Clinical and Pathological Features of Immune-Mediated Necrotising Myopathies in a Single-Centre Muscle Biopsy Cohort

Objective Immune-mediated necrotising myopathy (IMNM) is a recently entitled novel subset of idiopathic inflammatory myopathies (IIM) characterized by significant elevated creatine kinase (CK) level, muscle weakness and predominant muscle fibre necrosis in muscle biopsy. This study aimed to investigate the clinical and pathological characteristics of patients with IMNM in our single-centre muscle biopsy cohort. Methods A total of 860 patients who had muscle biopsy reports in our centre from May 2008 to December 2017 were enrolled in this study. IMNM was diagnosed in according with 2018 European Neuromuscular Centre (ENMC) clinicopathological diagnostic criteria for IMNM. Results The muscle biopsy cohort consisted of 531 patients with IIM (61.7%), 253 patients with non-IIM (29.4%), and 76 undiagnosed patients (8.8%). Among IIM patients, polymyositis (PM), dermatomyositis(DM), amyopathic dermatomyositis, juvenile DM, and inclusion body myositis were 182(21.2%), 236(27.4%), 83(9.7%), 18(2.1%) and 3(0.3%), respectively. In PM subgroup, 59 patients met serological and pathological characteristics of IMNM according to 2018 ENMC criteria including 29 anti-SRP-positive patients,10 anti-HMGCR-positive patients and 20 MSA-negative patients. Limb girdle muscular dystrophy (LGMD) 2B and lipid storage myopathy (LSM) were 29 and 16 respectively, which present similar manifestations of IMNM with elevated CK levels and muscle weakness among non-IIM group. IMNM patients had older age of onset (mean: 42.25 vs 21.66 and 24.56, p<0.0001), shorter duration of diseases (mean: 22.56 vs 66.69 and 48.94, p<0.0001) and more frequent of dysphagia (33.9% vs 3.4% and 6.3%, p<0.0001) compare to patients with LGMD 2B and LSM. Muscle biopsy from IMNM patients showed frequent muscle fibre necrosis (96.6% vs 72.4% and 56.3%, p<0.0001), overexpression of MHC-I on sarcolemma (81.4% vs 37.9% and 12.9%, p<0.0001) and CD4+ T cell endomysial infiltration (89.9% vs 53.6% and 50%, p<0.0001) compared with LGMD 2B and LSM patients. Conclusions It is easy to distinguish IMNM from other subtype of IIM according to clinical symptoms and MSAs profiles. However, distinguishing IMNM from disorders clinically similar non-IIM need to combine with clinical, serological and pathological features.

Predominant Myofibrillar Pathology with Preserved Sarcolemmal Aquaporin 4 Immunoreactivity in a Patient with Neuromyelitis Optica-Associated HyperCKemia

A 49-year-old man developed recurrent myalgia and hyperCKemia during acute attacks of neuromyelitis optica. Muscle biopsy was performed, and the pathological findings were analyzed. Predominant myofibrillar pathology was observed, which constitutes a unique finding that has not been reported before. This case result shows that neuromyelitis optica-associated hyperCKemia can produce variable pathologic phenotypes. Further studies are needed to elucidate the relationship between myofibril destruction and aquaporin 4 autoimmunity.

The diagnostic value of vacuolar characterization in muscular biopsy in Pompe's Disease

Introduction. Through muscle biopsy we can observe the formation of vacuoles that alter the structure of cells and tissues in Pompe's disease. The presence of these vacuoles varies as the disease progresses, relating to the broad clinical spectrum presented by the disease. Objectives. After confirming the disease, examine the possibility of diagnosing or excluding the diagnosis of Pompe's disease through the vacuolar characteristics presented. Method. Analysis of the muscle biopsy material of selected patients at the Neuromuscular Diseases Investigation Clinic at the Federal University of São Paulo. Through staining and histochemical techniques, a comparative study of the histological characteristics found was performed. Results. Thirty-three biopsies had the diagnosis of Pompe's disease confirmed, being 13 women and 20 men. Of this group, 23 received the diagnosis when they were 18 years old or more, and 10 received the diagnosis under the age of 18 years. Delimiting membrane and subsarcolemal location were the main vacuolar characteristic found, manifesting in 86.6% of the studied cases. Integration between the vacuole membranes was observed in 62.5% of the cases. We also found necrosis, replacement of muscle tissue by connective or adipose tissue, increased mitochondrial activity and absence of predominance in one type of fiber. Conclusion. Muscle biopsy allows to analyze a series of peculiarities presented by vacuoles in Pompe's Disease and, thus, it proves to be a sure technique, allowing to reach a quick conclusion and to identify determining factors for the clinical conduct and maintenance of quality of life of the patient with Pompe's disease.

OptimisAtion of Diagnostic Accuracy in idioPathic inflammaTory myopathies (ADAPT study): a protocol for a prospective diagnostic accuracy study of multimodality testing in patients suspected of a treatable idiopathic inflammatory myopathy

IntroductionIdiopathic inflammatory myopathies (IIMs) excluding inclusion body myositis (IBM) are a group of heterogeneous autoimmune disorders characterised by subacute-onset and progressive proximal muscle weakness, which are frequently part of a multisystem autoimmune disorder. Reaching the diagnosis can be challenging, and no gold standard for the diagnosis of IIM exists. Diagnostic modalities include serum creatine kinase activity, muscle imaging (MRI or ultrasound (US)), electromyography (EMG), myositis autoantibody testing and muscle biopsy. Several diagnostic criteria have been developed for IIMs, varying in reported sensitivity and specificity.HypothesisWe hypothesise that an evidence-based diagnostic strategy, using fewer and preferably the least invasive diagnostic modalities, can achieve the accuracy of a complete panel of diagnostic tests, including MRI, US, EMG, myositis-specific autoantibody testing and muscle biopsy.Methods and analysisThe OptimizAtion of Diagnostic Accuracy in idioPathic inflammaTory myopathies study is a prospective diagnostic accuracy study with an over-complete study design. 100 patients suspected of an IIM excluding IBM will be included. A reference diagnosis will be assigned by an expert panel using all clinical information and all results of all ancillary tests available, including 6 months of follow-up. Several predefined diagnostic strategies will be compared against the reference diagnosis to find the optimal diagnostic strategy.Ethics and disseminationEthical approval was obtained from the medical ethics committee of the Academic Medical Centre, University of Amsterdam, The Netherlands (2019-814). The results will be distributed through conference presentations and peer-reviewed publications.Trial registration numberNetherlands trial register; NL8764.

A Randomized Placebo-Controlled Trial of Metformin for Frailty Prevention in Older Adults

Frailty is a progressive physical decline leading to higher morbidity and mortality in older adults. Previous studies have demonstrated shared mechanisms between insulin resistance, inflammation, and frailty. The purpose of this trial is to determine whether metformin prevents frailty in non-frail, community-dwelling older adults (≥65 years) with pre-diabetes, determined by 2-hour oral glucose tolerance test (OGTT). Frail individuals (Fried criteria) and those with renal impairment (glomerular filtration rate &lt;45 mL/min) are excluded. Eligible participants are randomized to metformin or placebo and followed for two years. The primary outcome is frailty; secondary outcomes include physical function (short physical performance battery), systemic and skeletal muscle inflammation (plasma and muscle inflammatory markers), muscle insulin signaling (muscle biopsy), insulin sensitivity (insulin clamp), glucose tolerance (OGTT), and body composition (dual-energy x-ray absorptiometry) measurements. Participants are followed every 3 months for safety assessments, every 6 months for frailty assessment and OGTT, and every 12 months for muscle biopsy. Currently, 99 participants, including 53 (53.5%) male and 91 (91.9%) white, are active (54) or have completed the study (35). At baseline, mean age was 72.3 ± 5.5 years, body mass index was 30.7 ± 5.9 kg/m2, and Hemoglobin A1c was 5.73 ± 0.37%. Mean frailty score was 0.5 ± 0.6 and the proportion of non-frail and pre-frail participants were 58.6% (n = 58) and 41.5% (n = 41), respectively. Findings of this clinical trial may have future implications for the use of metformin in older adults with pre-diabetes in order to prevent the onset of frailty.

Diagnostic Value of Dystrophin Immunostaining in the Diagnosis of Duchenne and Becker Muscular Dystrophy Patients

Background: Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are X-linked recessive muscular disorders caused by the absence or reduction of the muscle cytoskeletal protein dystrophin. Standard procedures to detect deletion and duplication of the DMD gene use Multiplex Ligation-Dependent Probe Amplification (MLPA). However, genetic testing, such as MLPA, is not covered by the national insurance scheme in Indonesia. Immunohistochemical (IHC) staining of dystrophin from muscle biopsy in the form of Formalin-Fixed Paraffin-Embedded (FFPE) specimens can be an alternative method to detect dystrophin expression in protein levels to establish the diagnosis of DMD or BMD. Objectives: To determinate sensitivity, specificity and accuracy of IHC analysis of dystrophin in DMD/BMD patient in comparison with the standard genetic testing, MLPA. Methods: Twenty-six patients enrolled in this study were clinically diagnosed as DMD/BMD in Dr. Sardjito Hospital and Universitas Gadjah Mada Academic Hospital. Genomic DNA was isolated from 3 mL of EDTA-peripheral whole blood samples. The deletion and duplication of DMD genes were detected by MLPA. IHC examination was performed using a specific antibody dystrophin (DYS2). Complete loss of dystrophin staining indicated DMD, while partial loss of dystrophin staining indicated BMD. MLPA result was used as the gold standard to determine sensitivity, specificity, and accuracy of IHC technique using a 2x2 table. Results: MLPA results revealed 18 (18/26; 69.3%) patients with deletion and 3 (3/26; 11.5%) patients with duplication. Five (5/26; 19.2%) patients who showed no deletion nor duplication were excluded from the analysis. Among 21 patients with deletion or duplication, 18 (18/21; 85.7%) patients were out-of-frame (DMD) and 3 (3/21; 14.3%) patients were in-frame (BMD). Six patients showed a discrepancy between the IHC and MLPA results with 9.5% (2/21) false positive and 19% (4/21) false negative. The sensitivity of dystrophin IHC was 77.78%, specificity 33.33%, positive predictive value 87.5%, negative predictive value 20%, and accuracy 71.43%. Conclusion: Muscle biopsy followed by IHC can be one of the diagnostic tools to diagnose BMD or DMD, with high sensitivity. The protein-based strategy is probably the most efficient way to approach the diagnosis of Duchenne and Becker muscular dystrophy in limited health care settings.

A Rare Case of Sporadic Inclusion Body Myositis with Atypical Presentation

Sporadic inclusion body myositis (IBM) is the most common acquired inflammatory myopathy that occurs after the age of 50 years. IBM typically involves wrist and finger flexors and quadriceps, but all sporadic IBM may not have the classic presentation of distal arm and proximal leg involvement. Treating physicians must be aware of this atypical presentation to avoid the misdiagnosis of IBM, leading to treatment with immunosuppressive agents. The aim of this study is to increase the awareness among physicians about the atypical presentation of IBM and to emphasize the importance of muscle biopsy in such cases. Here we report a case of 52 years old male diagnosed with sporadic IBM by muscle biopsy presented with atypical presentation.

Sickle Cell Disease with Dermatomyositis - a Rare and Complex Comorbidity

Introduction and Case Presentation - A 4 yrs old female with sickle cell disease (SCD) and intermittent asthma presented with polyarthralgia predominantly involving bilateral hip and knee joints and became non-ambulatory over a course of 2 months. She developed chronic facial swelling, and a pruritic erythematous rash involving face, extensor surface of the hand and the right knee with significant weight loss. Physical examination was significant for heliotropic rash on the eyelids, Also present were Gottron's papules and macules on both hands and right knee along with right leg tenderness, muscle weakness, wasting and decreased range of motion at bilateral hip joints along with inguinal lymphadenopathy. Investigations were significant for severe anemia with hyperactive bone marrow, metabolic acidosis, normonatremic dehydration with absence of any evidence of an ongoing infectious process. Her Anti Nucleic acid antibody (ANA) panel, Aldolase, Rheumatoid factor and Angiotensin-1-Converting Enzyme levels were unremarkable. Creatine kinase levels were near normal. Her Neopterin and LDH levels were significantly elevated. Imaging with MRI scan with multiplanar multisequence of bilateral lower extremities and Pelvis showed significant diffuse myositis and soft tissue swelling. The diagnostic criterion for Juvenile Dermatomyositis include: (1) the typical pathognomonic rashes, (2) elevated muscle enzymes, (3) symmetric proximal muscle weakness and neck flexors, (4) muscle biopsy characteristic of juvenile dermatomyositis, and (5) EMG findings characteristic of juvenile dermatomyositis. Having ruled out an infectious process a muscle biopsy was performed, which also was subjected to Electron Microscopic (EM) analysis as the patient did not have extremely high muscle enzymes, necessitating a muscle biopsy . Hematoxylin & eosin stained sections were compatible with inflammatory myopathy. Ultrastructural examination demonstrated myofiber size variability, frequent rounded atrophic fibers with myofibrillar disarray, internalized nuclei, and increased interstitial collagen deposition. Endomysial capillaries were decreased in number, but showed reactive endothelial changes. Some showed prominent endothelial tubuloreticular inclusions (Figure),characteristic of JD. In summary, absence of serologic and tissue evidence of any other inflammatory myopathy, offending pharmacotherapy, infectious disease and presence of imaging and tissue evidence (vascular injury and tubuloreticular inclusions) comprised the work up of a child with SCD with Dermatomyositis. Management- Prompt treatment with prednisone (2 mg/kg/day), methotrexate (10 mg) weekly and monthly IVIG (2gm/kg/dose) infusions was started, once diagnosis was confirmed showing a dramatic clinical response. Prednisone was slowly tapered after 1 month of treatment. She showed gradual improvement in her symptoms, the strength in proximal muscle in both upper and lower limbs improved eventually to a point where the contractures in the elbows and knees improved and she started ambulating without support. Patient's Hydroxyurea was restarted at a low dose of 15mg/kg/day and increased to 20 mg/kg/day slowly, as her systemic symptoms of Dermatomyositis subsided. Discussion- Working up a child with SCD who presents with sudden onset non weight bearing can be complicated. Vaso-occlusive bony pain crisis , Osteomyelitis , septic arthritis are common clinical scenarios, but an underlying rheumatologic illness in pediatric SCD patient mimicking a sickle cell pain crisis presents a unique diagnostic challenge one which, albeit has been reported in literature, but rarely includes electron microscopic ultrastructural examination as part of evidence and work up. This patient's relatively mild muscle enzyme elevation and Hydroxyurea therapy made the initial diagnosis more challenging. We present the first pediatric SCD patient with clinically and pathologically proven case of Dermatomyositis with EM evidence, highlighting a unique clinical scenario ,diagnostic challenges and management strategies. Figure 1 Figure 1. Disclosures Jain: Octapharma: Consultancy; CSL Behring: Consultancy, Speakers Bureau; GBT: Consultancy; Blue Bird Bio: Consultancy; Takeda: Consultancy, Speakers Bureau.