-
Frontiers in Neurology 2020To estimate the jitter parameters (single-fiber electromyography) in myasthenia gravis patients mostly by electrical activation in , and muscles using a concentric...
To estimate the jitter parameters (single-fiber electromyography) in myasthenia gravis patients mostly by electrical activation in , and muscles using a concentric needle electrode. Between 2009 and 2019, a total of 97 myasthenia gravis patients, 52 male, and mean age 54 years were included. Any abnormal jitter parameter in individual muscles was 90.5% (), 88.5% (), and 86.6% (). Any jitter parameter combining and muscle was abnormal in 100% for the ocular, and in 92.9% for the generalized myasthenia gravis. The most abnormal muscle was for the generalized, and for the ocular myasthenia gravis. The decrement was abnormal in 78.4%, 85.9% for the generalized, and 25% for the ocular myasthenia gravis. The mean jitter ranged from 14.2 to 86 μs (mean 33.3 μs) for the ocular myasthenia gravis and from 14.4 to 220.4 μs (mean 66.3 μs) for the generalized myasthenia gravis. The antibody titers tested positive in 86.6%, 91.8% for the generalized, and 50% for the ocular myasthenia gravis. Thymectomy was done in 48.5%, thymoma was found in 19.6%, and myasthenic crisis occurred by 21.6%. The jitter parameters achieved a 100% abnormality in ocular myasthenia gravis if both the and muscles were tested. There was a high jitter abnormality in generalized myasthenia gravis cases with one muscle tested, with about a 2% increase in sensitivity when a second is added. Concentric needle electrode jitter had high sensitivity similar to the single fiber electrode (93.8%), followed by antibody titers (86.6%), and abnormal decrement (78.4%).
PubMed: 33281737
DOI: 10.3389/fneur.2020.600680 -
Revista de Neurologia Aug 2017Since Engel reported the first case of congenital myasthenia in 1977 and the first pathogenic gene was found in 1995, knowledge about congenital myasthenic syndromes has... (Review)
Review
Since Engel reported the first case of congenital myasthenia in 1977 and the first pathogenic gene was found in 1995, knowledge about congenital myasthenic syndromes has continued to grow. Over the years, the pathogenic basis, its clinical features, the phenotype-genotype correlations that have been established and its therapeutic management have all been described. In this group of diseases the safety margin of neuromuscular transmission is altered by different mechanisms: in the synthesis or storage of acetylcholine quanta in the synaptic vesicles, in the calcium-mediated release of acetylcholine in the nerve terminal or in the efficiency of the quantum released to generate a post-synaptic depolarisation. Increased knowledge about them has enabled a number of different therapeutic strategies to be established. In this review the main updates on these syndromes are reported, including: the genes described as classifying 50% of cases, their current classification based on the localisation of the proteins that alter neuromuscular transmission, including a new group of congenital myasthenias, glycosylation disorders, the main key diagnoses and the therapeutic management of this group of under-diagnosed patients.
Topics: Humans; Myasthenic Syndromes, Congenital
PubMed: 28726234
DOI: No ID Found -
American Journal of Ophthalmology Apr 2019To report the incidence, demographics, and ocular findings of children with myasthenia.
PURPOSE
To report the incidence, demographics, and ocular findings of children with myasthenia.
DESIGN
Retrospective cohort study.
METHODS
The medical records of all children (<19 years) examined at Mayo Clinic with any form of myasthenia from January 1 1966, through December 31, 2015, were retrospectively reviewed.
RESULTS
A total of 364 children were evaluated during the study period, of which 6 children were residents of the Olmsted County at the time of their diagnosis, yielding an annual age- and sex-adjusted incidence of 0.35 per 100 000 <19 years, or 1 in 285 714 <19 years. The incidence of juvenile myasthenia gravis (JMG) and congenital myasthenic syndrome (CMS) was 0.12 and 0.23 per 100 000, respectively. Of the 364 study children, 217 (59.6%) had JMG, 141 (38.7%) had CMS, and 6 (1.7%) had Lambert-Eaton syndrome, diagnosed at a median age of 13.5, 5.1, and 12.6 years, respectively. A majority of the JMG and CMS patients had ocular involvement (90.3% and 85.1%, respectively), including ptosis and ocular movement deficits. Among children with at least 1 year of follow-up (JMG; median, 7.1 years, CMS; median, 7.0 years), improvement was seen in 88.8% of JMG patients (complete remission in 31.3%) and in 58.3% of CMS patients.
CONCLUSION
Although relatively rare, myasthenia gravis in children has 2 predominant forms, CMS and JMG, both of which commonly have ocular involvement. Improvement is more likely in children with the juvenile form.
Topics: Adolescent; Age of Onset; Autoantibodies; Child; Child, Preschool; Disease Progression; Electromyography; Female; Humans; Incidence; Infant; Infant, Newborn; Male; Minnesota; Myasthenia Gravis; Oculomotor Muscles; Receptors, Cholinergic; Retrospective Studies
PubMed: 30653958
DOI: 10.1016/j.ajo.2019.01.004 -
Journal of Neuromuscular Diseases Sep 2015The Quantitative Myasthenia Gravis Score and the Myasthenia Gravis Composite are two commonly used outcome measures in Myasthenia Gravis. So far, their measurement...
BACKGROUND
The Quantitative Myasthenia Gravis Score and the Myasthenia Gravis Composite are two commonly used outcome measures in Myasthenia Gravis. So far, their measurement properties have not been compared, so we aimed to study their psychometric properties using the Rasch model.
METHODS
251 patients with stable myasthenia gravis were assessed with both scales, and 211 patients returned for a second assessment. We studied fit to the Rasch model at the first visit, and compared item fit, thresholds, differential item functioning, local dependence, person separation index, and tests for unidimensionality. We also assessed test-retest reliability and estimated the Minimal Detectable Change.
RESULTS
Neither scale fit the Rasch model (X2p < 0.05). The Myasthenia Gravis Composite had lower discrimination properties than the Quantitative Myasthenia Gravis Scale (Person Separation Index: 0.14 and 0.7). There was local dependence in both scales, as well as differential item functioning for ocular and generalized disease. Disordered thresholds were found in 6(60%) items of the Myasthenia Gravis Composite and in 4(31%) of the Quantitative Myasthenia Gravis Score. Both tools had adequate test-retest reliability (ICCs >0.8). The minimally detectable change was 4.9 points for the Myasthenia Gravis Composite and 4.3 points for the Quantitative Myasthenia Gravis Score.
CONCLUSIONS
Neither scale fulfilled Rasch model expectations. The Quantitative Myasthenia Gravis Score has higher discrimination than the Myasthenia Gravis Composite. Both tools have items with disordered thresholds, differential item functioning and local dependency. There was evidence of multidimensionality in the QMGS. The minimal detectable change values are higher than previous studies on the minimal significant change. These findings might inform future modifications of these tools.
PubMed: 27858737
DOI: 10.3233/JND-150082 -
Annals of Indian Academy of Neurology 2020Myasthenia gravis (MG) is an autoimmune disorder with a chronic fluctuating course. The outcome measures encapsulate disease severity, functional impact at diagnosis,...
BACKGROUND
Myasthenia gravis (MG) is an autoimmune disorder with a chronic fluctuating course. The outcome measures encapsulate disease severity, functional impact at diagnosis, and objective evaluation of clinical benefit from therapeutic interventions.
AIMS AND OBJECTIVE
To assess the disease severity, correlation between various outcome measures, and to evaluate the short-term outcome at 3 months and 6 months in a cohort of MG patients.
MATERIALS AND METHODS
Quantitative myasthenia gravis (QMG) score, myasthenia gravis composite (MGC) score, and myasthenia gravis quality of life-15 (MG-QoL-15) score were applied to 54 patients at first visit, 3 months and 6 months follow-up.
RESULTS
Mean quality of life-15 (QoL-15) score at base line was 15.241. Mean QMG and MGC scores at baseline were 14.63 ± 8.37 and 15.87 ± 9.14, respectively. QMG score showed a strong positive correlation with both MGC and MG-QoL-15 scores. QMG and MGC scores showed a moderate correlation with acetylcholine receptor antibody (AChR Ab) titers. Mean QMG at follow-up was 9.95 ± 5.49 at 3 months and 6.74 ± 4.74 at 6 months. Mean MGC at follow-up was 10.75 ± 5.58 at 3 months and 6.51 ± 4.36 at 6 months.
CONCLUSION
The combination of physician-evaluated and patient-reported outcome measures provided a more discerning picture of patient status and response to treatment. Incorporating MG outcome measures into clinical practice would aid in modulating therapies.
PubMed: 32189865
DOI: 10.4103/aian.AIAN_243_19 -
Tidsskrift For Den Norske Laegeforening... Jul 2016Around 700 people in Norway have myasthenia gravis, an autoimmune disease that affects neuromuscular transmission and results in fluctuating weakness in some muscles as... (Review)
Review
Around 700 people in Norway have myasthenia gravis, an autoimmune disease that affects neuromuscular transmission and results in fluctuating weakness in some muscles as its sole symptom. The diagnosis is based on typical symptoms and findings, detection of antibodies and neurophysiological examination. Symptomatic treatment with acetylcholinesterase inhibitors is generally effective, but most patients also require immunosuppressive drug treatment. Antigen-specific therapy is being tested in experimental disease models.
Topics: Cholinesterase Inhibitors; Electric Stimulation; Electromyography; Female; Humans; Immunosuppressive Agents; Myasthenia Gravis; Pregnancy; Thymectomy
PubMed: 27381787
DOI: 10.4045/tidsskr.15.1259 -
Annals of the Royal College of Surgeons... Feb 1952
Topics: Myasthenia Gravis; Thoracic Surgical Procedures; Thymus Gland
PubMed: 13017509
DOI: No ID Found -
Journal of Oral Science Sep 2015Myasthenia gravis is an autoimmune neuromuscular disorder characterized by fluctuating weakness and skeletal muscle fatigue. Clinical signs and symptoms may vary... (Review)
Review
Myasthenia gravis is an autoimmune neuromuscular disorder characterized by fluctuating weakness and skeletal muscle fatigue. Clinical signs and symptoms may vary considerably according to the age at presentation, patterns of autoantibodies and associated thymic abnormalities, so that therapeutic options are highly individualized. Facial and oropharyngeal muscle weakness is common at disease onset, and therefore dentists are often the first health professionals to encounter these patients. Myasthenic patients require special consideration and advice in order to ensure optimal and safe dental treatment. Oral manifestations, treatment timing and modality, the choice and effects of drugs and medications, and prevention of myasthenic crisis are all important aspects with which dentists and oral health care providers should be thoroughly acquainted.
Topics: Animals; Humans; Muscle, Skeletal; Myasthenia Gravis; Stomatognathic Diseases
PubMed: 26369478
DOI: 10.2334/josnusd.57.161 -
The Veterinary Clinics of North... Jul 1994The immunopathogenic mechanisms responsible for myasthenia gravis, polymyositis, masticatory myopathy, and dermatomyositis are discussed in light of their relevance to...
The immunopathogenic mechanisms responsible for myasthenia gravis, polymyositis, masticatory myopathy, and dermatomyositis are discussed in light of their relevance to the clinical disease. Current thinking concerning these disorders is presented as a prelude to further research and greater understanding.
Topics: Animals; Dermatomyositis; Dog Diseases; Dogs; Masticatory Muscles; Myasthenia Gravis; Myositis; Polymyositis
PubMed: 7975043
DOI: 10.1016/s0195-5616(94)50079-2