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ABSTRACT: This update begins with a section on inflammatory myopathies covering inclusion body myositis in younger patients, the possibility of a pathogenic role for anti-cN1A antibodies, and a negative trial of arimoclomol in inclusion body myositis. The potential study of Janus kinase inhibitors in dermatomyositis is discussed as well as the possible role of targeted therapy for immune checkpoint inhibitor neuromuscular complications. Next, studies of disease-modifying or potential disease-modifying therapies for inherited myopathies are addressed including the encouraging follow-up study of gene replacement therapy for Duchenne muscular dystrophy (DMD), a negative trial of tamoxifen in DMD, and the complex topic of gene therapy for X-linked myotubular myopathy. A newly identified condition of muscular dystrophy from 3-hydroxy-3-methylglutaryl-CoA reductase mutations is addressed along with possible therapy. Other papers regarding GNE myopathy and long-term outcome of enzyme replacement therapy in infantile onset Pompe disease round out that section. Updates on the expanding spectra of anoctamin-5 myopathies, caveolinopathies, and congenital and mylagic myopathies from CACNA1S mutations follow as well as extensive discussion of Valosin containing protein proteinopathies, comprehensive management of Becker muscular dystrophy, and gastrointestinal complications in adult DMD.
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Doenças Musculares , Humanos , Doenças Musculares/diagnóstico , Doenças Musculares/genética , Doenças Musculares/terapiaRESUMO
Reduced skeletal muscle mass and oxidative capacity coexist in patients with pulmonary emphysema and are independently associated with higher mortality. If reduced cellular respiration contributes to muscle atrophy in that setting remains unknown. Using a mouse with genetically induced pulmonary emphysema that recapitulates muscle dysfunction, we found that reduced activity of succinate dehydrogenase (SDH) is a hallmark of its myopathic changes. We generated an inducible, muscle-specific SDH knockout mouse that demonstrates lower mitochondrial oxygen consumption, myofiber contractility, and exercise endurance. Respirometry analyses show that in vitro complex I respiration is unaffected by loss of SDH subunit C in muscle mitochondria, which is consistent with the pulmonary emphysema animal data. SDH knockout initially causes succinate accumulation associated with a down-regulated transcriptome but modest proteome effects. Muscle mass, myofiber type composition, and overall body mass constituents remain unaltered in the transgenic mice. Thus, while SDH regulates myofiber respiration in experimental pulmonary emphysema, it does not control muscle mass or other body constituents.
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Respiração Celular , Camundongos Knockout , Contração Muscular , Músculo Esquelético , Enfisema Pulmonar , Succinato Desidrogenase , Animais , Enfisema Pulmonar/metabolismo , Enfisema Pulmonar/genética , Enfisema Pulmonar/patologia , Enfisema Pulmonar/etiologia , Succinato Desidrogenase/metabolismo , Succinato Desidrogenase/genética , Camundongos , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Complexo II de Transporte de Elétrons/metabolismo , Complexo II de Transporte de Elétrons/genética , Modelos Animais de Doenças , Camundongos Transgênicos , Mitocôndrias Musculares/metabolismo , Mitocôndrias Musculares/patologia , Consumo de OxigênioRESUMO
ABSTRACT: X-linked myopathy with excessive autophagy is a rare disorder caused by a mutation in the vacuolar ATPase assembly factor gene which causes slowly progressive early onset proximal weakness and loss of ambulation by the age of 50-70 years. Electrodiagnostic (EDx) testing usually shows widespread complex repetitive and myotonic discharges, even in muscles unaffected clinically. We report a 65-year-old man who presented with progressive proximal weakness since his teenage years. Extensive workup over 30 years revealed inconclusive EDx and muscle histopathology findings. The diagnosis was finally made with genetic testing. Subsequent neuromuscular ultrasound was more informative of disease severity than repeat EDx and directed a muscle biopsy that showed an autophagic vacuolar myopathy and the novel identification of vacuoles in capillary endothelial cells. Although genetic testing is required for confirmation, in milder cases of X-linked myopathy with excessive autophagy, neuromuscular ultrasound may aid in diagnosis even when EDx findings are inconclusive.
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Doenças Genéticas Ligadas ao Cromossomo X , Músculo Esquelético , Doenças Musculares , Ultrassonografia , Humanos , Masculino , Idoso , Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico por imagem , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico , Doenças Musculares/genética , Doenças Musculares/diagnóstico por imagem , Doenças Musculares/diagnóstico , Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/patologia , Eletrodiagnóstico , Autofagia/genética , Testes GenéticosRESUMO
OBJECTIVE: Neurotoxic chemicals are suggested in the etiology of amyotrophic lateral sclerosis (ALS). We examined the association of environmental and occupational risk factors including persistent organochlorine pesticides (OCPs) and ALS risk among cases from the Centers for Disease Control and Prevention National ALS Registry and age, sex, and county-matched controls. METHODS: Participants completed a risk factor survey and provided a blood sample for OCP measurement. ALS cases were confirmed through the Registry. Conditional logistic regression assessed associations between ALS and risk factors including OCP levels. RESULTS: 243 matched case-control pairs (61.7% male, mean [SD] age = 62.9 [10.1]) were included. Fifteen of the 29 OCPs examined had sufficient detectable levels for analysis. Modest correlations of self-reported years of exposure to residential pesticide mixtures and OCP serum levels were found (p<.001). Moreover, occupational exposure to lead including soldering and welding with lead/metal dust and use of lead paint/gasoline were significantly related to ALS risk (OR = 1.77, 95% CI: 1.11-2.83). Avocational gardening was a significant risk factor for ALS (OR = 1.57, 95% CI: 1.04-2.37). ALS risk increased for each 10 ng/g of α-Endosulfan (OR = 1.42, 95% CI: 1.14-1.77) and oxychlordane (OR = 1.24, 95% CI: 1.01-1.53). Heptachlor (detectable vs. nondetectable) was also associated with ALS risk (OR = 3.57, 95% CI: 1.50-8.52). CONCLUSION: This national case-control study revealed both survey and serum levels of OCPs as risk factors for ALS. Despite the United States banning many OCPs in the 1970s and 1980s, their use abroad and long half-lives continue to exert possible neurotoxic health effects.
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Esclerose Lateral Amiotrófica , Exposição Ambiental , Sistema de Registros , Humanos , Esclerose Lateral Amiotrófica/epidemiologia , Esclerose Lateral Amiotrófica/sangue , Esclerose Lateral Amiotrófica/induzido quimicamente , Masculino , Feminino , Pessoa de Meia-Idade , Estudos de Casos e Controles , Idoso , Fatores de Risco , Exposição Ambiental/efeitos adversos , Exposição Ambiental/estatística & dados numéricos , Exposição Ocupacional/efeitos adversos , Exposição Ocupacional/estatística & dados numéricos , Praguicidas/sangue , Praguicidas/efeitos adversos , Estados Unidos/epidemiologiaRESUMO
Transthyretin amyloidosis (ATTR) is a condition defined by accumulation of insoluble transthyretin amyloid deposits in multiple organs, especially in the peripheral nerve and heart muscle. ATTR may result from transthyretin mutations (variant ATTR or ATTRv) or may occur with normal transthyretin genotype (wild type ATTR or ATTRwt). ATTRwt was previously known as "senile amyloidosis" and causes cardiomyopathy which may lead to heart failure with a preserved ejection fraction, affecting predominantly elderly men. The exact prevalence of ATTRwt in the general population remains unclear, but its occurrence may be underestimated in women. It was observed that a proportion of ATTRwt cardiomyopathy patients may develop slowly progressing neuropathy that is milder and indolent in comparison with typical progressive neuropathy associated with ATTRv. Furthermore, the causality of neuropathy is often uncertain in patients with ATTRwt. Neuropathy symptoms, including distal sensory loss, unsteadiness and (neuropathic) pain are common in elderly patients with multiple potential causes, and as ATTRwt patients are typically older, relatively high prevalence of peripheral neuropathy is expected with frequent comorbidities. Relatively high prevalence of ATTRwt in elderly population contrasts few documented cases of neuropathy caused by ATTRwt, and there is uncertainty whether ATTRwt neuropathy is an infrequent occurrence or a significant manifestation of multisystemic ATTRwt. We review neurologic and musculoskeletal manifestations of ATTRwt and present clinical features of a single center cohort of ATTRwt patients with suspected peripheral neuropathy.
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ABSTRACT: This update covers several articles on diagnosis and misdiagnosis of myasthenia gravis (MG), the role of complement in MG, and then an impressive number of recent treatment trials. There is a negative study on any corticosteroid-sparing effect of intravenous immunoglobulin. A number of positive studies are reviewed. Open-label extension studies of phase 3 trials showed benefit regarding quality of life with efgartigimod and in functional measures with ravulizumab. The phase 3 RAISE trial of zilucoplan, a self-administered complement C5 inhibitor, is covered as well as the MyCarinG trial of rozanolixizumab. The notion of using fast-acting therapies early in the course of MG is addressed. The last sections center on MG and Lambert-Eaton myasthenic syndrome as a consequence of immune checkpoint inhibitor therapy.
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Síndrome Miastênica de Lambert-Eaton , Miastenia Gravis , Humanos , Qualidade de Vida , Junção Neuromuscular , Miastenia Gravis/diagnóstico , Miastenia Gravis/tratamento farmacológico , Síndrome Miastênica de Lambert-Eaton/diagnóstico , Síndrome Miastênica de Lambert-Eaton/terapia , Inativadores do ComplementoRESUMO
Objective: To systematically evaluate post-exercise outcomes related to function and quality of life in people with ALS. Methods: PRISMA guidelines were used for identifying and extracting articles. Levels of evidence and quality of articles were judged based on The Oxford Centre for Evidence-based Medicine Levels of Evidence and the QualSyst. Outcomes were analyzed with Comprehensive Meta-Analysis V2 software, random effects models, and Hedge's G. Effects were examined at 0-4 months, up to 6 months, and > 6 months. Pre-specified sensitivity analyses were performed for 1) controlled trials vs. all studies and 2) ALSFRS-R bulbar, respiratory, and motor subscales. Heterogeneity of pooled outcomes was computed with the I2 statistic. Results: 16 studies and seven functional outcomes met inclusion for the meta-analysis. Of the outcomes explored, the ALSFRS-R demonstrated a favorable summary effect size and had acceptable heterogeneity and dispersion. While FIM scores demonstrated a favorable summary effect size, heterogeneity limited interpretations. Other outcomes did not demonstrate a favorable summary effect size and/or could not be reported due to few studies reporting outcomes. Conclusions: This study provides inconclusive guidance regarding exercise regimens to maintain function and quality of life in people with ALS due to study limitations (e.g., small sample size, high attrition rate, heterogeneity in methods and participants, etc.). Future research is warranted to determine optimal treatment regimens and dosage parameters in this patient population.
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ABSTRACT: This update begins with the results of a positive trial of intravenous immunoglobulin in dermatomyositis and a study of molecular and morphologic patterns in inclusion body myositis that may explain treatment refractoriness. Single center reports of muscular sarcoidosis and immune-mediated necrotizing myopathy follow. There is also a report of caveolae-associated protein 4 antibodies as a potential biomarker and cause of immune rippling muscle disease. The remainder covers updates on muscular dystrophies as well as congenital and inherited metabolic myopathies with an emphasis on genetic testing. Rare dystrophies, including one involving ANXA11 mutations and a series on oculopharyngodistal myopathy, are discussed.
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Doenças Autoimunes , Distrofias Musculares , Miosite de Corpos de Inclusão , Miosite , Humanos , Imunoglobulinas IntravenosasRESUMO
OBJECTIVE: To assess the efficacy and tolerability of tocilizumab in a multicenter, randomized, double-blind, placebo-controlled trial in refractory adult patients with dermatomyositis (DM) and polymyositis (PM). METHODS: Thirty-six subjects with probable or definite DM/PM were enrolled in a 6-month phase 2B clinical trial and randomized 1:1 to receive tocilizumab (8 mg/kg intravenously) or placebo every 4 weeks for 24 weeks. Eligible subjects had either a DM rash, a myositis-associated autoantibody or an adjudicated PM diagnosis. Active disease was defined by at least three of six abnormal core set measures (CSMs), including a manual muscle testing (MMT)-8 score of less than 136/150. If the MMT-8 score was greater than 136, then a cutaneous score of 3 or more (10 cm visual analogue scale) was required along with three additional abnormal CSMs indicating disease activity. The primary endpoint compared the Total Improvement Score (TIS) between both arms from week 4 to 24. Secondary outcomes included time to meeting minimal TIS improvement, changes in CSMs, time to worsening, steroid-sparing effect, proportion of subjects meeting more stringent improvement criteria, and safety outcomes. RESULTS: There was no significant difference (P = 0.86) in the TIS over 24 weeks between tocilizumab and placebo arms. The secondary endpoints of time to improvement (minimal, moderate, or major), time to worsening, CSM changes, safety outcomes, and steroid-sparing effect were also not significantly different between arms. CONCLUSION: Tocilizumab was safe and well tolerated but did not meet the primary or secondary efficacy outcomes in refractory DM and PM in this 24-week phase 2B study.
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ABSTRACT: We cover intensive care unit-acquired neuromuscular disorders associated with coronavirus disease 2019. Outcomes may be worse than expected in these patients, and there is some evidence that coronavirus disease 2019 causes myopathy directly. Corticosteroid regimens in Duchenne muscular dystrophy are addressed including outcomes in pulmonary and cardiac function. A recent article notes a continued diagnostic delay in Duchenne muscular dystrophy. An interesting report of a Canary Islands cohort of patients with oculopharyngeal muscular dystrophy is discussed. Features and clinical pearls related to a series of patients with limb-girdle muscle dystrophy R12 (anoctaminopathy) and a misdiagnosis of idiopathic inflammatory myopathy are provided. The last section on autoimmune myopathy includes articles on clinical and pathologic features associated with myositis-specific antibodies and dermatomyositis, the epidemiology of immune-mediated necrotizing myopathies (IMNMs) in Olmsted County, Minnesota, and features of a German cohort of hydroxy-3-methylglutaryl coenzyme A reductase-associated IMNM. A recent article proposes the benefit of early intravenous immunoglobulin use for adults with IMNM. We also highlight a report of 2 unusual cases of antisignal recognition particle myopathy presenting with asymmetric distal weakness.
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Doenças Autoimunes , COVID-19 , Doenças Musculares , Distrofia Muscular de Duchenne , Miosite , Autoanticorpos , COVID-19/complicações , Diagnóstico Tardio , Humanos , Músculo Esquelético/patologia , Doenças Musculares/patologia , Miosite/diagnóstico , Necrose/patologiaRESUMO
ABSTRACT: This update covers a number of treatment topics starting with Fc receptor inhibitors and the Federal Drug Administration approval of efgartigimod. Some uncertainties regarding the use of corticosteroids are addressed, namely the risk of exacerbation with initiation of treatment and how to taper. The presence and potential importance of antibody overshoot following plasmapheresis is noted and the evolving increase in usefulness of acetylcholine receptor antibodies in diagnosing ocular myasthenia. Several recent series and case reports regarding coronavirus 2019 and myasthenia gravis are reviewed. The topics of myasthenia gravis and pregnancy, and another look at thymectomy in MG are provided. Finally, a couple of case reports on Lambert-Eaton myasthenic syndrome concentrate on the ice pack test and an autoantibody association with paraneoplastic cerebellar degeneration and Lambert-Eaton myasthenic syndrome in the same patient.
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Síndrome Miastênica de Lambert-Eaton , Miastenia Gravis , Autoanticorpos , Humanos , Síndrome Miastênica de Lambert-Eaton/diagnóstico , Miastenia Gravis/complicações , Miastenia Gravis/diagnóstico , Miastenia Gravis/terapia , Junção Neuromuscular , Receptores ColinérgicosRESUMO
INTRODUCTION/AIMS: Critical illness myopathy (CIM) and critical illness polyneuropathy (CIP) are common disorders associated with substantial morbidity. Electrodiagnostic studies (EDx) are effective in diagnosing CIM/CIP and identifying mimicking conditions. We surveyed intensive care unit (ICU) providers to better understand their approach to ICU-acquired weakness (ICU-AW) and the perceived utility of EDx. METHODS: This was a single health system, Web-based survey of ICU providers. RESULTS: Survey responses were received from 52 providers with a response rate of 22.1%. Most providers were somewhat familiar with CIM/CIP and median perceived prevalence was 30-49%. The majority (92.3%) of providers had no standard evaluation approach for ICU-AW. Electrodiagnostic testing was commonly considered, but many providers obtained it infrequently in presumed CIM/CIP cases. Electrodiagnostic studies were used to rule out other causes of weakness or to confirm the diagnosis of CIM/CIP. Many providers ordered EDx within 1 wk of identifying weakness. Finally, EDx were overshadowed by personal experience as the most helpful management tool for ICU-AW. DISCUSSION: Overall, ICU providers perceive that CIM/CIP are commonly encountered, but they may not have a standard approach to evaluation. Clinical experience increased familiarity of ICU-AW and is central to management. EDx results are usually thought to be helpful, albeit not often ordered, and more study is needed to determine when implementation is of most assistance. Increasing education and developing institutional standards may lead to increased awareness and improved evaluation of CIM/CIP, but more study is needed to determine if algorithmic approaches would change patient outcomes.
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Doenças Musculares , Polineuropatias , Estado Terminal , Humanos , Unidades de Terapia Intensiva , Doenças Musculares/complicações , Polineuropatias/complicaçõesRESUMO
BACKGROUND/OBJECTIVE: Immune-mediated necrotizing myopathy (IMNM) is a subtype of myositis that is associated with a refractory phenotype and poorer prognosis. The aim of the study was to provide single large center experience of outcomes of intravenous immunoglobulin (IVIg) for patients with IMNM using longitudinally collected data. METHODS: This case series longitudinally evaluated 4 of the 6 myositis core set measures at baseline and at 3 and 6 months after IVIg on 20 adult IMNM patients from 2014 to 2019 at the University of Pittsburgh. We assessed patients for improvement in core set measures, prednisone dose, adverse effects, and by the "limited" ACR/EULAR 2016 myositis response criteria. The mean differences in CK and manual muscle testing (MMT-8) were compared using a paired t test. A clinically significant response was defined as a >10% absolute improvement in the MMT-8 and a >50% absolute reduction in serum CK at 6 months of IVIg. RESULTS: Intravenous immunoglobulin treatment was associated with marked improvement in IMNM patients, with 85% of patient meeting clinically significant response. The median (interquartile range) relative percent improvement in CK level was 96% (85%-98%) and in MMT was 29% (14%-36%) at 6 months.There was a significant reduction in the mean (SD) dose of prednisone at 6 months and had minimal adverse effects. In addition, with IVIg, most (13/14) patients had at least minimal improvement as per ACR/EULAR 2016 myositis response criteria. CONCLUSIONS: Based on objective, meaningful improvement in MMT-8 and CK as well as marked reduction in prednisone doses with acceptable tolerability, early implementation of IVIg should be considered in adult IMNM.
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Doenças Autoimunes , Doenças Musculares , Miosite , Doenças Autoimunes/diagnóstico , Doenças Autoimunes/tratamento farmacológico , Humanos , Imunoglobulinas Intravenosas/uso terapêutico , Miosite/diagnóstico , Miosite/tratamento farmacológicoRESUMO
ABSTRACT: This edition concentrates on inflammatory myopathies with reports of reclassification of polymyositis, cancer associations, evaluation of subclinical cardiac involvement, myositis-specific and -associated antibodies, and immune checkpoint inhibitor myositis. A number of reports address sporadic late-onset nemaline myopathy and point out its diagnostic difficulty and the importance of identifying an associated monoclonal gammopathy that is likely of clinical significance and may warrant aggressive immunotherapy. Finally, treatment of nondystrophic channelopathies is addressed.
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Gamopatia Monoclonal de Significância Indeterminada , Doenças Musculares , Miopatias da Nemalina , Miosite , Humanos , Fatores Imunológicos , Doenças Musculares/diagnóstico , Doenças Musculares/terapiaRESUMO
Amyotrophic lateral sclerosis is an adult-onset neurodegenerative disorder characterized by loss of motor neurons. Mitochondria are essential for neuronal survival but the developmental timing and mechanistic importance of mitochondrial dysfunction in sporadic ALS (sALS) neurons is not fully understood. We used human induced pluripotent stem cells and generated a developmental timeline by differentiating sALS iPSCs to neural progenitors and to motor neurons and comparing mitochondrial parameters with familial ALS (fALS) and control cells at each developmental stage. We report that sALS and fALS motor neurons have elevated reactive oxygen species levels, depolarized mitochondria, impaired oxidative phosphorylation, ATP loss and defective mitochondrial protein import compared with control motor neurons. This phenotype develops with differentiation into motor neurons, the affected cell type in ALS, and does not occur in the parental undifferentiated sALS cells or sALS neural progenitors. Our work demonstrates a developmentally regulated unifying mitochondrial phenotype between patient derived sALS and fALS motor neurons. The occurrence of a unifying mitochondrial phenotype suggests that mitochondrial etiology known to SOD1-fALS may applicable to sALS. Furthermore, our findings suggest that disease-modifying treatments focused on rescue of mitochondrial function may benefit both sALS and fALS patients.
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Esclerose Lateral Amiotrófica/patologia , Diferenciação Celular , Mitocôndrias/patologia , Neurônios Motores/patologia , Células-Tronco Neurais/patologia , Biópsia , Células Cultivadas , Fibroblastos , Humanos , Células-Tronco Pluripotentes Induzidas , Neurônios Motores/citologia , Neurônios Motores/metabolismo , Células-Tronco Neurais/citologia , Cultura Primária de Células , Espécies Reativas de Oxigênio/metabolismo , Pele/patologiaRESUMO
ABSTRACT: Myasthenia gravis associated with concurrent inflammatory myopathy is a rare but well-described syndrome, most often seen in patients with thymoma. We present a case of biopsy-proven granulomatous myositis associated with positive acetylcholine receptor binding, blocking, and modulating and antistriated antibodies, without clear clinical symptoms of myasthenia gravis and in the absence of thymoma. In addition, we include rarely reported neuromuscular ultrasound findings of granulomatous myositis in a patient without sarcoidosis. Inflammatory myopathy may precede development of myasthenia gravis in myasthenia gravis associated with concurrent inflammatory myopathy, and it is important to remain vigilant for symptoms suggestive of myasthenia gravis, especially in the presence of positive myasthenia-associated antibodies.
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Miastenia Gravis , Miosite , Timoma , Neoplasias do Timo , Humanos , Miastenia Gravis/complicações , Miosite/complicações , Miosite/diagnóstico por imagem , Receptores Colinérgicos , Timoma/complicações , Timoma/diagnóstico por imagemRESUMO
Patients with pulmonary emphysema often develop locomotor muscle dysfunction, which is independently associated with disability and higher mortality in that population. Muscle dysfunction entails reduced force generation capacity, which partially depends on fibers' oxidative potential, yet very little mechanistic research has focused on muscle respiration in pulmonary emphysema. Using a recently established animal model of pulmonary emphysema-driven skeletal muscle dysfunction, we found downregulation of SDHC (succinate dehydrogenase subunit C) in association with lower oxygen consumption and fatigue tolerance in locomotor muscles. Reduced SDH activity has been previously observed in muscles from patients with pulmonary emphysema, and we found that SDHC is required to support respiration in cultured muscle cells. Moreover, in vivo gain of SDH function in emphysema animals' muscles resulted in better oxygen consumption rate and fatigue tolerance. These changes correlated with a larger number of relatively more oxidative type 2-A and 2X fibers and a reduced amount of 2B fibers. Our data suggest that SDHC is a key regulator of respiration and fatigability in pulmonary emphysema-driven skeletal muscles, which could be impactful in developing strategies aimed at attenuating this comorbidity.
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Fadiga/enzimologia , Proteínas de Membrana/metabolismo , Músculo Esquelético/enzimologia , Consumo de Oxigênio , Enfisema Pulmonar/enzimologia , Animais , Modelos Animais de Doenças , Fadiga/genética , Fadiga/patologia , Fadiga/fisiopatologia , Proteínas de Membrana/genética , Camundongos , Camundongos Transgênicos , Músculo Esquelético/patologia , Músculo Esquelético/fisiopatologia , Enfisema Pulmonar/genética , Enfisema Pulmonar/patologia , Enfisema Pulmonar/fisiopatologiaRESUMO
ABSTRACT: This update covers recommendations for myasthenia gravis (MG) in patients with coronavirus 2019 disease as well as reports of the clinical features of patients with MG and coronavirus 2019. Updated advisory committee recommendations for the use of thymectomy in generalized MG are also provided. Other MG topics include lipoprotein receptor-4 and agrin antibody associations, factors influencing conversion of ocular to generalized MG, the use of rituximab for more recent onset disease, immunoglobulins for maintenance therapy, and fatigue and depression.
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COVID-19/complicações , Miastenia Gravis/complicações , Junção Neuromuscular/patologia , COVID-19/patologia , COVID-19/terapia , Humanos , Miastenia Gravis/tratamento farmacológico , Miastenia Gravis/patologia , Miastenia Gravis/terapia , TimectomiaRESUMO
ABSTRACT: Lambert-Eaton myasthenic syndrome (LEMS) is a presynaptic neuromuscular junction disorder, and dermatomyositis (DM) is an idiopathic inflammatory myopathy. LEMS and DM are uncommon conditions that can present similarly and are often associated with autoantibodies. Concomitant LEMS and DM have only been reported a few times, and most of those cases were paraneoplastic. We present the first reported case of a patient with antivoltage gated calcium channel antibody positive LEMS who subsequently developed DM with antitranscription intermediary factor 1-gamma (anti-TIF1-γ) antibodies. Interestingly, both conditions occurred without evidence of malignancy. This diagnosis of LEMS and DM with characteristic clinical, electrodiagnostic, and histopathological evidence led to a beneficial modification of the patient's therapeutic regimen. Due to the fact that overlapping concurrent neuromuscular conditions are rare, a high clinical suspicion is needed to identify, evaluate (including appropriate cancer screenings), and appropriately treat these patients.