Myalgia in Patients with Dermatomyositis and Polymyositis Is Attributable to Fasciitis Rather Than Myositis: A Retrospective Study of 32 Patients who Underwent Histopathological Examinations

Anti-NXP2 Antibody-positive Juvenile Dermatomyositis with Characteristic Fascial Thickening on Muscle Ultrasound and Improvement with Immunotherapy

We herein report a 12-year-old boy who presented with a fever, erythematous rash on the cheeks, back pain, and dysphagia. Blood tests revealed increased creatine kinase levels, and muscle ultrasonography (MUS) revealed characteristic fascial thickening in the lumbar paraspinal muscles, where myalgia was prominent. Sarcoplasmic expression of myxovirus-resistant protein A on a muscle biopsy and the presence of anti-nuclear matrix protein 2 (NXP2) antibodies confirmed the diagnosis of dermatomyositis. Prednisolone and intravenous immunoglobulin therapy improved the clinical and laboratory parameters as well as fascial thickening. MUS is useful for evaluating fasciitis associated with anti-NXP2 autoantibodies and monitoring therapeutic efficacy.

Intramuscular lesions in musculoskeletal MRI as a favourable prognostic sign in patients with anti-MDA5 antibody-positive dermatomyositis

OBJECTIVES

Anti-differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis, which has been described as clinically amyopathic dermatomyositis, complicates rapidly progressive interstitial lung disease (ILD). Owing to the absence of significant muscle symptoms, musculoskeletal MRI is often not performed. In this study, we aimed to devise a simple evaluation method using musculoskeletal MRI findings to elucidate the relationship between MRI findings and ILD prognosis and development.

METHODS

The medical records and MRI scans of the proximal muscles at the time of diagnosis were retrospectively reviewed for 28 patients with anti-MDA5 antibody-positive dermatomyositis who were admitted to The Jikei University Hospital and The Jikei University Kashiwa Hospital between January 2008 and March 2022. Three observers evaluated nine proximal muscles for high signals on either short-tau inversion recovery images and/or fat-saturated gadolinium-enhanced T1-weighted images in the fascia and/or in the margins of the muscles in contact with the fascia (fascial pattern), and/or high signals in the muscles away from the fascia (intramuscular pattern), and a consensus was reached.

RESULTS

Of the 28 patients, 15 presented with 'radiological myositis', where an intramuscular pattern was observed at any site. Patients with radiological myositis had significantly higher survival rates than those without radiological myositis, despite the lower rate of triple therapy with prednisolone, calcineurin inhibitors and cyclophosphamide. The spread of ILD on chest CT negatively and significantly correlated with the proportion of intramuscular lesions.

CONCLUSION

The detection of intramuscular lesions on musculoskeletal MRI using our novel evaluation method could be clinically useful as a favourable prognostic marker.

Pain in autoimmune inflammatory myopathies: a scoping review

BACKGROUND

Pain is considered a priority for research by adult patients with autoimmune inflammatory myopathy (AIM) and their families. Our aim was to review the literature for studies reporting on pain in adult AIM and to summarise their findings.

METHODS

A scoping review was conducted searching for studies in PubMed and MEDLINE including more than five adult patients with AIM and assessing pain using a patient-reported outcome measure. Study population characteristics, pain measurement and clinical correlates of pain were extracted using a standardised protocol.

RESULTS

The search strategy identified 2831 studies with 33 meeting inclusion criteria. Most studies used visual analogue scales (n=14) and/or the Medical Outcomes Study 36-Item Short Form Bodily Pain Scale (n=17). Frequency of pain and/or myalgias ranged from 64% to 100%. Subjects with AIM had significantly more pain than the general population and comparable pain to other chronic rheumatic diseases. Insufficient results were available to identify significant clinical correlates of pain in AIM.

CONCLUSION

This review suggests that the burden of pain in AIM is considerable. Still, due to the heterogeneity and low quality of the evidence, significant knowledge gaps persist. Studies are needed to characterise pain trajectories of patients with AIM.

A New Method for the Assessment of Myalgia in Interstitial Lung Disease: Association with Positivity for Myositis-Specific and Myositis-Associated Antibodies

In this study, it was found that myositis-specific and myositis-associated antibodies (MSAs and MAAs) improved the recognition of idiopathic inflammatory myopathies (IIMs) in interstitial lung disease (ILD) patients. The objective of this study is to propose a clinical method to evaluate myalgia in respiratory settings as a possible tool for the recognition of MSA/MAA positivity in ILD patients. We prospectively enrolled 167 ILD patients with suspected myositis, of which 63 had myalgia evoked at specific points (M+ILD+). We also enrolled in a 174 patients with only myalgia (M+ILD-) in a rheumatological setting. The patients were assessed jointly by rheumatologists and pulmonologists and were tested for autoantibodies. M+ILD+ patients were positive for at least one MAA/MSA in 68.3% of cases, as were M-ILD+ patients in 48.1% of cases and M+ILD- patients in 17.2% of cases (p = 0.01 and <0.0001, respectively). A diagnosis of IIM was made in 39.7% of M+ILD+ patients and in 23.1% of the M-ILD+ group (p = 0.02). Myalgia was significantly associated with positivity for MSA/MAAs in ILD patients (p = 0.01, X2: 6.47). In conclusion, myalgia in ILD patients with suspected myositis is associated with MSA/MAA positivity, and could support a diagnosis of IIM. A significant proportion of M+ILD- patients also had MSA/MAA positivity, a phenomenon warranting further study to evaluate its clinical meaning.

Physical Characteristics of Injection Site Pain After COVID-19 mRNA BNT162b2 Vaccination

Background

BNT162b2, an mRNA COVID-19 vaccine, was launched in many countries as an intramuscular vaccination for COVID-19 infection. Few studies have assessed the physical indications of pain at the immunization site. This study aimed to characterize pain at the injection site and investigate morphological attributes using ultrasound.

Methods

Forty-three of 211 healthcare workers who received a second dose of BNT162b2 between February 2021 and March 2021 were enrolled in the study. The mean age of the subjects was 40 years. We evaluated patients' pain at the injection site using the Numerical Rating Pain Scale (NRPS). We also assessed the thickness of the deltoid muscle fascia at the injection site by ultrasound. Bayesian robust correlation was employed to explore the relationship between the pain intensity scores and ultrasound measurements.

Results

All eligible subjects complained of pain at the injection site. A median pain onset of 8 hours post-vaccination and a median peak intensity score of 4 were reported. Onset of relief occurred after 2 days. Ultrasound images demonstrated a 2.5-fold increase in fascia thickness at the injection site without intramuscular echogenicity change in all subjects. A correlation was established between the NRPS score and the non-injection-to-injection-side ratio of fascia thickness at the injection site (rho = 0.66).

Conclusion

A sore arm was the most prevalent side effect of BNT162b2 vaccination and could be attributed to temporal fasciitis.

Rheumatic manifestations of COVID-19: a systematic review and meta-analysis

BACKGROUND

Different proportions of musculoskeletal or autoimmune manifestations associated with COVID-19 have been reported in literature. We performed a systematic review and meta-analysis with the aim of assessing the prevalence of rheumatic manifestations in patients affected by COVID-19, as initial symptom or during disease course.

METHODS

A database search was run on May 18th, 2020, using two distinct strategies. We were interested in the percentage of symptoms of potential rheumatologic interest observed in large population studies of COVID-19 cases, and in identifying uncommon autoimmune disorders described in patients with COVID-19. For manifestations individually reported, a meta-analysis was performed taking into consideration the proportion of COVID-19 patients presenting the symptom.

RESULTS

Eighty eight original articles were included in the systematic review and 51 in the meta-analysis. We found pooled estimates of 19% for muscle pain and 32% for fatigue as initial symptom of COVID-19 presentation and, respectively, of 16 and 36% during the disease course. Only one article discussed arthralgia as unique symptom. Additionally, we found that vasculitis, chilblains, presence of autoantibodies commonly found in patients with rheumatic diseases, or autoimmune haematological and neurological disorders have all been reported in patients with COVID-19.

CONCLUSIONS

In conclusion, our review and meta-analysis emphasises that symptoms potentially leading to rheumatologic referral are common in patients with COVID-19. Therefore, COVID-19 is a new differential diagnosis to bear in mind when evaluating patients with musculoskeletal symptoms and rheumatologists might play a crucial role in identifying COVID-19 cases in early phases of the illness.

[Pain management in rare diseases]

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

MRI of skeletal muscles in patients with idiopathic inflammatory myopathies: characteristic findings and diagnostic performance in dermatomyositis

Objective

To define the characteristic findings on MRI of skeletal muscles in patients with dermatomyositis (DM) relative to those in patients with other idiopathic inflammatory myopathies (IIMs) and to assess their diagnostic performance in DM.

Methods

Thirty-six patients with DM, 17 patients with amyopathic DM, 19 patients with polymyositis and 16 patients with non-IIM classified by the 2017 European League Against Rheumatism/American College of Rheumatology criteria were included in this study. The following MRI findings (short-tau inversion recovery [STIR] and gadolinium-enhanced fat-suppressed T1-weighted imaging [Gd-T1WI]) for proximal limb muscles were compared between the disease groups and between myositis-specific autoantibodies/myositis-associated autoantibodies (MSAs/MAAs)-positive and MSAs/MAAs-negative groups: structures with high signal intensity (HSI) (subcutaneous, fascia, muscle); distributions of HSI areas in muscle (diffuse, patchy, peripheral) and patterns of HSI in muscle (honeycomb, foggy, strong HSI). Univariate, multivariate and receiver-operating characteristic [ROC] analyses were performed to assess the diagnostic performance of MRI in DM.

Results

The characteristic MRI findings in patients with DM were subcutaneous HSI, fascial HSI, peripheral distribution and honeycomb pattern. The MRI findings in the MSAs/MAAs-positive group included more frequent fascial HSI but less frequent foggy pattern compared with the MSAs/MAAs-negative group. Likelihood of DM score ≥ 3 (obtained by counting the number of characteristic MRI findings in patients with DM) showed good diagnostic performance in DM (STIR: sensitivity 72.2%, specificity 88.5%, area under ROC curve [AUC] 84.9%; Gd-T1WI: sensitivity 81.2%, specificity 91.5%, AUC 89.9%).

Conclusion

The characteristic MRI findings of skeletal muscles can predict patients with DM as well as patients with MSAs/MAAs.

Fasciae of the musculoskeletal system: normal anatomy and MR patterns of involvement in autoimmune diseases

Abstract

The fascial system is a three-dimensional continuum of connective tissues present everywhere throughout the body, from the head to the toes and from the skin to the bone. The current article aims to review the normal anatomy of the fasciae of the musculoskeletal system with macroscopic and microscopic correlations and to describe their appearance at MRI in normal subjects and in patients with autoimmune diseases of the musculoskeletal system.

Key Points

• The fascial system is a three-dimensional continuum of connective tissues.

• It is present everywhere throughout the body, from the head to the toes and from the skin to the bone.

• The normal fascial system is barely visible at MRI.

• MR patterns of fascial involvement in autoimmune diseases reflect the complex anatomy of the fasciae of the musculoskeletal system.

Autoimmune fasciitis triggered by the anti-programmed cell death-1 monoclonal antibody nivolumab

A 43-year-old woman with a history of recently diagnosed metastatic melanoma was commenced on systemic therapy with nivolumab, an anti-programmed cell death-1 monoclonal antibody and one of an increasing group of the so-called ‘immune checkpoint inhibitors’. She experienced a dramatic complete response within 6 months of initiation. However, in addition to developing incident autoimmune hypothyroidism, she also developed progressive fatigue, proximal weakness, myalgia and dysphagia. Initial investigations with blood tests, electrophysiology and a muscle biopsy were non-specific or normal. Subsequent examination revealed ‘woody’ thickening of the subcutaneous tissues of the forearms, thighs and calves consistent with fasciitis. MRI and a full-thickness skin–muscle biopsy were ultimately diagnostic of a likely iatrogenic autoimmune myofasciitis. The clinical manifestations only responded partly to prednisolone 30 mg orally and treatment was escalated to include intravenous immunoglobulin. At 3 months, this has only resulted in a modest incremental improvement.

Angiogenesis and VEGF-expressing cells are identified predominantly in the fascia rather than in the muscle during the early phase of dermatomyositis

Background

We previously demonstrated that fasciitis is a common lesion in dermatomyositis (DM) and that DM-associated fasciitis is detectable, as the result of the increased vascularity in the fascia, by power Doppler ultrasonography. We aimed to investigate whether angiogenesis and vascular endothelial growth factor (VEGF)-expressing cells in the fascia are histologically demonstrated during the early phase of DM, and whether inflammation is involved in angiogenesis and an increased number of VEGF-expressing cells.

Methods

We prospectively evaluated 22 patients with DM and 11 patients with polymyositis (PM). Immunohistochemical staining for CD31, VEGF, and tumor necrosis factor-α (TNF-α) were performed on paraffin-embedded sections. The total vascular inflammation score (TVIS), angiogenesis score (AS), and numbers of VEGF-expressing and TNF-α-expressing cells were analyzed in the fascia and muscle.

Results

Significant fasciitis was detected in most of the patients DM with or without myositis-specific/associated antibodies, while mild fasciitis was detected in four patients with PM, two of whom were positive for anti-aminoacyl-tRNA synthetase (anti-ARS) antibodies. The AS and the number of VEGF-expressing cells in the fascia of patients with DM were significantly greater than those of patients with PM; no significant difference was observed in muscle in patients with DM and PM. The number of VEGF-expressing cells in the fascia correlated with the AS of DM patients. In early-phase DM, the AS, the number of VEGF-expressing cells, and the TVIS in the fascia were significantly higher than in muscle. However, no significant differences were observed in these scores excluding the TVIS between muscle and the fascia in late-phase DM. In DM patients, the TVIS correlated with the AS in the fascia, while the number of TNF-α-expressing cells correlated with the TVIS and the number of VEGF-expressing cells in the fascia.

Conclusion

Angiogenesis, the number of VEGF-expressing cells, and the degree of inflammation were higher in the fascia in DM than in PM, and were increased predominantly in the fascia rather than in the muscle in early-phase DM. The degree of inflammation correlated with that of angiogenesis in the fascia of DM. The fascia can therefore be a primary site of inflammation and angiogenesis in the pathogenesis of DM.