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Jacob S. Treating myasthenia gravis beyond the eye clinic. Eye (Lond) 2024:10.1038/s41433-024-03133-x. [PMID: 38789789 DOI: 10.1038/s41433-024-03133-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/17/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
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.
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Affiliation(s)
- Saiju Jacob
- University Hospitals Birmingham, Birmingham, UK.
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, UK.
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Oculomotor fatigability with decrements of saccade and smooth pursuit for diagnosis of myasthenia gravis. J Neurol 2023; 270:2743-2755. [PMID: 36856847 PMCID: PMC10129983 DOI: 10.1007/s00415-023-11611-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/03/2023] [Accepted: 02/04/2023] [Indexed: 03/02/2023]
Abstract
BACKGROUND AND OBJECTIVES As the efficacy of current diagnostic methods for myasthenia gravis (MG) remains suboptimal, there is ongoing interest in developing more effective diagnostic models. As oculomotor fatigability is one of the most common and diagnostic symptoms in MG, we aimed to investigate whether quantitative saccadic and smooth-pursuit fatigability analyses with video-oculography (VOG) are useful for diagnosis of MG. METHODS A convenience cohort of 46 MG patients was recruited prospectively, including 35 with ocular and 11 with generalized MG (mean age, 50.9 ± 14.5 years; 17 females); 24 healthy controls (HCs) (mean age, 50.6 ± 16.3 years; 13 females) also were enrolled. Seventy-five repetitive saccades and smooth pursuits were recorded in ranges of 20° (horizontal plane) and 15° (vertical plane) using a three-dimensional VOG system. Based on the oculomotor range of the second saccade and smooth pursuit and the mean ranges of the last five of each, the estimated decrements (%) reflecting oculomotor fatigability were calculated. RESULTS The baseline oculomotor ranges did not show significant difference between the MG and HCs groups. However, following repetitive saccades and pursuits, the oculomotor ranges were decreased substantially during the last five cycles compared to baseline in the MG group. No such decrements were observed in the HC group (p < 0.01, Mann-Whitney U test). Receiver operating characteristic (ROC) analysis revealed that repetitive vertical saccades yielded the best differentiation between the MG and HC groups, with a sensitivity of 78.3% and specificity of 95.8% when using a decrement with an amplitude of 6.4% as the cutoff. CONCLUSION This study presents an objective and reproducible method for measuring decrements of oculomotor ranges after repetitive saccadic and pursuit movements. Quantification of oculomotor fatigability using VOG could be a sensitive and specific diagnostic tool for MG and allows easy, cost-effective, accurate, and non-invasive measurements. CLASSIFICATION OF EVIDENCE This study provides class III evidence that VOG-based quantification of saccadic and pursuit fatigability accurately identifies patients with MG.
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Abstract
BACKGROUND Around 60%--75% of myasthenia gravis (MG) patients initially present with nonspecific ocular symptoms. Failed recognition of these symptoms may delay the diagnosis of MG up to 5 years or more, leading to a reduced likelihood of remission and increased morbidity. Current diagnostic tests are either poorly sensitive for patients presenting with ocular symptoms alone or are time consuming, invasive, require a high level of technical expertise, and generally are universally difficult to obtain. This review will explore quantitative eye and pupil tracking as a potential noninvasive, time-effective, and less technically demanding alternative to current diagnostic tests of MG. EVIDENCE ACQUISITION Comprehensive literature review. RESULTS Thirty-two publications using oculography for the diagnosis of MG and 6 studies using pupillometry were evaluated. In MG patients, extra ocular muscle fatigue was evident in reports of intersaccadic, intrasaccadic and postsaccadic abnormalities, changes in optokinetic nystagmus, slow eye movements, disconjugate saccades, and pupillary constrictor muscle weakness. CONCLUSIONS Our review identified several potentially useful variables that derive from oculography and pupillometry studies that could assist with a timely diagnosis of MG. Limitations of this review include heterogeneity in design, sample size, and quality of the studies evaluated. There is a need for larger, well-designed studies evaluating eye-tracking measures in the diagnosis of MG, especially for patients presenting with purely ocular symptoms.
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Novel treatment strategies for acetylcholine receptor antibody-positive myasthenia gravis and related disorders. Autoimmun Rev 2022; 21:103104. [PMID: 35452851 DOI: 10.1016/j.autrev.2022.103104] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 04/18/2022] [Indexed: 11/21/2022]
Abstract
The presence of autoantibodies directed against the muscle nicotinic acetylcholine receptor (AChR) is the most common cause of myasthenia gravis (MG). These antibodies damage the postsynaptic membrane of the neuromuscular junction and cause muscle weakness by depleting AChRs and thus impairing synaptic transmission. As one of the best-characterized antibody-mediated autoimmune diseases, AChR-MG has often served as a reference model for other autoimmune disorders. Classical pharmacological treatments, including broad-spectrum immunosuppressive drugs, are effective in many patients. However, complete remission cannot be achieved in all patients, and 10% of patients do not respond to currently used therapies. This may be attributed to production of autoantibodies by long-lived plasma cells which are resistant to conventional immunosuppressive drugs. Hence, novel therapies specifically targeting plasma cells might be a suitable therapeutic approach for selected patients. Additionally, in order to reduce side effects of broad-spectrum immunosuppression, targeted immunotherapies and symptomatic treatments will be required. This review presents established therapies as well as novel therapeutic approaches for MG and related conditions, with a focus on AChR-MG.
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Nishadham V, Bardhan M, Polavarapu K, Vengalil S, Nashi S, Menon D, Ganaraja VH, Preethish-Kumar V, Valasani RK, Huddar A, Unnikrishnan GK, Thomas A, Saravanan A, Kulanthaivelu K, Nalini A, Nandeesh BN. Thymic Lesions in Myasthenia Gravis: A Clinicopathological Study from India. J Neuromuscul Dis 2022; 9:411-422. [DOI: 10.3233/jnd-210785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background and Objectives: Thymic pathology is common in Myasthenia Gravis(MG) and plays a crucial role in its pathogenesis and clinical outcome. This study aims to discuss the clinicohistopathological spectrum of thymic lesions in MG. Methods: In this retrospective study, MG patients who underwent thymectomy from 2011 to 2020 were included. Clinical, radiological, serological, and histopathological details are described. Results: Of 83 patients(F = 45; M = 38), 7(8%) had ocular myasthenia, and the remaining 76(92%) had the generalized form. At onset, the median age was 36 years(M = 44; F = 31). AChR antibody was positive in 71/79 patients. RNST showed decrement response in 68/78 patients. The histopathological study demonstrated thymoma in 44(53%), thymic hyperplasias [32(38%)], involuted thymus [5(6%)], thymic cyst (1) and thymic lipoma (1). WHO grading of thymoma: B2- 48%, AB-18%, B-18%, B3-14%, A-2.3% . In these, capsular infiltration was noted in 11/44, 9 had focal and 2 had diffuse infiltration. Active germinal centers were present in 20/32 patients with thymic hyperplasia and 4/44 with thymoma. Thymomas were predominant in males and thymic hyperplasia in females. The age of onset and antibody positivity rate was higher in thymoma patients. Conclusion: In our cohort, there is a female preponderance. Thymoma was the commonest pathology followed by hyperplasia. We observed earlier onset of myasthenia in females. AChR antibody positivity rate was more frequent in thymomas. This study indicates that clinico-radiological evaluation adequately supported by serology and histopathology can effectively recognize the type of thymic pathology that can guide these patients’ treatment planning, management, prognosis and follow-up.
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Affiliation(s)
- Vikas Nishadham
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
| | - Mainak Bardhan
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
| | - Kiran Polavarapu
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
| | - Seena Vengalil
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
| | - Saraswati Nashi
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
| | - Deepak Menon
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
| | | | - Veeramani Preethish-Kumar
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
| | - Ravi Kiran Valasani
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
| | - Akshata Huddar
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
| | - Gopi Krishnan Unnikrishnan
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
| | - Abel Thomas
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
| | - Akshaya Saravanan
- Neurointerventional and Imaging, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
| | - Karthik Kulanthaivelu
- Neurointerventional and Imaging, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
| | - Atchayaram Nalini
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka India
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Sivakumar P, Tagare S, Kumar M. Diagnostic accuracy and clinical utility of bed side tests versus laboratory tests in the diagnosis of ocular myasthenia. Indian J Ophthalmol 2022; 70:1331-1337. [PMID: 35326049 PMCID: PMC9240561 DOI: 10.4103/ijo.ijo_2015_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Purpose To assess the diagnostic accuracy of forced eyelid closure test (FECT), ice pack test (IPT), repetitive nerve stimulation test (RNS), and acetylcholine receptor (AchR) antibody test in patients with suspected ocular myasthenia. To assess the clinical utility of AchR antibody test in predicting disease progression. Methods Retrospective cohort study of patients diagnosed with ocular myasthenia at a South-Indian neuro-ophthalmology tertiary eye clinic. Baseline characteristics; ocular myasthenia symptoms; results of FECT, IPT, RNS, and AchR antibody test; and progression time to generalized myasthenia (GM) over 36 months from the time of diagnosis were recorded and analyzed using receiver operator curve analysis, multiple logistic regression, and Kaplan-Meier survival analysis. Results FECT had a sensitivity of 96.7% (95% CI: 88.5-99.6) and a specificity of 75% (95% CI: 34.9-96.8). Combination of FECT and IPT, using the positivity of at least one test, increased the sensitivity to 98.3% (95% CI: 91-100), reducing the specificity to 50% (95% CI: 15.7-84.3), whereas using the positivity of both tests, we obtained a sensitivity of 71.7% (95% CI: 58.6-82.5) and a specificity of 100% (95% CI: 63.1-100). In the subset of patients with double negative RNS and AchR antibodies, the positive predictive value of combined FECT and IPT (double positive) was 100%. Patients who developed GM were more likely to have a positive AchR antibody test result (P = 0.001). Conclusion Combined FECT and IPT (double positive) has high diagnostic accuracy even among patients with normal RNS and negative AchR antibodies. Despite low sensitivity, AchR-antibody test has a significant predictive value in disease progression.
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Affiliation(s)
- Priya Sivakumar
- Department of Neuro Ophthalmology and Low Vision Services, Aravind Eye Care, Puducherry, India
| | | | - Mahesh Kumar
- DNB Ophthalmology, Aravind Eye Care, Madurai, Tamil Nadu, India
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Evoli A, Iorio R. Controversies in Ocular Myasthenia Gravis. Front Neurol 2020; 11:605902. [PMID: 33329368 PMCID: PMC7734350 DOI: 10.3389/fneur.2020.605902] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 10/26/2020] [Indexed: 12/12/2022] Open
Abstract
Myasthenia gravis (MG) with symptoms limited to eye muscles [ocular MG (OMG)] is a rare disease. OMG incidence varies according to ethnicity and age of onset. In recent years, both an increase in incidence rate, particularly in the elderly, and a lower risk for secondary generalization may have contributed to the growing disease prevalence in Western countries. OMG should be considered in patients with painless ptosis and extrinsic ophthalmoparesis. Though asymmetric muscle involvement and symptom fluctuations are typical, in some cases, OMG can mimic isolated cranial nerve paresis, internuclear ophthalmoplegia, and conjugate gaze palsy. Diagnostic confirmation can be challenging in patients negative for anti-acetylcholine receptor and anti-muscle-specific tyrosine kinase antibodies on standard radioimmunoassay. Early treatment is aimed at relieving symptoms and at preventing disease progression to generalized MG. Despite the absence of high-level evidence, there is general agreement on the efficacy of steroids at low to moderate dosage; immunosuppressants are considered when steroid high maintenance doses are required. The role of thymectomy in non-thymoma patients is controversial. Prolonged exposure to immunosuppressive therapy has a negative impact on the health-related quality of life in a proportion of these patients. OMG is currently excluded from most of the treatments recently developed in generalized MG.
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Affiliation(s)
- Amelia Evoli
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.,Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Raffaele Iorio
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.,Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy
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Wilf-Yarkoni A, Alkalay Y, Brenner T, Karni A. High κ free light chain is a potential biomarker for double seronegative and ocular myasthenia gravis. NEUROLOGY-NEUROIMMUNOLOGY & NEUROINFLAMMATION 2020; 7:7/5/e831. [PMID: 32665296 PMCID: PMC7371374 DOI: 10.1212/nxi.0000000000000831] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 05/29/2020] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To investigate the hypothesis that free light chain (FLC) sera levels could serve as a biomarker for myasthenia gravis (MG), especially for the subgroups of seronegative MG and ocular MG. METHODS Sera from 73 patients with MG (20 seronegative for antiacetylcholine receptor [AChR] and anti-muscle-specific kinase and 53 positive for anti-AChR, which were clinically divided into 24 patients with ocular type, 45 with generalized type, and 4 with unequivocal clinical manifestation) and 49 healthy controls were studied for κ FLC and λ FLC levels with the Freelite human FLC kits. RESULTS The κ but not the λ levels of FLC were significantly increased in the patients with MG, including those with double seronegative MG and ocular MG, compared with the healthy controls. The specificity for double seronegative MG and ocular MG were both 98.0% when κ FLC was ≥25.0 mg/L. Increased κ FLC levels were not affected by the patient's sex, age at MG onset, the presence of thymic pathology, or different treatments. CONCLUSIONS Elevated serum κ FLC may serve as a biomarker for MG in suspected patients who are double seronegative and in those with only ocular manifestations when serology is inconclusive. CLASSIFICATION OF EVIDENCE This study provides Class III evidence that high κ FLC levels distinguished patients with MG, including those who were double seronegative, from healthy controls.
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Affiliation(s)
- Adi Wilf-Yarkoni
- From the Neuroimmunology and Multiple Sclerosis Unit of the Neurology Division (A.W.-Y., A.K.), Tel Aviv Sourasky Medical Center; Clinical Immunology Laboratory (Y.A.), Tel Aviv Sourasky Medical Center; Laboratory of Neuroimmunology (T.B.), Department of Neurology, the Agnes Ginges Center for Human Neurogenetics, Hadassah-Hebrew University Medical Center, Jerusalem; Sackler Faculty of Medicine (A.K.), Tel Aviv University; and Sagol School of Neuroscience (A.K.), Tel Aviv University, Israel
| | - Yifat Alkalay
- From the Neuroimmunology and Multiple Sclerosis Unit of the Neurology Division (A.W.-Y., A.K.), Tel Aviv Sourasky Medical Center; Clinical Immunology Laboratory (Y.A.), Tel Aviv Sourasky Medical Center; Laboratory of Neuroimmunology (T.B.), Department of Neurology, the Agnes Ginges Center for Human Neurogenetics, Hadassah-Hebrew University Medical Center, Jerusalem; Sackler Faculty of Medicine (A.K.), Tel Aviv University; and Sagol School of Neuroscience (A.K.), Tel Aviv University, Israel
| | - Talma Brenner
- From the Neuroimmunology and Multiple Sclerosis Unit of the Neurology Division (A.W.-Y., A.K.), Tel Aviv Sourasky Medical Center; Clinical Immunology Laboratory (Y.A.), Tel Aviv Sourasky Medical Center; Laboratory of Neuroimmunology (T.B.), Department of Neurology, the Agnes Ginges Center for Human Neurogenetics, Hadassah-Hebrew University Medical Center, Jerusalem; Sackler Faculty of Medicine (A.K.), Tel Aviv University; and Sagol School of Neuroscience (A.K.), Tel Aviv University, Israel
| | - Arnon Karni
- From the Neuroimmunology and Multiple Sclerosis Unit of the Neurology Division (A.W.-Y., A.K.), Tel Aviv Sourasky Medical Center; Clinical Immunology Laboratory (Y.A.), Tel Aviv Sourasky Medical Center; Laboratory of Neuroimmunology (T.B.), Department of Neurology, the Agnes Ginges Center for Human Neurogenetics, Hadassah-Hebrew University Medical Center, Jerusalem; Sackler Faculty of Medicine (A.K.), Tel Aviv University; and Sagol School of Neuroscience (A.K.), Tel Aviv University, Israel.
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Sabre L, Punga T, Punga AR. Circulating miRNAs as Potential Biomarkers in Myasthenia Gravis: Tools for Personalized Medicine. Front Immunol 2020; 11:213. [PMID: 32194544 PMCID: PMC7065262 DOI: 10.3389/fimmu.2020.00213] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/27/2020] [Indexed: 12/11/2022] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disease caused by antibodies which attack receptors at the neuromuscular junction. One of the main difficulties in predicting the clinical course of MG is the heterogeneity of the disease, where disease progression differs greatly depending on the subgroup that the patient is classified into. MG subgroups are classified according to: age of onset [early-onset MG (EOMG; onset ≤ 50 years) versus late-onset MG (LOMG; onset > 50 years]; the presence of a thymoma (thymoma-associated MG); antibody subtype [acetylcholine receptor antibody seropositive (AChR+) and muscle-specific tyrosine kinase antibody seropositive (MuSK+)]; as well as clinical subtypes (ocular versus generalized MG). The diagnostic tests for MG, such as antibody titers, neurophysiological tests, and objective clinical fatigue score, do not necessarily reflect disease progression. Hence, there is a great need for reliable objective biomarkers in MG to follow the disease course as well as the individualized response to therapy toward personalized medicine. In this regard, circulating microRNAs (miRNAs) have emerged as promising potential biomarkers due to their accessibility in body fluids and unique profiles in different diseases, including autoimmune disorders. Several studies on circulating miRNAs in MG subtypes have revealed specific miRNA profiles in patients’ sera. In generalized AChR+ EOMG, miR-150-5p and miR-21-5p are the most elevated miRNAs, with lower levels observed upon treatment with immunosuppression and thymectomy. In AChR+ generalized LOMG, the miR-150-5p, miR-21-5p, and miR-30e-5p levels are elevated and decrease in accordance with the clinical response after immunosuppression. In ocular MG, higher levels of miR-30e-5p discriminate patients who will later generalize from those remaining ocular. In contrast, in MuSK+ MG, the levels of the let-7 miRNA family members are elevated. Studies of circulating miRNA profiles in Lrp4 or agrin antibody-seropositive MG are still lacking. This review summarizes the present knowledge of circulating miRNAs in different subgroups of MG.
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Affiliation(s)
- Liis Sabre
- Department of Neurology and Neurosurgery, University of Tartu, Tartu, Estonia.,Department of Neuroscience, Clinical Neurophysiology, Uppsala University, Uppsala, Sweden
| | - Tanel Punga
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Anna Rostedt Punga
- Department of Neuroscience, Clinical Neurophysiology, Uppsala University, Uppsala, Sweden
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Sabre L, Maddison P, Wong SH, Sadalage G, Ambrose PA, Plant GT, Punga AR. miR-30e-5p as predictor of generalization in ocular myasthenia gravis. Ann Clin Transl Neurol 2019; 6:243-251. [PMID: 30847357 PMCID: PMC6389736 DOI: 10.1002/acn3.692] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 10/09/2018] [Accepted: 10/12/2018] [Indexed: 12/11/2022] Open
Abstract
Objective To determine a predictive factor for the risk of conversion from ocular myasthenia gravis (OMG) to generalized MG (GMG) in a prospective study. Methods RNA was isolated from serum samples and detection of microRNA (miRNA) expression analyzed with qPCR. In the discovery set, 179 human miRNAs were assayed for profiling of five OMG patients and four age‐ and gender‐matched healthy controls. Based on the specific accumulation pattern of 19 miRNAs from the discovery set, in addition to miRNAs previously found elevated in generalized MG (GMG; miR‐150‐5p and miR‐30e‐5p), 21 miRNAs were subsequently analyzed in a validation cohort of 83 OMG patients (82 immunosuppression treatment naive; 49 male) within 3 months of diagnosis and at a follow‐up visit (median duration 28 months from first visit). Results Thirteen patients generalized 14.8 ± 12.0 months after the diagnosis and the majority (85%) belonged to the late onset MG group. Two miRNAs were significantly higher in secondary GMG (SGMG) patients compared to OMG patients with late onset MG: miR‐30e‐5p (9.1 ± 0.5 vs. 6.3 ± 0.9; P < 0.0001) and miR‐150‐5p (7.4 ± 1.1 vs. 6.4 ± 1.1; P = 0.01). The sensitivity for miR‐30e‐5p in differentiating OMG and SGMG was 96% in all OMG patients and 100% in late onset OMG patients. Interpretation This is the first study to describe a potential predictive factor associated with the risk of generalization for patients with OMG. Raised levels (>8) of miR‐30e‐5p at initial presentation in patients with ocular MG symptoms, give a predictive cut‐off for subsequent generalization of 96–100%.
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Affiliation(s)
- Liis Sabre
- Department of Neuroscience Clinical Neurophysiology Uppsala University Uppsala Sweden
| | - Paul Maddison
- Department of Neurology Nottingham University Hospitals NHS Trust Queens Medical Centre Nottingham Nottinghamshire United Kingdom
| | - Sui H Wong
- Department of Neuro-ophthalmology Moorfields Eye Hospital NHS Foundation Trust London
| | - Girija Sadalage
- Department of Neurology Nottingham University Hospitals NHS Trust Queens Medical Centre Nottingham Nottinghamshire United Kingdom
| | - Philip A Ambrose
- Department of Neurology Nottingham University Hospitals NHS Trust Queens Medical Centre Nottingham Nottinghamshire United Kingdom
| | - Gordon T Plant
- Department of Neuro-ophthalmology Moorfields Eye Hospital NHS Foundation Trust London
| | - Anna R Punga
- Department of Neuroscience Clinical Neurophysiology Uppsala University Uppsala Sweden
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Crestati F, Shaladi A, Preteroti S, Tartari S. Auricular Acupuncture to Resolve the Exacerbations in Ocular Myasthenia – a Case Report. Acupunct Med 2018; 25:107-8. [PMID: 17906603 DOI: 10.1136/aim.25.3.107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Ocular myasthenia is a neuromuscular autoimmune disorder in which the clinical symptoms are restricted to the external ocular muscles with either ptosis or diplopia, or both. The condition may follow a relapsing and remitting course. Conventional therapy consists of anticholinergic drugs, corticosteroids and immunosuppressants. We report a case in which auricular acupuncture was used as an adjunct to pharmacological treatment. The time course of the response suggests that acupuncture appeared to help resolve the current relapse.
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Affiliation(s)
- Francesco Crestati
- Pain Service, Local Health Care, Authority 18, San Luca Hospital, Trecenta, Italy.
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Ahn J, Park KS, Kim JS, Hwang JM. Efficacy of Gaze Photographs in Diagnosing Ocular Myasthenia Gravis. J Clin Neurol 2018; 14:333-338. [PMID: 29856158 PMCID: PMC6031998 DOI: 10.3988/jcn.2018.14.3.333] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 02/20/2018] [Accepted: 02/20/2018] [Indexed: 11/24/2022] Open
Abstract
Background and Purpose The various tests that are routinely used to diagnose generalized myasthenia gravis, such as the edrophonium test, serum anti-acetylcholine-receptor antibodies (AChR-Ab), and repetitive nerve stimulation (RNS) tests, have lower diagnostic sensitivity in ocular myasthenia gravis (OMG). Diagnosing OMG becomes even more difficult when the clinical symptoms are subtle. There is no gold-standard diagnostic test available for OMG patients, and so this study compared the diagnostic sensitivity of gaze photographs with conventional tests in OMG. Methods Records of gaze photographs were available for 25 of 31 consecutive patients diagnosed with OMG. Each patient underwent a neuro-ophthalmologic examination, serum AChR-Ab, RNS, edrophonium test, ice tests, and the acquisition of gaze photographs. The margin reflex distance 1 (MRD1) was measured on each of the gaze photographs, with MRD1 <2 mm or an interlid MRD1 difference of ≥2 mm on any of the gaze photographs defined as a positive sign of OMG. The diagnostic sensitivities of the tests were assessed. Results The mean age at onset was 38.5 years (range, 2–76 years), and 13 patients (52%) were men. The diagnostic sensitivities of the RNS test, AChR-Ab test, gaze photographs, and ice test were 56%, 64%, 80%, and 73%, respectively. Conclusions The diagnostic sensitivity was higher for gaze photographs than for the other tests applied to OMG patients.
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Affiliation(s)
- Jeeyun Ahn
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea.,Department of Ophthalmology, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, Korea
| | - Kyung Seok Park
- Department of Neurology, Seoul National University College of Medicine, Seoul, Korea.,Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Ji Soo Kim
- Department of Neurology, Seoul National University College of Medicine, Seoul, Korea.,Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Jeong Min Hwang
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea.,Department of Ophthalmology, Seoul National University Bundang Hospital, Seongnam, Korea.
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Klimiec E, Quirke M, Leite MI, Hilton-Jones D. Thymus imaging in myasthenia gravis: The relevance in clinical practice. Muscle Nerve 2018; 58:153-156. [PMID: 29424940 DOI: 10.1002/mus.26096] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2018] [Indexed: 11/10/2022]
Abstract
INTRODUCTION The ability to distinguish between normal thymus, thymic hyperplasia, and thymoma should aid clinical management and decision making in patients with myasthenia gravis (MG). We sought to determine the accuracy of routine imaging in predicting thymic pathology. METHODS We retrospectively analyzed records of patients with MG from the Oxford Myasthenia Centre registry who had undergone thymectomy. Each patient received 1 radiological diagnosis and 1 histological diagnosis. RESULTS We included 106 patients. Radiological and histological diagnoses agreed in 73 (68.9%) patients. Sensitivity and specificity, respectively, were calculated for each radiological diagnosis as follows: thymoma 90% and 95.5%, hyperplasia 17.6% and 98.6%, and normal 96.9% and 60.8%. DISCUSSION Routine chest computed tomography and MRI can effectively identify thymoma. However, they are not reliable tools to differentiate between thymic hyperplasia and normal thymus in patients with MG. Muscle Nerve, 2018.
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Affiliation(s)
- Elzbieta Klimiec
- Department of Neurology, Jagiellonian University Medical College, Krakow, Poland
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford University Hospitals, Headley Way Headington, Oxford, OX3 9DU, United Kingdom
| | - Mary Quirke
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford University Hospitals, Headley Way Headington, Oxford, OX3 9DU, United Kingdom
| | - Maria Isabel Leite
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford University Hospitals, Headley Way Headington, Oxford, OX3 9DU, United Kingdom
| | - David Hilton-Jones
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford University Hospitals, Headley Way Headington, Oxford, OX3 9DU, United Kingdom
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Evoli A, Alboini PE, Iorio R, Damato V, Bartoccioni E. Pattern of ocular involvement in myasthenia gravis with MuSK antibodies. J Neurol Neurosurg Psychiatry 2017; 88:761-763. [PMID: 28601810 DOI: 10.1136/jnnp-2017-315782] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/10/2017] [Accepted: 04/11/2017] [Indexed: 01/14/2023]
Abstract
BACKGROUND Myasthenia gravis (MG) with antibodies to the muscle-specific kinase (MuSK) has a characteristic phenotype. Ocular manifestations have not been systematically evaluated. OBJECTIVE To investigate the features of extrinsic ocular muscle involvement in patients with MuSK-MG. METHODS We retrospectively evaluated the prevalence, time of onset, clinical pattern and outcome of ocular symptoms in 82 patients with a clinical follow-up ≥2 years. RESULTS Ocular manifestations were observed in 79 patients (96.4%) and were the presenting symptoms in 48 (58.5%). Intermittent diplopia with subtle ophthalmoparesis was the most common complaint, ptosis was generally symmetrical and conjugated gaze paresis occurred in 35% of the patients. Ocular manifestations responded well to prednisone and partially to symptomatic treatment. A few patients developed chronic symmetrical ophthalmoparesis, associated with persistent weakness in other muscle groups. All patients with ocular presentation progressed to generalised disease, though weakness spread to other muscle groups was considerably delayed in a few cases. CONCLUSIONS In MG with antibodies to MuSK, ocular manifestations were as frequent as in other disease subtypes. Symmetrical ophthalmoparesis with conjugated gaze limitation was rather common and associated with low functional disability. A proportion of these patients developed chronic eye muscle paresis.
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Affiliation(s)
- Amelia Evoli
- Institute of Neurology, Catholic University, Fondazione Policlinico A. Gemelli, Rome, Italy
| | - Paolo E Alboini
- Institute of Neurology, Catholic University, Fondazione Policlinico A. Gemelli, Rome, Italy
| | - Raffaele Iorio
- Institute of Neurology, Catholic University, Fondazione Policlinico A. Gemelli, Rome, Italy
| | - Valentina Damato
- Institute of Neurology, Catholic University, Fondazione Policlinico A. Gemelli, Rome, Italy
| | - Emanuela Bartoccioni
- Institute of General Pathology, Catholic University, Fondazione Policlinico A. Gemelli, Rome, Italy
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Wu X, Tuzun E, Saini SS, Wang J, Li J, Aguilera-Aguirre L, Huda R, Christadoss P. Ocular myasthenia gravis induced by human acetylcholine receptor ϵ subunit immunization in HLA DR3 transgenic mice. Immunol Lett 2015; 168:306-12. [DOI: 10.1016/j.imlet.2015.10.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 10/08/2015] [Accepted: 10/13/2015] [Indexed: 11/28/2022]
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Zambelis T, Pappas V, Kokotis P, Zouvelou V, Karandreas N. Patients with ocular symptoms referred for electrodiagnosis: how many of them suffer from myasthenia gravis? Acta Neurol Belg 2015; 115:671-4. [PMID: 25822064 DOI: 10.1007/s13760-015-0460-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Accepted: 03/16/2015] [Indexed: 11/28/2022]
Abstract
The aim of this study was the diagnosis of patients with isolated ocular manifestations (ptosis and/or diplopia) referred for electrophysiological evaluation to the electrodiagnostic laboratory of a University Neurological Department. Examination was performed either in inpatient status or in outpatient basis. We analyzed the clinical, electrophysiological and other laboratory data in 79 subjects. Myasthenia gravis (MG) was diagnosed in 38 %, 45.6 % in other diseases (Graves disease, blepharospasm, IIId cranial verve palsy, multiple sclerosis, stroke, etc.), while in 16.5 %, the cause remained unidentified. Symptoms fluctuation was significantly more frequent in the myasthenic patients, compared to patients with other diseases. The presence of both diplopia and ptosis are more likely due to MG rather than other pathology.
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Affiliation(s)
- Th Zambelis
- Department of Neurology, EMG Laboratory, University of Athens, Aeginition Hospital, 74, Vass. Sofias Ave., 115-28, Athens, Greece.
| | - V Pappas
- Department of Neurology, EMG Laboratory, University of Athens, Aeginition Hospital, 74, Vass. Sofias Ave., 115-28, Athens, Greece
| | - P Kokotis
- Department of Neurology, EMG Laboratory, University of Athens, Aeginition Hospital, 74, Vass. Sofias Ave., 115-28, Athens, Greece
| | - V Zouvelou
- Department of Neurology, EMG Laboratory, University of Athens, Aeginition Hospital, 74, Vass. Sofias Ave., 115-28, Athens, Greece
| | - N Karandreas
- Department of Neurology, EMG Laboratory, University of Athens, Aeginition Hospital, 74, Vass. Sofias Ave., 115-28, Athens, Greece
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Almog Y, Ben-David M, Nemet AY. Inferior oblique muscle paresis as a sign of myasthenia gravis. J Clin Neurosci 2015; 25:50-3. [PMID: 26531848 DOI: 10.1016/j.jocn.2015.08.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 08/14/2015] [Indexed: 10/22/2022]
Abstract
Myasthenia gravis may affect any of the six extra-ocular muscles, masquerading as any type of ocular motor pathology. The frequency of involvement of each muscle is not well established in the medical literature. This study was designed to determine whether a specific muscle or combination of muscles tends to be predominantly affected. This retrospective review included 30 patients with a clinical diagnosis of myasthenia gravis who had extra-ocular muscle involvement with diplopia at presentation. The diagnosis was confirmed by at least one of the following tests: Tensilon test, acetylcholine receptor antibodies, thymoma on chest CT scan, or suggestive electromyography. Frequency of involvement of each muscle in this cohort was inferior oblique 19 (63.3%), lateral rectus nine (30%), superior rectus four (13.3%), inferior rectus six (20%), medial rectus four (13.3%), and superior oblique three (10%). The inferior oblique was involved more often than any other muscle (p<0.01). Eighteen (60%) patients had ptosis, six (20%) of whom had bilateral ptosis. Diagnosing myasthenia gravis can be difficult, because the disease may mimic every pupil-sparing pattern of ocular misalignment. In addition diplopia caused by paresis of the inferior oblique muscle is rarely encountered (other than as a part of oculomotor nerve palsy). Hence, when a patient presents with vertical diplopia resulting from an isolated inferior oblique palsy, myasthenic etiology should be highly suspected.
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Affiliation(s)
- Yehoshua Almog
- Department of Ophthalmology, Meir Medical Center, 59 Tschernihovsky St., Kfar Sava 44281, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Merav Ben-David
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Neurology Department, Rabin Medical Center, Petach Tikva, Israel
| | - Arie Y Nemet
- Department of Ophthalmology, Meir Medical Center, 59 Tschernihovsky St., Kfar Sava 44281, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
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Ariatti A, Stefani M, Miceli P, Benuzzi F, Galassi G. Prognostic factors and health-related quality of life in ocular Myasthenia Gravis (OMG). Int J Neurosci 2013; 124:427-35. [PMID: 24228829 DOI: 10.3109/00207454.2013.853664] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We evaluate the factors predictive of prognosis in 91 Caucasian patients affected by ocular myasthenia gravis (OMG), followed at our Institution during an observational time, ranging from 12 to 240 months. The Myasthenia Gravis Foundation of America (MGFA) clinical classification was used to grade the disease severity. We considered as outcome measures the variation in two subscores, ocular (O-QMG) and nonocular (NO-QMG); the last one reflected bulbar, neck, extremity functions. None of the independent variables evaluated for association with the outcome, as age of onset, type of therapy, length of interval between first and last examinations, and presence of antibodies to acetylcholine receptors (AChR-Abs) significantly affected the evolution of O-QMG and of NO-QMG. Health-related quality of life (HRQol) was assessed in 63 patients. Variations of diplopia or ptosis did not affect significantly physical (PCS) or mental composite subscores (MCS) of the Short-Form Health Survey (SF-36). Human leukocyte antigen (HLA) genotyping was studied to explore whether HLA class I and II allelic distribution differed among MG patients and controls. None of the studied HLA alleles significantly differed between OMG patients and controls. Similarly, none of the alleles with frequencies higher than 15% either in OMG patients or in controls was significantly associated, after Bonferroni correction, with the presence or absence of anti-AChR-Abs in serum.
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Affiliation(s)
- Alessandra Ariatti
- Department of Neurosciences, and Department of Onco-Haematology, University Hospitals of Modena & Reggio Emilia , Italy
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Treatment for diplopia in patients with myasthenia gravis. Graefes Arch Clin Exp Ophthalmol 2012; 251:895-901. [PMID: 23275035 DOI: 10.1007/s00417-012-2227-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 11/01/2012] [Accepted: 11/26/2012] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND The purpose of this study was to describe the treatment experiences and outcomes of patients with myasthenia gravis (MG) whose initial presenting symptom was diplopia METHODS A retrospective review was performed on a group of patients with MG whose initial presenting symptom was diplopia. RESULTS The mean age of onset was 45.5 ± 16.9 years, and the mean follow-up period was 45.4 ± 39.7 months. Exotropia with vertical heterotropia was the most common type of deviation. The mean horizontal deviation was 20.1 ± 17.9 prism diopters, and the mean vertical deviation was 14.8 ± 11.1 prism diopters. Limitation of eye movement was found in 20 patients (71.4 %) during the follow-up period. After conventional treatment for MG, six patients (21.4 %) showed a good response with resolution of diplopia. Four patients (14.3 %) showed a partial response to treatment. Eighteen patients (64.3 %) showed minimal or no response; among them, ten (35.7 %) had an angle of deviation of 15 prism diopters or more. Six patients underwent strabismus surgery. Four were symptom free, and satisfactorily aligned after surgical treatment. One patient had intermittent diplopia despite the small amount of deviation, and one patient experienced recurrence of exotropia with diplopia during the 10-year follow-up. In multivariable analysis, the only factor associated with the need for strabismus surgery was the initial angle of deviation (p = 0.016). CONCLUSIONS Patients with MG who have a larger angle of deviation at presentation tend to require strabismus surgery after stabilization of the disease. Strabismus surgery is one treatment option for patients with MG who have a large angle of deviation and respond poorly to conventional treatment.
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Shi QG, Wang ZH, Ma XW, Zhang DQ, Yang CS, Shi FD, Yang L. Clinical significance of detection of antibodies to fetal and adult acetylcholine receptors in myasthenia gravis. Neurosci Bull 2012; 28:469-74. [PMID: 22961471 DOI: 10.1007/s12264-012-1256-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 05/23/2012] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE To evaluate the frequency, distribution and clinical significance of the antibodies to the fetal and/or adult acetylcholine receptor (AChR) in patients with myasthenia gravis (MG). METHODS AChR antibodies were detected by cell-based assay in the serum of ocular MG (OMG) (n = 90) and generalized MG (GMG) patients (n = 110). The fetal-type (2α: β: γ: δ) and adult-type (2α: β: ε: δ) AChR were used as antigens, and their relevance to disease presentation was assessed. RESULTS The overall frequencies of anti-adult and anti-fetal AChR antibodies were similar in all 200 patients examined, with 14 having serum specific to the AChR-Γ subunit, and 22 to the AChR-ε subunit. The overall sensitivity when using the fetal and adult AChR antibodies was higher than that when using the fetal AChR antibody only (P = 0.015). Compared with OMG patients, the mean age at disease onset and the positive ratio of antibodies to both isoforms of the AChR were significantly higher in patients who subsequently progressed to GMG. Older patients and patients with both anti-fetal and anti-adult AChR antibodies had a greater risk for developing generalized disease [odds ratio (OR), 1.03; 95% confidence interval (CI), 1.01-1.06 and OR, 5.09; 95% CI, 2.23-11.62]. CONCLUSION Using both fetal- and adult-type AChRs as the antigens may be more sensitive than using either subtype. Patients with serum specific to both isoforms are at a greater risk of progressing to GMG. Patients with disease onset at an advanced age appear to have a higher frequency of GMG conversion.
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Affiliation(s)
- Qi-Guang Shi
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, 300052, China
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Wu X, Tuzun E, Li J, Xiao T, Saini SS, Qi H, Allman W, Christadoss P. Ocular and generalized myasthenia gravis induced by human acetylcholine receptor γ subunit immunization. Muscle Nerve 2012; 45:209-16. [DOI: 10.1002/mus.22273] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Zambelis T, Kokotis P, Karandreas N. Repetitive nerve stimulation of facial and hypothenar muscles: relative sensitivity in different myasthenia gravis subgroups. Eur Neurol 2011; 65:203-7. [PMID: 21412008 DOI: 10.1159/000324915] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 02/06/2011] [Indexed: 11/19/2022]
Abstract
AIM To assess the utility of repetitive nerve stimulation (RNS) in facial and hypothenar muscles in the clinical groups of myasthenia gravis (MG). PATIENTS AND METHODS We performed RNS study in the orbicularis oculi (O.O.), nasalis and abductor digiti quinti (ADQ) in 115 consecutive myasthenic patients and classified them according to the classifications of the Myasthenia Gravis Foundation of America. Patients were classified into three groups: group 1, group 2 (IIa, IIIa and IVa) and group 3 (IIb, IIIb and IVb). RESULTS RNS was abnormal in 95 patients (82.6%): 78.3% in the O.O., 66.1% in the nasalis and 19.1% in the ADQ. Both facial muscles were statistically more sensitive than the ADQ in all groups of patients. RNS in the O.O. was more frequently abnormal than in the nasalis only in group 1. Sensitivity to acetylcholine antibodies in myasthenic patients was 84%. Acetylcholine receptor (AChR) and muscle-specific tyrosine kinase antibodies were present in 96.7% of the patients with abnormal RNS in both facial muscles. Single-fiber electromyogram (SFEMG) was abnormal in 91.3% of the tested patients. One of the three tests used for the diagnosis of MG (AChR antibodies, SFEMG, RNS) was abnormal in 99.1% of the patients. DISCUSSION O.O. is the most sensitive muscle in all groups of MG followed by nasalis, while the ADQ is the muscle with the lowest sensitivity. Facial muscles, especially the O.O., should be the first to be tested in MG. The negativity of all tests (RNS, AChR antibodies, SFEMG) should question the diagnosis of MG, even in the presence of symptoms consistent with MG.
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Affiliation(s)
- T Zambelis
- Department of Neurology, University of Athens, Aeghinition Hospital, Athens, Greece.
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Kusner LL, Kaminski HJ, Soltys J. Effect of complement and its regulation on myasthenia gravis pathogenesis. Expert Rev Clin Immunol 2010; 4:43-52. [PMID: 20477586 DOI: 10.1586/1744666x.4.1.43] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Myasthenia gravis (MG) is primarily caused by antibodies directed towards the skeletal muscle acetylcholine receptor, leading to muscle weakness. Although these antibodies may induce compromise of neuromuscular transmission by blocking acetylcholine receptor function or antigenic modulation, the predominant mechanism of injury to the neuromuscular junction is complement-mediated lysis of the postsynaptic membrane. The vast majority of data to support the role of complement derives from experimentally acquired MG (EAMG). In this article, we review studies that demonstrate the central role of complement in EAMG and MG pathogenesis along with the emerging role of complement in T- and B-cell function, as well as the potential for complement inhibitor-based therapy to treat human MG.
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Affiliation(s)
- Linda L Kusner
- Department of Neurology & Psychiatry, Saint Louis University, 1438 South Grand Blvd, St Louis, MO 63104, USA.
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Soltys J, Gong B, Kaminski HJ, Zhou Y, Kusner LL. Extraocular muscle susceptibility to myasthenia gravis: unique immunological environment? Ann N Y Acad Sci 2008; 1132:220-4. [PMID: 18567871 DOI: 10.1196/annals.1405.037] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Extraocular muscle (EOM) is susceptible to neuromuscular junction disorders, in particular, myasthenia gravis (MG). While EOM physiological characteristics and the ocular motor system requirements contribute to the propensity of ocular motor deficits observed among patients with MG, the authors propose that EOM have immunological features that place the muscles at risk for immune attack. Genomic profiling studies have demonstrated that genes associated with the immune response are differentially expressed in EOM, with particular differences in both classical and alternative complement-mediated immune response pathways. Intrinsic complement regulators are expressed at lower levels at rodent EOM neuromuscular junctions, which would put them at risk for the complement-mediated injury that occurs in MG. In fact, systemic C inhibition in experimental autoimmune MG (EAMG) induced by administration of acetylcholine receptor (AChR) antibodies or immunization with AChR will eliminate complement deposition at junctions of other skeletal muscle, but not EOM. Also, EOM junctions have greater injury in active and passive EAMG by several measures, suggesting that the lack of complement inhibition puts the EOM at risk. Among ocular myasthenia patients, serum AChR antibody levels are low, which would support the concept that EOM junctions are more susceptible to antibody injury than are other junctions. These observations suggest that complement inhibitory therapies may prove to be particularly effective in treatment of ocular myasthenia.
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Affiliation(s)
- Jindrich Soltys
- Department of Neurology & Psychiatry, Saint Louis University, 1438 South Grand Avenue, St. Louis, MO 63104, USA
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Abstract
PURPOSE OF REVIEW Increasing rigor is being applied to medical decision making, but myasthenia gravis, commonly considered the best understood autoimmune disorder from a pathophysiological basis, lags other disciplines in the evidence base used to make clinical decisions. The review attempts to provide a focused, practical guideline for the diagnosis and treatment of ocular myasthenia within the limits of largely retrospective case series and expert opinion. RECENT FINDINGS Confirmation of clinical diagnosis continues to be challenging for ocular myasthenia. Despite the recognition of a new autoantigen, the muscle-specific kinase protein in generalized myasthenia gravis, it has been found to be only rarely identified in ocular myasthenia patients and therefore the majority of patients lack detectable autoantibodies and confirmation of a neuromuscular transmission disorder relies on specialized testing of single-fiber electromyography. The visual compromise of ocular myasthenia responds poorly to nonpharmacological and cholinesterase inhibitor therapy, and although corticosteroids are thought to be extremely effective, their toxicity is poorly defined in ocular myasthenia patients and whether they reduce the risk of development of generalized disease is not known. SUMMARY Rigorous clinical trials or large databases with outcome assessments are necessary in order to allow development of rational treatment strategies.
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Khanna S, Liao K, Kaminski HJ, Tomsak RL, Joshi A, Leigh RJ. Ocular myasthenia revisited: Insights from pseudo-internuclear ophthalmoplegia. J Neurol 2007; 254:1569-74. [PMID: 17713827 DOI: 10.1007/s00415-007-0591-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 03/01/2007] [Accepted: 03/13/2007] [Indexed: 10/22/2022]
Abstract
Ocular myasthenia can mimic central disorders of eye movements. We compared horizontal saccades in two patients with myasthenia gravis who presented as pseudo-internuclear ophthalmoplegia (pseudo-INO), two patients with true INO due to multiple sclerosis (MS), and five healthy subjects. In myasthenics, peak velocity of horizontal saccades was similar to, or greater than, controls; in MS patients, adducting saccades were slower than controls. Differences between the peak velocity of abducting and adducting eyes for each saccade were similar to controls for myasthenic pseudo-INO, but greater than controls for true INO. Using the technique of phase-plane analysis, in which eye velocity is plotted against eye position, we found that initial components of abducting and adducting saccades in the myasthenics were as conjugate as controls, even though later components of myasthenic saccades were highly and variably disjunctive. Conversely, phase planes of saccades in true INO showed disjunctive early components of abducting and adducting saccades. Two hypotheses have been offered to account for preservation of fast saccades despite reduced range of eye movements in ocular myasthenia. The first is intrasaccadic neuromuscular fatigue, which is variable over time. Our finding that initial components of saccades were consistently conjugate in the myasthenics gives support to a second hypothesis: selective sparing of pale global fibers, which are important for generating highspeed eye movements, and which are unique amongst extraocular fibers in possessing well developed synaptic folding.
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Affiliation(s)
- Sangeeta Khanna
- Daroff-Dell'Osso Laboratory, Department of Neurology, Veterans Affairs Medical Center and University Hospitals Case Western Reserve University, Cleveland, Ohio 44106, USA
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Abstract
In recent years, understanding of the pathogenesis and clinical presentation of distinct myasthenia subtypes has increased significantly. This article reviews the clinical manifestations of autoimmune myasthenia gravis (including myasthenia associated with anti-muscle-specific kinase antibodies), ocular myasthenia, and antibody negative myasthenia. The following treatments are examined: cholinesterase inhibitors, immunosuppressants, and thymectomy. Inherited congenital myasthenic syndromes (CMS) are now increasingly recognized, and most commonly present during childhood. This article outlines the presynaptic, synaptic basal lamina-associated, and postsynaptic classification of CMS and the clinical presentation and aetiology of individual syndromes. Relevant investigations and treatment options (including the role of pyridostigmine, 3,4-diaminopyridine, fluoxetine, and ephedrine) are discussed.
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Affiliation(s)
- J R Parr
- University of Oxford Department of Paediatrics, Children's Hospital, Oxford, UK.
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