Search

Introduction: The conversion rate from ocular myasthenia gravis (OMG) to generalized myasthenia gravis (GMG) was reported to be much lower in Asian population since most OMG patients are juvenile onset. However, the exact conversion rate for adult-onset OMG to GMG is still unknown., Objective: We aimed to delineate the conversion rate and risk factors for adult patients with ocular onset to GMG., Methods: Adult myasthenia gravis (MG) patients with ocular onset (age > 18 years) were retrospectively reviewed. Patients with confined ocular involvement lasting more than 2 years (pure OMG group) and those who converted into GMG (converted OMG group) were enrolled for subsequent analysis. We then analyzed 5 clinical variables, including onset age, sex, onset symptoms, anti-acetylcholine receptor antibody (AChR Ab), and thymus CT. Survival analysis was applied to all enrolled patients to explore risk factors associated with conversion., Results: In a total number of 249 ocular-onset MG patients initially enrolled, we excluded 122 patients with OMG lasting less than 2 years. The remaining 127 patients were enrolled, including 106 converted OMG and 21 pure OMG patients. Converted OMG patients had an older onset age (threshold: 43 years) and higher anti-AChR Ab titer (threshold: 6.13 nmol/L). The estimated conversion rate was 70.64%. Moreover, 67% of conversion occurred within 2 years after onset. Cox regression of survival analysis revealed that higher anti-AChR Ab titer and bilateral ptosis were associated with a higher conversion rate., Conclusions: The conversion of adult OMG was associated with anti-AChR Ab titer, onset age, and bilateral ptosis. The estimated conversion rate of Chinese adult OMG patients was 70%., (© 2020 S. Karger AG, Basel.)

Introduction: Myasthenic crisis (MC) is a life-threatening condition usually occurred in patients with myasthenia gravis (MG)., Objective: On the basis of a retrospective case series review, we try to develop a scoring system to evaluate the probability for in-hospital death in MC patients., Methods: We retrospectively reviewed 78 MC patients who were hospitalized from January 2014 to December 2018. Clinical and laboratory data including 17 variables were analyzed univariately. The main clinical outcome was defined as the in-hospital death. Then eligible variables were evaluated by a stepwise multivariate regression and a scoring system was then generated. Calibration and discrimination methods were used to evaluate and validate the model performance., Results: The overall in-hospital mortality was 11.5% (9/78) in the MC cohort. Five clinical variables including Myasthenia Gravis Foundation of America (MGFA) classification at onset, septic shock, thymoma classification, cardiac arrest, and the lowest serum albumin were found to be associated with in-hospital mortality. Further 3 variables entered the final regression, and internal validation showed that the area under the curve was 0.919 (95% CI 0.788-1.000). A scoring system with a full credit of 7 points was generated to predict the in-hospital mortality (MGFA at onset, 2 points; septic shock, 4 points; and cardiac arrest, 3 points)., Conclusions: A 7-point scoring model was established on the basis of a retrospective review of MC patients to predict the in-hospital mortality., (© 2019 S. Karger AG, Basel.)

Repetitive nerve stimulation (RNS) is a valuable diagnostic method for myasthenia gravis (MG). However, its association with clinical severity was scarcely studied. We reviewed medical records and retrospectively enrolled 121 generalized MG patients. Sensitivity of different muscles to RNS and clinical scoring systems was evaluated. RNS testing revealed facial muscles have the highest positive rate, followed by proximal muscles and distal muscles, with the palpebral portion of the orbicularis oculi muscle most sensitive. Amplitude decrement of compound muscle action potential (CMAP) in the palpebral portion of the orbicularis oculi muscle is related to quantitative myasthenia gravis (QMG) scores, MG-specific manual muscle testing (MMT) scores and myasthenia gravis-related activities of daily living (MG-ADL) scores. We suggest that RNS testing of the palpebral portion of the orbicularis oculi muscle is a potential assessment indicator in patients with generalized MG., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

We report a case of a 40-year-old woman who developed generalized muscle weakness over a period of 2 months. Physical examination revealed palpable masses in her arms and hands. Serum creatine kinase levels were elevated. Electromyography showed myopathic changes and 3 Hz repetitive nerve stimulation revealed a decremental pattern on repetitive nerve stimulation. Muscle MRI demonstrated increased signal intensity in the biceps brachii on T1-weighted images. Chest CT scan showed a mediastinal mass suggestive of thymoma. Muscle biopsy revealed giant cell polymyositis. The patient was treated with cholinesterase inhibitors and corticosteroids with improvement of strength, and subsequently underwent thymectomy followed by radiotherapy., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Objective: Our aim was to investigate the correlation between onset age, clinical features and HLA-DQA1/DQB1 genetic variability in myasthenia gravis (MG) patients in Southern Han Chinese., Methods: 205 MG patients and 100 controls were genotyped for HLA-DQA1 and -DQB1 using sequence-based typing (SBT) and analyzed for haplotype frequencies. Anti-acetylcholine receptor (AChR) autoantibodies were measured in all, and muscle-specific tyrosine kinase (MuSK) antibodies were tested in AChR antibody negative patients., Results: HLA-DQA1/DQB1 haplotypes showed association only with childhood-onset MG. Haplotype DQA1*03:02/DQB1*03:03:02 (DQ9) was positively associated with the childhood-onset MG, while haplotype DQA1*02:01/DQB1*02:02 and DQA1*05:01:01/DQB1*02:01:01 (DQ2) were negatively associated with this group. Childhood-onset ocular MG patients had an extremely high phenotype frequency of DQ9 haplotype (90.1% of patients, 34.0% of controls, p≤0.0001, OR=17.8)., Conclusions: The childhood-onset ocular MG in Southern Han Chinese may present a particular subgroup of distinct genetic background. Its correlation to the HLA haplotype DQA1*03:02/DQB1*03:03:02 might explain the phenotypic difference of MG between Han Chinese and Caucasians., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background: Congenital myasthenic syndrome caused by mutations in AGRN, a gene encoding a protein with a crucial function at the neuromuscular junction, is a rare disorder. There are few studies in this area. We here present two cases with novel mutations of AGRN of which we further investigated possible pathogenesis.Results: Patient 1 had general limb weakness with fluctuation and deterioration in the afternoon and in hot weather. Patient 2 had early-onset weakness of lower extremities with suspected fluctuation in the early stages, which then progressed to the upper limbs. Both distal and proximal muscles were involved. Repetitive stimulation on EMG in both patients showed decrement in proximal and distal limbs. Patient 2 showed a marked response to salbutamol while Patient 1 did not. By targeted exome sequencing, two novel homozygous missense variants, p.L1176P and p.R1698C, in the SEA and LG2 domain of agrin were identified respectively. Further functional analysis revealed instability of the protein and impaired clustering of the acetylcholine receptor (AChR) by both mutations.Conclusions: The mutations identified in AGRN in our study may cause congenital myasthenic syndrome by damaging protein stability and interfering with AChR clustering. These results broaden the understandings on the phenotype, genotype and pathogenesis of this rare disorder. [ABSTRACT FROM AUTHOR]