A review of inflammatory idiopathic myopathy focusing on polymyositis

Myositis and Its Mimics: Guideline Updates, MRI Characteristics, and New Horizons

Myositis is defined as inflammation within skeletal muscle and is a subcategory of myopathy, which is more broadly defined as any disorder affecting skeletal muscle. Myositis may be encountered as a component of autoimmune and connective tissue disease, where it is described as idiopathic inflammatory myopathy. Myositis can also be caused by infections, as well as toxins and drugs, including newer classes of medications. MRI plays an important role in the diagnosis and evaluation of patients with suspected myositis, but many entities may have imaging features similar to myositis and can be considered myositis mimics. These include muscular dystrophies, denervation, deep venous thrombosis, diabetic myonecrosis, muscle injury, heterotopic ossification, and even neoplasms. In patients with suspected myositis, definitive diagnosis may require integrated analysis of imaging findings with clinical, laboratory, and pathology data. The objectives of this article are to review the fundamental features of myositis, including recent updates in terminology and consensus guidelines for idiopathic inflammatory myopathies, the most important MRI differential diagnostic considerations for myositis (i.e., myositis mimics), and new horizons, including the potential importance of artificial intelligence and multimodal integrated diagnostics in the evaluation of patients with muscle disorders.

Muscle glycome in idiopathic inflammatory myopathies: Impact in IL-6 production and disease prognosis

Idiopathic inflammatory myopathies (IIM) are a group of chronic autoimmune diseases mainly affecting proximal muscles. Absence of meaningful prognostic factors in IIM has hindered new therapies development. Glycans are essential molecules that regulate immunological tolerance and consequently the onset of autoreactive immune response. We showed that muscle biopsies from patients with IIM revealed a deficiency in the glycosylation pathway resulting in loss of branched N-glycans. At diagnosis, this glycosignature predicted disease relapse and treatment refractoriness. Peripheral CD4⁺ T cells from active-disease patients shown a deficiency in branched N-glycans, linked to increased IL-6 production. Glycan supplementation, restoring homeostatic glycosylation profile, led to a decrease in IL-6 levels. This study highlights the biological and clinical importance of glycosylation in IIM immunopathogenesis, providing a potential mechanism for IL-6 production. This pinpoints muscle glycome as promising biomarker for personalized follow-up and a potential target for new therapies in a patients' subgroup with an ominous evolution.

The role of bDMARDs in idiopathic inflammatory myopathies: A systematic literature review

Idiopathic inflammatory myopathies (IIM) are a group of different conditions typically affecting striate muscle, lung, joints, skin and gastrointestinal tract. Treatment typically relies on glucocorticoids and synthetic immunosuppressants, but the occurrence of refractory, difficult to treat, manifestations, may require more aggressive treatment, borrowed from other autoimmune diseases, including biologic disease modifying drugs (bDMARDs). In this regard, we conducted a systemic literature review in order to depict the current evidence about the use of bDMARDs in IIM. A total of 78 papers, published during the last 21 years, were retrieved. The majority of patients was treated with TNF-α inhibitors, whose effectiveness was assessed particularly in recalcitrant striate muscle, skin and joints involvement. Rituximab, whose evidence is supported by a large number of real-life studies and trials, seems to be an excellent option in case of ILD and anti-synthetase syndrome, while Tocilizumab, despite not meeting primary and secondary endpoints in a recently published clinical trial, proved its effectiveness in rapidly progressing ILD. Similarly, Abatacept, studied in a phase IIb clinical trial with conflicting evidence, was reported to be effective in some case reports of refractory dermatomyositis. Less data exist for anti-IL1 and anti-IL23 agents, which were employed particularly for inclusion body myositis and severe skin disease, respectively. This study provides an organ-focused assessment of bDMARDs in IIM, which display encouraging results in the treatment of refractory subsets of disease.

Fibromyalgia: Recognition and Management in the Primary Care Office

Fibromyalgia is a chronic pain condition manifested by chronic generalized pain, fatigue, disordered sleep, and cognitive difficulties, persistent for at least 3 months. Other common complaints/conditions include symptoms of irritable bowel syndrome, headaches, intermittent paresthesias, and various mood disorders. Women are more commonly affected than men. The treatment approach should be individualized and focused on associated mood disorders, sleep, exercise, correction of maladaptive responses to pain, and coping with stress.

Polymyositis Presenting With Nontraumatic Rhabdomyolysis and Dysphagia: A Case Report

Idiopathic inflammatory myopathies (IIMs) are a rare, heterogeneous group of diseases with a characteristic clinical presentation consisting of muscle inflammation and weakness. They often present with accompanying extra-muscular findings, most notably in the skin, lungs, and joints. Inflammatory myopathies are also identified by their characteristic laboratory abnormalities, including a 10- to 50-fold increase in creatinine kinase, elevated liver enzymes, and characteristic electromyography and magnetic resonance imaging findings. Distinct autoimmune markers and clinical phenotypes have advanced our understanding of IIMs and have led to the recognition of 5 distinct entities, each with its unique pathophysiology, autoimmune markers, and clinical features. While autoimmune panels and muscle biopsies help clinicians distinguish one entity from the other, their sensitivity and specificity vary. Of the various inflammatory myopathies, polymyositis remains the most elusive. Often, the diagnosis is ultimately made by combining clinical findings and laboratory data. As our case report illustrates, clinicians must use this constellation of data to initiate treatment for suspected polymyositis despite negative autoimmune panels and negative muscle biopsy.

Myositis autoantibodies in Iranian myositis patients: assessment the frequency and clinical relevancy

INTRODUCTION

Dermatomyositis (DM) and polymyositis (PM) are known as two major types of idiopathic inflammatory myopathies (IMMs). During the past years, growing data strongly suggest the clinical significance of myositis-associated autoantibodies (MAAs) and myositis-specific autoantibodies (MSAs). The present study aimed to determine the profile of MSAs and MAAs, subsequently to address the clinical significance of these autoantibodies in Iranian myositis patients.

METHODOLOGY

In this cross-sectional study, 28 DM and 24 PM patients were entered. Demographic and clinical characteristics were collected by direct examination and patients' medical record. The existence of MSAs and MAAs was assessed by indirect immunofluorescence then using immunoblotting (FA 1510-1005-1, DL 1530-1601-4 G; Euroimmun, Germany). Data were analyzed using the SPSS software (v22; SPSS Inc. Chicago, IL, USA).

RESULTS

The mean age of the patients was 46.18 ± 12.95 years and male/female ratio was 28.8/71.2. Autoantibodies were positive in 63.46% of myositis patients. Interestingly, anti-TIF1γ and anti-PL7 were significantly associated with malignancy (P < 0.001, P = 0.008; respectively). The existence of autoantibody and anti-Jo1 had significant relation with interstitial lung disease (ILD) (P = 0.034, P = 0.006; respectively). Joint involvements including arthritis and arthralgia were significantly associated with anti-Ro52 and anti-Jo1 (P = 0.04, P = 0.02; respectively).

CONCLUSION

Taken together, it can be concluded that certain myositis autoantibodies present clinical significance which is in line with the literature. The use of these autoantibodies as biomarkers by line blotting along with indirect immunofluorescence facilitates diagnosis of inflammatory myopathies and makes it more accurate as well as better management of myositis patients if used based on a science-based manner. Key Points • Identification of MSAs and MAAs facilitates the diagnosis of inflammatory myopathies and provides better myositis patient's management if used according to a science-based manner. • Anti-rod and ring antibody was detected in a patient with ovarian cancer-induced dermatomyositis. • Malignancy and ILD are integrated parts of myositis which can be associated with MSAs and MAAs.

Severe onset of inflammatory myositis in a child: think to paraneoplastic myositis

Background

Juvenile idiopathic inflammatory myopathies (JIIMs) are a group of heterogenous, acquired, autoimmune disorders that affect the muscle. While the association between IIMs and malignancy has been widely reported in adults, cancer-associated myositis (CAM) is rare in children, so that routine malignancy screening is not generally performed. This report shows a case of severe CAM in a child.

Case presentation

An 11-years-old girl presented with worsening dyspnea after a 3-weeks history of progressive proximal weakness, myalgia, dysphagia, and weight loss. Her past history was remarkable for a type I Arnold-Chiari malformation associated with an anterior sacral meningocele. Physical examination showed severe hypotony and hypotrophy. Pulse oximetry and blood test showed a type II respiratory failure (SpO₂ 88%, pCO₂ 68 mmHg) and increased muscle enzyme levels (CPK 8479 U/L, AST 715 U/L, ALT 383 U/L, LDH 1795 U/L). The patient needed invasive mechanical ventilation. Inflammatory myositis was considered and treatment with intravenous methylprednisolone (30 mg/Kg/day for 3 days followed by 2 mg/Kg/day) and IVIG (1 g/kg/day for 2 days) was started. Muscle biopsy showed endomysial and perimysial necrosis and inflammation. The presence of serum anti-TIF1-γ antibody positivity led to a malignancy screening. Whole-body MRI showed a mature teratoma underneath sacral meningocele and both lesions were surgically removed.

Given the histological and clinical severity of the myopathy, mycophenolate (500 mg twice a day) and rituximab (360 mg/m², 4 weekly infusions) were added. Due to extreme muscular wasting, severe malnutrition and intolerance to enteral feeding the patient needed a transient tracheostomy and parenteral nutrition, followed by physiotherapy, speech therapy and nocturnal non-invasive ventilation. A complete remission was achieved 3 months after.

Conclusions

Among cancer-associated autoantibodies (CAAs) in adult patients, anti-TIF1-γ carries the highest risk of CAM, which recognizes with a high likelihood a paraneoplastic pathogenesis. In children, anti-TIF1-γ antibody has been associated with severe cutaneous disease, lipodystrophy, and chronic disease course, but not with CAM, which is overall rare in younger patients. Severe onset of a JIIM, especially if anti-TIF1-γ antibody positive, should prompt suspect of a CAM and lead to a screening for malignancy.

Efficacy and safety of statins in ethnic differences: a lesson for application in Indigenous Australian patient care

Although statins are effective in treating high cholesterol, adverse effects do occur with their use. Efficacy and tolerability vary among statins in different ethnic groups. Indigenous Australians have a high risk for cardiovascular and kidney diseases. Prescribing statins to Indigenous Australians with multi-morbidity requires different strategies to increase efficacy and reduce their toxicity. Previous studies have reported that Indigenous Australians are more susceptible to severe statin-induced myopathies. However, there is a lack of evidence in the underlying genetic factors in this population. This review aims to identify: inter-ethnic differences in the efficacy and safety of statins; major contributing factors accounting for any identified differences; and provide an overview of statin-induced adverse effects in Indigenous Australians.

When Is It Not Diabetic Neuropathy? Atypical Peripheral Neuropathies, Neurologic Mimics, and Laboratory Work-up

Peripheral neuropathies have many nonspecific features that are shared by various neurologic disorders. These disorders include atypical peripheral neuropathies along with neurologic disorders outside of the peripheral nervous system. An understanding of clinical fundamentals and a measured approach to laboratory work-up can assist the provider in achieving diagnostic confidence.

Fibromyalgia: Recognition and Management in the Primary Care Office

Fibromyalgia is a chronic pain condition manifested by chronic generalized pain, fatigue, disordered sleep, and cognitive difficulties, persistent for at least 3 months. Other common complaints/conditions include symptoms of irritable bowel syndrome, headaches, intermittent paresthesias, and various mood disorders. Women are more commonly affected than men. The treatment approach should be individualized and focused on associated mood disorders, sleep, exercise, correction of maladaptive responses to pain, and coping with stress.

Reappraisal of the incidence, various types and risk factors of malignancies in patients with dermatomyositis and polymyositis in Taiwan

Our study aimed to investigate the incidence, risk factors and time to occurrence of malignancy in patients with dermatomyositis (DM) and polymyositis (PM). The electronic medical records of 1100 patients with DM and 1164 patients with PM were studied between January 2001 and May 2019. Malignancies after myositis were diagnosed in 61 (5.55%) patients with DM and 38 (3.26%) patients with PM. The cumulative incidence of malignancies in patients with DM were significantly higher than patients with PM (hazard ratio = 1.78, log-rank p = 0.004). Patients with DM had a greater risk of developing malignancy than those with PM at 40–59 years old (p = 0.01). Most malignancies occurred within 1 year after the initial diagnosis of DM (n = 35; 57.38%). Nasopharyngeal cancer (NPC) was the most common type of malignancy in patients with DM (22.95%), followed by lung, and breast cancers. In patients with PM, colorectal, lung and hepatic malignancies were the top three types of malignancy. The risk factors for malignancy included old age (≥ 45 years old) and low serum levels of creatine phosphokinase (CPK) for patients with DM and male sex and low serum levels of CPK for patients with PM. Low serum levels of CPK in patients with myositis with malignancy represented a low degree of muscle destruction/inflammation, which might be attributed to activation of the PD-L1 pathway by tumor cells, thus inducing T-cell dysfunction mediating immune responses in myofibers. A treatment and follow-up algorithm should explore the occurrence of malignancy in different tissues and organs and suggested annual follow-ups for at least 5.5 years to cover the 80% cumulative incidence of malignancy in patients with DM and PM.

Temporomandibular Disorders and Oral Features in Idiopathic Inflammatory Myopathies (IIMs) Patients: An Observational Study

Aim: Inflammatory idiopathic myopathies (IIMs) are inflammatory processes affecting skeletal musculature and extramuscular organs. Temporomandibular disorders (TMD) involve jaw muscles and temporomandibular joint. The aim of this observational study was to investigate the prevalence of the main TMD symptoms and signs as well as oral implications in IIM patients. Methods: The study group included 54 patients (42 women and 12 men), 22 of whom affected by dermatomyositis (DM), 29 by polymyositis (PM) and 3 by inclusion body myositis (IBM). A group of 54 patients not affected by this disease, served as CG. Oral and TMD signs and symptoms were evaluated by means of a questionnaire and through clinical examination. Results: About oral symptoms, the study group complained more frequently dysgeusia, with loss of taste or unpleasant taste (p<0.0001) and feeling of burning mouth (9.4% versus 0 controls). Xerostomia was more prevalent in the study group respect to the CG (p<0.0001). Dysphagia was reported by 48.1% of IIM patients while was absent in CG (p<0.0001). About oral signs, cheilitis (p<0.05) and oral ulcers (p<0.05) were significantly more frequent in CG. As regard to TMD symptoms, arthralgia and tinnitus didn't showed significant differences between the two groups, while neck/shoulders and masticatory muscle pain was significantly more referred in IIM patients than in the CG (p<0.05). About TMJ signs, sounds were overlapping in the two groups: click=11.1% in both IIM patients and CG (p>0.05), crepitation in 11.1% of IIM and 9.3% of controls (p>0.05). No significant difference was detected about deflection (9.3%, p>0.05), while deviation was wider in CG (p<0.05). Active opening and lateralities showed no significant differences, while endfeel was significantly increased in IIM group for a higher presence of muscular contracture. Bruxism was present only in CG. Conclusion: The data collected from this observational study seem to support the existence of a relationship between the prevalence of TMD symptoms and signs as well as oral features in patients with myositis. A remarkable reduction of salivary flow and dysphagia were more frequent and severe in IIM patients, as well as muscle contracture and myofacial pain evoked by palpation, this result being highly significant.

Myositis-specific autoantibodies in adults with idiopathic inflammatory myopathy: correlations with diagnosis and disease activity

OBJECTIVE

To determine the relationship of myositis autoantibodies with the diagnosis and severity of idiopathic inflammatory myopathy (IIM) using the 2017 EULAR/ACR idiopathic inflammatory myopathy classification criteria and the myositis disease activity assessment tool (MDAAT).

METHODS

Patients who met the new diagnostic criteria were tested for serum myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs), and then classified into different subgroups based on autoantibody positivity. Patients were also diagnosed with possible IIM, probable IIM, and definite IIM. The MDAAT was used to evaluate muscular and extramuscular disease activity. The relationships of diagnostic classification with positivity for different myositis autoantibodies were determined.

RESULTS

There were 118 patients, and 81% of them had one or more myositis autoantibody. Anti-Jo-1 was the most common MSA, and anti-Ro-52 was the most common MAA. Sixteen patients (14%) had possible IIM, 36 (31%) had probable IIM, and 66 (56%) had definite IIM. MSA-positive patients were significantly more common in the definite IIM group, but MAA positivity was unrelated to diagnostic classification. Positivity for MSAs or MAAs had no correlations with muscle disease activity. Extramuscular disease activity was greater in MSA-positive than MSA-negative patients, but MAA positivity had no significant association with extramuscular disease activity.

CONCLUSIONS

MSA positivity aids in the diagnosis of IIM. MSA positivity was associated with greater extramuscular disease activity. Improving the clinical application of MSAs may enhance the individualized treatment of patients with IMM. Key Points • In this paper, we explore the relationships between the myositis autoantibodies and the diagnosis and the disease activity of inflammatory myopathy. • Positive myositis-specific autoantibodies is associated with the establishment of diagnosis and higher extramuscular disease activity. • Thus, more extensive application of myositis autoantibodies maybe the key for further disease assessment and research.

Anti-inflammatory Property of AMP-activated Protein Kinase

BACKGROUND

One of the many debated topics in inflammation research is whether this scenario is really an accelerated form of human wound healing and immunityboosting or a push towards autoimmune diseases. The answer requires a better understanding of the normal inflammatory process, including the molecular pathology underlying the possible outcomes. Exciting recent investigations regarding severe human inflammatory disorders and autoimmune conditions have implicated molecular changes that are also linked to normal immunity, such as triggering factors, switching on and off, the influence of other diseases and faulty stem cell homeostasis, in disease progression and development.

METHODS

We gathered around and collected recent online researches on immunity, inflammation, inflammatory disorders and AMPK. We basically searched PubMed, Scopus and Google Scholar to assemble the studies which were published since 2010.

RESULTS

Our findings suggested that inflammation and related disorders are on the verge and interfere in the treatment of other diseases. AMPK serves as a key component that prevents various kinds of inflammatory signaling. In addition, our table and hypothetical figures may open a new door in inflammation research, which could be a greater therapeutic target for controlling diabetes, obesity, insulin resistance and preventing autoimmune diseases.

CONCLUSION

The relationship between immunity and inflammation becomes easily apparent. Yet, the essence of inflammation turns out to be so startling that the theory may not be instantly established and many possible arguments are raised for its clearance. However, this study might be able to reveal some possible approaches where AMPK can reduce or prevent inflammatory disorders.

Biologic therapy in the idiopathic inflammatory myopathies

The idiopathic inflammatory myopathies (IIM) are a group of autoimmune diseases resulting from inflammation of muscle and manifesting as weakness, though a range of extra-muscular manifestations are observed. These are often correlated closely with disease subtype and the presence of myositis-specific/myositis-associated antibodies. IIM are notoriously difficult to treat and often refractory to glucocorticoid therapy and synthetic immunosuppressants. Both the innate and adaptive immune systems are implicated in the pathogenesis of IIM. A growing understanding of the key cytokines as well as the cell-mediated and antibody effectors of disease has identified multiple potential targets for biologic therapy. The most widely used of these is B-cell depletion via rituximab though the tumour necrosis factor inhibitors and other biologic therapies used in diseases such as rheumatoid arthritis, systemic lupus erythematosus and multiple sclerosis have also been trialled. This review summarises the literature thus far on biologic therapy in IIM, highlighting both the significant trials that influence current treatment regimens and also the continuing need for further research to inform more effective therapies.

Benign acute viral myositis in African migrants: A clinical, serological, and pathological study

BACKGROUND

Several viruses have been described as causes of acquired inflammatory myopathies; however, the mechanisms by which they cause muscle disease are still unclear. The aim of this study was to describe the laboratory features of benign acute myositis in a small case series.

METHODS

A detailed pathological and serological analysis was performed in five African migrants who developed an acute viral myositis complicated by rhabdomyolysis.

RESULTS

Muscle biopsies clearly documented an inflammatory myopathy with histological features similar to polymyositis including CD8+ T cells surrounding and invading nonnecrotic muscle fibers, CD68+ macrophages and major histocompatibility complex class I antigen upregulation. In addition, positivity for myositis-specific antibodies (MSA), in particular anti-aminoacyl tRNA synthetases, was found in the serum of two patients.

CONCLUSIONS

Our study demonstrated that T-cell mediated injury occurs in muscle of patients with acute viral myositis, and that MSA may be present in the serum of these patients.