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Yang L, Chen X, Wu R. Afterdischarges in myotonic dystrophy type 1. Neurol Sci 2024; 45:735-740. [PMID: 37584878 DOI: 10.1007/s10072-023-07013-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 08/07/2023] [Indexed: 08/17/2023]
Abstract
OBJECTIVE Electrodiagnostic testing is an important screening test for myotonic dystrophy type 1 (DM1). Although myotonic discharges are observed on electromyography in cases of DM1, it is difficult to distinguish DM1 from other myotonic disorders clinically. In the present study, afterdischarges, another type of pathological potential revealed by electrodiagnostic testing, were analyzed, and their role in distinguishing DM1 from other myotonic disorders was explored. METHODS Data from 33 patients with myotonic discharges on electromyography were analyzed retrospectively. According to gene testing, the patients were divided into DM1 (n = 20) and non-DM1 myotonia (n = 13) groups. Afterdischarges were investigated by retrospectively evaluating the electrodiagnostic findings of motor nerve conduction studies, F-waves, and repetitive nerve stimulations. RESULTS Afterdischarges were observed in 17 of the 20 patients with DM1, with an occurrence rate of approximately 85%. However, afterdischarges were absent in all patients with non-DM1 myotonia. There were significant differences in the occurrence rate between the two groups (P < 0.01). CONCLUSION Afterdischarges may serve as a suggestive role in clinical diagnosis of DM1. The discovery that DM1 can present with afterdischarges may pave a new way to study the pathogenesis of DM1.
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Affiliation(s)
- Li Yang
- Electromyography Room, Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, 324 Jingwu Road, Jinan, Shandong, China.
| | - Xiuying Chen
- Electromyography Room, Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, 324 Jingwu Road, Jinan, Shandong, China
| | - Rui Wu
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, 324 Jingwu Road, Jinan, Shandong, China
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2
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Horibe T, Shimomura H, Tokunaga S, Taniguchi N, Lee T, Kimura S, Takeshima Y. A Pediatric Case of COLQ-Related Congenital Myasthenic Syndrome with Marked Fatigue. CHILDREN (BASEL, SWITZERLAND) 2023; 10:children10050769. [PMID: 37238317 DOI: 10.3390/children10050769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 04/19/2023] [Accepted: 04/21/2023] [Indexed: 05/28/2023]
Abstract
Congenital myasthenic syndrome (CMS) is a clinically and genetically heterogeneous inherited disorder that is treatable. Although the disease usually develops at birth or during infancy, some patients develop the disease in the second to third decades of life. Collagen-like tail subunit of asymmetric acetylcholinesterase (COLQ)-related CMS is CMS with mutations in the COLQ, which results in end-plate acetylcholinesterase deficiency. Diagnostic delay is common in patients with later-onset CMS due to slow progression and fluctuating symptoms. Understanding CMS with atypical and unusual presentations is important to treat this condition effectively. Here, we report a case of COLQ-related CMS. A 10-year-old girl presented with only marked fatigue, which was provoked by exercise but improved after 30-60 min of rest. While motor nerve conduction velocity was normal, a compound muscle action potential (CMAP) with four peaks was recorded. Repetitive stimulation of the accessory nerve exhibited a decrease in CMAP amplitude. Genetic tests revealed compound heterozygous mutations in COLQ (c.1196-1_1197delinsTG and c.1354C>T). Treatment with salbutamol improved fatigue but not the electrophysiological markers. Thus, significant fatigue is a hallmark of COLQ-related CMS; early diagnosis is essential for ensuring appropriate treatment.
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Affiliation(s)
- Takuya Horibe
- Department of Pediatrics, Hyogo Medical University School of Medicine, Nishinomiya 663-8501, Japan
| | - Hideki Shimomura
- Department of Pediatrics, Hyogo Medical University School of Medicine, Nishinomiya 663-8501, Japan
| | - Sachi Tokunaga
- Department of Pediatrics, Hyogo Medical University School of Medicine, Nishinomiya 663-8501, Japan
| | - Naoko Taniguchi
- Department of Pediatrics, Hyogo Medical University School of Medicine, Nishinomiya 663-8501, Japan
| | - Tomoko Lee
- Department of Pediatrics, Hyogo Medical University School of Medicine, Nishinomiya 663-8501, Japan
| | - Shigemi Kimura
- Children's Rehabilitation, Sleep and Development Medical Center, Hyogo Prefectural Rehabilitation Central Hospital, Kobe 651-2134, Japan
| | - Yasuhiro Takeshima
- Department of Pediatrics, Hyogo Medical University School of Medicine, Nishinomiya 663-8501, Japan
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3
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Modoni A, Mastrorosa A, Spagni G, Evoli A. Cholinergic hyperactivity in patients with myasthenia gravis with MuSK antibodies: A neurophysiological study. Clin Neurophysiol 2021; 132:1845-1849. [PMID: 34147009 DOI: 10.1016/j.clinph.2021.04.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/18/2021] [Accepted: 04/21/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Patients with myasthenia gravis associated with muscle-specific tyrosine kinase antibodies (MuSK-MG) often manifest signs of cholinergic hyperactivity with standard doses of acetylcholinesterase inhibitors (AChE-Is). Aim of the study was to investigate whether repetitive compound muscle action potential (R-CMAP), the neurophysiological correlate of cholinergic hyperactivity, was present in MuSK-MG irrespective of AChE-I treatment. METHODS Patients with confirmed diagnosis of MuSK-MG were consecutively enrolled during follow-up visits, from January 2019 to April 2020. All these subjects underwent the same neurophysiological protocol, including motor nerve conduction studies and repetitive nerve stimulation. In patients taking pyridostigmine, neurophysiological testing was performed at least 12 hours after the last dose. For comparison, the presence of R-CMAP was investigated in 20 consecutive acetylcholine receptor antibody positive myasthenia gravis (AChR-MG) patients. RESULTS We enrolled 25 MuSK-MG patients (20 females), aged 16-79 years at the study time, with disease duration ranging 0.6-48.8 years (median: 17.7 years). R-CMAP was detected in 12/25 (48%) MuSK-MG cases and in none of the AChR-MG controls (p = 0.0003). In the MuSK-MG population, a history of muscle cramps and fasciculations, during low-dose pyridostigmine therapy, was significantly more frequent in R-CMAP positive than in R-CMAP negative patients (100% vs 31%, p = 0.001). At the time of the study, the proportion of patients still symptomatic for MG was higher among R-CMAP positive cases (92% vs 23%, p = 0.0005). CONCLUSIONS Cholinergic hyperactivity is a relatively common finding in MuSK-MG patients, independent of AChE-I treatment, and may constitute an intrinsic feature of the disease. SIGNIFICANCE R-CMAP detection can represent a useful diagnostic clue for MuSK-MG and predicts poor tolerance to AChE-Is.
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Affiliation(s)
- Anna Modoni
- Unità Operativa Complessa di Neurologia, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Largo A. Gemelli, 8 - 00168 Rome, Italy
| | - Alessia Mastrorosa
- IRCCS Fondazione Don Gnocchi ONLUS, via di Scandicci 269, 50143, Florence, Italy
| | - Gregorio Spagni
- Dipartimento di Neuroscienze, Università Cattolica del Sacro Cuore, Largo F. Vito, 1 - 00168 Rome, Italy.
| | - Amelia Evoli
- Unità Operativa Complessa di Neurologia, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Largo A. Gemelli, 8 - 00168 Rome, Italy; Dipartimento di Neuroscienze, Università Cattolica del Sacro Cuore, Largo F. Vito, 1 - 00168 Rome, Italy
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4
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Yang L, Guo S, Chen X. Afterdischarges in Myasthenia Gravis. Front Neurol 2021; 12:599744. [PMID: 33927677 PMCID: PMC8078411 DOI: 10.3389/fneur.2021.599744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 03/17/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: This study aimed to analyze the clinical features of myasthenia gravis (MG) in combination with the afterdischarges and compare the characteristics of afterdischarges in MG with different serum antibodies. Methods: Ninety-two patients with MG were analyzed retrospectively. The afterdischarges were investigated using motor nerve conduction examination, F-wave examination, and repetitive nerve stimulation (RNS). Results: Afterdischarges were observed after the M wave in 14 of 92 patients. Three of these 14 patients tested positive for the muscle-specific tyrosine kinase antibody (MuSK-Ab), and 11 patients tested positive for the acetylcholine receptor antibody (AchR-Ab). The characteristics of the afterdischarges on RNS differed distinctly between the two antibody groups. The afterdischarges occurred on the first stimulation, but decreased on the second and subsequent stimulations in patients with MuSK-MG, while the afterdischarges continued to occur on each stimulation in patients with AchR-MG. Discussion: The characteristics of the afterdischarges on RNS enabled easy identification of their synaptic or neurogenic nature.
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Affiliation(s)
- Li Yang
- Electromyography Room, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Shougang Guo
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Xiuying Chen
- Electromyography Room, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
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5
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Parissis D, Ioannidis P. After discharges following compound muscle action potential in CASPR2 antibody-related disease. Pract Neurol 2021; 21:practneurol-2020-002901. [PMID: 33658285 DOI: 10.1136/practneurol-2020-002901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2021] [Indexed: 11/04/2022]
Affiliation(s)
- Dimitrios Parissis
- AHEPA Hospital, 2nd Department of Neurology, Aristotle University of Thessaloniki, Faculty of Health Sciences, Thessaloniki, Central Macedonia, Greece
| | - Panagiotis Ioannidis
- AHEPA Hospital, 2nd Department of Neurology, Aristotle University of Thessaloniki, Faculty of Health Sciences, Thessaloniki, Central Macedonia, Greece
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6
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Muscle-Specific Tyrosine Kinase Antibody Positive Myasthenia Gravis With Peripheral Nerve Hyperexcitability: Case Report and Literature Review. Clin Neuropharmacol 2021; 44:57-61. [PMID: 33470659 DOI: 10.1097/wnf.0000000000000432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Administration of acetylcholinesterase inhibitors can bring about peripheral nerve hyperexcitability symptom in muscle-specific tyrosine kinase antibody positive myasthenia gravis, but the changes in electromyography before and after drug withdrawal have not been described in detail. METHODS Electromyography was performed on a case of muscle-specific tyrosine kinase antibody positive myasthenia gravis with peripheral nerve hyperexcitability correlated with the administration of pyridostigmine bromide before and after drug withdrawal, respectively. RESULTS Afterdischarges close after M waves appeared on the tibial nerve, common peroneal nerve, median nerve, and ulnar nerve, and these presented unique characteristics in repetitive nerve stimulation. Ten days after pyridostigmine bromide withdrawal, the second electromyography examination was carried out and showed that the afterdischarges on all nerves disappeared dramatically and the amplitude of tibial nerve F waves was elevated than before. CONCLUSIONS Afterdischarges can be an important indicator of muscle-specific tyrosine kinase antibody positive myasthenia gravis with peripheral nerve hyperexcitability correlated with acetylcholinesterase inhibitors.
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7
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Stephens BD, Kang MK. Pearls & Oy-sters: The Myasthenic Double Humps. Neurology 2020; 96:545-547. [PMID: 33277409 DOI: 10.1212/wnl.0000000000011287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Brian D Stephens
- From the Department of Neurology, University of California, San Francisco.
| | - Min K Kang
- From the Department of Neurology, University of California, San Francisco
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8
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Kang PB, McMillan HJ, Kuntz NL, Lehky TJ, Alter KE, Fitzpatrick KF, El Kosseifi C, Quijano-Roy S. Utility and practice of electrodiagnostic testing in the pediatric population: An AANEM consensus statement. Muscle Nerve 2020; 61:143-155. [PMID: 31724199 DOI: 10.1002/mus.26752] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 11/06/2019] [Indexed: 12/17/2022]
Abstract
Nerve conduction studies and needle electromyography, collectively known as electrodiagnostic (EDX) studies, have been available for pediatric patients for decades, but the accessibility of this diagnostic modality and the approach to testing vary significantly depending on the physician and institution. The maturation of molecular diagnostic approaches and other diagnostic technologies such as neuromuscular ultrasound indicate that an analysis of current needs and practices for EDX studies in the pediatric population is warranted. The American Association of Neuromuscular & Electrodiagnostic Medicine convened a consensus panel to perform literature searches, share collective experiences, and develop a consensus statement. The panel found that electrodiagnostic studies continue to have high utility for the diagnosis of numerous childhood neuromuscular disorders, and that standardized approaches along with the use of high-quality reference values are important to maximize the diagnostic yield of these tests in infants, children, and adolescents.
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Affiliation(s)
- Peter B Kang
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, Florida.,Department of Neurology, University of Florida College of Medicine, Gainesville, Florida
| | - Hugh J McMillan
- Department of Pediatrics, University of Ottawa and Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Nancy L Kuntz
- Department of Pediatrics, Northwestern University Feinberg School of Medicine and Lurie Children's Hospital, Chicago, Illinois
| | - Tanya J Lehky
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland
| | - Katharine E Alter
- Functional and Applied Biomechanics Section, Rehabilitation Medicine, National Institutes of Health Clinical Center, Bethesda, Maryland
| | - Kevin F Fitzpatrick
- Inova Neuroscience and Spine Institute, Inova Fairfax Hospital, Falls Church, Virginia
| | - Charbel El Kosseifi
- Centre de Référence Maladies Neuromusculaires, Service de Neurologie, Réanimation et Réeducation Pédiatriques, Hôpital Raymond Poincaré, Garches, France
| | - Susana Quijano-Roy
- Centre de Référence Maladies Neuromusculaires, Service de Neurologie, Réanimation et Réeducation Pédiatriques, Hôpital Raymond Poincaré, Garches, France
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Naik KR, Saroja AO, Hesarur N, Patil RS. Prospective Hospital-Based Clinical and Electrophysiological Evaluation of Acute Organophosphate Poisoning. Ann Indian Acad Neurol 2019; 22:91-95. [PMID: 30692766 PMCID: PMC6327708 DOI: 10.4103/aian.aian_137_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Introduction: Acute organophosphate (OP) poisoning is one of the most common poisoning causing significant morbidity and mortality in developing countries. Acute cholinergic manifestations predominate with many patients requiring intensive care management and ventilator support. Nerve conduction studies including repetitive nerve stimulation can evaluate the altered neuromuscular transmission and peripheral nerve function by OPs. Objective: To evaluate the electrophysiological abnormalities in patients with acute OP poisoning and correlate with clinical status. Materials and Methods: Patients with acute OP poisoning admitted from August 2016 to August 2017 were prospectively studied. Nerve conduction studies including phrenic nerve conduction were performed within 24 h of admission. Repetitive nerve stimulation was performed at 3 and 30 Hz. Nerve conduction findings were compared with data from age-matched healthy controls. Results: Thirty patients were included (18 men and 12 women) in the study. Their age ranged from 16 to 47 years (30 ± 9.2). The first assessment revealed a mild reduction of compound muscle action potential (CMAP) amplitude and reduced F-wave persistence. Eleven patients had repetitive CMAPs suggesting cholinergic excess. Seven among the 11 patients requiring mechanical ventilation had decrement–increment response with 30 Hz stimulation and reduced diaphragmatic CMAP amplitude (P = 0.02). Conclusion: The presence of repetitive CMAPs, decrement–increment response to tetanic stimulation and reduced diaphragmatic CMAP amplitude in OP poisoning patients correlate with neuromuscular paralysis and need for mechanical ventilation.
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Affiliation(s)
- Karkal Ravishankar Naik
- Department of Neurology, Jawaharlal Nehru Medical College and KLES Dr. Prabhakar Kore Hospital and MRC, Belagavi, Karnataka, India
| | - Aralikatte Onkarappa Saroja
- Department of Neurology, Jawaharlal Nehru Medical College and KLES Dr. Prabhakar Kore Hospital and MRC, Belagavi, Karnataka, India
| | - Nagabushan Hesarur
- Department of Neurology, Jawaharlal Nehru Medical College and KLES Dr. Prabhakar Kore Hospital and MRC, Belagavi, Karnataka, India
| | - Rekha Satish Patil
- Department of Medicine, Jawaharlal Nehru Medical College and KLES Dr. Prabhakar Kore Hospital and MRC, Belagavi, Karnataka, India
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10
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[Congenital myasthenic syndromes in adulthood : Challenging, rare but treatable]. DER NERVENARZT 2018; 90:148-159. [PMID: 29974128 DOI: 10.1007/s00115-018-0562-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The congenital myasthenic syndromes (CMS) represent a heterogeneous group of diseases with a broad spectrum of phenotypes. The common characteristic is an inherited genetic defect of the neuromuscular junction. Although in some patients the specific gene defect remains to be detected, the increasing identification of causative genes in recent years has already provided unique insights into the functionality of structural proteins at the neuromuscular junction. Neonatal and early childhood onset is observed in most CMS subtypes; however, late onset in adolescence or adulthood also occurs and establishing the diagnosis at these stages imposes particular challenges. To enable appropriate therapeutic interventions for an at least in principle treatable condition, determining the genetic cause is warranted. In this overview, the critical clinical and diagnostic features of the different CMS subtypes are presented and illustrated using typical cases. Furthermore, specific diagnostic clues are outlined. Finally, the overlap between CMS and muscular dystrophies is discussed. Illustrating characteristic patient examples, the essential clinical and additional diagnostic findings of various CMS subtypes and special diagnostic indications are presented.
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11
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Ding Q, Shen D, Dai Y, Hu Y, Guan Y, Liu M, Cui L. Mechanism hypotheses for the electrophysiological manifestations of two cases of endplate acetylcholinesterase deficiency related congenital myasthenic syndrome. J Clin Neurosci 2017; 48:229-232. [PMID: 29150079 DOI: 10.1016/j.jocn.2017.10.084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 10/23/2017] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To summarize the electrophysiological characteristics of two cases of endplate acetylcholinesterase deficiency (EAD) related congenital myasthenic syndrome (CMS) caused by COLQ mutation and to discuss the possible mechanism of these electrophysiological phenomena. METHODS Electrophysiological examinations were conducted including nerve conduction studies, routine electromyography (EMG), repetitive nerve stimulation (RNS) and single fiber EMG (SFEMG). The ulnar nerve was also stimulated at 50 Hz followed by 0.5 Hz to record the recovery process of compound muscle action potential (CMAP). RESULTS Repetitive CMAP (R-CMAP) was found in motor nerve conduction in both cases. Needle EMG showed myogenic damages and SFEMG showed remarkably increased jitter values. Of note, the amplitude of CMAP and R-CMAP showed regular changing trends, and so did their time intervals in RNS studies. CONCLUSIONS The change patterns of CMAP and R-CMAP, in combination with other electrophysiological features are very useful for the diagnosis of EAD related CMS, especially in predicting the presence of correct gene mutations.
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Affiliation(s)
- Qingyun Ding
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China.
| | - Dongchao Shen
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China.
| | - Yi Dai
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China.
| | - Youfang Hu
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China.
| | - Yuzhou Guan
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China.
| | - Mingsheng Liu
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China; Neuroscience Center, Chinese Academy of Medical Sciences, Beijing 100730, China.
| | - Liying Cui
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China; Neuroscience Center, Chinese Academy of Medical Sciences, Beijing 100730, China.
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12
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Lee HE, Kim YH, Kim SM, Shin HY. Clinical Significance of Repetitive Compound Muscle Action Potentials in Patients with Myasthenia Gravis: A Predictor for Cholinergic Side Effects of Acetylcholinesterase Inhibitors. J Clin Neurol 2016; 12:482-488. [PMID: 27819419 PMCID: PMC5063876 DOI: 10.3988/jcn.2016.12.4.482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/05/2016] [Accepted: 05/09/2016] [Indexed: 01/27/2023] Open
Abstract
Background and Purpose Acetylcholinesterase inhibitors (AChEIs) are widely used to treat myasthenia gravis (MG). Although AChEIs are usually tolerated well, some MG patients suffer from side effects. Furthermore, a small proportion of MG patients show cholinergic hypersensitivity and cannot tolerate AChEIs. Because repetitive compound muscle action potentials (R-CMAPs) are an electrophysiologic feature of cholinergic neuromuscular hyperactivity, we investigated the clinical characteristics of MG patients with R-CMAPs to identify their clinical usefulness in therapeutic decision-making. Methods We retrospectively reviewed the clinical records and electrodiagnostic findings of MG patients who underwent electrodiagnostic studies and diagnostic neostigmine testing (NT). Results Among 71 MG patients, 9 could not tolerate oral pyridostigmine bromide (PB) and 17 experienced side effects of PB. R-CMAPs developed in 24 patients after NT. The highest daily dose of PB was lower in the patients with R-CMAPs (240 mg/day vs. 480 mg/day, p<0.001). The frequencies of PB intolerance and side effects were higher in the patients with R-CMAPs than in those without R-CMAPs [37.5% vs. 0% (p<0.001) and 45.8% vs. 12.8% (p=0.002), respectively]. The MG Foundation of America postintervention status did not differ significantly between MG patients with and without R-CMAPs, and the response to immunotherapy was also good in both groups. Conclusions Side effects of and intolerance to AChEIs are more common in MG patients with R-CMAPs than in those without R-CMAPs. AChEIs should be used carefully in MG patients with R-CMAPs. The presence of R-CMAPs after NT may be a good indicator of the risks of PB side effects and intolerance.
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Affiliation(s)
- Hyo Eun Lee
- Department of Neurology, Keimyung University Kyungju Dongsan Hospital, Gyeongju, Korea
| | - Yool-hee Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - Seung Min Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - Ha Young Shin
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
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13
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Shin HY, Park HJ, Lee HE, Choi YC, Kim SM. Clinical and Electrophysiologic Responses to Acetylcholinesterase Inhibitors in MuSK-Antibody-Positive Myasthenia Gravis: Evidence for Cholinergic Neuromuscular Hyperactivity. J Clin Neurol 2014; 10:119-24. [PMID: 24829597 PMCID: PMC4017014 DOI: 10.3988/jcn.2014.10.2.119] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 10/25/2013] [Accepted: 10/28/2013] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND AND PURPOSE Patients with muscle-specific tyrosine kinase (MuSK) antibody (MuSK-Ab)-positive myasthenia gravis (MG) show distinct responses to acetylcholinesterase inhibitors (AChEIs). Although clinical responses to AChEIs in MuSK-Ab MG are reasonably well known, little is known about the electrophysiologic responses to AChEIs. We therefore investigated the clinical and electrophysiologic responses to AChEIs in MuSK-Ab-positive MG patients. METHODS We retrospectively reviewed the medical records and electrodiagnostic findings of 17 MG patients (10 MuSK-Ab-positive and 7 MuSK-Ab-negative patients) who underwent electrodiagnostic testing before and after a neostigmine test (NT). RESULTS The frequency of intolerance to pyridostigmine bromide (PB) was higher in MuSK-Ab-positive patients than in MuSK-Ab-negative patients (50% vs. 0%, respectively; p=0.044), while the maximum tolerable dose of PB was lower in the former (90 mg/day vs. 480 mg/day, p=0.023). The frequency of positive NT results was significantly lower in MuSK-Ab-positive patients than in MuSK-Ab-negative patients (40% vs. 100%, p=0.035), while the nicotinic side effects of neostigmine were more frequent in the former (80% vs. 14.3%, p=0.015). Repetitive compound muscle action potentials (R-CMAPs) developed more frequently after NT in MuSK-Ab-positive patients than in MuSK-Ab-negative patients (90% vs. 14.3%, p=0.004). The frequency of a high-frequency-stimulation-induced decrement-increment pattern (DIP) was higher in MuSK-Ab-positive patients than in MuSK-Ab-negative patients (100% vs. 17.7%, p=0.003). CONCLUSIONS These results suggest that MuSK-Ab-positive MG patients exhibit unique and hyperactive responses to AChEIs. Furthermore, R-CMAP and DIP development on a standard AChEI dose may be a distinct neurophysiologic feature indicative of MuSK-Ab-positive MG.
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Affiliation(s)
- Ha Young Shin
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - Hyung Jun Park
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - Hyo Eun Lee
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - Young-Chul Choi
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - Seung Min Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
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14
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Byun JI, Moon HJ, Hong YH. Myasthenia in acquired neuromyotonia. J Clin Neurol 2014; 10:69-71. [PMID: 24465267 PMCID: PMC3896653 DOI: 10.3988/jcn.2014.10.1.69] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 12/17/2012] [Accepted: 12/17/2012] [Indexed: 11/17/2022] Open
Abstract
Background Acquired neuromyotonia (NMT) forms part of the spectrum of acquired peripheral nerve hyperexcitability syndrome, and is thought to be caused by antibodies to voltage-gated potassium channels (VGKC). Exertional weakness is unusual unless autoimmune myasthenia gravis (MG) is superimposed. Case Report A case of acquired NMT accompanied by exertional weakness without coexistence of seropositive MG is reported herein. Conclusions Clinical and electrophysiological observations suggest that the cholinergic overactivity in NMT can compromise the safety factor sufficiently to cause a defect in neuromuscular junction transmission.
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Affiliation(s)
- Jung-Ick Byun
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Hye-Jin Moon
- Department of Neurology, Keimyung University Dongsan Medical Center, Daegu, Korea
| | - Yoon-Ho Hong
- Department of Neurology, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, Korea
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So NF, Rubin DI, Jones LK, Litchy WJ, Sorenson EJ. Motor unit potential induced repetitive discharges (MIRDs): Description of an unusual iterative discharge. Muscle Nerve 2013; 48:977-9. [DOI: 10.1002/mus.24074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 09/01/2013] [Accepted: 09/03/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Noel F. So
- Department of Physical Medicine and Rehabilitation; Mayo Clinic; Rochester Minnesota USA
| | - Devon I. Rubin
- Department of Neurology; Mayo Clinic; Jacksonville Florida USA
| | - Lyell K. Jones
- Mayo Clinic; Department of Neurology; 200 First Street SW Rochester Minnesota 55905 USA
| | - William J. Litchy
- Mayo Clinic; Department of Neurology; 200 First Street SW Rochester Minnesota 55905 USA
| | - Eric J. Sorenson
- Mayo Clinic; Department of Neurology; 200 First Street SW Rochester Minnesota 55905 USA
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16
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Zhang RX, Lu ZH, Wan DS, Wu XJ, Ding PR, Kong LH, Pan ZZ, Chen G. Neuroprotective effect of neurotropin on chronic oxaliplatin-induced neurotoxicity in stage II and stage III colorectal cancer patients: results from a prospective, randomised, single-centre, pilot clinical trial. Int J Colorectal Dis 2012; 27:1645-50. [PMID: 22664945 DOI: 10.1007/s00384-012-1509-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/23/2012] [Indexed: 02/04/2023]
Abstract
BACKGROUND Oxaliplatin is effective in adjuvant and first-line colorectal cancer chemotherapy. Oxaliplatin-induced severe chronic neurotoxicity is the main dose-limiting adverse event. No standard treatment for oxaliplatin-induced chronic neurotoxicity has been identified. MATERIALS AND METHODS We conducted a prospective pilot clinical trial to explore whether neurotropin has neuroprotective effects on chronic neurotoxicity. From May 1, 2010 to May 1, 2011, 80 stage II and III colorectal cancer patients who were eligible to receive oxaliplatin-based chemotherapy voluntarily enrolled in the trial. The patients were randomly divided into two groups, one of which received neurotropin treatment. RESULTS The patients in the control group experienced significantly ≥ grade 2 and ≥ grade 3 neurotoxicity (by NCI CTCAE grading) than those in the neurotropin group (60.9 vs. 21.1 %, for at least grade 2 neurotoxicity, P = 0.001; 39 vs. 2.7 %, for at least grade 3 neurotoxicity, P < 0.001). If neurotoxicity was assessed by oxaliplatin-specific neurotoxicity grading, the patients in the control group also experienced significantly more ≥ grade 2 neurotoxicity (51.2 vs. 12.5 %, P = 0.001). Neurotropin was the only factor that affected the incidence of ≥ grade 2 neurotoxicity in the multivariate Cox proportional hazards regression analysis. CONCLUSION Neurotropin combined with oxaliplatin decreases chronic neurotoxicity effectively and safely.
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Affiliation(s)
- R X Zhang
- Department of Colorectal Surgery, Sun Yat-sen University Cancer Centre, Guangzhou, Guangdong, 510060, People's Republic of China.
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17
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Abstract
This article reviews the use of electrodiagnostic testing in disorders of neuromuscular transmission and discusses the differences between various presynaptic and postsynaptic disorders. Attention is paid to quality control issues that influence the sensitivity of repetitive nerve stimulation and single fiber electromyography. Electrodiagnostic testing, when used as an extension of the clinician's history and physical examination, will provide appropriate direction in establishing the diagnosis.
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Affiliation(s)
- James F Howard
- Neuromuscular Disorders Section, Department of Neurology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7025, USA.
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18
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Chroni E, Punga AR. Neurophysiological characteristics of MuSK antibody positive myasthenia gravis mice: focal denervation and hypersensitivity to acetylcholinesterase inhibitors. J Neurol Sci 2012; 316:150-7. [PMID: 22251934 DOI: 10.1016/j.jns.2011.12.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 12/20/2011] [Accepted: 12/22/2011] [Indexed: 11/17/2022]
Abstract
Myasthenia Gravis (MG) patients with antibodies against the muscle specific tyrosine kinase (MuSK+) typically present with focal fatigue and atrophy of the facial and bulbar muscles, along with unbeneficial reactions upon administration of acetylcholinesterase inhibitors (AChEIs). This study addresses the neurophysiological characteristics in facial versus limb muscles, before and after intraperitoneal injection of AChEIs, in mice immunized with MuSK. We performed in-vivo neurophysiological examinations in the masseter and gastrocnemius muscles of mice with MuSK+experimental autoimmune MG (EAMG) and in healthy control mice before and after administration of AChEIs. Abnormal spontaneous activity (fibrillations) was observed in the masseter muscle of MuSK+mice. Furthermore, 94% of MuSK-immunized mice displayed so called extra discharges (EDs) upon administration of a therapeutic AChEI dose, in contrast to 22% of the control mice, indicating neuromuscular hyperactivity. These findings support functional denervation in the masseter muscle and neuromuscular hypersensitivity already at a standard dose of AChEIs in MuSK+EAMG.
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Affiliation(s)
- Elisabeth Chroni
- Department of Neurology, School of Medicine, University of Patras, Patras, Greece
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19
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20
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Pelkonen A, Yavich L. Neuromuscular pathology in mice lacking alpha-synuclein. Neurosci Lett 2010; 487:350-3. [PMID: 21029764 DOI: 10.1016/j.neulet.2010.10.054] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 10/19/2010] [Accepted: 10/19/2010] [Indexed: 10/18/2022]
Abstract
This work was undertaken in order to study the possible role of alpha-synuclein in the function of the neuro-muscular junction in skeletal muscles. Repeated stimulation of skeletal muscle motor neurons revealed signs of neuromuscular pathology in alpha-synuclein null mutated (C57Bl/6JOlaHsd) and knockout (B6;129X1-Snca(tm1Rosl)/J) mice. This stimulation produced repetitive compound muscle action potentials in both lines of alpha-synuclein deficient mice. Muscle strength and muscle coordination during ambulation were unaffected, though motor learning was slower in alpha-synuclein deficient mice in the Rotarod test. We conclude that alpha-synuclein may play a role in acetylcholine compartmentalization at the neuromuscular junction, and in the fine control of activity of skeletal muscles.
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Affiliation(s)
- Anssi Pelkonen
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland.
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21
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Kumar RS, Kuruvilla A. Repetitive compound muscle action potentials in electrophysiological diagnosis of congenital myasthenic syndromes: a case report and review of literature. Ann Indian Acad Neurol 2010; 13:139-41. [PMID: 20814500 PMCID: PMC2924514 DOI: 10.4103/0972-2327.64645] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 04/24/2009] [Accepted: 05/22/2009] [Indexed: 11/04/2022] Open
Abstract
Congenital myasthenic syndromes (CMSs) are a heterogeneous group of disorders, characterized by dysfunction of neuromuscular junction (NMJ) transmission. These syndromes are genetically inherited and are present since birth. Some have characteristic clinical or electrodiagnostic features but in many cases determination of the specific form requires genetic studies or specialized morphological and electrophysiological studies on muscle tissue. We report a case of a 4-year-old boy with progressive ptosis and limitation of ocular movements who was diagnosed as slow-channel CMS based on the characteristic electrodiagnostic features. Repetitive compound muscle action potentials (R-CMAPs) were recorded after single nerve stimulus, with decremental response after repetitive trains performed at 3 Hz. CMSs are at times clinically difficult to distinguish from acquired myasthenia. The characteristic clinical and electrodiagnostic features help in the diagnosis and enable rational therapy. In this article we discuss the characteristics of synaptic R-CMAPs.
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Affiliation(s)
- R Shiva Kumar
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India.
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22
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Hill A, Bergin P, Hanning F, Thompson P, Findlay M, Damianovich D, McKeage MJ. Detecting acute neurotoxicity during platinum chemotherapy by neurophysiological assessment of motor nerve hyperexcitability. BMC Cancer 2010; 10:451. [PMID: 20731872 PMCID: PMC2936328 DOI: 10.1186/1471-2407-10-451] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Accepted: 08/23/2010] [Indexed: 12/22/2022] Open
Abstract
Background Platinum-based drugs, such as cisplatin and oxaliplatin, are well-known for inducing chronic sensory neuropathies but their acute and motor neurotoxicities are less well characterised. Use was made of nerve conduction studies and needle electromyography (EMG) to assess motor nerve excitability in cancer patients during their first treatment cycle with platinum-based chemotherapy in this study. Methods Twenty-nine adult cancer patients had a neurophysiological assessment either before oxaliplatin plus capecitabine, on days 2 to 4 or 14 to 20 after oxaliplatin plus capecitabine, or on days 2 to 4 after carboplatin plus paclitaxel or cisplatin, undertaken by a neurophysiologist who was blinded to patient and treatment details. Patients completed a symptom questionnaire at the end of the treatment cycle. Results Abnormal spontaneous high frequency motor fibre action potentials were detected in 100% of patients (n = 6) and 72% of muscles (n = 22) on days 2 to 4 post-oxaliplatin, and in 25% of patients (n = 8) and 13% of muscles (n = 32) on days 14 to 20 post-oxaliplatin, but in none of the patients (n = 14) or muscles (n = 56) tested prior to oxaliplatin or on days 2 to 4 after carboplatin plus paclitaxel or cisplatin. Repetitive compound motor action potentials were less sensitive and less specific than spontaneous high frequency motor fibre action potentials for detection of acute oxaliplatin-induced motor nerve hyperexcitability but were present in 71% of patients (n = 7) and 32% of muscles (n = 32) on days 2 to 4 after oxaliplatin treatment. Acute neurotoxicity symptoms, most commonly cold-induced paraesthesiae and jaw or throat tightness, were reported by all patients treated with oxaliplatin (n = 22) and none of those treated with carboplatin plus paclitaxel or cisplatin (n = 6). Conclusions Abnormal spontaneous high frequency motor fibre activity is a sensitive and specific endpoint of acute oxaliplatin-induced motor nerve hyperexcitability, detectable on EMG on days 2 to 4 post-treatment. Objective EMG assessment of motor nerve excitability could compliment patient-reported symptomatic endpoints of acute oxaliplatin-induced neurotoxicity in future studies.
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Affiliation(s)
- Andrew Hill
- Cancer Clinical Pharmacology Research Group, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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23
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Abstract
Myasthenia gravis (MG) is an autoimmune disorder usually caused by antibodies against either the acetylcholine receptor (AChR) or muscle-specific tyrosine kinase (MuSK) at the neuromuscular junction. Neuromuscular transmission failure results in muscle fatigue and weakness that can be treated symptomatically with acetylcholinesterase inhibitors (AChEIs). Long-term treatment with nonselective AChEIs may have considerable drawbacks; thus, this medication is ideally tapered when strength improves. Patients with AChR antibodies respond beneficially to treatment, whereas patients with MuSK antibodies generally do not. Recently, the selective AChEI EN101, which specifically targets the isoform of "read-through" AChE (AChE-R), has been developed and may be of importance for symptomatic relief in AChR-antibody seropositive MG. This article is a review of the mechanisms, therapeutic effects, and drawbacks, with both old and new AChEIs in MG.
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Affiliation(s)
- Anna Rostedt Punga
- Department of Clinical Neurophysiology, Uppsala University Hospital, 75185 Uppsala, Sweden.
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24
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Lorenzoni PJ, Scola RH, Gervini BL, Kay CSK, Werneck LC. Electrophysiological study in synaptic congenital myasthenic syndrome: end-plate acetylcholinesterase deficiency. ARQUIVOS DE NEURO-PSIQUIATRIA 2009; 67:502-4. [DOI: 10.1590/s0004-282x2009000300024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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25
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Punga AR, Sawada M, Stålberg EV. Electrophysiological signs and the prevalence of adverse effects of acetylcholinesterase inhibitors in patients with myasthenia gravis. Muscle Nerve 2008; 37:300-7. [PMID: 18069667 DOI: 10.1002/mus.20935] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The aim of this prospective study was to assess whether extra discharges (EDs), sometimes following the compound muscle action potential, could be used as a neurophysiological indicator of overdose of acetylcholinesterase inhibitors (AChEIs) in patients with myasthenia gravis (MG). The characteristics and frequency of EDs were explored and the correlation of EDs with cholinergic side effects was also determined. Twenty-two MG patients (14 women, 8 men; 61 +/- 16 years of age) with daily AChEI treatment were examined. The mean disease duration was 10 years (range 2-62 years) and all patients had been treated with AChEI since MG onset. Both single and repetitive stimulation of the ulnar and accessory nerves were performed before and 60 min after oral pyridostigmine bromide (PB) administration and after additional edrophonium injection. Fatigue, side effects, and AChE activity in blood were assessed before and 60 min after PB intake. The daily dose of PB ranged from 150 to 900 mg/day. Fourteen patients (64%) experienced daily cholinergic adverse effects, and muscarinic side effects correlated with AChE activity. Eleven patients (50%) developed EDs after oral PB. Among the eight patients with daily nicotinic side effects, EDs were significantly (P < 0.05) more common. Additionally, older patients were more prone to develop cholinergic side effects and EDs. Thus, when EDs are found, patients should be asked about daily muscular symptoms, which may be related to AChEI treatment and not solely to MG.
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Affiliation(s)
- Anna Rostedt Punga
- Department of Clinical Neurophysiology, Uppsala University Hospital, 751 85 Uppsala, Sweden.
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26
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Argyriou AA, Polychronopoulos P, Iconomou G, Chroni E, Kalofonos HP. A review on oxaliplatin-induced peripheral nerve damage. Cancer Treat Rev 2008; 34:368-77. [PMID: 18281158 DOI: 10.1016/j.ctrv.2008.01.003] [Citation(s) in RCA: 212] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Revised: 01/07/2008] [Accepted: 01/08/2008] [Indexed: 01/24/2023]
Abstract
Platinum compounds are a class of chemotherapy agents that posses a broad spectrum of activity against several solid malignancies. Oxaliplatin (OXL) is a third-generation organoplatinum compound with significant activity mainly against colorectal cancer (CRC). Peripheral neuropathy is a well recognized toxicity of OXL, usually resulting in dose modification. OXL induces two types of peripheral neuropathy; acute and chronic. The acute oxaliplatin-induced peripheral neuropathy (OXLIPN) may be linked to the rapid chelation of calcium by OXL-induced oxalate and OXL is capable of altering the voltage-gated sodium channels through a pathway involving calcium ions. On the other hand, decreased cellular metabolism and axoplasmatic transport resulting from the accumulation of OXL in the dorsal root ganglia cells is the most widely accepted mechanism of chronic oxaliplatin-induced peripheral neuropathy (OXLIPN). As a result, OXL produces a symmetric, axonal, sensory distal primary neuronopathy without motor involvement. The incidence of OXLIPN is usually related to various risk factors, including treatment schedule, dosage, cumulative dose and time of infusion. The assessment of OXLIPN is primarily based on neurologic clinical examination and quantitative methods, such as nerve conduction study. To date, several neuroprotective agents including thiols, neurotrophic factors, anticonvulsants and antioxidants have been tested for their ability to prevent OXLIPN. However, the clinical data are still controversial. We herein review and discuss the pathogenesis, incidence, risk factors, diagnosis, characteristics and management of OXLIPN. We also highlight areas of future research.
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Affiliation(s)
- Andreas A Argyriou
- Department of Neurology, EMG Laboratory, University of Patras Medical School, Rion-Patras, Greece
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27
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Vernino S. Peripheral nerve hyperexcitability and the neuromuscular junction. HANDBOOK OF CLINICAL NEUROLOGY 2008; 91:433-443. [PMID: 18631852 DOI: 10.1016/s0072-9752(07)01514-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Steven Vernino
- University of Texas Southwestern Medical Center, Dallas, TX, USA.
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28
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Lorenzoni PJ, Kay CSK, Arruda WO, Scola RH, Werneck LC. Estudo neurofisiológico na síndrome miastênica congênita do canal lento: relato de caso. ARQUIVOS DE NEURO-PSIQUIATRIA 2006; 64:318-21. [PMID: 16791378 DOI: 10.1590/s0004-282x2006000200028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A síndrome do canal lento é uma das síndromes miastênicas congênitas atribuída a desordem dinâmica do canal iônico do receptor de acetilcolina da junção neuromuscular. Descrevemos o caso de um homem de 25 anos com progressiva ptose palpebral e limitação da movimentação ocular desde infância, que evoluiu há 6 anos com piora da oftalmoparesia externa e diminuição da força muscular em ombros e mãos. O estudo da condução nervosa motora após estímulo único demonstrou duplo potencial de ação muscular composto (PAMC) com desaparecimento do segundo após esforço de 30 segundos. Ao estímulo repetitivo dos nervos facial e acessório observou-se um decremento da amplitude do PAMC maior que 10% com desaparecimento do segundo potencial. O paciente fez uso de fluoxetina mostrando discreta melhora da força muscular, porém persiste com: ptose palpebral, limitação dos movimentos oculares e PAMC repetitivo ao estudo da condução nervosa motora. As características da doença são discutidas.
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Affiliation(s)
- Paulo José Lorenzoni
- Serviço de Doenças Neuromusculares, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, PR, Brazil
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29
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Maddison P, Mills KR, Newsom-Davis J. Clinical electrophysiological characterization of the acquired neuromyotonia phenotype of autoimmune peripheral nerve hyperexcitability. Muscle Nerve 2006; 33:801-8. [PMID: 16570308 DOI: 10.1002/mus.20536] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Acquired autoimmune neuromyotonia is regarded as part of the spectrum of peripheral nerve hyperexcitability disorders. We aimed to use clinical neurophysiological measurements to study the extent, distribution, and characteristics of spontaneous motor unit potentials in 11 patients with acquired neuromyotonia. Investigations revealed that most spontaneous discharges recorded were motor unit, or partial motor unit potentials of normal size. Bursts of motor unit potentials arose more commonly from distal portions of the peripheral nerve and had abnormal absolute and relative refractory periods. Spontaneous discharges in some patients occurred in semirhythmic bursts in certain muscles. No patient had neurophysiological abnormalities detectable in first-order neurons of the central nervous system when using transcranial magnetic stimulation to estimate the threshold for corticomotor excitation and determine central motor conduction time. Only patients with coexistent myasthenia gravis had neurophysiologically detectable defects in neuromuscular transmission. The pathogenic region of abnormality in peripheral nerve hyperexcitability disorders therefore seems to lie within the terminal branches of peripheral motor nerves.
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Affiliation(s)
- Paul Maddison
- University Department of Clinical Neurology, Radcliffe Infirmary, Oxford, UK.
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Lehky TJ, Leonard GD, Wilson RH, Grem JL, Floeter MK. Oxaliplatin-induced neurotoxicity: acute hyperexcitability and chronic neuropathy. Muscle Nerve 2004; 29:387-92. [PMID: 14981738 DOI: 10.1002/mus.10559] [Citation(s) in RCA: 238] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Oxaliplatin, a platinum-based chemotherapeutic agent, is effective in the treatment of solid tumors, particularly colorectal cancer. During and immediately following oxaliplatin infusion, patients may experience cold-induced paresthesias, throat and jaw tightness, and occasionally focal weakness. We assessed nerve conduction studies and findings on needle electromyography of patients with metastatic colorectal cancer before and during treatment with oxaliplatin. Twenty-two patients had follow-up studies within 48 h following oxaliplatin infusions, and 14 patients had follow-up studies after 3-9 treatment cycles. Repetitive compound muscle action potentials and neuromyotonic discharges were observed in the first 24-48 h following oxaliplatin infusion, but resolved by 3 weeks. After 8-9 treatment cycles, sensory nerve action potential amplitudes declined, without conduction velocity changes or neuromyotonic discharges. The acute neurological symptoms reflect a state of peripheral nerve hyperexcitability that likely represents a transient oxaliplatin-induced channelopathy. Chronic treatment causes an axonal neuropathy similar to other platinum-based chemotherapeutic agents.
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Affiliation(s)
- T J Lehky
- Department of Neurology, National Naval Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA.
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31
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Kohara N, Lin TS, Fukudome T, Kimura J, Sakamoto T, Kaji R, Shibasaki H. Pathophysiology of weakness in a patient with congenital end-plate acetylcholinesterase deficiency. Muscle Nerve 2002; 25:585-92. [PMID: 11932977 DOI: 10.1002/mus.10073] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A Japanese patient with congenital end-plate acetylcholinesterase (AChE) deficiency developed severe proximal and truncal muscle weakness with preservation of distal strength. Electrophysiological studies included a train of stimuli at 3 HZ, which induced a marked decremental response in the deltoid but not in the first dorsal interosseous (FDI) muscle. Single fiber electromyography (EMG) revealed a high blocking rate (23.1 +/- 30.5%, n = 13) with a markedly increased jitter (mean consecutive difference [MCD] 297 +/- 218 micros) in the deltoid, but a low blocking rate (6.2 +/- 7.4%, n = 16) despite an equally increased jitter (MCD 227 +/- 147 micros) in the FDI. In vitro microelectrode study and computer simulation suggested that the combination of a large jitter and a low blocking rate may be ascribed to a reduced end-plate potential (EPP) amplitude with an abnormally prolonged decay time constant (tau). These characteristics may constitute the primary underlying pathophysiologic mechanism in our patient and in similar cases of congenital myasthenic syndrome.
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Affiliation(s)
- Nobuo Kohara
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
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32
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Nicole S, Davoine CS, Topaloglu H, Cattolico L, Barral D, Beighton P, Hamida CB, Hammouda H, Cruaud C, White PS, Samson D, Urtizberea JA, Lehmann-Horn F, Weissenbach J, Hentati F, Fontaine B. Perlecan, the major proteoglycan of basement membranes, is altered in patients with Schwartz-Jampel syndrome (chondrodystrophic myotonia). Nat Genet 2000; 26:480-3. [PMID: 11101850 DOI: 10.1038/82638] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Schwartz-Jampel syndrome (SJS1) is a rare autosomal recessive disorder characterized by permanent myotonia (prolonged failure of muscle relaxation) and skeletal dysplasia, resulting in reduced stature, kyphoscoliosis, bowing of the diaphyses and irregular epiphyses. Electromyographic investigations reveal repetitive muscle discharges, which may originate from both neurogenic and myogenic alterations. We previously localized the SJS1 locus to chromosome 1p34-p36.1 and found no evidence of genetic heterogeneity. Here we describe mutations, including missense and splicing mutations, of the gene encoding perlecan (HSPG2) in three SJS1 families. In so doing, we have identified the first human mutations in HSPG2, which underscore the importance of perlecan not only in maintaining cartilage integrity but also in regulating muscle excitability.
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Affiliation(s)
- S Nicole
- INSERM CJF9711, Faculté de Médecine Pitié-Salpêtrière, Paris, France
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33
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Abstract
We report the case of a 37-year-old man with clinical and electrophysiological features of hereditary slow-channel syndrome (SCS) and antibodies against acetylcholine receptors (AChR-Abs). He presented with weakness of shoulder and hand muscles. A supramaximal single stimulus to the motor nerves disclosed a double compound muscle action potential (CMAP). Repetitive stimulation of ulnar, suprascapular, and median nerves showed a CMAP decrement greater than 10%. The patient responded to pyridostigmine. This report confirms the importance of AChR-Ab titers in suspected cases of hereditary SCS because patients with positive AChR-Abs may have a better response to available treatments.
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Affiliation(s)
- R H Scola
- Neuromuscular Disorders Division, Hospital de Clinicas of Federal University of Parana, 181 General Carneiro Street, Curitiba 80.069-900, Brazil
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34
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van Dijk JG, van der Hoeven BJ, van der Hoeven H. Repetitive nerve stimulation: effects of recording site and the nature of 'pseudofacilitation'. Clin Neurophysiol 2000; 111:1411-9. [PMID: 10904222 DOI: 10.1016/s1388-2457(00)00331-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To describe changes in the waveform of the compound muscle action potential (CMAP) during repetitive nerve stimulation for various recording sites. METHODS Responses to trains of 10 stimuli given at 0.1, 1, 3, 5, 10 and 30 Hz to the ulnar nerve were recorded simultaneously from 8 hand sites in 15 healthy subjects. Percentile changes of amplitude, duration and area of both negative and positive phases were analyzed. RESULTS Duration consistently decreased during the trains. At 30 Hz, the mean amplitude of the negative phase increased on 5 sites but decreased on 3. Area consistently decreased, but least for hypothenar sites. Repeated stimulation causes an alteration in the waveform of the CMAP that consists of 4 elements: (1) shorter duration; (2) changed amplitude of the negative phase (up or down); (3) merging of bifid peaks; (4) changes were more pronounced for positive than negative phases. CONCLUSIONS As the term 'pseudofacilitation' implies an increase in amplitude, it is often not appropriate. Increased muscle fiber conduction velocity can explain most of the waveform alterations. Movement and shortening of muscles may play additional roles. Consequences for diagnostic yield await a comparison with disease groups.
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Affiliation(s)
- J G van Dijk
- Department of Neurology and Clinical Neurophysiology, Leiden University Medical Centre, The, Leiden, Netherlands.
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35
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Tanosaki M, Baba M, Miura H, Matsunaga M, Arimura K. Reversible F-wave hyperexcitability associated with antibodies to potassium channels in Isaacs' syndrome. Eur J Neurol 1999; 6:95-8. [PMID: 10209357 DOI: 10.1046/j.1468-1331.1999.610095.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We report a case of Isaacs' syndrome showing F-wave hyperexcitability which was reversible after either epidural block or plasmapheresis. A 14-year-old girl with progressive muscle cramp and myokymia in the legs showed high amplitude, long duration, polyphasic F-waves after either tibial nerve or peroneal nerve stimulation. Potassium current of PC-12 cell membrane was suppressed by her serum, IgM of which strongly reacted with proteins of approximately 50 kDa of the lysates of a PC-12 cell line. After an epidural nerve block with 1 per cent lidocaine 10 ml, the myokymia temporally improved, during which time the hyperexcitable F-waves became normalized. We treated her with double filtration plasmapheresis, which resulted in remarkable improvement of myokymia; simultaneously, the abnormal F-waves showed a decrease in amplitude, duration, and in the number of phases. We concluded that there was hyperexcitability of the proximal site of motor fibers in our patient, and possible immune mechanisms gave rise to the myokymia and unusual F-wave features.
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Affiliation(s)
- M Tanosaki
- Department of Neurology, Institute of Neurological Diseases, Hirosaki University School of Medicine, Hirosaki, Japan
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Rowiñska-Marciñska K, Zalewska E, Hausmanowa-Petrusewicz I. Double discharges of motor units in neuromuscular disorders. JOURNAL OF PHYSIOLOGY, PARIS 1999; 93:175-82. [PMID: 10084721 DOI: 10.1016/s0928-4257(99)80148-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Repetitive discharges (RDs) are observed in electromyograms recorded from healthy as well as diseased muscles. We have evaluated the prevalence of RDs in some neuromuscular diseases and analysed the time parameters of recordings displaying RDs as well as shapes of the potentials. In our clinical material, RDs have been observed exclusively in lower motor neuron lesions, never in healthy or in myopathic muscles. The prevalence index of RDs in amyotrophic lateral sclerosis (0.06) was found to be different from that in chronic spinal muscle atrophy (0.004). The types of double potential shape have been categorised. The relationships between the amplitude of the second component and the interspike duration and that between the interspike duration and the jitter were calculated. The amplitude of the second component diminished and jitter of the components increased with the shortening of the interval between components. The authors suggest that in lower motor neuron lesions, the RDs of the motorunit (MU) may be one of the first signs of the MU's dysfunction.
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Wintzen AR, Plomp JJ, Molenaar PC, van Dijk JG, van Kempen GT, Vos RM, Wokke JH, Vincent A. Acquired slow-channel syndrome: a form of myasthenia gravis with prolonged open time of the acetylcholine receptor channel. Ann Neurol 1998; 44:657-64. [PMID: 9778265 DOI: 10.1002/ana.410440412] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A 32-year-old female presented with a 2-year history of fluctuating generalized weakness including extraocular, bulbar, and limb muscles, suggesting myasthenia gravis, but with poor response to pyridostigmine and unusual electromyographic findings. After rest, power increased on repeated maximal contractions, followed by progressive weakness. There were decremental responses at low-frequency stimulation, but incremental responses at high frequencies, and single stimuli evoked repetitive compound muscle action potentials. Plasmapheresis was ineffective. In a conventional assay, antibodies against acetylcholine receptors (AChRs) were borderline. However, in an assay using cells expressing mainly adult-type human AChRs, the patient's serum was positive. Thymectomy revealed a hyperplastic thymus. An intercostal muscle specimen revealed small miniature end-plate potentials, 0.22+/-0.02 mV instead of 0.56+/-0.05 mV in controls. The number of 125I-alpha-bungarotoxin binding sites was normal. The decay time constant of end-plate potentials was increased from 5.3+/-0.6 msec in controls to 23+/-3.6 msec in the patient. Ultrastructurally, there was no destruction of the end plate. Transfer of the patient's plasma to mice in vivo produced similar physiological changes in their diaphragms. We conclude that the patient has an immune-mediated disorder, in which an antibody specific to the adult form of the AChRs alters the channel properties, reducing total current and slowing the closure. We propose the name "acquired slow-channel syndrome" for this variant of myasthenia gravis.
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Affiliation(s)
- A R Wintzen
- Department of Neurology and Clinical Neurophysiology, Leiden University Medical Centre, The Netherlands
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