Myalgia in myositis and myopathies

Update on Exercise in Persons With Muscle Disease

Myopathies are heterogeneous in their etiology, muscle group involvement, clinical manifestation, and progression. Deficits in myopathy may include muscle weakness, atrophy, stiffness, myalgia, and extra-muscular manifestations. Consequently, these deficits could lead to impaired musculoskeletal function, inadequate engagement in daily activities and reduced participation in social activities. Exercise has been viewed as a potentially efficacious intervention to halt the loss of muscle function and to improve secondary symptoms that result from muscle loss, such as pain and fatigue. The purpose of this review is to discuss research findings within the last 10 years that examine effects of exercise interventions in many types of myopathies in humans. In general, most studies were small scale, and they varied with respect to exercise type, intensity, and outcome measures. Despite the different pathologies, various exercise subtypes of aerobic/endurance or strength/resistance training are generally beneficial and may improve muscle strength and functional outcomes. Exercise therapies are generally safe and well tolerated. Exercise prescription should be part of routine neuromuscular care for patients with myopathy, and ideally with input from a multidisciplinary team, with a focus on providing individualized exercise regimens. Further work is needed to define the optimal intensity and type of exercise to result in the best functional outcomes for persons with myopathy, as well as the effects of combining exercise and novel disease modifying therapies.

Causal association between depression and myalgia-related disorders: A bidirectional mendelian randomization study

OBJECTIVE

The connection between depression and myalgia-related disorders remains unclear. We investigated the bidirectional causal relationship between depression and five such disorders using Mendelian randomization (MR).

METHOD

Genetic instrumental variables for depression were obtained from a GWAS of 170,756 individuals with depression and 329,443 controls. The primary two-sample MR analysis used the inverse variance-weighted (IVW) method. Robustness was tested with MR Egger, weighted median, and weighted mode approaches. We also conducted heterogeneity, pleiotropy, and sensitivity analyses to ensure result reliability.

RESULTS

Depression showed significant positive associations with myalgia [IVW, OR = 1.468, 95 % CI: 1.246-1.729, P = 4.19 × 10-6], fibromyalgia [OR = 2.328, 95 % CI: 1.771-3.061, P = 1.39 × 10-9], and osteoarthritis [OR = 1.242, 95 % CI: 1.147-1.345, P = 9.58 × 10-8]. No causal association was found with myositis or rheumatoid arthritis (P > 0.05). In reverse MR, osteoarthritis showed a significant association with depression [OR = 1.113, 95 % CI: 1.025-1.210, P = 0.011], while other disorders did not (P > 0.05).

CONCLUSION

Our findings suggest a genetic causal relationship between depression and increased risk of myalgia, fibromyalgia, and osteoarthritis. Moreover, osteoarthritis may increase depression risk, supporting a potential bidirectional link. These results underscore the importance of timely depression management to mitigate risks of myalgia-related conditions.

Global weakness with no clear precipitant: thymoma presenting as a necrotising myositis and myasthenia gravis overlap syndrome

Overlap syndromes involving myasthenia gravis, myositis and myocarditis are recognised adverse effects of immune checkpoint inhibitors (ICI). We report a similar syndrome of myasthenia gravis and myositis in a patient without prior ICI exposure. Diagnostic tests showed signs of both immune-mediated necrotising myopathy and myasthenia gravis. Symptoms included proximal muscle weakness, ophthalmoplegia, bulbar symptoms and neuromuscular respiratory failure. Initial treatment with glucocorticoids and intravenous immunoglobulin for myositis was partially effective. Significant improvement occurred with rituximab and an acetylcholinesterase inhibitor. Although imaging had not revealed a thymic mass suggestive of thymoma, the patient underwent thymectomy several weeks after recovering from the acute illness. Histopathological examination of the resected tissue confirmed the presence of thymoma. This case illustrates that myasthenia gravis and myositis can spontaneously co-present. Clinicians should consider the possibility that a seemingly atypical presentation of a condition may reflect a more typical presentation of two conditions, such as in this case. In this situation, paraneoplastic causes should be considered.

Small and large fiber neuropathy in adults with myotonic dystrophy type 1

Introduction

Myotonic dystrophy type 1 (DM1) is an inherited neuromuscular disorder that affects multiple organs. In this study, we investigated symptoms of pain and presence of small and large fiber neuropathy in the juvenile and adult form of DM1.

Method

Twenty genetically verified DM1 patients were included. Pain was assessed, and neurological examination and investigations of the peripheral nervous system by quantification of small nerve fibers in skin biopsy, quantitative sensory testing and nerve conduction studies were performed. Results from skin biopsies were compared to healthy controls.

Result

Seventeen patients reported chronic pain. Large and/or small fiber abnormalities were present in 50% of the patients. The intraepidermal nerve fiber density was significantly lower in the whole group of patients compared to healthy controls.

Conclusion

Small-fiber neuropathy might be an important cause of pain in DM1.

Water-soluble pristine C60 fullerenes attenuate isometric muscle force reduction in a rat acute inflammatory pain model

BACKGROUND

Being a scavenger of free radicals, C₆₀ fullerenes can influence on the physiological processes in skeletal muscles, however, the effect of such carbon nanoparticles on muscle contractility under acute muscle inflammation remains unclear. Thus, the aim of the study was to reveal the effect of the C₆₀ fullerene aqueous solution (C₆₀FAS) on the muscle contractile properties under acute inflammatory pain.

METHODS

To induce inflammation a 2.5% formalin solution was injected into the rat triceps surae (TS) muscle. High-frequency electrical stimulation has been used to induce tetanic muscle contraction. A linear motor under servo-control with embedded semi-conductor strain gauge resistors was used to measure the muscle tension.

RESULTS

In response to formalin administration, the strength of TS muscle contractions in untreated animals was recorded at 23% of control values, whereas the muscle tension in the C₆₀FAS-treated rats reached 48%. Thus, the treated muscle could generate 2-fold more muscle strength than the muscle in untreated rats.

CONCLUSIONS

The attenuation of muscle contraction force reduction caused by preliminary injection of C₆₀FAS is presumably associated with a decrease in the concentration of free radicals in the inflamed muscle tissue, which leads to a decrease in the intensity of nociceptive information transmission from the inflamed muscle to the CNS and thereby promotes the improvement of the functional state of the skeletal muscle.

Effects of Conventional Rehabilitative and Aerobic Training in Patients with Idiopathic Inflammatory Myopathy

OBJECTIVE

To investigate the efficacy of conventional rehabilitation alone and conventional rehabilitation combined with aerobic training on muscle strength and function, health condition, and quality of life for patients with stable idiopathic inflammatory myopathy (IIM).

METHODS

This is a historical retrospective cohort study, in which the medical records of patients with IIM, who received the combination of conventional rehabilitative therapy and aerobic training (combined training group [CTG]), from February 2015 to December 2017 were reviewed. Patients with IIM who received conventional therapy alone were matched based on their age, gender, and disease activity as the control group (CG). Scores obtained on manual muscle testing of eight designated muscles (MMT8) was the primary outcome measure, and scores on the myositis Functional Index-2 (FI-2), Health Assessment Questionnaire (HAQ), and 36-item Short Form Medical Outcomes Study Questionnaire (SF-36) at 12 weeks during training were the secondary outcomes.

RESULTS

Fifty-six patients (28 in the CTG and 28 in the CG) were included in this analysis. Patients in both groups had improved MMT8, FI-2, HAQ, and SF-36 scores after 12 weeks of physical therapy. The CTG had a significantly higher score on the MMT8 and HAQ than the CG in the 12th week. The FI-2 scores were significantly higher in the CTG for the four items (P < 0.05) of hip flexion, step test, heel lift, and toe lift. SF-36 scores of the CTG were also higher than those of the CG for the five items (P < 0.05) of physical functioning, general health, vitality, social functioning, and mental health.

CONCLUSIONS

Physical exercise training including conventional rehabilitation and aerobic training improved muscle function, health condition, and quality of life. Conventional rehabilitative training combined with aerobic training achieved better improvement compared with conventional rehabilitation training alone.

Unraveling Muscle Impairment Associated With COVID-19 and the Role of 3D Culture in Its Investigation

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been considered a public health emergency, extensively investigated by researchers. Accordingly, the respiratory tract has been the main research focus, with some other studies outlining the effects on the neurological, cardiovascular, and renal systems. However, concerning SARS-CoV-2 outcomes on skeletal muscle, scientific evidence is still not sufficiently strong to trace, treat and prevent possible muscle impairment due to the COVID-19. Simultaneously, there has been a considerable amount of studies reporting skeletal muscle damage in the context of COVID-19. Among the detrimental musculoskeletal conditions associated with the viral infection, the most commonly described are sarcopenia, cachexia, myalgia, myositis, rhabdomyolysis, atrophy, peripheral neuropathy, and Guillain-Barré Syndrome. Of note, the risk of developing sarcopenia during or after COVID-19 is relatively high, which poses special importance to the condition amid the SARS-CoV-2 infection. The yet uncovered mechanisms by which musculoskeletal injury takes place in COVID-19 and the lack of published methods tailored to study the correlation between COVID-19 and skeletal muscle hinder the ability of healthcare professionals to provide SARS-CoV-2 infected patients with an adequate treatment plan. The present review aims to minimize this burden by both thoroughly exploring the interaction between COVID-19 and the musculoskeletal system and examining the cutting-edge 3D cell culture techniques capable of revolutionizing the study of muscle dynamics.

Anti-inflammatory Effect of Predimenol, A Bioactive Extract from Phaleria macrocarpa, through the Suppression of NF-κB and COX-2

BACKGROUND

Inflammation is the response to the reaction of any type of bodily injury by elevating cellular metabolism and releasing soluble mediators. It is also a contributing factor of pain. Predimenol, which has previously been known as DLBS1442, is a bioactive extract from Phaleria macrocarpa (Scheff.) Boerl (Thymelaceae). It can be an alternative treatment for pain relief, especially for long-term use.

OBJECTIVE

The objective of this study is to evaluate the anti-inflammatory activities of predimenol through the evaluation of several parameters involved in the inflammatory pathway.

METHODS

Cyclooxygenase 2 (COX-2), inducible nitric oxide synthase (iNOS), tumor necrosis factor-  (TNF-), interleukin-1β (IL-1β), interleukin-2 (IL-2), interleukin-6 (IL-6), and nuclear factor B (NF-B) were observed after 24 h exposure of predimenol (0-180 µg/mL) to lipopolysaccharides (LPS)-activated RAW 264.7 cell. The inflammatory markers were measured using nitric oxide (NO) assay and enzyme-linked immunosorbent assay (ELISA) for COX-2 inhibitor assay. The gene expressions of TNF-α, IL-1β, IL-2 and IL-6 were quantified using the polymerase chain reaction (PCR) method. Western blotting was applied to detect phosphorylated IB kinase (IKK) protein to confirm the activation of NF-κB.

RESULTS

Our study showed a similar mechanism with most non-steroidal anti-inflammatory drugs (NSAIDs). Predimenol consistently downregulated the expression of iNOS and inhibited COX-2 activity. Moreover, predimenol significantly inhibited the LPS-induced production of NO, TNF-α, IL-1β, IL-2 and IL-6. Down-regulation of these markers was suggested due to the reduction of NF-κB transcription level and activation by predimenol.

CONCLUSION

Predimenol exhibits anti-inflammatory activities through NF-kB inactivation-mediated COX-2 suppression, which may suggest that predimenol is a potential analgesic and anti-inflammatory agent.

Masticatory Myofascial Pain Syndrome: Implications for Endodontists

INTRODUCTION

Masticatory myofascial pain syndrome can present similarly to other dental conditions in odontogenetic structures. Endodontists should be familiar with the symptomology and pathophysiology of masticatory myofascial pain syndrome to avoid misdiagnosis, incorrect treatment, and medicolegal repercussions. The aim of this review was to provide a foundational summary for endodontists to identify and correctly manage masticatory myofascial pain syndrome.

METHODS

A narrative review of the literature was performed through a MEDLINE search and a hand search of the major myofascial pain textbooks.

RESULTS

Masticatory myofascial pain syndrome is a musculoligamentous syndrome that can present similarly to odontogenic pain or refer pain to the eyebrows, ears, temporomandibular joints, maxillary sinus, tongue, and hard palate. Currently, the most comprehensive pathophysiology theory describing masticatory myofascial pain syndrome is the expanded integrated hypothesis. The most widely accepted diagnostic guidelines for masticatory myofascial pain syndrome are the Diagnostic Criteria for Temporomandibular Disorders; however, their diagnostic capability is limited. There is no hierarchy of treatment methods because each patient requires a tailored and multidisciplinary management aimed at regaining the muscle's range of motion, deactivating the myofascial trigger points, and maintaining pain relief.

CONCLUSIONS

The pain patterns for masticatory myofascial pain syndrome are well-known; however, there is a lack of consensus on the most proper method of trigger point diagnosis or pain quantification. The diagnostic strategies for masticatory myofascial pain syndrome vary, and the diagnostic aids are not well developed.

Idiopathische inflammatorische Myopathien: Aktuelles zu Diagnose und Klassifikation

Auf dem Sektor der Kollagenosen ist der wissenschaftliche Fortschritt bei der Myositis in den letzten 15–20 Jahren bemerkenswert. Durch kontinuierliche Forschung und intensive Vernetzung der Myositis-Experten ist es gelungen, neue Untergruppen zu identifizieren und somit für die Prognose wichtige Organmanifestationen rechtzeitig zu erkennen. Vor dem Hintergrund dieser Neuerungen verfolgt diese Übersichtsarbeit sowohl das Ziel, möglichst alle Facetten der Erkrankung zu präsentieren, als auch die moderne Einteilung der idiopathischen inflammatorischen Myopathien zu erläutern. Außerdem werden die neuen Klassifikationskriterien vorgestellt, die die Kriterien von Bohan und Peter aus dem Jahr 1975 abgelöst haben. Im Artikel werden ihre Stärken und Schwächen sowie ihr Optimierungspotenzial diskutiert.

[Pain management in rare diseases]

In this article we address the relevance of rare diseases and their peculiarities with respect to pain therapy. Towards this end, four rare diseases (hemophilia, Morbus Fabry, dermatomyositis, and facioscapulohumeral dystrophy (FSHD)) will be presented and fundamental aspects of their pain therapies described. The diseases were chosen to showcase a pain therapy based on the WHO-step-by-step plan (hemophilia), a complex but established pain therapy (M. Fabry), and two less well established, individually adapted pain therapies (dermatomyositis, FSHD).