New Myositis Classification Criteria-What We Have Learned Since Bohan and Peter

Treatment guidelines for idiopathic inflammatory myopathies in adults: a comparative review

Myositis, or idiopathic inflammatory myopathy, encompasses a group of autoimmune diseases with broad-spectrum clinical presentations, with a common presentation of muscle weakness and inflammation. The management of myositis presents significant challenges due to the rarity and variability of the disease and lack of large-scale, randomized controlled trials. Due to limited evidence available from smaller studies as well as variation in treatment practices across geographical regions and disease subtypes, available published treatment recommendations vary significantly. There is a need, therefore, to develop multidisciplinary consensus-driven guidelines that appropriately reflect the diverse and complex nature of the disease. This comparative review presents an in-depth analysis of existing myositis treatment guidelines from diverse organizations, highlighting similarities and key differences in diagnoses, treatment and management recommendations. We propose that there is a need for developing globally unified, consensus-driven standardized set of guidelines for effective myositis management.

Clinicopathological collaboration in adult muscle disease: a pragmatic pathway to approach diagnostic dilemmas

The role of muscle biopsy in the investigation of neuromuscular disease remains firmly established but has evolved. Expertise in diagnostic myopathology remains relevant and supports clinical practice. Neuromuscular disease is rare; thus clinicopathological correlation, or better, collaboration is important. The process starts in the clinic with the identification of patients for whom muscle biopsy will be beneficial for diagnosis and management in a multidisciplinary neuromuscular care setting. In this review article, we describe the current use of muscle biopsy in our adult practice and discuss several carefully selected real cases [e.g., asymmetric hand weakness, dysphagia and proximal weakness, subacute weakness with raised creatine kinase (CK), non-specific presentation], where biopsy and collaboration have been instrumental in achieving the correct diagnosis for the patient. We discuss areas of diagnostic difficulty, such as fairly common starting scenarios leading to unusual entities, atypical presentations of common diseases and novel pathological findings. We will focus on the idiopathic inflammatory myopathies (IIMs), the most common indication for adult muscle biopsies in many diagnostic settings, whereby the use of an integrated clinical-serological-pathological classification is now firmly established. We will also explore the evolving role for and continuing need of muscle biopsy in the genomic era, particularly with assessing the potential pathogenicity of reported genetic variants of uncertain significance (VUS). We describe a pragmatic approach to detecting the more common disorders, which also enables us to distinguish 'the horses from the zebras' and manage diagnostic uncertainty.

Validity of Diagnosis Codes to Identify a Dermatomyositis Cohort from Electronic Health Records

INTRODUCTION

Dermatomyositis (DM) is an uncommon idiopathic inflammatory myopathy resulting in characteristic patterns of cutaneous lesions and myositis. Observational evidence related to the disease is limited by small case cohorts. We aimed to evaluate the validity of specialist-specific diagnostic coding for DM in an outpatient clinical database.

METHODS

Adults having an outpatient encounter between January 1, 2010, and June 30, 2023, at a US regional health system with ICD-9/-10 coding for DM were identified. We randomly sampled 156 patients with ≥1 code applied by a dermatologist or rheumatologist. The primary reference standard for case adjudication was a confirmed diagnosis of DM by the treating physician in the medical chart. Fulfilment of the 2017 European Alliance of Associations for Rheumatology/American College of Rheumatology (EULAR/ACR) criteria for "probable" or "definite" DM was used as a secondary, more stringent reference standard. Positive predictive values (PPVs) for several case definitions were calculated with 95% confidence intervals.

RESULTS

Among eligible patients, the median age was 51.5 years, and 81% were female. Using the treating physician's diagnosis as reference, PPVs of ≥1 and ≥2 codes applied by a dermatologist were 93.2% (95% CI 82.0-98.3%) and 96.4% (82.2-99.8%), respectively. The PPVs of ≥1 and ≥2 codes from a rheumatologist were 82.0% (77.1-86.9%) and 85.8% (80.6-91.1%), respectively. At least one and at least two codes from a rheumatologist or dermatologist had PPVs of 82.1% (77.3-86.8%) and 85.7% (80.7-90.8%), respectively. The rate of confirmed cases based on EULAR/ACR criteria ranged from 44.9% to 57.1%.

CONCLUSION

All tested algorithms yielded an accurate case cohort with high PPV. Studies prioritizing sensitivity may use ≥1 code by dermatology or rheumatology to identify patients with DM.

Dyslipidemia in Juvenile Dermatomyositis

This study investigates the prevalence of dyslipidemia and its association with disease activity in children with Juvenile Dermatomyositis (JDM). A retrospective chart review of 142 JDM patients who had fasting lipid profiles was conducted. Clinical, and laboratory indicators of disease activity at the time of lipid assessment were obtained. JDM patients displayed a high prevalence (72%) of abnormal or borderline fasting lipid profiles, particularly involving HDL and triglycerides. Treatment-naïve patients exhibited the most significant dyslipidemia, with significantly lower median HDL levels compared to those on medication (30 vs. 49 mg/dL, p < 0.0001). HDL levels inversely correlated with various disease activity measures, including disease activity score (DAS) total (r= -0.38, p < 0.001), DAS muscle weakness (r= -0.5, p < 0.001), DAS skin (r= -0.25, p = 0.003), neopterin (r= -0.41, p < 0.001), ESR (r= -0.25, p = 0.006), and vWF Ag (r= -0.21, p = 0.02). In conclusion, JDM patients have a high prevalence of dyslipidemia, especially low HDL and elevated triglycerides. The severity of dyslipidemia (low HDL) correlates with disease activity, with treatment-naïve patients demonstrating the lowest HDL levels. These findings suggest the importance of annual lipid profile monitoring in JDM patients, potentially followed by early interventions such as dietary adjustments and exercise programs.

Current efforts and historical perspectives on classification of idiopathic inflammatory myopathies

PURPOSE OF REVIEW

The classification of idiopathic inflammatory myopathies is challenging due to the large number of clinical, serological, histopathological and genetic findings, as well as the latest findings and developments in the field of myositis research. The latest official classification criteria are the 2017 European Alliance of Associations for Rheumatology (EULAR)/American College of Rheumatology (ACR) classification criteria for adult and juvenile idiopathic inflammatory myopathies, which have been extensively reviewed in recent years for their applicability, sensitivity and specificity.

RECENT FINDINGS

The sensitivity and specificity of the 2017 ACR/EULAR criteria are sometimes performing better, but usually at the same level as the previous criteria. A large number of further suggestions for amendments to the criteria have been made. In particular there is a need to revise the criteria with regard to the addition of new myositis-specific autoantibodies, newly defined subgroups (especially antisynthetase syndrome, immune medicated necrotizing myopathy and overlap myositis) and possibly the addition of further diagnostic procedures (for instance, muscle MRI or PET CT) to improve the accuracy and timeliness of the criteria.

SUMMARY

Efforts to optimize the myositis classification criteria have been extensive in recent years and a new global interdisciplinary collaboration of clinicians is currently taking place based on the previous results with the aim of revising the 2017 EULAR/ACR classification criteria.

Construct validity of PROMIS pain interference, fatigue, and physical function as patient-reported outcomes in adults with idiopathic inflammatory myopathies: An international study from the OMERACT myositis working group

BACKGROUND

Validated patient-reported outcome measures to assess disease impact in patients with adult idiopathic inflammatory myopathies (IIMs) are needed. The objective of this study was to assess the construct validity of PROMIS Pain Interference, Fatigue, and Physical Function measures in comparison with core disease activity measures.

METHODS

Adults with IIM, excluding inclusion body myositis, from OMERACT Myositis Working Group (MWG) clinic sites completed PROMIS Short Form v1.0-Pain Interference 6a, PROMIS Short Form v1.0-Fatigue 7a, and PROMIS Short Form v2.0-Physical Function 8b measures. Core disease activity measures including patient and physician global disease activity assessments, manual muscle testing, serum creatine kinase activity, and Health Assessment Questionnaire Disability Index (HAQ-DI) were simultaneously assessed. To evaluate construct validity, a priori hypotheses for the expected correlations between PROMIS measures, age, and core disease measures were determined by >70 % agreement among MWG members and were compared against observed Pearson's correlations. Internal consistency of items and floor or ceiling effects for the PROMIS measures were also assessed. Subgroup analysis according to IIM subtype (dermatomyositis vs. non-dermatomyositis IIM) was performed.

RESULTS

135 adults with IIM from 5 countries across North America, Europe, Asia, and Australia were included. For construct validity, a priori hypotheses were confirmed for 5 of 6 (83 %) PROMIS Pain Interference, 4 of 5 (80 %) PROMIS Fatigue, and 3 of 4 (75 %) PROMIS Physical Function correlations. Internal consistency was high for each PROMIS measure (Cronbach's alpha >0.9). Ceiling effects were observed only for PROMIS Pain Interference, with low/no pain in 29 % of patients. Subgroup analysis between dermatomyositis (n = 65) and non-dermatomyositis (n = 70) subtypes demonstrated similar correlations between PROMIS measures and disease activity measures.

CONCLUSIONS

PROMIS Short Form v1.0-Pain Interference 6a, PROMIS Short Form v1.0-Fatigue 7a, and PROMIS Short Form v2.0-Physical Function 8b measures demonstrate strong construct validity when compared to core disease activity measures in IIM, with consistent results across IIM subtypes. These findings support the use of these selected PROMIS measures to assess core domains of interest for measuring life impact in IIMs.

Clinical characteristics and prognostic factor in juvenile dermatomyositis: data of the Spanish registry

BACKGROUND

Juvenile Dermatomyositis (JDM) is the most common chronic idiopathic inflammatory myopathy in children. The diagnosis is clinical. Baseline laboratory and complementary studies trace the phenotype of these patients. The objective of this study was to describe epidemiological, clinical and laboratory characteristics at diagnosis of JDM patients included in the Spanish JDM registry, as well as to identify prognostic factors on these patients.

METHODS

We retrospectively reviewed clinical features, laboratory tests, and complementary studies at diagnosis of JDM patients included on the Spanish JDM registry. These data were analyzed to assess whether there was a relationship with the development of complications and time to disease inactivity.

RESULTS

One hundred and sixteen patients from 17 Spanish paediatric rheumatology centres were included, 76 girls (65%). Median age at diagnosis was 7.3 years (Interquartile range (IQR) 4.5-10.2). All patients had pathognomonic skin lesions at the beginning of the disease. Muscle weakness was present in 86.2%. Median Childhood Muscle Assessment Scale was 34 (IQR 22-47). Twelve patients (34%) had dysphagia and 3,5% dysphonia. Anti-p155 was the most frequently detected myositis specific antibody, followed by anti-MDA5. Twenty-nine patients developed calcinosis and 4 presented with macrophage activation syndrome. 70% reached inactivity in a median time of 8.9 months (IQR 4.5-34.8). 41% relapsed after a median time of 14.4 months (IQR 8.6-22.8) of inactivity. Shorter time to treatment was associated with better prognosis (Hazard ratio (HR) = 0.95 per month of evolution, p = 0.02). Heliotrope rash at diagnosis correlates with higher risk of development complications.

CONCLUSIONS

We describe heliotrope rash as a risk factor for developing complications in our cohort of JDM patients, an easy-to-evaluate clinical sign that could help us to identify the group of patients we should monitor closely for this complication.

Novel B-cell subsets as potential biomarkers in idiopathic inflammatory myopathies: insights into disease pathogenesis and disease activity

Idiopathic inflammatory myopathies are a heterogeneous group of rare autoimmune disorders characterized by progressive muscle weakness and the histopathologic findings of inflammatory infiltrates in muscle tissue. Although their pathogenesis remains indefinite, the association of autoantibodies with clinical manifestations and the evidence of high effectiveness of depleting therapies suggest that B cells could be implicated. Therefore, we explored the landscape of peripheral B cells in this disease by multiparametric flow cytometry, finding significant numerical decreases in memory and double-negative subsets, as well as an expansion of the naive compartment relative to healthy controls, that contribute to defining disease-associated B-cell subset signatures and correlating with different clinical features of patients. Additionally, we determined the potential value of these subsets as diagnostic biomarkers, thus positioning B cells as neglected key elements possibly participating in idiopathic inflammatory myopathy onset or development.

Decreased Peripheral Blood Natural Killer Cell Count in Untreated Juvenile Dermatomyositis Is Associated with Muscle Weakness

Juvenile Dermatomyositis (JDM) is the most common inflammatory myopathy in pediatrics. This study evaluates the role of Natural Killer (NK) cells in Juvenile Dermatomyositis (JDM) pathophysiology. The study included 133 untreated JDM children with an NK cell count evaluation before treatment. NK cell subsets (CD56low/dim vs. CD 56bright) were examined in 9 untreated children. CD56 and perforin were evaluated in situ in six untreated JDM and three orthopedic, pediatric controls. 56% of treatment-naive JDM had reduced circulating NK cell counts, designated "low NK cell". This low NK group had more active muscle disease compared to the normal NK cell group. The percentage of circulating CD56low/dim NK cells was significantly lower in the NK low group than in controls (0.55% vs. 4.6% p < 0.001). Examination of the untreated JDM diagnostic muscle biopsy documented an increased infiltration of CD56 and perforin-positive cells (p = 0.023, p = 0.038, respectively). Treatment-naive JDM with reduced circulating NK cell counts exhibited more muscle weakness and higher levels of serum muscle enzymes. Muscle biopsies from treatment-naive JDM displayed increased NK cell infiltration, with increased CD56 and perforin-positive cells.

Diagnosis and subtyping of idiopathic inflammatory myopathies: caution required in the use of myositis autoantibodies

Detection of myositis autoantibodies (MAs) has utility in both the diagnosis and subtyping of idiopathic inflammatory myopathies (IIMs). Multiplex assays such as the Euroimmun line immunoassay (LIA) have significant limitations in rare diseases like IIM. A retrospective cohort study was performed on positive MA detected on LIA in 171 patients using the manufacturer's recommended cut-off. Only 16.7% were deemed true positive after clinical correlation. Autoantibody-specific cut-offs were created and applied to the original cohort, along with generically applied higher cut-offs. Positive predictive value (PPV) improved, but there was variable increase in false negatives. False positive MA results are common using LIA, but locally derived cut-offs can improve performance. Clinicians must be aware of the limitations of LIA, which is the commonest method for MA detection in Australasia.

Dermatomyositis: Practical Guidance and Unmet Needs

Dermatomyositis is a heterogeneous idiopathic inflammatory myopathy associated with various cutaneous manifestations and variable presence of myositis, interstitial lung disease, and other visceral organ involvement. An accurate diagnosis of dermatomyositis requires correlating clinical examination findings with serological and histological findings. Familiarity with pathognomonic and common cutaneous manifestations of dermatomyositis, which are highlighted here, can be especially helpful in making an accurate diagnosis. Additionally, evaluating patients for presence of myositis-specific autoantibodies can further support or refute a dermatomyositis diagnosis. When present, myositis-specific autoantibodies can also help guide workups for various dermatomyositis-associated manifestations, as each is associated with relatively distinct clinical characteristics. Evaluating patients for various systemic manifestations often relies on expert opinion recommendations; however, societal guideline statements concerning the evaluation of some manifestations have recently been described. Although malignancy-associated dermatomyositis is a well-accepted subtype, there is limited evidence to support extensive malignancy screening has a favorable benefit-risk ratio in most dermatomyositis patients. However, recent research has uncovered novel associations between dermatomyositis and malignancy, suggesting the possibility of identifying high-risk subsets of dermatomyositis patients in whom malignancy screening may have a high value. Treatment for dermatomyositis has remained largely unchanged over the past several decades. Although many dermatomyositis patients can be effectively treated with current options, either as monotherapy or with combination regimens, there is a need for more targeted and effective DM therapies, in general, and for MDA5(+) dermatomyositis-associated rapidly progressive interstitial lung disease. Fortunately, significant current and emerging research activities evaluating various novel medications for dermatomyositis provide hope for exciting future advances in patients with this intriguing immune-mediated disease.

Responsiveness and meaningful thresholds of PROMIS pain interference, fatigue, and physical function forms in adults with idiopathic inflammatory myopathies: Report from the OMERACT Myositis Working Group

BACKGROUND

A series of qualitative studies conducted by the OMERACT Myositis Working Group identified pain interference, fatigue, and physical function as highly important life impact domains for adults with idiopathic inflammatory myositis (IIM). In this study, our goal was to assess the responsiveness and minimal important difference of PROMIS pain interference (6a), fatigue (7a), and physical function (8b).

METHODS

Adults with IIM from USA, Netherlands, Korea, Sweden, and Australia with two "clinical" visits were enrolled in this prospective study. Anchor questions on a Likert scale were collected at baseline, and manual muscle testing (MMT), physician and patient reported global disease activity, and PROMIS instruments were collected at both visits. Responsiveness was assessed with i) ANOVA, ii) paired t-test, effect size and standardized response mean, and iii) Pearson correlation. Minimal important difference (MID), minimal important change (MIC) and minimal detectable change (MDC) values were calculated.

RESULTS

114 patients with IIM (median age 60, 60 % female) completed both visits. Changes in PROMIS instruments were significantly different among anchor categories. Patients who reported improvement had a significant improvement in their PROMIS scores with at least medium effect size, while patients who reported worsening and stability did not show a significant change with weak effect size. PROMIS instruments had weak to moderate correlations with MMT, patient and physician global disease activity. MID was approximately 2-3 points for Pain Interference and 3-4 points for Fatigue and Physical Function forms based on the method used. MIC was approximately 4-5 for improvement of all the instruments, while MDC was 1.7-2 points for Pain Interference and Physical Function and 3.2-3.9 for Fatigue.

CONCLUSION

This study provides evidence towards the responsiveness of the PROMIS instruments in a large international prospective cohort of adults with IIM supporting their use as PROMs in adult myositis.

Frequency of EMG abnormalities in idiopathic inflammatory myopathies under the EULAR/ACR classification criteria

The European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria for idiopathic inflammatory myopathies (IIM) have been widely used in recent times. However, no studies have focused on electromyography (EMG) findings of IIM, considering the criteria. This study aimed to elucidate the frequency of EMG abnormalities, particularly fibrillation potentials and positive sharp waves (Fib/PSW), the most objective EMG findings of IIM. Clinical and EMG records of adult patients who were clinically diagnosed with polymyositis (PM), dermatomyositis (DM), amyopathic DM (ADM), or inclusion body myositis (IBM) were retrospectively reviewed and classified according to the EULAR/ACR classification criteria. The frequency of Fib/PSW in EMG was investigated in the recruited cases. Seventy-nine patients with clinically diagnosed IIM (44 with PM, 17 with DM, 7 with ADM, and 11 with IBM) were recruited. After classification using EULAR/ACR, 75 satisfied definite or probable IIM (61 and 14, respectively), and the frequency of Fib/PSW in this group was 95%. Furthermore, the remaining 4 patients with insufficient IIM probability also showed Fib/PSW. Fib/PSW may also be seen in cases with insufficient IIM probability not satisfying the criteria. EMG may help detect muscle involvement in these cases through Fib/PSW.

Dermatomyositis in Association With SARS-CoV-2 Infection or COVID-19 Vaccine

OBJECTIVE

New-onset and relapsed dermatomyositis (DM) has been reported following SARS-CoV-2 infection or COVID-19 vaccination. This study aims to show the characteristics of a DM cohort after COVID-19 infection and vaccination.

METHODS

A retrospective review was performed on patients treated for DM between March 1, 2020, and October 31, 2022. Charts were evaluated for the presence of new-onset DM or relapse of preexisting DM following either SARS-CoV-2 infection or COVID-19 vaccination. Data on symptom onset, timing of vaccination, type of vaccination, and disease characteristics were collected.

RESULTS

Ninety-eight patients treated for DM at our institution in the Division of Rheumatology were included. In total, 12 of 98 patients (12.2%) experienced DM symptoms (either incident or relapse) following either infection or vaccination. Of the 12 patients who developed incident disease or relapse, 7 (58.3%) developed postinfection symptoms, and 8 (66.7%) developed symptoms after vaccination (3 patients had symptoms following both infection and vaccination). The mean onset of symptoms following COVID-19 infection was 3.2 days (median 0.5 days), and mean onset following COVID-19 vaccination was 5.75 days (median 3.5 days). Nine of 12 patients (75%) had a positive myositis-specific antibody, and the remaining 3 (25%) had myositis-associated antibodies. There was no predominant vaccine associated with the development of postvaccination DM symptoms.

CONCLUSION

This retrospective review revealed a strong temporal relationship between DM symptoms and COVID-19 infection or vaccination in 12.2% of all patients with DM evaluated in our clinic during the pandemic. Additional studies are required to understand the possible pathophysiology behind this association.

Polymyositis following varicella and mumps infection in adults: report of two cases

Idiopathic immune myopathies (IIMs) are autoimmune diseases caused by immune-mediated muscle damage. The etiology remains unclear. Epidemiological and experimental studies, both in animals and humans, hint at viruses as major environmental factors able to trigger aberrant immune responses through many different mechanisms. However, only a few cases of either dermatomyositis or polymyositis following a specific viral infection have been reported in the literature. The objective of this study is to describe the clinical features and the treatment strategy of 2 cases of polymyositis developing shortly after chickenpox and mumps, respectively, and to review the existing literature on the topic. The clinical records of the 2 patients suspected to have developed inflammatory myositis following a viral infection were reviewed. Their clinical history, main laboratory findings, and treatment outcome are presented here. Moreover, a literature search was performed in the PubMed and MEDLINE databases to identify reports describing the association between viral infections and IIMs in patients aged ≥18. The 2 patients reported here developed polymyositis shortly after chickenpox and mumps, respectively, suggesting a causal role for viruses in triggering autoimmunity. Only a few reports published between 1990 and 2020 were found in the literature, possibly linking infections to myositis development. Intravenous immunoglobulin and rituximab were effective for the treatment of viral-triggered polymyositis.

Polymyositis concomitant with hepatitis B virus infection: Treatment challenges

Polymyositis is a chronic autoimmune disease that presents with symmetrical progressive proximal muscle weakness. The cause of this disease due to abnormal activation of macrophages that might be associated with systemic diseases such as other autoimmune diseases, malignancy or viral infections including hepatitis B virus. The aim of this case report was to highlight treatment challenges in a patient with polymyositis concomitant with hepatitis B. A 28-years-old man with history of completed hepatitis B treatment with negative viral load presented with symmetrical progressive weakness on both inferior proximal extremities. The patient complained of pain predominantly in both tights and calves. No dermatological manifestation was observed. Elevated muscle enzymes and liver function were observed. Along with the course of the disease, hepatitis B reactivation was discovered as hepatitis B virus DNA was re-detected. Treatment options of this patient (polymyositis concomitant with hepatitis B viral infection) remain challenging. The main treatment of polymyositis consists of high dose methylprednisolone and this immunosuppressant could worsen the hepatitis B virus infection. The patient was finally treated with combination of mycophenolic acid and methylprednisolone for polymyositis and entecavir for hepatitis B. After one month of treatment, the patient showed a clinical improvement. This case highlights that viral screening must be done prior to starting polymyositis treatment as it could concomitant with viral infections such as hepatitis B. Antiviral prophylaxis must be given 1-2 weeks before immunosuppression starts. Management for both polymyositis and hepatitis B is important with entecavir or tenofovir as the optimal agents against hepatitis B virus.

Autoimmune Dysphagia Related to Rheumatologic Disorders: A Focused Review on Diagnosis and Treatment

Autoimmune dysphagia is defined as dysphagia caused by autoimmune processes affecting various components of the swallowing process such as muscle, neuromuscular junction, nerves, roots, brainstem, or cortex. These autoimmune causes can be classified into gastroenterological, dermatological, rheumatologic, and neurologic. Rheumatological disorders, such as scleroderma, Sjogren's syndrome, systemic lupus erythematosus, rheumatoid arthritis, sarcoidosis, Behcet's disease, anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, or granulomatosis with polyangiitis, have been associated with dysphagia. Autoimmune dysphagia in the context of rheumatological disorders is particularly significant because it can occur as a sole manifestation or as part of a symptom complex associated with the underlying disorder and often responds to immunosuppressive therapies. However, diagnosing autoimmune dysphagia can be challenging as it requires the exclusion of structural and primary motility disorders through procedures such as endoscopy and manometry. Early diagnosis is important to improve the quality of life and prevent significant mortality and morbidity. Management focuses on treating the underlying disease activity, and a multidisciplinary approach involving various medical specialties may be necessary to achieve success. This article aims to review the autoimmune rheumatological conditions that can lead to dysphagia and discuss the associated pathophysiological mechanisms. We also outline the clinical clues and laboratory testing methods that facilitate early diagnosis, with the goal of improving patient outcomes through timely intervention and appropriate management.

Myositis interstitial lung disease and autoantibodies

The aim of this review is to examine and evaluate published literature associated with idiopathic inflammatory myopathies (IIM) and interstitial lung disease (ILD) based on myositis specific autoantibodies (MSA) and the potential clinical significance of each autoantibody subtype for the practicing clinician. The review is a comprehensive search of literature published in PubMed from the year 2005 and onward coinciding with the surge in the discovery of new MSAs. Additionally, we comment on recommended multidisciplinary longitudinal care practices for patients with IIM-ILD with regard to imaging and other testing. Treatment is not covered in this review.

A Case of Antisynthetase Syndrome in the Setting of SARS-Cov-2 Infection

Antisynthetase syndrome is a complex autoimmune disorder, and one of the key criteria for diagnosis is the presence of myositis. Additionally, evidence of interstitial lung disease (ILD) is another important indicator for diagnosis; other clinical features associated with antisynthetase syndrome include arthritis, unexplained and persistent fever, Raynaud's phenomenon, and the presence of mechanic's hands. We report a case of a 36-year-old male who presented to the emergency department with shortness of breath and proximal muscle weakness in the setting of severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) infection, as his inflammatory markers were elevated and he exhibited features suspicious for antisynthetase syndrome, he was started on methylprednisolone 40 mg intravenously every eight hours, and a myositis panel was checked. In addition, a chest computed tomography (CT) exhibited ground-glass opacities which were compatible with coronavirus disease 2019 (COVID-19). A magnetic resonance image (MRI) of both thighs was done, revealing significant swelling and confirming the suspicion of myositis as his muscle strength in his lower extremities took significant time to improve. As days passed, his muscle strength improved significantly and his creatine phosphatase kinase (CPK) values trended down, indicating that his myositis was improving as well. He was transitioned to oral prednisone 60 mg daily and was discharged home with a rheumatology follow-up to define long-term treatment. A myositis panel revealed anti-glycyl-transferRNA synthetase (EJ) autoantibody positivity and a diagnosis was established. Our case revealed how sometimes laboratory values do not necessarily correlate with disease severity and how we have to do a thorough history of present illness and physical exam to think about unusual diagnoses before putting laboratory data into context.

Combination of sporadic inclusion body myositis and primary Sjцgren’s syndrome: clinical case and review of literature

The article presents a review of the literature and a clinical observation of a patient with long-term anamnesis of primary Sjцgren's syndrome (SS) in combination with sporadic inclusion body myositis (sIBM). The diagnosis of SS was confirmed in accordance with the Russian diagnostic criteria for SS 2001, as well as with the ACR 2012 and ACR/EULAR 2016 criteria. The diagnosis of sIBM was established on the basis of a characteristic clinical picture: the development of the disease in a woman after 50 years of age with slowly progressive asymmetric muscle weakness and a typical distribution, a moderate increase in the level of creatine phosphokinase (<10 norms for the entire observation period), the presence of a generalized primary muscle process according to needle electromyography, a typical picture of muscle involvement according to magnetic resonance imaging, and the ineffectiveness of high doses of glucocorticoids. The absence of histological confirmation does not contradict the diagnosis, since morphological examination of muscles in patients with a typical course of the disease fails to detect characteristic signs of sIBM in 20% of cases.Currently, there is no effective pathogenetic therapy for sIBM. Understanding the mechanisms of sIBM development will allow to develop effective methods of its treatment.

The von Willebrand Factor Antigen Reflects the Juvenile Dermatomyositis Disease Activity Score

OBJECTIVE

This study determined if an accessible, serologic indicator of vascular disease activity, the von Willebrand factor antigen (vWF:Ag), was useful to assess disease activity in children with juvenile dermatomyositis (JDM), a rare disease, but the most common of the pediatric inflammatory myopathies.

METHODS

A total of 305 children, median age 10 years, 72.5% female, 76.5% white, with definite/probable JDM at diagnosis, were enrolled in the Ann & Robert H. Lurie Cure JM Juvenile Myositis Repository, a longitudinal database. Disease Activity Score (DAS) and vWF:Ag data were obtained at each visit. These data were analyzed using generalized estimating equation (GEE) models (both linear and logistic) to determine if vWF:Ag reflects disease severity in children with JDM. A secondary analysis was performed for untreated active JDM to exclude the effect of medications on vWF:Ag.

RESULT

The vWF:Ag test was elevated in 25% of untreated JDM. We found that patients with elevated vWF:Ag had a 2.55-fold higher DAS total (CI95: 1.83-3.27, p < 0.001). Patients with difficulty swallowing had 2.57 higher odds of elevated vWF:Ag (CI95: 1.5-4.38, p < 0.001); those with more generalized skin involvement had 2.58-fold higher odds of elevated vWF:Ag (CI95: 1.27-5.23, p = 0.006); and those with eyelid peripheral blood vessel dilation had 1.32-fold higher odds of elevated vWF:Ag (CI95: 1.01-1.72, p = 0.036). Untreated JDM with elevated vWF:Ag had more muscle weakness and higher muscle enzymes, neopterin and erythrocyte sedimentation rate compared to JDM patients with a normal vWF:Ag.

CONCLUSION

vWF:Ag elevation is a widely accessible concomitant of active disease in 25% of JDM.

Myositis in Germany: epidemiological insights over 15 years from 2005 to 2019

BACKGROUND

The medical care of patients with myositis is a great challenge in clinical practice. This is due to the rarity of these disease, the complexity of diagnosis and management as well as the lack of systematic analyses.

OBJECTIVES

Therefore, the aim of this project was to obtain an overview of the current care of myositis patients in Germany and to evaluate epidemiological trends in recent years.

METHODS

In collaboration with BARMER Insurance, retrospective analysis of outpatient and inpatient data from an average of approximately 8.7 million insured patients between January 2005 and December 2019 was performed using ICD-10 codes for myositis for identification of relevant data. In addition, a comparative analysis was performed between myositis patients and an age-matched comparison group from other populations insured by BARMER.

RESULTS

45,800 BARMER-insured individuals received a diagnosis of myositis during the observation period, with a relatively stable prevalence throughout. With regard to comorbidities, a significantly higher rate of cardiovascular disease as well as neoplasm was observed compared to the control group within the BARMER-insured population. In addition, myositis patients suffer more frequently from psychiatric disorders, such as depression and somatoform disorders. However, the ICD-10 catalogue only includes the specific coding of "dermatomyositis" and "polymyositis" and thus does not allow for a sufficient analysis of all idiopathic inflammatory myopathies subtypes.

CONCLUSION

The current data provide a comprehensive epidemiological analysis of myositis in Germany, highlighting the multimorbidity of myositis patients. This underlines the need for multidisciplinary management. However, the ICD-10 codes currently still in use do not allow for specific analysis of the subtypes of myositis. The upcoming ICD-11 coding may improve future analyses in this regard.

Validation of methods to identify people with idiopathic inflammatory myopathies using hospital episode statistics

OBJECTIVE

Hospital episode statistics (HES) are routinely recorded at every hospital admission within the National Health Service (NHS) in England. This study validates diagnostic ICD-10 codes within HES as a method of identifying cases of idiopathic inflammatory myopathies (IIMs).

METHODS

All inpatient admissions at one NHS Trust between 2010 and 2020 with relevant diagnostic ICD-10 codes were extracted from HES. Hospital databases were used to identify all outpatients with IIM, and electronic care records were reviewed to confirm coding accuracy. Total hospital admissions were calculated from NHS Digital reports. The sensitivity and specificity of each code and code combinations were calculated to develop an optimal algorithm. The optimal algorithm was tested in a sample of admissions at another NHS Trust.

RESULTS

Of the 672 individuals identified by HES, 510 were confirmed to have IIM. Overall, the positive predictive value (PPV) was 76% and sensitivity 89%. Combination algorithms achieved PPVs between 89 and 94%. HES can also predict the presence of IIM-associated interstitial lung disease (ILD) with a PPV of 79% and sensitivity of 71%. The optimal algorithm excluded children (except JDM code M33.0), combined M33.0, M33.1, M33.9, M36.0, G72.4, M60.8 and M33.2, and included M60.9 only if it occurred alongside an ILD code (J84.1, J84.9 or J99.1). This produced a PPV of 88.9% and sensitivity of 84.2%. Retesting this algorithm at another NHS Trust confirmed a high PPV (94.4%).

CONCLUSION

IIM ICD-10 code combinations in HES have high PPVs and sensitivities. Algorithms tested in this study could be applied across all NHS Trusts to enable robust and cost-effective whole-population research into the epidemiology of IIM.

Inflammatory Bowel Diseases Are Associated with Polymyositis and Dermatomyositis-A Retrospective Cohort Analysis

Background and Objectives: Polymyositis and dermatomyositis (PM/DM) are classified as polygenic autoimmune diseases, whereas inflammatory bowel disease (IBD) is considered a polygenic autoinflammatory disease. In the literature, several cases exist reporting the co-occurrence of both conditions. At the molecular level, PM/DM and IBD share common genetic determinants including interferon regulatory factor and vitamin D receptor susceptibility loci. Accumulating evidence underline several indicators that confer poor prognosis in IBD, including antinuclear antibody positivity and the presence of other autoimmune diseases, therefore the aim of this study is to assess the association between these entities. Materials and Methods: This is a population-based retrospective study using data retrieved from a large electronic medical record in Israel, the Clalit health registry. The sample included PM/DM patients and age- and sex-frequency matched controls. The prevalence of IBD in PM/DM was compared between the two groups and logistic regression was applied to control for confounding variables. Predictors of IBD in patients with PM/DM were also explored. Results: Our study included 12,278 subjects with 2085 PM/DM patients and 10,193 age- and sex- frequency-matched controls. The incidence of IBD in patients with PM/DM was significantly higher even after controlling for various confounding variables (OR of 1.73, 95% CI 1.05-2.86, p-value = 0.033). Anti-nuclear antibodies (ANA) positivity was found to be an independent predictor for IBD diagnosis in patients with PM/DM (OR 3.67, 95% CI 1.01-13.36, p = 0.048). Conclusion: Our analysis reports an association between IBD and PM/DM. Such association could point towards a common pathophysiological background. Further research is needed to further describe the clinical courses and whether a unique therapeutic approach is warranted.

Coexistence of Multiple Myositis-Specific Antibodies in Patients with Idiopathic Inflammatory Myopathies

The mutual exclusivity of myositis-specific antibodies (MSAs) has been reported before, but the coexistence of 2 or more MSAs was still found in a few case reports. This study aims to confirm the existence and prevalence of double MSAs in patients with idiopathic inflammatory myopathy (IIM) and to clarify the clinical features of these patients. One hundred fifty-one patients with IIM diagnosed from 1 July 2018 to 31 July 2022, at National Cheng Kung University Hospital, Taiwan, were enrolled and divided into two groups, patients with ≤1 MSA (n = 128, 84.8%) and those with ≥2 MSAs (n = 23, 15.2%) according to the initial serology results. After being re-examined by ANA-IIF assay, 8 out of 23 patients were confirmed to have ≥2 MSAs. The demographic data and clinical features were presented. The prevalence of double-positive MSAs among IIM was 5.3% in this cohort. The coexistence of two MSAs in an IIM patient does exist but is rare. Patients with two MSAs belonging to two distinct IIM subtypes presented clinical features skewed to one subtype instead of "mixed phenotypes". No apparent difference in clinical severity was found between patients with ≥2 MSAs and ≤1 MSA. Longer follow-ups and more studies are required to characterize the patients of IIM with ≥2 MSAs.

Diagnostic delay of myositis: an integrated systematic review

BACKGROUND

Idiopathic inflammatory myopathies (IIM) are a heterogenous group of rare muscular autoimmune diseases characterised by skeletal muscle inflammation with possible diagnostic delay. Our aim was to review the existing evidence to identify overall diagnostic delay for IIM, factors associated with diagnostic delay, and people's experiences of diagnostic delay.

METHODS

Three databases and grey literature sources were searched. Diagnostic delay was defined as the period between the onset of symptoms and the year of first diagnosis of IIM. We pooled the mean delay using random effects inverse variance meta-analysis and performed subgroup analyses.

RESULTS

328 titles were identified from which 27 studies were included. Overall mean diagnostic delay was 27.91 months (95% CI 15.03-40.79, I2 = 99%). Subgroup analyses revealed a difference in diagnostic delay between non-inclusion body myositis (IBM) and IBM types. There was no difference in diagnostic delay between studies in which myositis specific autoantibodies (MSA) were tested or not tested. In countries with gatekeeper health systems, where primary care clinicians authorize access to specialty care, people experienced longer periods of diagnostic delay than people with IIM in countries with non-gatekeeper systems. While studies discussed factors that may influence diagnostic delay, significant associations were not identified. No qualitative studies examining people's experiences of diagnostic delay were identified.

CONCLUSION

Diagnostic delay of IIM has extensive impacts on the quality of life of people living with this disease. Understanding the experiences of people with IIM, from symptom onset to diagnosis, and factors that influence diagnostic delay is critical to inform clinical practice and training activities aimed at increasing awareness of this rare disease and expediting diagnosis.

TRIAL REGISTRATION

PROSPERO Registration number: CRD42022307236 URL of the PROSPERO registration: https://www.crd.york.ac.uk/PROSPEROFILES/307236_PROTOCOL_20220127.pdf.

Post-COVID-19 Polymyositis: A Case Report

Post-Coronavirus disease 2019 (COVID-19) development of polymyositis is rare, with very few cases documented in the literature. In patients developing vague symptoms after recovery from COVID-19, it is important to investigate all avenues, including the possibility of polymyositis. Polymyositis is typically characterized as symmetrical muscle weakness and histological, electrical, and chemical evidence of muscle injury. Patients identified can be treated with immunosuppressants to return some quality of life and prevent disease progression. In this report, we describe a 58-year-old Caucasian male who presented with symptoms of weakness, myalgias, and arthralgias, six months after recovering from flu-like symptoms of COVID-19. The patient was tested for other autoimmune etiologies and myopathies without positive results. He was treated with prednisone and reported moderate improvement in symptoms. Unfortunately, the patient declined a muscle biopsy or electromyographic testing. According to the criteria for polymyositis set by the Myositis Association and the response to therapy, the patient's symptoms pointed to a likely diagnosis of post-COVID-19 polymyositis.

A case of clinically amyopathic dermatomyositis in a Filipino woman

This is a case of a 59-year-old woman who presented with a 2-year history of heliotrope rash, Gottron's papules, shawl sign, V-neck sign, and muscle weakness. She was previously managed as a case of systemic lupus erythematosus and initially responded to unrecalled corticosteroids. She was admitted due to a 1-month progressively enlarging sacral mass, which eventually turned out to be an abscess. While the abscess was being treated, her autoimmune condition was worked up, and she was then managed as a case of clinically amyopathic dermatomyositis (CADM) with interstitial lung disease (ILD). She received corticosteroids and underwent the first cycle of cyclophosphamide infusion prior to discharge.

Proximal myopathy: causes and associated conditions

Proximal myopathy presents as generalized muscle weakness commonly involving the muscles of upper and/or lower limbs. Toxins, long-term use of statins, corticosteroids, alcohol, SGLT2 inhibitors, COVID-19 vaccination, and antimalarials have been attributed to its development. In endocrine and metabolic disorders, adrenal dysfunction including both overproduction and insufficiency of the adrenal gland hormones has been reported to cause myopathy. Moreover, parathyroid and thyroid disorders along with pituitary gland disorders can also directly or indirectly contribute to this condition. In idiopathic inflammatory myopathies including polymyositis, dermatomyositis, inclusion body myositis (IBM), and Systemic Lupus Erythematosus (SLE), Sjögren's Syndrome, and overlap syndromes, moderate to severe muscle weakness has been observed. IBM has been reported to be the most prevalent acquired myopathy above the age of 50. Hereditary or congenital myopathies include limb girdle muscular dystrophies, facioscapulohumeral muscular dystrophy, Duchenne and Becker muscular dystrophy, and proximal myotonic myopathy. In addition to these, glycogen storage diseases such as the McArdle disease can also cause fast exhaustion, myalgia, and cramping in working muscles. It is pertinent to mention here that a class of hereditary metabolic myopathies, referred to as "lipid deposition myopathy" causes lipids to accumulate in skeletal muscle fibers, leading to lesions and degeneration. Among viral causes, HIV, dengue virus, influenza virus, hepatitis B virus, hepatitis C virus, SARS-CoV2 are also associated with muscle weakness. Sarcoidosis, an inflammatory disease, can also manifest as muscle weakness and myalgia. Owing to this complicated pathophysiology of proximal myopathy, this review aims to summarize the existing literature on conditions associated with this phenomenon and other recent developments that have been made regarding events leading to development of generalized muscle weakness. To the authors' knowledge this is the first narrative review that discusses causes and conditions associated with proximal myopathy in thorough detail.

Immune checkpoint inhibitor therapy in a patient with small cell lung cancer and anti-transcriptional intermediary factor 1-γ antibody-positive dermatomyositis: A case report

Autoimmune diseases (ADs) are closely related to cancers; 30% of dermatomyositis (DM) cases are associated with malignancy. In lung cancer patients accompanied by DM, the most frequent cancer type is small cell lung cancer (SCLC). Anti‐transcriptional intermediary factor 1 γ (anti‐TIF1γ) antibody is a promising marker for the assessment of cancer risk in DM patients. The recent use of immune checkpoint inhibitors (ICIs) for extensive‐stage SCLC has improved patient outcomes. However, clinical trials of ICI excluded most patients with ADs because of the increased risk of toxicity. Nevertheless, recent evidences suggest that ICI may be appropriate for AD patients. A 76‐year‐old man diagnosed with extensive‐stage SCLC and anti–TIF1γ Ab‐positive DM developed limb weakness and typical skin manifestations of DM. Positron emission tomography‐computed tomography showed diffuse uptake in all muscles. The results of a nerve conduction study and electromyography were consistent with acute myopathy. Electron microscopy showed tubuloreticular inclusions in endothelial cells. He was treated with corticosteroids for DM and chemotherapy with atezolizumab for SCLC. Despite concerns regarding the use of ICI because of DM, atezolizumab was administered under close observation. After treatment, tumor size decreased and his symptoms improved significantly. We believe that the response of SCLC to chemotherapy including ICI, had a positive effect on the improvement of DM. Clinicians should consider ICIs for SCLC patients with DM and carefully monitor the patient's symptoms during treatment.

Not a Statin-Induced Myopathy: Metastatic Pancreatic Adenocarcinoma Presenting As Paraneoplastic Myositis

Polymyositis is an inflammatory disease that causes bilateral proximal muscle weakness; unlike dermatomyositis, it is not usually associated with malignancy. However, there are a handful of case reports documenting polymyositis in patients with lymphoma, breast, lung, and bladder cancer. Here we report a case of metastatic pancreatic adenocarcinoma disguised by presenting as polymyositis. Clinical presentation, laboratory values, muscle biopsy, and imaging were all diagnostic of paraneoplastic polymyositis. The patient has significantly improved in symptoms are receiving systemic steroids and pancreaticoduodenectomy.

Standardised interpretation of capillaroscopy in autoimmune idiopathic inflammatory myopathies: A structured review on behalf of the EULAR study group on microcirculation in Rheumatic Diseases

OBJECTIVE

We conducted a systematic review, on behalf of the EULAR Study Group on Microcirculation in Rheumatic Diseases (EULAR SG MC/RD), to investigate the value of nailfold videocapillaroscopy (NVC) in idiopathic inflammatory myopathies (IIM).

METHODS

Three electronic databases were systematically searched to find all relevant manuscripts reporting NVC outcomes in IIM patients. Articles were assessed based on study design, population, NVC methodology and description of NVC results. To allow comparison between the articles, all NVC results were interpreted according to standardised capillaroscopic terminology, as previously consented by the EULAR SG MC/RD and the Scleroderma Clinical Trials Consortium (SCTC) Group on Capillaroscopy.

RESULTS

Of the 653 identified records; five were retained after critical appraisal on title, abstract and manuscript level. A marked difference in NVC was observed between (juvenile) dermatomyositis [(j)DM] versus polymyositis, healthy controls and systemic sclerosis patients. In addition, reduced capillary density and scleroderma pattern seem to be associated with active disease in (j)DM, while immunosuppressive treatment appears to reduce NVC abnormalities.

CONCLUSION

This is the first systematic review investigating NVC in IIM, interpreting the results according to an international consented standardised manner, as proposed by the EULAR SG MC/RD and SCTC Group on Capillaroscopy. We can conclude that NVC presents a promising asset in the diagnosis of (j)DM. Moreover, NVC could be a biomarker for organ involvement and follow-up. Large multicentre prospective standardised studies are further needed to definitely describe associations with clinical and laboratory parameters in the different IIM subtypes.

Treatment Outcomes of Infectious and Non-infectious Acute Exacerbation of Myositis-Related Interstitial Lung Disease

Introduction

Although respiratory infections are common causes of acute respiratory failure (ARF) in patients with myositis-interstitial lung disease (ILD), limited data are available regarding the treatment outcomes by the etiologies of acute exacerbation (AE) of myositis-related ILD (infectious vs. non-infectious). Our study aimed to investigate the treatment outcomes of AE in patients with myositis-related ILD focused on the infectious etiology.

Methods

A single center-based retrospective cohort was performed at Hanyang University Hospital between January 2000 and December 2018. A total of 36 patients with AE of myositis-related ILD were consecutively included. The exposure was the etiologies of AE in myositis-related ILD, and the outcome was in-hospital mortality. The infectious etiology was defined as confirmation of bacteria, virus, or fungus in samples obtained from the respiratory tract.

Results

Among the 36 patients, 17 were diagnosed with infectious AE. The overall in-hospital mortality rate of AE was 47.2%. Although the mortality rate in patients with infectious AE was lower (41.2%) than in those with non-infectious AE (52.6%), this difference was not statistically significant (p = 0.724). A survival analysis showed no significant difference in mortality between patients with infectious AE versus those with non-infectious AE [risk ratio = 0.78, 95% CI = 0.38–1.59].

Conclusion

Our study showed that infectious AE is an important cause of mortality in patients with myositis-related ILD, showing a similar risk of mortality as non-infectious AE.

Growth differentiation factor-15 as an emerging biomarker for identifying myositis

INTRODUCTION

The autoimmune disorders of the skeletal muscle tissue termed myositis are a rare yet diverse group of diseases with distinct clinical and pathological features and with different prognoses and treatment responses. Subtyping of patients is necessary for appropriate disease management, and requires specialized expertise and elaborate diagnostic testing of clinico-pathological disease features.

AREAS COVERED

Current clinical practice and diagnostic criteria for subtyping patients are searched on medical online platforms including PubMed and Web of Science. Recent publications on growth differentiation factor-15 (GDF-15) and muscle disorders are summarized and analyzed, and comparisons are made of data published in studies describing disease cohorts as well as individual patients. Influence of age and physical activity on GFD-15 levels and potential as a diagnostic criterion are discussed. This review contains supportive evidence of the elevated levels of GDF-15 in the blood of myositis patients, a feature which distinguishes these autoimmune muscle disorders from muscular dystrophy with secondary inflammation.

EXPERT OPINION

GDF-15 represents a novel and promising serological biomarker for diagnosing myositis, yet more studies are needed to assay its sensitivity and specificity. Increased diagnostic power is expected by combining GDF-15 levels with other blood-derived biomarkers.

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.

Clues to Disease Activity in Juvenile Dermatomyositis: Neopterin and Other Biomarkers

Easily accessible biomarkers are urgently needed to evaluate immune activation in Juvenile Dermatomyositis (JDM). The goal of this retrospective study is to define immunological and clinical differences between untreated JDM patients with either normal or elevated (>10 mmol/L) levels of neopterin, a biomarker of macrophage activation. We included all JDM with neopterin data obtained before initiating medical therapy. We assessed T, B, NK cell populations, muscle enzymes, and disease activity scores for skin (sDAS), muscle (mDAS), total (tDAS), the duration of untreated disease, disease course, and myositis-specific antibody (MSA). Seventy-nine percent of 139 untreated JDM patients had elevated serum neopterin. The group with elevated neopterin had significantly more active disease: tDAS 11.9 vs. 8.1 (p < 0.0001), mDAS 5.8 vs. 3.1 (p < 0.0001), sDAS 6.1 vs. 4.9 (p = 0.0002), aldolase 24.0 vs. 7.6 U/L (p < 0.0001), von Willebrand factor antigen (p < 0.0001), and ESR 19.8 vs. 11.5 mm/hr (p = 0.01). The flow cytometry documented both reduced T cells (1494 vs. 2278/mm3, p = 0.008) and NK cells (145 vs. 240/mm3, p = 0.003). TNFα-308AA/AG polymorphism was more common in children with elevated neopterin than TNFα-308GG (p 0.05). We conclude that the availability of neopterin data will contribute to the rapid assessment of untreated JDM disease activity.

Performance of ENMC and EULAR/ACR classification systems applied to a single tertiary center cohort of dermatomyositis patients

Background

There have been numerous classification systems to diagnose corresponding myositis subtypes and select appropriate therapeutic measures. However, the lack of a broad consensus on diagnostic criteria has led to clinical uncertainties. The objective of this study was to compare two commonly used dermatomyositis-classification systems regarding their clinical practicability and to point out their specific advantages and disadvantages.

Methods

This study included 30 patients diagnosed with dermatomyositis at the Charité university hospital, Berlin, Germany from 2010 to 2017. Patient files with complete data and defined historical classifications were enrolled and ENMC (2003) and EULAR/ACR (2017) criteria retrospectively applied.

Results

According to the ENMC approach, 14 patients were classified as "definite" and 12 as "probable" dermatomyositis. One patient exhibited an "amyopathic dermatomyositis" and three a "DM without dermatitis". Regarding the criteria probability of the EULAR/ACR set, 16 patients had a "high", 13 a "medium" and one a "low probability". There was a significant difference (p = 0.004) between the subclasses of the ENMC in relation to the EULAR/ACR score. The agreement between the classification probabilities of "definite/high" (κ = 0.400) and "possible/medium" (κ = 0.324) was fair.

Conclusions

It is important to find a consensus among the medical disciplines involved and to establish a structured procedure. Future studies with newer approaches are warranted to conclusively decide which system to use for the physician.

Comparison of treatments and outcomes of children with juvenile dermatomyositis followed at two European tertiary care referral centers

OBJECTIVES

To compare the treatment approaches and disease outcomes of children with JDM followed in two European tertiary care peadiatric rheumatology centres.

METHODS

The medical notes of patients with JDM seen at Istituto Giannina Gaslini (IGG) of Genoa, Italy or Great Ormond Street Hospital (GOSH) of London, UK between January 2000 and December 2015 within 6 months after disease onset and followed for at least 6 months were reviewed. Demographic, clinical and therapeutic data were collected. At each visit, the caring physician was asked to rate the disease state subjectively.

RESULTS

A total of 127 patients were included, 88 at GOSH and 39 at IGG. At 24 months, the median values of muscle strength and disease activity were at the normal end of the scale and around three quarters of patients were said to have inactive disease. Also, at 2 years, 38.6% and 36% of British and Italian patients, respectively, had damage. Cyclophosphamide, azathioprine, infliximab, rituximab and mycophenolate mofetil were used more frequently by UK physicians, whereas ciclosporin, intravenous immunoglobulin and hydroxychloroquine were prescribed by Italian physicians.

CONCLUSION

This study shows a significant difference in the choice of medications between pediatric rheumatologists practising in the two centres. Despite this, a high proportion of patients had inactive disease at 2 years and there was a low frequency of damage: modern treatments have improved outcomes.

Polymyositis: does it really exist as a distinct clinical subset?

PURPOSE OF REVIEW

To summarize information on polymyositis; diagnosis, definitions, published data and opinions.

RECENT FINDINGS

Polymyositis originally referred to inflammatory muscle diseases presenting with muscle weakness and inflammatory cell infiltrates on muscle tissue visible by microscopy. Over time and with improved technology to immunophenotype infiltrating inflammatory cells and characterize muscle fibres, the meaning of polymyositis changed and became more specific. There is ongoing controversy over the term polymyositis, with proponents for a strict definition based on histopathological and immunohistochemical features on muscle biopsies whereas others advocate for a broader clinical and histopathological phenotype. Over the past decades, the discovery of several myositis-specific autoantibodies together with distinct histopathological features have enabled the identification of new subsets previously labelled as polymyositis notably the antisynthetase syndrome and the immune-mediated necrotizing myopathies thus reducing the number of patients classified as polymyositis.

SUMMARY

There are still a small number of patients among the idiopathic inflammatory myopathies that can be classified as polymyositis as discussed in this review but the entity is now considered relatively rare.

Development and Preliminary Validation of an Electromyography-Scoring Protocol for the Assessment and Grading of Muscle Involvement in Patients With Juvenile Idiopathic Inflammatory Myopathies

INTRODUCTION

We performed a pilot study in order to investigate the feasibility of an electromyography (EMG)-scoring protocol for the assessment of disease activity in juvenile idiopathic inflammatory myopathies (JIIM).

METHODS

Children with JIIM followed up in a tertiary-level care center underwent standardized clinical, laboratory, and EMG assessment. An EMG-scoring protocol was devised by a consensus panel including a pediatric neurophysiologist and two pediatric rheumatologists, based on a combined score obtained as the sum of (1) the presence of denervation signs (fibrillation potentials) and (2) motor unit remodeling (mixed pattern of short- and long-duration motor unit action potentials). The EMG-scoring protocol was then validated following the Outcome Measures in Rheumatoid Arthritis Clinical Trials filter for outcome measures in rheumatology and the consensus-based standards for the selection of health measurement instruments methodology.

RESULTS

Thirteen children (77% females) were included in the study, with a median age of 10 years (interquartile range: 7-17 years) and median disease duration of 11.8 months (interquartile range: 2.1-44.5). A total of 39 EMG examinations were evaluated. A strong positive association between a standardized tool for muscle strength assessment and the combined score was observed. No significant associations were found with both creatine kinase and erythrocyte sedimentation rate levels.

DISCUSSION

Our EMG-scoring protocol is the first standardized and reproducible tool for the neurophysiologic evaluation and grading of muscle involvement in patients with JIIM and could provide relevant additional information in the assessment and follow-up of these rare conditions.

Nailfold Capillaroscopy With USB Digital Microscopy in Connective Tissue Diseases: A Comparative Study of 245 Patients and Healthy Controls

Background: Nailfold capillaroscopy (NFC) is a valuable tool to detect microcirculation abnormalities in connective tissue diseases (CTDs). However, whether the universal serial bus (USB) digital microscopy used as onychoscopy is as effective as the videocapillaroscopy in determining the diagnostic and prognostic values of CTDs remains to be determined. Objective: This study aims to investigate NFC features of systemic lupus erythematosus (SLE), dermatomyositis (DM), and systemic sclerosis (SSc) patients and compare with normal controls as well as examine which feature could differentiate among CTDs. Furthermore, we aim to explore different capillaroscopic abnormalities and their association with disease activity. Methods: Nailfold images were taken from patients and healthy controls using a USB digital microscopy. Patterns on the capillary morphology, diameter, architecture, and density were recorded and compared. We further determined the NFC findings in SLE, DM, and SSc and corresponded to their respective disease activity scoring system. Results: A total of 245 participants, consisting of 54 SLE, 32 DM, and 51 SSc patients, as well as 108 controls, were enrolled. All capillaroscopic features, except for tortuous capillaries, were significantly more common in CTDs than healthy control (all p < 0.05). A multinomial logistic regression analysis revealed that bushy capillaries had significantly higher odds for both SLE and DM than SSc (OR: 4.10, 95% confidence interval (CI): 1.71-9.81, p = 0.002 and OR: 7.82, 95% CI, 2.86-21.38, p < 0.001, respectively). Elongated capillaries demonstrated significant odds for SLE compared with SSc (OR: 3.35, 95% CI: 1.005-11.20, p = 0.049), while prominent subpapillary plexus showed greater odds for SLE compared with both DM and SSc (OR: 2.75, 95% CI: 1.07-7.02, p = 0.03 and OR: 5.78, 95% CI: 2.29-14.58, p < 0.001, respectively). The presence of hemorrhage, enlarged capillaries, and the low-density index had significantly higher odds in favor of SSc than SLE. Bushy capillaries were the only pattern with a strong association for DM over SSc. The presence of enlarged capillaries indicated higher SLE severity, but no specific finding was related to DM or SSc skin scores. Conclusions: Nailfold capillaroscopic examination using a digital microscope is a valuable method for the diagnosis of SLE, DM, and SSc. Several morphologic patterns can help differentiate among CTDs; however, the prognostic significance of this method requires further investigations.

Anasarca as the presenting symptom of juvenile dermatomyositis: a case series

BACKGROUND

Juvenile Dermatomyositis (JDM) is an autoimmune disease that typically presents with classic skin rashes and proximal muscle weakness. Anasarca is a rare manifestation of this disease and is associated with a more severe and refractory course, requiring increased immunosuppression. Early recognition of this atypical presentation of JDM may lead to earlier treatment and better outcomes.

CASE PRESENTATION

We present two female patients, ages 11 years old and 4 years old, who presented to the ED with anasarca and were subsequently diagnosed with JDM. Both patients required ICU-level care and significant immunosuppression, including prolonged courses of IV methylprednisolone, IVIG, and Rituximab.

CONCLUSIONS

Anasarca is a rare presentation of Juvenile Dermatomyositis, but it is important for clinicians to recognize this manifestation of the disease. Early recognition and treatment will lead to better outcomes in these children and hopefully decrease the need for prolonged hospitalization and ICU level care.

Historie der idiopathischen entzündlichen Myopathien

Die ersten Beschreibungen idiopathischer entzündlicher Myopathien (Myositiden), initial durchweg Dermatomyositiden, reichen über 150 Jahre zurück (E. L. Wagner, C E. Potain, H. Unverricht). G. Stertz vermutete 1916 erstmals einen Zusammenhang zwischen einem Malignom und einer Dermatomyositis. Die charakteristischen Hautveränderungen und histopathologischen Veränderungen bei den Dermatomyositiden sind schon früh beschrieben worden, wohingegen die typischen proximalen Extremitätenparesen in den ersten Jahrzehnten keineswegs regelmäßig in den Beschreibungen auftauchten. Die Behandlungsmöglichkeit mit Glukokortikoiden wurde erst vor 70 Jahren in den U.S.A. entdeckt, eine bis heute akzeptierte Klassifikation 1977 vom US-Amerikaner Bohan und Mitarbeitern beschrieben. Der Beitrag beschreibt die Erstbeschreibungen der nicht infektiösen entzündlichen Myopathien und deren Therapie.

Diagnosing muscle disease in a cohort of classic dermatomyositis patients seen at a rheumatologic dermatology outpatient clinic

BACKGROUND

Existing criteria to improve the probability of capturing dermatomyositis (DM) include muscle biopsy but little is known about whether less invasive diagnostic procedures may be just as useful.

OBJECTIVE

We aimed to determine whether skin biopsy, electromyography, or magnetic resonance imaging of the involved muscle could be done in lieu of muscle biopsy.

METHODS

Two hundred and seventy-five patients were reviewed to investigate the presence of cutaneous and muscle disease, their timing in relation to diagnosis, and results of skin biopsies, muscle biopsies, magnetic resonance imaging, and electromyography.

RESULTS

Of the cases with findings consistent with DM on muscle biopsy, 65% were in agreement with diagnostic features on electromyography or magnetic resonance imaging. Results of skin and muscle biopsies supported DM in 67% of patients who underwent both procedures.

LIMITATIONS

A limited number of patients had muscle biopsies.

CONCLUSION

In the presence of DM-specific skin findings, less invasive procedures may be sufficient to diagnose DM and guide its management.

External validation of the EULAR/ACR idiopathic inflammatory myopathies classification criteria with a Japanese paediatric cohort

OBJECTIVES

To assess the performance of the EULAR/ACR idiopathic inflammatory myopathies (IIMs) classification criteria to classify juvenile IIMs (JIIMs) in an Asian paediatric population.

METHODS

Sixty-eight JIIM patients and 49 non-JIIM patients diagnosed at seven major paediatric rheumatology centres in Japan between 2008 and 2015 were enrolled. Retrospective data were collected, and each patient's data form was submitted. The expert group reviewed the forms and re-examined the diagnoses. The EULAR/ACR criteria were then applied and the probability of having JIIM was determined for each case. The sensitivity and specificity of the EULAR/ACR criteria were compared with those of other existing criteria.

RESULTS

The sensitivity/specificity of the EULAR/ACR classification criteria were 92.1/100% with muscle biopsy data (n = 38); 86.7/100% without muscle biopsy data (n = 30) and 89.7/100% in our total cohort (n = 68). The sensitivity of Bohan and Peter's criteria and Tanimoto's criteria were 80.9 and 64.7% in our total cohort, respectively. Among 68 physician-diagnosed JIIM patients, seven cases (three JDM and four overlap myositis) were not classified as JIIM because the probability did not reach the cut-off point (55%). The three JDM patients all presented with only one of the three skin manifestations that are listed in the criteria: Gottron's sign.

CONCLUSION

Our validation study with Japanese JIIM cases indicates that the EULAR/ACR classification criteria for IIM generally perform better than existing diagnostic criteria for myositis.

Real world utilization of the myositis autoantibody panel

OBJECTIVE

Myositis autoantibody panel results can offer diagnostic and prognostic information in patients with concern for idiopathic inflammatory myopathy (IIM). However, there has been widespread utilization of myositis autoantibody testing clinically, often in situations where concern for an IIM is unclear. We sought to determine ordering practices and factors predicting positive results on ordered myositis antibody panels.

METHODS

We included all patients in the Duke University Health System who had a "myositis antibody panel" ordered from October 2014 through December 2016. Retrospective chart review was performed evaluating antibody positivity, provider specialty, ordering location, demographics, medical history, review of systems (ROS), physical examination (PE), and laboratory values. Fisher's exact and t test tests and backward multivariable regression analysis were performed for statistical analysis.

RESULTS

There were 642 unique tests obtained with 114 positive autoantibodies (17.7%) over the 26-month period. Myositis-specific autoantibodies (MSAs) were the most common and anti-Mi-2 was the most frequent (40% of MSAs). Pulmonology providers ordered the majority of tests (383; 59.6%). Adult Rheumatology had the highest antibody positivity rate (34.3%, p=0.0001) among specialties with at least 10 panels ordered. In backward multivariable regression analysis, factors independently associated with a positive myositis antibody panel were chronic corticosteroid use (OR: 2.10, 95% CI: 1.30-3.38) and sclerodermoid skin changes (OR: 6.89; 95% CI: 2.02-23.47).

CONCLUSION

The positivity rate of myositis antibody panel testing in this real-world clinical setting was 18%. Anti-Mi-2 antibody was the most frequent autoantibody present. Specific factors associated with positive results can be utilized to identify patients at higher risk for IIM.

KEY POINTS

• Only eighteen percent of all myositis antibody panel tests ordered returned positive. • Anti-Mi-2 antibody was the most frequent autoantibody in our cohort. • Specific factors associated with positive results can help identify patients at higher risk for IIM, particularly for non-rheumatologists.

Dysphagia in adult myopathies

Dysphagia (impaired swallowing) is not a rare problem in various neuromuscular disorders, both in the pediatric and the adult patient population. On many occasions such patients are first presented to other medical specialists or health professionals. Disorders of deglutition are probably underrecognized in patients with a neuromuscular disease as a result of patient's and doctor's delay. This review will focus on dysphagia in adults suffering from a myopathy. Dysphagia in myopathies usually affects the oropharyngeal phases which rely mostly on voluntary muscle activity of the mouth, pharynx and upper esophageal sphincter. Dysphagia is known to contribute to a reduction of quality of life and may also lead to increased morbidity and mortality. The review includes an overview on symptomatology and tools of assessments, and elaborates on dysphagia in specific hereditary and acquired myopathies.