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1.
Sci Rep ; 14(1): 19523, 2024 08 22.
Artículo en Inglés | MEDLINE | ID: mdl-39174610

RESUMEN

Mechanical ventilation in myasthenic crisis is not standardized and is at high risk of failure. We investigated liberation from mechanical ventilation during myasthenic crisis using a prolonged spontaneous breathing trials (SBT) and sequential pulmonary function tests (PFT). In this retrospective monocenter study, we included patients admitted for a first episode of myasthenic crisis between January 2001 and January 2018. The primary outcome was the incidence of weaning failure upon first extubation in our cohort of patients with MC. Secondary objectives were to determine risk factors and outcome associated with weaning failure upon first extubation in MC. We also compared the characteristics of patients with prolonged weaning. 126 episodes of MC were analyzed. Patient's age was 64 [42-76] years with 72/126 (56.5%) being women. The median delay between weaning initiation and first extubation was 6 [3-10] days and the median total length of MV was 14 [10-23] days. 118/126 (93.7%) patients underwent prolonged SBT of 8 h or more prior to first extubation. The overall weaning failure rate was 18/126 (14.3%). Extubation was more often successful when the factor precipitating the myasthenic crisis was identified (86/108 (79.6%) vs. 8/18 (44.4%); p = 0.004), whereas PFT was similar in failure or successes. Most weaning failures upon first extubation attempt (11/18; 61%) were attributed to an insufficient stabilization of myasthenia gravis. Duration of mechanical ventilation, an infectious trigger and maximal inspiratory pressure upon intubation were independent risk factors for prolonged weaning. In myasthenic crisis, a standardized protocol including prolonged SBT and respiratory function tests might improve the success of first extubation without prolonging mechanical ventilation. The results of this single center study warrant further evaluation in interventional trials.


Asunto(s)
Miastenia Gravis , Respiración Artificial , Desconexión del Ventilador , Humanos , Femenino , Masculino , Miastenia Gravis/terapia , Miastenia Gravis/fisiopatología , Persona de Mediana Edad , Estudios Retrospectivos , Anciano , Adulto , Respiración Artificial/métodos , Respiración Artificial/efectos adversos , Pruebas de Función Respiratoria , Factores de Riesgo
2.
Neuromuscul Disord ; 41: 29-34, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38870650

RESUMEN

Decreased cough strength in myasthenia gravis (MG) leads to aspiration and increases the risk of MG crisis. The aim of this study was to clarify the reliability and validity of cough peak flow (CPF) measurements in MG. A total of 26 patients with MG who underwent CPF measurements using the peak flow meter by themselves were included. MG symptoms were evaluated by pulmonary function tests and clinical MG assessment scales before and after immune-treatments. The relationship between CPF and pulmonary function tests and MG comprehensive were assessed. The cut-off value of CPF for aspiration risk was determined and the area under the curve (AUC) was calculated. The intraclass correlation coefficient was more than 0.95 for pre-and post-treatment. Positive correlations were found between CPF and almost all spirometric values as well as between the differences of pre-and post-treatment in CPF and quantitative myasthenia gravis score. The CPF for identifying the aspiration risk was used to calculate the CPF cut-off value of 205 L/min with a sensitivity of 0.77, specificity of 0.90, and AUC of 0.85. The CPF, a convenient measure by patients themselves, has a high reliability in patients with MG, and is a useful biomarker reflecting MG symptoms.


Asunto(s)
Tos , Miastenia Gravis , Humanos , Miastenia Gravis/fisiopatología , Miastenia Gravis/diagnóstico , Masculino , Femenino , Persona de Mediana Edad , Tos/fisiopatología , Reproducibilidad de los Resultados , Adulto , Anciano , Ápice del Flujo Espiratorio , Pruebas de Función Respiratoria , Sensibilidad y Especificidad
3.
Neuromuscul Disord ; 40: 1-6, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38776756

RESUMEN

Patients with myasthenia gravis (MG) can present with respiratory dysfunction, ranging from exercise intolerance to overt respiratory failure, increased fatigue, or sleep-disordered breathing. To investigate the value of multiple respiratory tests in MG, we performed clinical and respiratory assessments in patients with mild to moderate generalized disease. One-hundred and thirty-six patients completed the myasthenia gravis quality-of-life score(MG-QOL-15), myasthenia gravis impairment index(MGII), Epworth sleepiness scale(ESS), University of California-San Diego Shortness of Breath Questionnaire(UCSD-SOB), Modified Medical Research Council Dyspnea Scales(MRC-DS), supine and upright forced vital capacity(FVC), maximal inspiratory pressures(MIPs) and sniff nasal inspiratory pressures(SNIP). Seventy-three (54 %) had respiratory and/or bulbar symptoms and 45 (33 %) had baseline abnormal FVC, with no significant postural changes (p = 0.89); 55 (40.4 %) had abnormal MIPs and 50 (37 %) had abnormal SNIPs. Overall, there were low scores on respiratory and disability scales. Females had increased odds of presenting with abnormal FVC (OR 2.89, p = 0.01) and MIPs (OR 2.48, p = 0.022). There were significant correlations between MIPs, FVC and SNIPs; between MGII/MG-QOL15 and UCSD-SOB/MRC-DS and between ESS and respiratory scales in the whole group. Our data suggests that office-based respiratory measurements are a useful screening method for stable MG patients, even when presenting with minimal respiratory symptoms and no significant disability.


Asunto(s)
Miastenia Gravis , Calidad de Vida , Pruebas de Función Respiratoria , Humanos , Miastenia Gravis/fisiopatología , Miastenia Gravis/diagnóstico , Femenino , Masculino , Persona de Mediana Edad , Adulto , Anciano , Capacidad Vital , Encuestas y Cuestionarios
4.
J Neurol ; 271(8): 5035-5045, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38796801

RESUMEN

BACKGROUND AND OBJECTIVES: The diagnostic challenge of myasthenia gravis (MG) is exacerbated by the variable efficacy of current testing methodologies, necessitating innovative approaches to accurately identify the condition. This study aimed to assess ocular muscle fatigue in patients with MG using video-oculography (VOG) by examining repetitive saccadic eye movements and comparing these metrics to those of healthy control participants. METHODS: This prospective, cross-sectional study was conducted at a tertiary care center and involved 62 patients diagnosed with MG (48 with ocular MG and 14 with generalized MG) and a control group of 31 healthy individuals, matched for age and sex. The assessment involved recording saccadic eye movements within a ± 15° range, both horizontally and vertically, at a rate of 15 saccades per minute over a 5-min period, resulting in 75 cycles. Participants were afforded a 3-min rest interval between each set to mitigate cumulative fatigue. The primary outcome was the detection of oculomotor fatigue, assessed through changes in saccadic waveforms, range, peak velocity, latency, and the duration from onset to target, with a focus on comparing the second saccade against the average of the last five saccades. RESULTS: In the evaluation of repetitive saccadic movements, patients with MG exhibited a reduced saccadic range and a prolonged duration to reach the target, compared to healthy subjects. Furthermore, a significant elevation in the frequency of multistep saccades was observed among MG patients, with a marked rise observed over consecutive trials. Receiver operating characteristic (ROC) analysis revealed the discriminative performance of multistep saccade frequency, in conjunction with variations in saccadic range and duration from onset to target achievement between the second saccade and the mean of the final five saccades, as effective in distinguishing MG patients from healthy subjects. Although alterations in peak saccadic velocity and latency were less pronounced, they were nevertheless detectable. DISCUSSION: The utilization of VOG for repetitive saccadic testing in the diagnosis of MG has demonstrated considerable diagnostic precision. This methodology affords significant accuracy in evaluating ocular muscle fatigue in MG patients, providing class III evidence supportive of its clinical application.


Asunto(s)
Miastenia Gravis , Movimientos Sacádicos , Humanos , Miastenia Gravis/diagnóstico , Miastenia Gravis/fisiopatología , Miastenia Gravis/complicaciones , Masculino , Femenino , Movimientos Sacádicos/fisiología , Estudios Transversales , Persona de Mediana Edad , Adulto , Estudios Prospectivos , Anciano , Fatiga Muscular/fisiología , Trastornos de la Motilidad Ocular/diagnóstico , Trastornos de la Motilidad Ocular/fisiopatología , Trastornos de la Motilidad Ocular/etiología , Curva ROC , Grabación en Video
5.
Eye (Lond) ; 38(12): 2422-2436, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38789789

RESUMEN

Myasthenia gravis (MG) is one of the most well characterised autoimmune disorders affecting the neuromuscular junction with autoantibodies targeting the acetylcholine receptor (AChR) complex. The vast majority of patients present with ocular symptoms including double vision and ptosis, but may progress on to develop generalised fatiguable muscle weakness. Severe involvement of the bulbar muscles can lead to dysphagia, dysarthria and breathing difficulties which can progress to myasthenic crisis needing ventilatory support. Given the predominant ocular onset of the disease, it is important that ophthalmologists are aware of the differential diagnosis, investigations and management including evolving therapies. When the disease remains localised to the extraocular muscles (ocular MG) IgG1 and IgG3 antibodies against the AChR (including clustered AChR) are present in nearly 50% of patients. In generalised MG this is seen in nearly 90% patients. Other antibodies include those against muscle specific tyrosine kinase (MuSK) and lipoprotein receptor related protein 4 (LRP4). Even though decremental response on repetitive nerve stimulation is the most well recognised neurophysiological abnormality, single fibre electromyogram (SFEMG) in experienced hands is the most sensitive test which helps in the diagnosis. Initial treatment should be using cholinesterase inhibitors and then proceeding to immunosuppression using corticosteroids and steroid sparing drugs. Patients requiring bulbar muscle support may need rescue therapies including plasma exchange and intravenous immunoglobulin (IVIg). Newer therapeutic targets include those against the B lymphocytes, complement system, neonatal Fc receptors (FcRn) and various other elements of the immune system.


Asunto(s)
Inhibidores de la Colinesterasa , Miastenia Gravis , Humanos , Miastenia Gravis/diagnóstico , Miastenia Gravis/terapia , Miastenia Gravis/fisiopatología , Inhibidores de la Colinesterasa/uso terapéutico , Autoanticuerpos , Receptores Colinérgicos/inmunología , Inmunosupresores/uso terapéutico , Intercambio Plasmático
7.
Pediatr Neurol ; 156: 10-14, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38688232

RESUMEN

BACKGROUND: Juvenile myasthenia gravis (JMG) is a rare autoimmune disease that causes fatigable muscle weakness in children aged <18 years. There is currently no curative treatment or internationally accepted standard of care for JMG. The objective is to investigate relationships between clinical presentation, antibody status, severity of disease onset, electrodiagnostic evaluation, and response to therapy in JMG. METHODS: This study was a retrospective chart review. Congenital myasthenic syndromes were excluded. Data on demographics, treatments, and outcomes were collected. Disease severity was evaluated using Myasthenia Gravis Foundation of America (MGFA) clinical classifications. RESULTS: We identified 84 patients with JMG at Children's Medical Center Dallas between January 2014 and February 2022. It was found that 52% of patients presented with ocular JMG (median onset age 4.5 years) and 48% with generalized JMG (median onset age 11.5 years); 81% tested positive for acetylcholine receptor antibodies. Patients were 17% non-Hispanic white, 29% Hispanic, 39% black, and 12% Asian. There was a significant difference in average MGFA scores between ethnicities (P = 0.047) and age groups (P = 0.004), with postpubertal patients having higher average MGFA scores than prepubertal patients. Seventy-one percent of patients who underwent thymectomy experienced a decrease in MGFA scores postprocedure. CONCLUSIONS: Our study showed that there were significant differences in disease severity between ethnicities and age groups and that most patients who underwent thymectomy showed clinical improvement. These outcomes highlight the need for additional therapies in the treatment of JMG and the importance of extending clinical trials to the pediatric population.


Asunto(s)
Miastenia Gravis , Humanos , Miastenia Gravis/terapia , Miastenia Gravis/diagnóstico , Miastenia Gravis/fisiopatología , Niño , Masculino , Femenino , Estudios Retrospectivos , Texas , Adolescente , Preescolar , Resultado del Tratamiento , Timectomía , Índice de Severidad de la Enfermedad , Edad de Inicio
8.
Eur J Neurosci ; 59(12): 3292-3308, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38650308

RESUMEN

Muscle-specific kinase myasthenia gravis (MuSK MG) is caused by autoantibodies against MuSK in the neuromuscular junction (NMJ). MuSK MG patients have fluctuating, fatigable skeletal muscle weakness, in particular of bulbar muscles. Severity differs greatly between patients, in spite of comparable autoantibody levels. One explanation for inter-patient and inter-muscle variability in sensitivity might be variations in compensatory muscle responses. Previously, we developed a passive transfer mouse model for MuSK MG. In preliminary ex vivo experiments, we observed that muscle contraction of some mice, in particular those with milder myasthenia, had become partially insensitive to inhibition by µ-Conotoxin-GIIIB, a blocker of skeletal muscle NaV1.4 voltage-gated sodium channels. We hypothesised that changes in NaV channel expression profile, possibly co-expression of (µ-Conotoxin-GIIIB insensitive) NaV1.5 type channels, might lower the muscle fibre's firing threshold and facilitate neuromuscular synaptic transmission. To test this hypothesis, we here performed passive transfer in immuno-compromised mice, using 'high', 'intermediate' and 'low' dosing regimens of purified MuSK MG patient IgG4. We compared myasthenia levels, µ-Conotoxin-GIIIB resistance and muscle fibre action potential characteristics and firing thresholds. High- and intermediate-dosed mice showed clear, progressive myasthenia, not seen in low-dosed animals. However, diaphragm NMJ electrophysiology demonstrated almost equal myasthenic severities amongst all regimens. Nonetheless, low-dosed mouse diaphragms showed a much higher degree of µ-Conotoxin-GIIIB resistance. This was not explained by upregulation of Scn5a (the NaV1.5 gene), lowered muscle fibre firing thresholds or histologically detectable upregulated NaV1.5 channels. It remains to be established which factors are responsible for the observed µ-Conotoxin-GIIIB insensitivity and whether the NaV repertoire change is compensatory beneficial or a bystander effect.


Asunto(s)
Músculo Esquelético , Animales , Ratones , Músculo Esquelético/metabolismo , Músculo Esquelético/efectos de los fármacos , Proteínas Tirosina Quinasas Receptoras/metabolismo , Humanos , Miastenia Gravis/metabolismo , Miastenia Gravis/fisiopatología , Miastenia Gravis/inmunología , Modelos Animales de Enfermedad , Femenino , Receptores Colinérgicos/metabolismo , Receptores Colinérgicos/inmunología , Canales de Sodio Activados por Voltaje/metabolismo , Unión Neuromuscular/metabolismo , Unión Neuromuscular/efectos de los fármacos , Autoanticuerpos , Masculino , Conotoxinas/farmacología , Inmunización Pasiva
9.
Neurology ; 102(10): e209395, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38669629

RESUMEN

BACKGROUND AND OBJECTIVES: We developed repetitive ocular vestibular-evoked myogenic potentials (roVEMP) as an electrophysiologic test that allows us to elicit the characteristic decrement of extraocular muscles in patients with ocular myasthenia gravis (OMG). Case-control studies demonstrated that roVEMP reliably differentiates patients with OMG from healthy controls. We now aimed to evaluate the diagnostic accuracy of roVEMP for OMG diagnosis in patients with ptosis and/or diplopia. METHODS: In this blinded prospective diagnostic accuracy trial, we compared roVEMP in 89 consecutive patients presenting with ptosis and/or diplopia suspicious of OMG with a multimodal diagnostic approach, including clinical examination, antibodies, edrophonium testing, repetitive nerve stimulation of accessory and facial nerves, and single-fiber EMG (SFEMG). We calculated the roVEMP decrement as the ratio between the mean of the first 2 responses compared with the mean of the sixth-ninth responses in the train and used cutoff of >9% (unilateral decrement) in a 30 Hz stimulation paradigm. RESULTS: Following a complete diagnostic work-up, 39 patients (44%) were diagnosed with ocular MG, while 50 patients (56%) had various other neuro-ophthalmologic conditions, but not MG (non-MG). roVEMP yielded 88.2% sensitivity, 30.2% specificity, 50% positive predictive value (PPV), and 76.5% negative predictive value (NPV). For comparison, SFEMG resulted in 75% sensitivity, 56% specificity, 55.1% PPV, and 75.7% NPV. All other diagnostic tests (except for the ice pack test) also yielded significantly higher positive results in patients with MG compared with non-MG. DISCUSSION: The study revealed a high sensitivity of 88.2% for roVEMP in OMG, but specificity and PPV were too low to allow for the OMG diagnosis as a single test. Thus, differentiating ocular MG from other neuro-ophthalmologic conditions remains challenging, and the highest diagnostic accuracy is still obtained by a multimodal approach. In this study, roVEMP can complement the diagnostic armamentarium for the diagnosis of MG. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that in patients with diplopia and ptosis, roVEMP alone does not accurately distinguish MG from non-MG disorders. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov: NCT03049956.


Asunto(s)
Blefaroptosis , Diplopía , Miastenia Gravis , Potenciales Vestibulares Miogénicos Evocados , Humanos , Miastenia Gravis/diagnóstico , Miastenia Gravis/fisiopatología , Miastenia Gravis/complicaciones , Masculino , Femenino , Diplopía/diagnóstico , Diplopía/fisiopatología , Diplopía/etiología , Persona de Mediana Edad , Potenciales Vestibulares Miogénicos Evocados/fisiología , Adulto , Blefaroptosis/diagnóstico , Blefaroptosis/fisiopatología , Blefaroptosis/etiología , Anciano , Estudios Prospectivos , Electromiografía/métodos , Sensibilidad y Especificidad , Músculos Oculomotores/fisiopatología , Adulto Joven
11.
J Neurol ; 271(5): 2824-2839, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38421419

RESUMEN

BACKGROUND: Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune-mediated neuromuscular disorder leading to muscle weakness, autonomic dysregulation and hyporeflexia. Psychosocial well-being is affected. Previously, we assessed burden of disease for Myasthenia gravis (MG). Here, we aim to elucidate burden of disease by comparing health-related quality of life (HRQoL) of patients with LEMS to the general population (genP) as well as MG patients. METHODS: A questionnaire-based survey included sociodemographic and clinical data along with standardized questionnaires, e.g. the Short Form Health (SF-36). HRQoL was evaluated through matched-pairs analyses. Participants from a general health survey served as control group. RESULTS: 46 LEMS patients matched by age and gender were compared to 92 controls from the genP and a matched cohort of 92 MG patients. LEMS participants showed lower levels of physical functioning (SF-36 mean 34.2 SD 28.6) compared to genP (mean 78.6 SD 21.1) and MG patients (mean 61.3 SD 31.8). LEMS patients showed lower mental health sub-scores compared to genP (SF-36 mean 62.7 SD 20.2, vs. 75.7 SD 15.1) and MG patients (SF-36 mean 62.7 SD 20.2, vs. 66.0 SD 18.). Depression, anxiety and fatigue were prevalent. Female gender, low income, lower activities of daily living, symptoms of depression, anxiety and fatigue were associated with a lower HRQoL in LEMS. DISCUSSION: HRQoL is lower in patients with LEMS compared to genP and MG in a matched pair-analysis. The burden of LEMS includes economic and social aspects as well as emotional well-being. TRIAL REGISTRATION INFORMATION: drks.de: DRKS00024527, submitted: February 02, 2021, https://drks.de/search/en/trial/DRKS00024527 .


Asunto(s)
Costo de Enfermedad , Síndrome Miasténico de Lambert-Eaton , Calidad de Vida , Humanos , Síndrome Miasténico de Lambert-Eaton/fisiopatología , Síndrome Miasténico de Lambert-Eaton/complicaciones , Síndrome Miasténico de Lambert-Eaton/epidemiología , Masculino , Femenino , Persona de Mediana Edad , Anciano , Adulto , Miastenia Gravis/complicaciones , Miastenia Gravis/psicología , Miastenia Gravis/fisiopatología , Miastenia Gravis/epidemiología
13.
J Korean Med Sci ; 37(10): e50, 2022 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-35289135

RESUMEN

As coronavirus disease 2019 (COVID-19) has spread worldwide, the rate of COVID-19 vaccination uptake is encouraging. Neurological complications associated with COVID-19 vaccines such as stroke, Guillain-Barré syndrome, and Bell's palsy have been reported. Recently, late-onset myasthenia gravis (MG) following COVID-19 vaccination has been reported. To date, however, there has been no evidence of increased risk of early-onset MG following COVID-19. Here, we report a case of a patient with new-onset MG that arose after receiving a COVID-19 vaccine. A 33-year-old woman suddenly experienced generalized weakness and diplopia on the evening she had received the second dose of the Pfizer-BioNTech COVID-19 vaccine. The temporal relationship suggests that this new-onset MG is related to the vaccination. It also implies that COVID-19 vaccination could trigger early-onset MG symptoms in patients at risk of MG.


Asunto(s)
Vacuna BNT162/efectos adversos , Miastenia Gravis/etiología , Adulto , Electromiografía , Femenino , Humanos , Miastenia Gravis/diagnóstico , Miastenia Gravis/fisiopatología , Neostigmina/farmacología , República de Corea , Factores de Tiempo
14.
Isr Med Assoc J ; 24(1): 9-10, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35077038

RESUMEN

BACKGROUND: The Oxford-AstraZeneca vaccine ChAdOx1 (AZD1222, Vaxzevria) is playing a crucial role in counteracting the coronavirus disease-2019 (COVID-19) pandemic [1]. Since March 2021, reports of unexpected thrombotic events associated with thrombocytopenia and vaccination have been published [2]. To the best of our knowledge there is only one report about vaccination-associated myasthenia gravis (MG) occurring after a second dose of BNT162b2 (Pfizer-BioNTech).


Asunto(s)
COVID-19 , ChAdOx1 nCoV-19 , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/diagnóstico , Miastenia Gravis , Bromuro de Piridostigmina/administración & dosificación , Anciano , COVID-19/epidemiología , COVID-19/prevención & control , Vacunas contra la COVID-19/administración & dosificación , Vacunas contra la COVID-19/efectos adversos , Vacunas contra la COVID-19/inmunología , ChAdOx1 nCoV-19/administración & dosificación , ChAdOx1 nCoV-19/efectos adversos , ChAdOx1 nCoV-19/inmunología , Inhibidores de la Colinesterasa/administración & dosificación , Diagnóstico Diferencial , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/etiología , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/inmunología , Fiebre/etiología , Fiebre/terapia , Humanos , Masculino , Mialgia/etiología , Mialgia/terapia , Miastenia Gravis/diagnóstico , Miastenia Gravis/tratamiento farmacológico , Miastenia Gravis/inmunología , Miastenia Gravis/fisiopatología , SARS-CoV-2 , Resultado del Tratamiento
15.
PLoS One ; 16(12): e0261401, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34928978

RESUMEN

OBJECTIVES: To evaluate CT-derived radiomics for machine learning-based classification of thymic epithelial tumor (TET) stage (TNM classification), histology (WHO classification) and the presence of myasthenia gravis (MG). METHODS: Patients with histologically confirmed TET in the years 2000-2018 were retrospectively included, excluding patients with incompatible imaging or other tumors. CT scans were reformatted uniformly, gray values were normalized and discretized. Tumors were segmented manually; 15 scans were re-segmented after 2 weeks by two readers. 1316 radiomic features were calculated (pyRadiomics). Features with low intra-/inter-reader agreement (ICC<0.75) were excluded. Repeated nested cross-validation was used for feature selection (Boruta algorithm), model training, and evaluation (out-of-fold predictions). Shapley additive explanation (SHAP) values were calculated to assess feature importance. RESULTS: 105 patients undergoing surgery for TET were identified. After applying exclusion criteria, 62 patients (28 female; mean age, 57±14 years; range, 22-82 years) with 34 low-risk TET (LRT; WHO types A/AB/B1), 28 high-risk TET (HRT; WHO B2/B3/C) in early stage (49, TNM stage I-II) or advanced stage (13, TNM III-IV) were included. 14(23%) of the patients had MG. 334(25%) features were excluded after intra-/inter-reader analysis. Discriminatory performance of the random forest classifiers was good for histology(AUC, 87.6%; 95% confidence interval, 76.3-94.3) and TNM stage(AUC, 83.8%; 95%CI, 66.9-93.4) but poor for the prediction of MG (AUC, 63.9%; 95%CI, 44.8-79.5). CONCLUSIONS: CT-derived radiomic features may be a useful imaging biomarker for TET histology and TNM stage.


Asunto(s)
Algoritmos , Técnicas Histológicas/métodos , Aprendizaje Automático , Miastenia Gravis/fisiopatología , Neoplasias Glandulares y Epiteliales/patología , Neoplasias del Timo/patología , Tomografía Computarizada por Rayos X/métodos , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Miastenia Gravis/diagnóstico por imagen , Estadificación de Neoplasias , Neoplasias Glandulares y Epiteliales/diagnóstico por imagen , Neoplasias Glandulares y Epiteliales/cirugía , Estudios Retrospectivos , Neoplasias del Timo/diagnóstico por imagen , Neoplasias del Timo/cirugía , Adulto Joven
16.
Neuromuscul Disord ; 31(12): 1279-1281, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34690051

RESUMEN

Myasthenia gravis is a treatable autoimmune disease caused by autoantibodies directed against membrane proteins at the neuromuscular junction. While acetylcholine receptor antibodies are most common, a minority of patients have antibodies directed against muscle-specific kinase (MuSK-antibody). Differentiating features often include subacute onset and rapid progression of bulbar, respiratory and neck extensor muscles, with sparing of distal appendicular muscles, most commonly in middle-aged females. Here we present an atypical presentation of MuSK-antibody myasthenic syndrome in a young male consisting of a gradual-onset, insidiously-progressive, non-fatigable and non-fluctuating ocular, bulbar and oesophageal weakness, with a normal frontalis single fibre EMG. This case clinically resembled a mitochondrial myopathy (Mitochondrial Neurogastrointestinal Encephalopathy-MNGIE) with a poor prognosis. Because of the atypical presentation, MuSK antibodies were identified very late in the disease course, at which point the patient responded very well to immunotherapy. We report an unusual presentation of an uncommon but treatable condition, illustrating significant phenotypic heterogeneity possible in MuSK-antibody myasthenic syndrome.


Asunto(s)
Miastenia Gravis/diagnóstico , Proteínas Tirosina Quinasas Receptoras/inmunología , Receptores Colinérgicos/inmunología , Autoanticuerpos , Niño , Diagnóstico Diferencial , Humanos , Masculino , Miastenia Gravis/inmunología , Miastenia Gravis/fisiopatología
17.
Artículo en Inglés | MEDLINE | ID: mdl-34561276

RESUMEN

BACKGROUND AND OBJECTIVES: To investigate intrathymic B lymphopoiesis in patients with myasthenia gravis (MG) and explore thymus pathology associated with clinical impact. METHODS: Thymic lymphocytes from 15 young patients without MG, 22 adult patients without MG, 14 patients with MG without thymoma, and 11 patients with MG with thymoma were subjected to flow cytometry analysis of T follicular helper (Tfh), naive B, memory B, plasmablasts, CD19+B220high thymic B cells, B-cell activating factor receptor, and C-X-C chemokine receptor 5 (CXCR5). Peripheral blood mononuclear cells of 16 healthy subjects and 21 untreated patients with MG were also analyzed. Immunologic values were compared, and correlations between relevant values and clinical parameters were evaluated. RESULTS: The frequencies of circulating and intrathymic plasmablasts were significantly higher in patients with MG than controls. On the other hand, the frequency of CD19+B220high thymic B cells was not increased in MG thymus. We observed a significant increase in CXCR5 expression on plasmablasts in MG thymus and an increased frequency of intrathymic plasmablasts that was correlated with preoperative disease activity. The frequency of intrathymic Tfh cells was significantly lower in patients who received immunosuppressive (IS) therapy than those without IS therapy. However, there was no significant difference in the frequency of intrathymic plasmablasts irrespective of IS therapy. DISCUSSION: Our findings confirmed a correlation between increased frequency of intrathymic plasmablasts and disease activity before thymectomy. We postulate that activated intrathymic plasmablasts endow pathogenic capacity in MG.


Asunto(s)
Linfocitos B , Leucocitos Mononucleares , Linfopoyesis , Miastenia Gravis , Células Madre , Linfocitos T , Timoma , Neoplasias del Timo , Adolescente , Adulto , Anciano , Linfocitos B/inmunología , Niño , Preescolar , Femenino , Humanos , Leucocitos Mononucleares/inmunología , Masculino , Persona de Mediana Edad , Miastenia Gravis/sangre , Miastenia Gravis/inmunología , Miastenia Gravis/fisiopatología , Células Madre/inmunología , Linfocitos T/inmunología , Timectomía , Timoma/sangre , Timoma/inmunología , Timoma/fisiopatología , Neoplasias del Timo/sangre , Neoplasias del Timo/inmunología , Neoplasias del Timo/fisiopatología , Adulto Joven
18.
J Neuromuscul Dis ; 8(5): 831-844, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34334412

RESUMEN

BackgroundIn myasthenia gravis, impaired postsynaptic sensitivity to acetylcholine results in failure of neuromuscular transmission and fatiguing muscle weakness.ObjectiveDevelop an ex vivo muscle contraction assay to test cannabinoids and other substances that might act on the myasthenic neuromuscular junction to restore control of the muscle.MethodsTubocurarine was added to an ex vivo, mouse phrenic nerve-hemidiaphragm muscle preparation to reduce acetylcholine sensitivity. This produced a myasthenia-like decrement in twitch force during a train of 10 nerve impulses (3 / sec). Endplate potential (EPP) recordings were used to confirm and extend the findings.ResultsSurprisingly, addition to the bath of dimethylsulphoxide (DMSO), at concentrations as low as 0.1%(v/v), partially reversed the decrement in nerve-evoked force. Intracellular electrophysiology, conducted in the presence of tubocurarine, showed that DMSO increased the amplitudes of both the spontaneous miniature EPP (MEPP) and the (nerve-evoked) EPP. In the absence of tubocurarine (synaptic potentials at physiological levels), an adaptive fall in quantal content negated the DMSO-induced rise in EPP amplitude. The effects of cannabinoid receptor agonists (solubilized with DMSO) in the contraction assay do not support their further exploration as useful therapeutic agents for myasthenia gravis. CP 55,940 (a dual agonist for cannabinoid receptor types 1 and 2) reversed the beneficial effects of DMSO.Conclusions:We demonstrate a powerful effect of DMSO upon quantal amplitude that might mislead pharmacological studies of synaptic function wherever DMSO is used as a drug vehicle. Our results also show that compounds targeting impaired neuromuscular transmission should be tested under myasthenic-like conditions, so as to avoid confounding effects of synaptic homeostasis.


Asunto(s)
Cannabinoides/farmacología , Dimetilsulfóxido/farmacología , Homeostasis/efectos de los fármacos , Miastenia Gravis/fisiopatología , Potenciales de Acción , Animales , Diafragma/fisiopatología , Ratones , Placa Motora , Contracción Muscular , Unión Neuromuscular/efectos de los fármacos , Receptores Colinérgicos , Transmisión Sináptica/efectos de los fármacos , Tubocurarina/farmacología
19.
Muscle Nerve ; 64(4): 490-493, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34196418

RESUMEN

INTRODUCTION/AIMS: Ulnar nerve repetitive nerve stimulation (RNS) has been traditionally used in the electrophysiological evaluation of myasthenia gravis (MG). However, its low diagnostic sensitivity remains a limitation. Existing data may suggest that median nerve RNS outperforms that of the ulnar nerve, but a direct comparison is currently lacking. The aim of this study was to directly compare the diagnostic yields between median and ulnar nerve RNS in patients with generalized MG. METHODS: We performed a retrospective analysis of patients with MG who underwent median and ulnar nerve RNS at a single tertiary center. RESULTS: RNS studies of median nerve recording from the abductor pollicis brevis and ulnar nerve recording from the adductor digiti minimi were completed in 28 patients with generalized MG. Abnormal RNS was more frequently observed in the median compared with the ulnar nerve (60.7% vs 35.7%, P = .046). The average magnitude of decrement was higher in the median nerve compared with the ulnar nerve (17.3% vs 9.6%, P = .017). Differences between the median and ulnar nerve RNS studies were restricted to patients with mild manifestations (Myasthenia Gravis Foundation of America class II). DISCUSSION: Median nerve RNS has superior diagnostic sensitivity as compared with ulnar nerve RNS in the assessment of mild generalized MG.


Asunto(s)
Terapia por Estimulación Eléctrica/normas , Nervio Mediano/fisiología , Miastenia Gravis/diagnóstico , Miastenia Gravis/fisiopatología , Nervio Cubital/fisiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Terapia por Estimulación Eléctrica/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Adulto Joven
20.
Curr Rheumatol Rep ; 23(8): 63, 2021 07 03.
Artículo en Inglés | MEDLINE | ID: mdl-34216297

RESUMEN

PURPOSE: Myositis as a rare manifestation of COVID-19 is only recently being reported. This review examines the current literature on COVID-19-induced myositis focusing on etiopathogenesis, clinical presentations, diagnostic practices, and therapeutic challenges with immunosuppression, and the difficulties experienced by rheumatologists in established myositis in the COVID-19 era. RECENT FINDINGS: COVID-19 is associated with a viral myositis attributable to direct myocyte invasion or induction of autoimmunity. COVID-19-induced myositis may be varied in presentation, from typical dermatomyositis to rhabdomyolysis, and a paraspinal affliction with back pain. It may or may not present with acute exponential elevations of enzyme markers such as creatine kinase (CK). Virus-mediated muscle inflammation is attributed to ACE2 (angiotensin-converting enzyme) receptor-mediated direct entry and affliction of muscle fibers, leading on to innate and adaptive immune activation. A greater recognition of the stark similarity between anti-MDA5-positive myositis with COVID-19 has thrown researchers into the alley of exploration - finding common etiopathogenic basis as well as therapeutic strategies. For patients with established myositis, chronic care was disrupted during the pandemic with several logistic challenges and treatment dilemmas leading to high flare rates. Teleconsultation bridged the gap while ushering in an era of patient-led care with the digital transition to tools of remote disease assessment. COVID-19 has brought along greater insight into unique manifestations of COVID-19-related myositis, ranging from direct virus-induced muscle disease to triggered autoimmunity and other etiopathogenic links to explore. A remarkable shift in the means of delivering chronic care has led patients and caregivers worldwide to embrace a virtual shift with teleconsultation and opened doorways to a new era of patient-led care.


Asunto(s)
COVID-19/fisiopatología , Miositis/fisiopatología , Rabdomiólisis/fisiopatología , Inmunidad Adaptativa/inmunología , Enzima Convertidora de Angiotensina 2/metabolismo , Autoanticuerpos/inmunología , Dolor de Espalda/etiología , COVID-19/complicaciones , COVID-19/inmunología , COVID-19/metabolismo , Creatina Quinasa/metabolismo , Dermatomiositis/etiología , Dermatomiositis/inmunología , Dermatomiositis/metabolismo , Dermatomiositis/fisiopatología , Humanos , Inmunidad Innata/inmunología , Helicasa Inducida por Interferón IFIH1/inmunología , Miastenia Gravis/etiología , Miastenia Gravis/inmunología , Miastenia Gravis/metabolismo , Miastenia Gravis/fisiopatología , Miositis/etiología , Miositis/inmunología , Miositis/metabolismo , Músculos Paraespinales/fisiopatología , Receptores de Coronavirus/metabolismo , Rabdomiólisis/etiología , Rabdomiólisis/inmunología , Rabdomiólisis/metabolismo , SARS-CoV-2
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