of-life impairments and some inflammatory biomarker elevations were associated with the persistence of long-COVID pain symptoms.

CONCLUSION

This study's findings suggest that although not well characterized, long-COVID pain symptoms are being experienced by non-negligible proportions of those recovering from acute COVID-19 episodes, thus highlighting the importance of future research efforts to focus on this aspect.

Efficacy of rehabilitation treatments in improving functioning in patients with fibromyalgia: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Fibromyalgia is a debilitating condition marked by persistent pain and reduced functionality. Various therapeutic methods have been suggested to alleviate symptoms in individuals with fibromyalgia, yet the impact of diverse rehabilitation strategies remains unclear.

OBJECTIVE

This systematic review and meta-analysis aimed at assessing the efficacy of rehabilitation interventions in improving functioning in fibromyalgia patients.

METHODS

We conducted a comprehensive literature search of multiple international databases (PubMed, Scopus, and Web of Science) from their inception until November 22nd, 2023. We identified 23 randomized controlled trials (RCTs) assessing multiple rehabilitation strategies. The primary outcome was the Fibromyalgia Impact Questionnaire (FIQ). Study quality was assessed using the Cochrane Risk-of-Bias Tool for Randomized Trials (RoB 2). The study protocol was registered in PROSPERO (CRD42020197666).

RESULTS

Our meta-analysis rehabilitation interventions significantly reduce FIQ scores (MD =-11.74, 95% CI: -16.88 to -6.59, p< 0.0001). Notably, the subgroup analysis showed that different rehabilitation modalities seem to induce different therapeutic responses.

CONCLUSIONS

Rehabilitation strategies hold promise in addressing the functional impairments and improving the overall well-being of individuals with fibromyalgia. The study underscores the need for further research to determine the optimal rehabilitation approach and its potential impact on the multilevel disability characterizing patients with fibromyalgia.

An overview of myofascial pain syndrome with a focus on trigger point injection

ABSTRACT

Myofascial pain syndrome (MPS) is a very common condition, with an estimated lifetime prevalence of 85% in the general population. MPS is commonly underdiagnosed or misdiagnosed due to the lack of standardized diagnostic criteria and the symptoms' overlap with those of other musculoskeletal pain conditions. The most notable and bothersome feature of MPS is the presence of myofascial trigger points (MTrPs), hypersensitive areas of muscle commonly characterized as knots, nodules, or bumps that cause strain and pain with and oftentimes without stimulation. A low-risk, low-cost procedure, trigger point injection (TPI) is the gold standard for MPS treatment, and NPs can perform the procedure in an outpatient practice setting. Through administration of TPIs and use of other treatment modalities, primary care NPs can significantly impact the quality of life for those patients affected by acute and chronic MPS. This article aims to educate primary care NPs on MPS diagnosis and provide an overview of treatment options, with a focus on TPI use and administration for MPS relief.

Evaluation of sexual dysfunction in females with neck and upper back myofascial pain syndrome: a cross-sectional study

Myofascial pain syndrome (MPS) is a prevalent chronic musculoskeletal pain disorder that is frequently encountered in clinical practice and can cause sexual dysfunction in women. While there have been studies examining sexual function in various painful rheumatic conditions, particularly fibromyalgia, no studies have been conducted specifically on primary MPS. In this context, we aimed to investigate the frequency of sexual intercourse and the factors associated with it in women diagnosed with MPS. The study was designed as a cross-sectional study at a tertiary rehabilitation center between May 2022 and April 2023. Forty-five consecutive sexually active women (mean age: 38.1 ± 6.8 years) diagnosed with primary MPS were included in the study. They were compared to 45 healthy women of similar ages. The participants were interviewed regarding their weekly frequency of sexual intercourse and the importance of sexual life. Also, the Beck Depression Inventory (BDI) and the Visual Analog Scale (VAS) were assessed. The importance of sexual life score (p = 0.008), BDI (p < 0.001), VAS pain (p < 0.001), and VAS fatigue (p < 0.001) values were found to be lower in the patient group compared to the control group. The frequency of sexual intercourse was lower in the patient group, although this difference did not reach statistical significance (p = 0.083). In patients with a higher BDI score (≥ 17), the number of sexual intercourse was lower (p = 0.044), and the severity of fatigue was higher (p = 0.013). Significant associations were observed in MPS patients between the weekly frequency of sexual intercourse and VAS pain, VAS fatigue, BDI, and the importance of the sexual life score. A positive correlation was observed between the number of weekly sexual intercourses and the importance of the sexual life score (r = 0.577, p < 0.001), and negative correlations were found between BDI (r = - 0.478, p < 0.001), VAS pain (r = - 0.409, p < 0.001), and VAS fatigue (r = - 0.439, p < 0.001). Patients with MPS should be assessed for depressive mood and fatigue, as these factors may contribute to sexual dysfunction. These results may also emphasize the importance of adopting a multidisciplinary approach in the management of MPS patients with concurrent sexual dysfunction. Clinicaltrials.gov identifier: NCT05727566.

Current advances and novel research on minimal invasive techniques for musculoskeletal disorders

The present review summarized the current advances and novel research on minimal invasive techniques for musculoskeletal disorders. Different invasive approaches were proposed in the physical therapy field for the management of musculoskeletal disorders, such as ultrasound-guided percutaneous needle electrolysis, dry needling, acupuncture and other invasive therapy techniques, discussing about their worldwide status, safety and interventional ultrasound imaging. Indeed, dry needling may be one of the most useful and studies invasive physical therapy applications in musculoskeletal disorders of different body regions, such as back, upper limb, shoulder, arm, hand, pelvis, lower limb, neck, head, or temporomandibular joint, and multiple soreness location disorders, such as fibromyalgia. In addition, the assessment and treatment by acupuncture or electro-acupuncture was considered and detailed for different conditions such as plantar fasciitis, osteoarthritis, spasticity, myofascial pain syndrome, osteoporosis and rheumatoid arthritis. As an increasing technique in physical therapy, the use of ultrasound-guided percutaneous needle electrolysis was discussed in injuries of the musculoskeletal system and entrapment neuropathies. Also, ultrasound-guided percutaneous neuromodulation was established as a rising technique combined with ultrasound evaluation of the peripheral nerve system with different clinical applications which need further studies to detail their effectiveness in different musculoskeletal conditions. Thus, invasive physical therapy may be considered as a promising approach with different novel applications in several musculoskeletal disorders and a rising use in the physiotherapy field.

Fibromyalgia: Pathogenesis, Mechanisms, Diagnosis and Treatment Options Update

Fibromyalgia is a syndrome characterized by chronic and widespread musculoskeletal pain, often accompanied by other symptoms, such as fatigue, intestinal disorders and alterations in sleep and mood. It is estimated that two to eight percent of the world population is affected by fibromyalgia. From a medical point of view, this pathology still presents inexplicable aspects. It is known that fibromyalgia is caused by a central sensitization phenomenon characterized by the dysfunction of neuro-circuits, which involves the perception, transmission and processing of afferent nociceptive stimuli, with the prevalent manifestation of pain at the level of the locomotor system. In recent years, the pathogenesis of fibromyalgia has also been linked to other factors, such as inflammatory, immune, endocrine, genetic and psychosocial factors. A rheumatologist typically makes a diagnosis of fibromyalgia when the patient describes a history of pain spreading in all quadrants of the body for at least three months and when pain is caused by digital pressure in at least 11 out of 18 allogenic points, called tender points. Fibromyalgia does not involve organic damage, and several diagnostic approaches have been developed in recent years, including the analysis of genetic, epigenetic and serological biomarkers. Symptoms often begin after physical or emotional trauma, but in many cases, there appears to be no obvious trigger. Women are more prone to developing the disease than men. Unfortunately, the conventional medical therapies that target this pathology produce limited benefits. They remain largely pharmacological in nature and tend to treat the symptomatic aspects of various disorders reported by the patient. The statistics, however, highlight the fact that 90% of people with fibromyalgia also turn to complementary medicine to manage their symptoms.

Feasibility of Ultrasound-Guided Trigger Point Injection in Patients with Myofascial Pain Syndrome

We compared the feasibility of ultrasound (US)-guided myofascial trigger point (MTrP) injection with that of a blind injection technique following the use of shear wave elastography (SWE) for the measurement of stiffness at the MTrPs in patients with trapezius myofascial pain syndrome (MPS). A total of 41 patients (n = 41) were randomized to either the trial group (n = 21, SWE combined with US-guided injection) or the control group (n = 20, SWE combined with blind injection). At baseline and four weeks, they were evaluated for the manual muscle test (MMT), the range of motion (ROM), pain visual analogue scale (VAS) scores, Shoulder Pain and Disability Index (SPADI) scores and Neck Disability Index (NDI) scores during the abduction, adduction, flexion, extension, external rotation and internal rotation of the shoulder joint. Differences in changes in pain VAS scores, NDI scores and SPADI scores at four weeks from baseline between the two groups reached statistical significance (p = 0.003, 0.012, and 0.018, respectively). US-guided MTrP injection is a more useful modality as compared with a blind injection in patients with MPS.

The GC-MS metabolomics signature in patients with fibromyalgia syndrome directs to dysbiosis as an aspect contributing factor of FMS pathophysiology

INTRODUCTION

Fibromyalgia syndrome (FMS) is a chronic pain syndrome. Previous analyses of untargeted metabolomics data indicated altered metabolic profile in FMS patients.

OBJECTIVES

We report a semi-targeted explorative metabolomics study on the urinary metabolite profile of FMS patients; exploring the potential of urinary metabolite information to augment existing medical diagnosis.

METHODS

All cases were females. Patients had a medical history of persistent FMS (n = 18). Control groups were first-generation family members of the patients (n = 11), age-related individuals without indications of FMS (n = 10), and healthy, young (18-22 years) individuals (n = 41). The biofluid investigated was early morning urine samples. Data generation was done through gas chromatography-mass spectrometry (GC-MS) analysis and data processing and analyses were performed using Matlab, R, SPSS and SAS software.

RESULTS

Quantitative analysis revealed the presence of 196 metabolites. Unsupervised and supervised multivariate analyses distinguished all three control groups and the FMS patients, which could be related to 14 significantly increased metabolites. These metabolites are associated with energy metabolism, digestion and metabolism of carbohydrates and other host and gut metabolites.

CONCLUSIONS

Overall, urinary metabolite profiles in the FMS patients suggest: (1) energy utilization is a central aspect of this pain disorder, (2) dysbiosis seems to prevail in FMS patients, indicated by disrupted microbiota metabolites, supporting the model that microbiota may alter brain function through the gut-brain axis, with the gut being a gateway to generalized pain, and (3) screening of urine from FMS is an avenue to explore for adding non-invasive clinical information for diagnosis and treatment of FMS.

A diagnostic biomarker profile for fibromyalgia syndrome based on an NMR metabolomics study of selected patients and controls

BACKGROUND

Fibromyalgia syndrome (FMS) is a chronic pain syndrome. A plausible pathogenesis of the disease is uncertain and the pursuit of measurable biomarkers for objective identification of affected individuals is a continuing endeavour in FMS research. Our objective was to perform an explorative metabolomics study (1) to elucidate the global urinary metabolite profile of patients suffering from FMS, and (2) to explore the potential of this metabolite information to augment existing medical practice in diagnosing the disease.

METHODS

We selected patients with a medical history of persistent FMS (n = 18), who described their recent state of the disease through the Fibromyalgia Impact Questionnaire (FIQR) and an in-house clinical questionnaire (IHCQ). Three control groups were used: first-generation family members of the patients (n = 11), age-related individuals without any indications of FMS or related conditions (n = 10), and healthy young (18-22 years) individuals (n = 20). All subjects were female and the biofluid under investigation was urine. Correlation analysis of the FIQR showed the FMS patients represented a well-defined disease group for this metabolomics study. Spectral analyses of urine were conducted using a 500 MHz ¹H nuclear magnetic resonance (NMR) spectrometer; data processing and analyses were performed using Matlab, R, SPSS and SAS software.

RESULTS AND DISCUSSION

Unsupervised and supervised multivariate analyses distinguished all three control groups and the FMS patients, and significant increases in metabolites related to the gut microbiome (hippuric, succinic and lactic acids) were observed. We have developed an algorithm for the diagnosis of FMS consisting of three metabolites - succinic acid, taurine and creatine - that have a good level of diagnostic accuracy (Receiver Operating Characteristic (ROC) analysis - area under the curve 90%) and on the pain and fatigue symptoms for the selected FMS patient group.

CONCLUSION

Our data and comparative analyses indicated an altered metabolic profile of patients with FMS, analytically detectable within their urine. Validation studies may substantiate urinary metabolites to supplement information from medical assessment, tender-point measurements and FIQR questionnaires for an improved objective diagnosis of FMS.

Myofascial pain and fibromyalgia: two different but overlapping disorders

There is good evidence supporting that people with fibromyalgia syndrome (FMS) exhibit central sensitization. The role of peripheral nociception is under debate in FMS. It seems that widespread pain experienced in FMS is considered multiple regional pains; therefore, several authors proposed that muscles play a relevant role in FMS. Trigger points (TrPs) have long been a contentious issue in relation to FMS. Preliminary evidence reported that the overall spontaneous pain is reproduced by referred pain from active TrPs, suggesting that FMS pain is largely composed of pain arising, at least partially, from TrPs. Finally, there is preliminary evidence suggesting that management of TrPs is able to modulate the CNS and is effective for reducing pain in FMS, although results are conflicting and future studies are clearly needed.

Muscle Trigger Points and Pressure Pain Sensitivity Maps of the Feet in Women with Fibromyalgia Syndrome

OBJECTIVE : To investigate the presence of trigger points (TrPs) in feet musculature and topographical pressure sensitivity maps of the feet as well as the relationship between TrPs, pressure pain maps, and clinical variables in women with fibromyalgia (FMS). METHODS : Fifty-one FMS women and 24 comparable healthy women participated. TrPs within the flexor hallucis brevis, adductor hallucis, dorsal interossei, extensor digitorum brevis, and quadratus plantae, as well as external and internal gastrocnemius, were explored. Pressure pain thresholds (PPTs) were assessed in a blind manner over seven locations on each foot. Topographical pressure sensitivity maps of the plantar region were generated using the averaged PPT of each location. RESULTS : The prevalence rate of foot pain was 63% (n = 32). The number of active TrPs for each FMS woman with foot pain was 5 ± 1.5 without any latent TrPs. Women with FMS without foot pain and healthy controls had only latent TrPs (2.2 ± 0.8 and 1.5 ± 1.3, respectively). Active TrPs in the flexor hallucis brevis and adductor hallucis muscles were the most prevalent. Topographical pressure pain sensitivity maps revealed that FMS women with foot pain had lower PPT than FMS women without pain and healthy controls, and higher PPT on the calcaneus bone (P < 0.001). CONCLUSIONS : The presence of foot pain in women with FMS is high. The referred pain elicited by active TrPs in the foot muscles reproduced the symptoms in these patients. FMS women suffering foot pain showed higher pressure hypersensitivity in the plantar region than those FMS women without pain.

Fibromyalgia, myofascial pain, tender points and trigger points: splitting or lumping?

Myofascial trigger points (MTPs) have long been a contentious issue in relation to fibromyalgia, and poorly defined pain complaints in general. Can MTPs be reproducibly identified? Do MTPs have valid objective findings, such as spontaneous electromyographic activity, muscle microdialysis evidence for an inflammatory milieu or visualization with newer ultrasound techniques? Is fibromyalgia a syndrome of multiple MTPs, or is focal muscle tenderness a manifestation of central sensitization? These issues are discussed with relevance to a recent paper reporting that manual palpation of active MTPs elicits the spontaneous pain experienced by fibromyalgia patients.

Neurophysiopathogenesis of fibromyalgia syndrome: a unified hypothesis

The characteristic presenting complaint of patients with fibromyalgia syndrome (FMS) is chronic widespread allodynia. Research findings support the view that FMS is an understandable and treatable neuropathophysiologic disorder. The pain of FMS is often accompanied by one or more other manifestations, such as affective moods, cognitive insecurity, autonomic dysfunction, or irritable bowel or bladder. Growing evidence suggests that this is a familial disorder with many underlying genetic associations. New findings from brain imaging and polysomnography imply that FMS may be a disorder of premature neurologic aging. A conceptual model at the molecular level is proposed to explain many of the observed features of FMS. The model can also explain anticipated responses to FDA approved pharmacologic therapies.

A preliminary comparison of the efficacy and tolerability of botulinum toxin serotypes A and B in the treatment of myofascial pain syndrome: a retrospective, open-label chart review

BACKGROUND

Myofascial pain syndrome (MPS) is characterized by acute or chronic regional muscle pain associated with single or multiple trigger points within taut bands of muscle. Botulinum toxins have clinical utility when sustained focal muscle relaxation is required and may be a useful addition to the treatment armamentarium for MPS.

OBJECTIVE

The purpose of the present article was to compare the efficacy and tolerability of botulinum toxin serotypes A and B (BTX-A and BTX-B) in the treatment of MPS.

METHODS

This was a retrospective, open-label, single-center chart review. Charts of all patients who received either BTX-A or BTX-B for MPS between January and November 2001 were included in the review. Patients rated the intensity of their pain on a visual analog scale (VAS) from 0 = no pain to 10 = worst pain imaginable before and after receiving BTX-A or BTX-B.

RESULTS

The charts of 91 patients (74.7% female, 25.3% male; mean [SD] age, 47 [10.2] years) who received BTX-A (n = 56; mean dose, 256.9 U; range, 100-600 U) or BTX-B (n = 35; mean dose, 9000 U; range, 2500-20,000 U) were included in this retrospective review. Patients who received BTX-A had significantly greater mean reductions in VAS pain scores compared with those who received BTX-B (mean reduction, 2.7 vs 1.8, respectively; P < 0.001). Patients who received BTX-A also reported significantly longer durations of pain relief compared with those who received BTX-B (4.5 vs 2.7) months; P < 0.001). Eight of 56 patients (14.3%) in the group that received BTX-A reported mild adverse events that included flulike symptoms, injection-site pain, and weakness of the neck muscles. Seven of 35 patients (20.0%) in the group that received BTX-B reported adverse events that included mild flulike symptoms, dry eyes, severe visual disturbances, and severe dry mouth.

CONCLUSION

Patients with MPS who received BTX-A reported significantly greater reductions in pain for longer durations compared with those who received BTX-B. No patients who received BTX-A experienced severe systemic adverse events, compared with 4 patients who received BTX-B. The results of this comparison are consistent with the US Food and Drug Administration-approved labeling indicating that BTX-A is not interchangeable with any other botulinum toxin in terms of biological activity.