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Meadows JC, Ross-Russell RW, Wise RP. A re-evaluation of the decamethonium test for myasthenia gravis. Acta Neurol Scand 2009; 50:248-56. [PMID: 4835620 DOI: 10.1111/j.1600-0404.1974.tb02775.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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52
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Urbano FJ, Pagani MR, Uchitel OD. Calcium channels, neuromuscular synaptic transmission and neurological diseases. J Neuroimmunol 2008; 201-202:136-44. [PMID: 18678414 DOI: 10.1016/j.jneuroim.2008.06.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 06/16/2008] [Accepted: 06/17/2008] [Indexed: 01/20/2023]
Abstract
Voltage-dependent calcium channels are essential in neuronal signaling and synaptic transmission, and their functional alterations underlie numerous human disorders whether monogenic (e.g., ataxia, migraine, etc.) or autoimmune. We review recent work on Ca(V)2.1 or P/Q channelopathies, mostly using neuromuscular junction preparations, and focus specially on the functional hierarchy among the calcium channels recruited to mediate neurotransmitter release when Ca(V)2.1 channels are mutated or depleted. In either case, synaptic transmission is greatly compromised; evidently, none of the reported functional replacements with other calcium channels compensates fully.
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Affiliation(s)
- Francisco J Urbano
- Laboratorio de Fisiología y Biología Molecular, Instituto de Fisiología y Biología Molecular y Neurociencias, Universidad de Buenos Aires-CONICET, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, C1428-Buenos Aires, Argentina
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53
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The spectrum of intermediate syndrome following acute organophosphate poisoning: a prospective cohort study from Sri Lanka. PLoS Med 2008; 5:e147. [PMID: 18630983 PMCID: PMC2459203 DOI: 10.1371/journal.pmed.0050147] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2007] [Accepted: 05/22/2008] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Intermediate syndrome (IMS) is a major cause of death from respiratory failure following acute organophosphate poisoning. The objective of this study was to determine repetitive nerve stimulation (RNS) predictors of IMS that would assist in patient management and clinical research. METHODS AND FINDINGS Seventy-eight consenting symptomatic patients with organophosphate poisoning were assessed prospectively with daily physical examination and RNS. RNS was done on the right and left median and ulnar nerves at 1, 3, 10, 15, 20, and 30 Hz. The study was conducted as a prospective observational cohort study in the Central Province, Sri Lanka. IMS was diagnosed in ten out of 78 patients using a priori clinical diagnostic criteria, and five of them developed respiratory failure. All ten patients showed progressive RNS changes correlating with the severity of IMS. A decrement-increment was observed at intermediate and high frequencies preceding the onset of clinical signs of IMS. As the patient developed clinical signs of IMS, decrement-increment was progressively noted at low and intermediate frequencies and a combination of decrement-increment and repetitive fade or severe decrement was noted at high frequencies. Severe decrement preceded respiratory failure in four patients. Thirty patients developed forme fruste IMS with less severe weakness not progressing to respiratory failure whose RNS was characterized by decrement-increment or a combination of decrement-increment and repetitive fade but never severe decrements. CONCLUSIONS Characteristic changes in RNS, preceding the development of IMS, help to identify a subgroup of patients at high risk of developing respiratory failure. The forme fruste IMS with the characteristic early changes on RNS indicates that IMS is a spectrum disorder. RNS changes are objective and precede the diagnosis and complications of IMS. Thus they may be useful in clinical management and research.
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Flagstad A. A new hereditary neuromuscular disease in the dog breed "Gammel Dansk Honsehund". Genetic investigations. Hereditas 2008; 96:211-4. [PMID: 7201985 DOI: 10.1111/j.1601-5223.1982.tb00851.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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Lorenzoni PJ, Scola RH, Lang B, Kay CSK, Teive HAG, Kowacs PA, Werneck LC. Cerebellar ataxia in non-paraneoplastic Lambert-Eaton myasthenic syndrome. J Neurol Sci 2008; 270:194-6. [PMID: 18374949 DOI: 10.1016/j.jns.2008.02.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 02/05/2008] [Accepted: 02/07/2008] [Indexed: 11/29/2022]
Abstract
Lambert-Eaton myasthenic syndrome (LEMS) is an immune-mediated disorder of the neuromuscular junction that rarely is associated with cerebellar ataxia (CA). We describe two patients with non-paraneoplastic LEMS associated with CA who showed high levels of anti-P/Q-type voltage-gated calcium channels antibodies in the serum and cerebrospinal fluid, and reduced CMAP with increment after brief maximum voluntary contraction in electrophysiological studies. We suggest that LEMS should be considered in the differential diagnosis of patients with CA.
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Affiliation(s)
- Paulo J Lorenzoni
- Department of Internal Medicine, Universidade Federal do Paraná, Curitiba, Brazil
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56
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Anti-Ca2+ channel antibody attenuates Ca2+ currents and mimics cerebellar ataxia in vivo. Proc Natl Acad Sci U S A 2008; 105:2705-10. [PMID: 18272482 DOI: 10.1073/pnas.0710771105] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Voltage-gated Ca(2+) channels (VGCCs) are membrane proteins that determine the activity and survival of neurons, and mutations in the P/Q-type VGCCs are known to cause cerebellar ataxia. VGCC dysfunction may also underlie acquired peripheral and central nervous system diseases associated with small-cell lung cancer, including Lambert-Eaton myasthenic syndrome (LEMS) and paraneoplastic cerebellar ataxia (PCA). The pathogenic role of anti-VGCC antibody in LEMS is well established. Although anti-VGCC antibody is also found in a significant fraction of PCA patients, its contribution to PCA is unclear. Using a polyclonal peptide antibody against a major immunogenic region in P/Q-type VGCCs (the extracellular Domain-III S5-S6 loop), we demonstrated that such antibody was sufficient to inhibit VGCC function in neuronal and recombinant VGCCs, alter cerebellar synaptic transmission, and confer the phenotype of cerebellar ataxia. Our data support the hypothesis that anti-VGCC antibody may play a significant role in the pathogenesis of cerebellar dysfunction in PCA.
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57
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Sanders DB, Juel VC. The Lambert-Eaton myasthenic syndrome. HANDBOOK OF CLINICAL NEUROLOGY 2008; 91:273-83. [PMID: 18631847 DOI: 10.1016/s0072-9752(07)01509-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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58
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Abstract
BACKGROUND Neuromuscular junction disorders are usually categorized as either presynaptic or postsynaptic. The most frequently encountered disorder of the postsynaptic neuromuscular junction is acquired myasthenia gravis. Lambert-Eaton myasthenic syndrome is a well-known prototype of the presynaptic autoimmune disorders of neuromuscular transmission. These major disorders of neuromuscular transmission are relatively common and distinctly recognized, but co-occurrence of these disorders (overlap myasthenic syndrome) is rare and has so far attracted little attention. REVIEW SUMMARY This report describes a patient with acquired myasthenia gravis and immunologic coexistence of Lambert-Eaton myasthenic syndrome (overlap myasthenic syndrome) in association with abdominal/uterine leiomyosarcoma. The patient presented with acute respiratory failure, making identification and management of her illness challenging. A general overview of the complexities associated with overlap between myasthenia gravis and Lambert-Eaton myasthenic syndrome is provided and this patient's complicated clinical course and response to therapy are discussed. CONCLUSION To our knowledge, this is the first report of overlap myasthenic syndrome in conjunction with abdominal leiomyosarcoma. The immunologic coexistence of acquired myasthenia gravis and Lambert-Eaton myasthenic syndrome in a patient with a malignant smooth-muscle tumor is intriguing and suggests that a common paraneoplastic process targeting 2 different onconeural antigens was the underlying pathogenic mechanism in this patient.
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Affiliation(s)
- Fereydoon Roohi
- Department of Neurology and the Division of Pulmonary Medicine, Long Island College Hospital, Brooklyn, New York 11201, USA.
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59
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Abstract
Ion channels are crucial elements in neuronal signaling and synaptic transmission, and defects in their function are known to underlie rare genetic disorders, including some forms of epilepsy. A second class of channelopathies, characterized by autoantibodies against ligand- and voltage-gated ion channels, cause a variety of defects in peripheral neuromuscular and ganglionic transmission. There is also emerging evidence for autoantibody-mediated mechanisms in subgroups of patients with central nervous system disorders, particularly those involving defects in cognition or sleep and often associated with epilepsy. In all autoimmune channelopathies, the relationship between autoantibody specificity and clinical phenotype is complex. But with this new information, autoimmune channelopathies are detected and treated with increasing success, and future research promises new insights into the mechanisms of dysfunction at neuronal synapses and the determinants of clinical phenotype.
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Affiliation(s)
- Angela Vincent
- Neurosciences Group, Department of Clinical Neurology, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom.
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60
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Ferlito A, Devaney KO, Rinaldo A. Neuroendocrine neoplasms of the larynx: Advances in identification, understanding, and management. Oral Oncol 2006; 42:770-88. [PMID: 16815077 DOI: 10.1016/j.oraloncology.2006.01.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2005] [Accepted: 01/06/2006] [Indexed: 10/24/2022]
Abstract
While 85-90% of laryngeal malignancies prove to be squamous carcinomas, the second most common tumour type found in the laryngeal region will prove to be a member of the family of neuroendocrine tumours. Laryngeal carcinoid tumours have a capacity for metastasis, and so are more aggressive tumours than their light microscopic features might imply--5-year survival rates are in the vicinity of 50%. Laryngeal atypical carcinoid tumours are lesions with a well-recognized capacity for local recurrence as well as metastasis, with a 5-year survival of just under 50%. Laryngeal small cell neuroendocrine carcinomas are particularly aggressive tumours, with a 5-year survival of no more than 5-10%. Laryngeal paragangliomas are lesions without any real capacity for metastasizing. Surgical excision is the mainstay of treatment of carcinoid tumours, atypical carcinoid tumours, and paragangliomas. Small cell neuroendocrine carcinomas are chiefly treated by way of radiation and chemotherapy; the role of adjuvant therapy in the treatment of atypical carcinoid tumours remains to be established.
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Affiliation(s)
- Alfio Ferlito
- Department of Surgical Sciences, ENT Clinic, University of Udine, Policlinico Universitario, Piazzale S. Maria della Misericordia, I-33100 Udine, Italy.
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61
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Baslo MB, Deymeer F, Serdaroglu P, Parman Y, Ozdemir C, Cuttini M. Decrement pattern in Lambert–Eaton myasthenic syndrome is different from myasthenia gravis. Neuromuscul Disord 2006; 16:454-8. [PMID: 16806929 DOI: 10.1016/j.nmd.2006.05.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Revised: 05/02/2006] [Accepted: 05/08/2006] [Indexed: 10/24/2022]
Abstract
The decrement pattern at low rates of repetitive nerve stimulation in myasthenia gravis (MG) is characterized by a decrease of compound muscle action potential size within the first 4-5 responses. With subsequent stimuli, compound muscle action potential size either increases or does not change. Following an observation that the pattern of decrement might be different in patients with Lambert-Eaton myasthenic syndrome (LEMS), we retrospectively studied traces from eight LEMS patients and 14 patients with seropositive generalized MG, calculating decrement percent from first to fourth and from first to ninth compound muscle action potential. In the LEMS patients, compound muscle action potential amplitude decreased progressively from first to ninth stimulus at 2, 3 or 5Hz in all traces but one. In contrast, MG patients demonstrated the expected improvement after the initial decrement in all traces except one. In the evaluation of patients suspected of having myasthenia gravis, the finding of progressive decrement pattern at low rates of repetitive nerve stimulation may alert the electromyographer to the possibility of Lambert-Eaton syndrome and prompt the performance of further electrodiagnostic tests.
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Affiliation(s)
- M Baris Baslo
- Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, 34390 Capa, Istanbul, Turkey
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62
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Abstract
Disorders of the neuromuscular junction have a wide range of clinical presentations, which frequently poses a diagnostic challenge to evaluating clinicians. This article describes the tests used in the diagnosis of diseases of the neuromuscular junction, reviews the evidence supporting the use of each test, and proposes guidelines for their efficient utilization. A focused review of the literature was employed. Reports from four main categories of diagnostic tests (pharmacologic, electrodiagnostic, immunologic, and miscellaneous tests) were reviewed, and the sensitivity and specificity of each test in the diagnosis of specific neuromuscular junction diseases were examined. The clinical presentation determines which diagnostic tests should be utilized in individual cases of suspected neuromuscular junction disease. However, knowledge of the sensitivity and specificity of each test can help to focus the diagnostic evaluation and maximize the diagnostic yield of each test.
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Affiliation(s)
- Matthew N Meriggioli
- Department of Neurology and Rehabilitation, Section of Neuromuscular Disease, University of Illinois Medical Center, Chicago, Illinois, USA
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63
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Burns TM, Russell JA, LaChance DH, Jones HR. Oculobulbar involvement is typical with Lambert-Eaton myasthenic syndrome. Ann Neurol 2003; 53:270-3. [PMID: 12557298 DOI: 10.1002/ana.10477] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Oculobulbar symptoms and/or signs were present in 18 of 23 (78%) of Lambert-Eaton myasthenic syndrome (LEMS) patients evaluated at the Lahey Clinic (Table). Sixty-five percent (15 of 23) of our patients had ptosis and/or diplopia, each present in 11 individuals. Bulbar signs and symptoms, including dysarthria in 10 and dysphagia in 8 patients, also were observed among our LEMS population. More than one prereferral oculobulbar feature occurred in 13 of our LEMS patients. Prereferral diagnostic considerations included myasthenia gravis, myopathies, and psychiatric disorders. These findings suggest that these atypical characteristics served to dissuade some colleagues from a diagnosis of LEMS. Thus, the presence of oculobulbar symptoms and signs cannot be used to exclude LEMS from the differential diagnosis.
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Affiliation(s)
- Ted M Burns
- Department of Neurology, Lahey Clinic, Burlington, MA, USA.
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64
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Abstract
Cancer can affect the nervous system through many metastatic and nonmetastatic mechanisms, including side effects of cancer treatment, infections, coagulopathy, and metabolic or nutritional deficits. Paraneoplastic neurologic disorders (PND) are an extensive group of syndromes that cannot be explained by any of these complications and may affect any part of the nervous system. PND often develop before the presence of a cancer is known and their recognition may lead to the tumor diagnosis.
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Affiliation(s)
- Luis Bataller
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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65
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Fukuda T, Motomura M, Nakao Y, Shiraishi H, Yoshimura T, Iwanaga K, Tsujihata M, Eguchi K. Reduction of P/Q-type calcium channels in the postmortem cerebellum of paraneoplastic cerebellar degeneration with Lambert-Eaton myasthenic syndrome. Ann Neurol 2003; 53:21-8. [PMID: 12509844 DOI: 10.1002/ana.10392] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The aim of this study was to clarify whether autoimmunity against P/Q-type voltage-gated calcium channels (VGCCs) in the cerebellum was associated with the pathogenesis of paraneoplastic cerebellar degeneration (PCD) with Lambert-Eaton myasthenic syndrome (LEMS). We used human autopsy cerebellar tissues from three PCD-LEMS patients and six other disease patients including one with LEMS as the controls. We compared cerebellar P/Q-type VGCC in these patients and controls for the amount and ratio of autoantibody-channel complex using an 125I-omega-conotoxin MVIIC-binding assay with Scatchard analysis, and their distribution using autoradiography. The quantity of cerebellar P/Q-type VGCC measured by Scatchard analysis were reduced in PCD-LEMS patients (63.0 +/- 7.0 fmol/mg, n = 3), compared with the controls (297.8 +/- 38.9 fmol/mg, n = 6). The ratio of autoantibody-VGCC complexes to total P/Q-type VGCCs measured by immunoprecipitation assay were increased in PCD-LEMS patients. We analysed cerebellar specimens by autoradiography using (125)I-omega-conotoxin MVIIC, which specifically binds to P/Q-type VGCCs. In PCD-LEMS cerebellum, the toxin binding sites of P/Q-type VGCCs were markedly reduced compared with controls, especially in the molecular layer, which is the richest area of P/Q-type VGCCs in the normal cerebellum. This suggests that P/Q-type VGCCs of the cerebellar molecular layer is the immunological target in developing PCD-LEMS.
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Affiliation(s)
- Taku Fukuda
- First Department of Internal Medicine, Nagasaki University School of Medicine, Japan
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66
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Fletcher CF, Lennon VA. Do calcium channel autoantibodies cause cerebellar ataxia with Lambert-Eaton syndrome? Ann Neurol 2003; 53:5-7. [PMID: 12509841 DOI: 10.1002/ana.10497] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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67
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Lin JT, Lachmann E. Lambert-eaton myasthenic syndrome: a case report and review of the literature. J Womens Health (Larchmt) 2002; 11:849-55. [PMID: 12626085 DOI: 10.1089/154099902762203696] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Lambert-Eaton myasthenic syndrome (LEMS) is a type of paraneoplastic syndrome that may initially manifest with weakness and gait abnormalities. These symptoms may precede the diagnosis of malignancy by months or years, and morbidity and mortality may be significantly affected by early detection of the malignancy. A case report and review of the diagnosis, management, and treatment of these syndromes are presented, with particular emphasis on the rehabilitation management of these patients, often overlooked in medical treatment.
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Affiliation(s)
- Julie T Lin
- Physiatry Service, Hospital for Special Surgery, and Department of Rehabilitation Medicine, The New York Presbyterian Hospital, Weill Medical College of Cornell University, New York, New York 10021, USA.
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68
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Abstract
Paraneoplastic disorders may affect any part of the central or peripheral nervous systems. Although relatively uncommon, these disorders are a significant cause of neurologic morbidity for cancer patients. At least some paraneoplastic syndromes are believed to be caused by an autoimmune reaction against shared tumor-neural antigens. This article summarizes the clinical features of paraneoplastic disorders, the current evidence for autoimmunity, and guidelines for diagnosis and treatment.
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Affiliation(s)
- Edward J Dropcho
- Department of Neurology, Indiana University Medical Center, The Richard Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana 46202, USA.
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69
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Literature review of the usefulness of repetitive nerve stimulation and single fiber EMG in the electrodiagnostic evaluation of patients with suspected myasthenia gravis or Lambert-Eaton myasthenic syndrome. Muscle Nerve 2001; 24:1239-47. [PMID: 11494281 DOI: 10.1002/mus.1140] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A retrospective literature review of the electrodiagnosis of myasthenia gravis (MG) and Lambert--Eaton myasthenic syndrome (LEMS) through July 1998 was performed for the purpose of generating evidence-based practice parameters. There were 545 articles identified, of which 13 articles met at least three of the six criteria set previously by the American Association of Electrodiagnostic Medicine (AAEM). An additional 21 articles were identified from review articles or the references of these first 13 articles leading to a total of 34 articles. Results of studies utilizing repetitive nerve stimulation (RNS) showed that a 10% decrement in amplitude from the first to fourth or fifth intravolley waveform while stimulating at 2--5 HZ is valid for the diagnosis of MG. The degree of increment needed for the diagnosis of LEMS is at least 25% but most accurate when greater than 100%. Abnormal jitter or impulse blocking are the appropriate criteria for diagnosis of neuromuscular junction (NMJ) disorders when using single fiber electromyography (SFEMG). SFEMG is more sensitive than RNS for the diagnosis of disorders of neuromuscular transmission, but may be less specific and may not be available. Therefore, RNS remains the preferred initial test for MG and LEMS.
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Abstract
Reliable transmission of activity from nerve to muscle is necessary for the normal function of the body. The term 'safety factor' refers to the ability of neuromuscular transmission to remain effective under various physiological conditions and stresses. This is a result of the amount of transmitter released per nerve impulse being greater than that required to trigger an action potential in the muscle fibre. The safety factor is a measure of this excess of released transmitter. In this review we discuss the practical difficulties involved in estimating the safety factor in vitro. We then consider the factors that influence the safety factor in vivo. While presynaptic transmitter release may be modulated on a moment to moment basis, the postsynaptic features that determine the effect of released transmitter are not so readily altered to meet changing demands. Different strategies are used by different species to ensure reliable neuromuscular transmission. Some, like frogs, rely on releasing a large amount of transmitter while others, like man, rely on elaborate postsynaptic specialisations to enhance the response to transmitter. In normal adult mammals, the safety factor is generally 3-5. Both pre- and postsynaptic components change during development and may show plasticity in response to injury or disease. Thus, both acquired autoimmune and inherited congenital diseases of the neuromuscular junction (NMJ) can significantly reduce, or even transiently increase, safety factor.
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Affiliation(s)
- S J Wood
- Department of Physiology, School of Medical Sciences, University of Bristol, University Walk, BS8 1TD, Bristol, UK.
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71
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Abstract
We describe the anaesthetic management of a 72-year-old man with myasthenic syndrome. Pre-operatively, he was treated with 3,4-diaminopyridine and showed a strong hand grip. During general anaesthesia with nitrous oxide and sevoflurane in oxygen, a mechanomyograph and two accelerographs were set up for the hands and left foot to monitor neuromuscular function. Insufficient force and acceleration of contraction with 1 Hz stimulation was observed in the hands. In the foot, the twitches produced by 1 Hz and train-of-four stimulation could barely be detected using the accelerograph, and the train-of-four ratio fluctuated between 70 and 100%. No neuromuscular blocking drugs were used during surgery. After discontinuation of sevoflurane, responses to train-of-four stimulation remained small, but a strong response to tetanic stimulation was observed, with post-tetanic facilitation. Extubation was successful, and recovery from anaesthesia was uneventful. Tetanic stimulation and post-tetanic facilitation are important in monitoring neuromuscular function in patients with myasthenic syndrome whose train-of-four responses are insufficient.
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Affiliation(s)
- H Itoh
- Department of Anaesthesiology and Intensive Care Medicine, Kanazawa University School of Medicine, 13-1 Takara-machi, Kanazawa 920-8641, Japan.
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72
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Katz J, Barohn RJ. Update on the Evaluation and Therapy of Autoimmune Neuromuscular Junction Disorders. Phys Med Rehabil Clin N Am 2001. [DOI: 10.1016/s1047-9651(18)30076-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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73
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Abstract
Cancer can affect the peripheral nervous system by non-metastatic, sometimes immune-mediated mechanisms. Recognition of these paraneoplastic syndromes is important because it can lead to the detection of the tumor, and also helps to avoid unnecessary studies to determine the cause of the neurologic symptoms in patients with cancer. Many paraneoplastic syndromes of the peripheral nervous system are not associated with serum antibodies that serve as markers of paraneoplasia. For this group of disorders the diagnosis depends on the clinician's index of suspicion and conventional electrophysiologic and laboratory tests. Treatment of the tumor, immunotherapy, or both may improve some of these syndromes. This review focuses on paraneoplastic syndromes of the spinal cord, peripheral nerve, and muscle.
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Affiliation(s)
- S A Rudnicki
- Department of Neurology, University of Arkansas for Medical Sciences, 4301 West Markham, Slot 500, Little Rock, Arkansas 72205, USA
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74
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Abstract
The Lambert-Eaton myasthenic syndrome is a neuromuscular disorder characterised by defective neurotransmitter release at autonomic neurones and presynaptic terminals of the neuromuscular junction. It is caused by an IgG autoantibody formed against especially the P/Q type of voltage-gated calcium channels (VGCC) which is an essential component of the mechanism of neurotransmitter release. Many patients have an associated small cell carcinoma of the lung which appears to provide the antigenic stimulus for antibody production, although there is another group with no underlying malignancy. Both groups show an association with immunological disorders. Assay of VGCC antibody titres and electrophysiological tests help to differentiate Lambert-Eaton myasthenic syndrome from other disorders of the neuromuscular junction. Several drugs and therapeutic interventions capable of producing significant clinical improvement are currently available. Patients should also be investigated for underlying tumours, the specific treatment of which can result in remission or amelioration of symptoms.
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Affiliation(s)
- U Seneviratne
- Department of Neurology, Southern General Hospital, Glasgow, UK
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75
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Collins DR, Connolly S, Burns M, Offiah L, Grainger R, Walsh JB. Lambert-eaton myasthenic syndrome in association with transitional cell carcinoma: a previously unrecognized association. Urology 1999; 54:162. [PMID: 10754123 DOI: 10.1016/s0090-4295(98)00583-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Lambert-Eaton myasthenic syndrome is known to occur with, or precede, a variety of malignancies, most commonly oat cell carcinoma of the lung. We report the first case of this syndrome associated with transitional cell carcinoma of the bladder and ureter. A brief review of published reports on the presentation, diagnosis, and treatment is included.
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Affiliation(s)
- D R Collins
- Department of Medicine for the Elderly, St. James's Hospital, Dublin, Ireland
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76
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Voltz R, Carpentier AF, Rosenfeld MR, Posner JB, Dalmau J. P/Q-type voltage-gated calcium channel antibodies in paraneoplastic disorders of the central nervous system. Muscle Nerve 1999; 22:119-22. [PMID: 9883867 DOI: 10.1002/(sici)1097-4598(199901)22:1<119::aid-mus19>3.0.co;2-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Whether P/Q-type voltage-gated calcium channel (VGCC) antibodies are present in the serum of patients with paraneoplastic syndromes other than the Lambert-Eaton myasthenic syndrome (LEMS) and tumors other than small-cell lung cancer (SCLC) is controversial. Using a commercially available radioimmunoprecipitation assay kit, we examined the sera of 93 patients with paraneoplastic syndromes of the central nervous system (CNS), including 27 patients with paraneoplastic cerebellar degeneration (PCD) associated with tumors other than SCLC and 66 SCLC patients with paraneoplastic encephalomyelitis and sensory neuronopathy (PEM/SN). All PCD sera from patients with tumors other than SCLC were negative for P/Q-type VGCC antibodies. Eight of 66 (12%) SCLC patients with PEM/SN had P/Q-type VGCC antibodies; 4 had LEMS and the other 4 had no symptoms of LEMS or they were overlooked and, therefore, not examined electrophysiologically. In patients with paraneoplastic syndromes of the CNS, the detection of P/Q-type VGCC antibodies supports the diagnosis of LEMS; in our series, only 6% of patients with SCLC and PEM/SN may have had a false positive antibody result, or undiagnosed LEMS.
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Affiliation(s)
- R Voltz
- Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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77
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Scola RH, Iwamoto FM, Ramos CS, Sanderson AM, Lopardo D, Cantarelli A, Watanabe M, Horta W, Werneck LC. Lambert-Eaton myasthenic syndrome. Report of two cases. ARQUIVOS DE NEURO-PSIQUIATRIA 1998; 56:457-64. [PMID: 9754429 DOI: 10.1590/s0004-282x1998000300017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two cases of Lambert-Eaton myasthenic syndrome, in female patients whose neoplasm investigation was negative, are reported. Repetitive stimulation of ulnar nerve showed an incremental response (+187% and +198%). Needle EMG was normal in one of them, however, the other patient showed fibrillation potentials, positive sharp waves, potentials of low amplitude and short duration. The authors discuss the clinical, electrophysiological, and pathological features of the disease, as well as some aspects of the treatment and follow-up of these patients.
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Affiliation(s)
- R H Scola
- Serviço de Doenças Neuromusculares do Hospital de Clínicas da Universidade Federal do Paraná, Brasil
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78
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Stevens JC. AAEM minimonograph #26: the electrodiagnosis of carpal tunnel syndrome. American Association of Electrodiagnostic Medicine. Muscle Nerve 1997; 20:1477-86. [PMID: 9390659 DOI: 10.1002/(sici)1097-4598(199712)20:12<1477::aid-mus1>3.0.co;2-5] [Citation(s) in RCA: 335] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The electrodiagnosis of carpal tunnel syndrome (CTS) is reviewed, including discussions of old and new techniques of motor and sensory nerve conduction, anomalous innervation, and needle electrode examination. A variety of sensitive nerve conduction studies (NCSs) are available for the evaluation of a patient with suspected CTS. For any particular patient, the NCS method chosen by the clinical neurophysiologist may vary for a number of reasons, including the severity of the deficit and the presence of superimposed conditions.
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Affiliation(s)
- J C Stevens
- Department of Neurology, Mayo Clinic Scottsdale, Arizona 85259, USA
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79
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Abstract
Although paraneoplastic syndromes are rare, a number of well- defined, neuromuscular paraneoplastic syndromes have been described and their pathophysiology listed. Many different malignancies have been associated with these syndromes, but small-cell lung cancer is the most common. Features shared by these conditions include onset of the underlying malignancy, rapid progression, severe disability, and the potential for some improvement, owing to treatment of the cancer. This article discusses Lambert-Eaton myasthenic syndrome, motor neuron disorders, peripheral neuropathies, and disorders of continuous muscle fiber activity, such as Stiffman syndrome.
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Affiliation(s)
- K H Levin
- Department of Neurology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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80
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Reduction of calcium currents by Lambert-Eaton syndrome sera: motoneurons are preferentially affected, and L-type currents are spared. J Neurosci 1996. [PMID: 8756422 DOI: 10.1523/jneurosci.16-16-04903.1996] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Previous work has demonstrated that Lambert-Eaton syndrome (LES) antibodies reduce calcium currents in nonneuronal cells and neurons and reduce the amplitude of extracellularly recorded currents at mouse motor nerve terminals. We compared effects of LES sera on whole-cell currents of cultured nerve and muscle. LES sera more strongly reduced calcium currents in motoneurons than in sensory neurons. Motoneuronal potassium currents were unaffected. The sera minimally affected calcium currents in skeletal and cardiac muscle. In motoneurons, both low voltage-activated (LVA) and high voltage-activated (HVA) components of calcium current were decreased, demonstrating that the sera targeted more than one calcium channel type. The HVA current remaining in LES-treated motoneurons was little affected by micromolar omega-conotoxin MVIIC but was reduced > 70% by micromolar nimodipine. This pharmacological profile contrasts with untreated cells and suggest that LES sera primarily spare L-type currents in motoneurons.
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81
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82
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Abstract
Two cases of Lambert-Eaton myasthenic syndrome (LEMS) who presented with primary respiratory failure are reported. In each case, although not initially suspected clinically, the electrophysiological findings, which included reduced compound muscle action potential amplitudes, decrement to 3-Hz stimulation, and potentiation after 40-Hz stimulation, led to the diagnosis in the critical care unit. Electrophysiological studies of the respiratory system, including repetitive nerve stimulation of the phrenic nerve, were extremely valuable in management. As shown by these cases, the severe respiratory failure in LEMS is reversible with treatment. Thus, LEMS should be considered in cases of unexplained respiratory failure, other clinical features of the disorder sought, and the electrophysiological hallmarks looked for including studies of the respiratory system.
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Affiliation(s)
- M W Nicolle
- Department of Clinical Neurological Sciences, Victoria Hospital, University of Western Ontario, London, Canada
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83
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Acetylcholinesterase inhibition in neuromuscular synapses in different background states: model studies. NEUROPHYSIOLOGY+ 1996. [DOI: 10.1007/bf02262776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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84
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Agarawal SK, Birch BR, Abercrombie GF. Adenocarcinoma of the prostate and Eaton-Lambert syndrome. A previously unreported association. SCANDINAVIAN JOURNAL OF UROLOGY AND NEPHROLOGY 1995; 29:351-3. [PMID: 8578283 DOI: 10.3109/00365599509180590] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Eaton-Lambert myasthenic syndrome is rare. We report the first case of adenocarcinoma of prostate associated with this syndrome. Subsequent treatment by orchidectomy caused tumour regression and remission of the syndrome. The patient remains well 9 months after the treatment.
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Affiliation(s)
- S K Agarawal
- Department of Urology, St. Mary's Hospital, Portsmouth, England
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85
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Fred HL, Wu CC. Proximal muscle weakness and pulmonary hilar prominence in a smoker. Hosp Pract (1995) 1995; 30:30L-30Q. [PMID: 7601894 DOI: 10.1080/21548331.1995.11443225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Affiliation(s)
- H L Fred
- University of Texas Health Science Center at Houston, USA
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86
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Sanders DB. Lambert-Eaton myasthenic syndrome: clinical diagnosis, immune-mediated mechanisms, and update on therapies. Ann Neurol 1995; 37 Suppl 1:S63-73. [PMID: 8968218 DOI: 10.1002/ana.410370708] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The Lambert-Eaton myasthenic syndrome (LEMS) is a rare condition in which weakness results from a presynaptic abnormality of acetylcholine release at the neuromuscular junction. It was first described as a paraneoplastic syndrome in patients with lung cancer but we now know about half of the patients with LEMS do not have cancer. The diagnosis is made on the basis of the clinical findings and characteristic electromyographic patterns. Recent evidence indicates that LEMS results from an autoimmune attack directed against the voltage-gated calcium channels on the presynaptic motor nerve terminal. In patients with LEMS who have cancer, effective treatment of the underlying tumor frequently produces marked improvement of weakness as well. Otherwise, treatment involves the use of agents that improve neuromuscular transmission by increasing the release of neurotransmitter, and immunosuppression.
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Affiliation(s)
- D B Sanders
- Duke University Medical Center, Durham, NC 27710, USA
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87
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Affiliation(s)
- J Bauer
- Centre Pluridisciplinaire d'Oncologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
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88
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Trontelj JV, Stålberg E. Single fiber electromyography in studies of neuromuscular function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1995; 384:109-19. [PMID: 8585443 DOI: 10.1007/978-1-4899-1016-5_9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Single-fiber electromyography (SFEMG) allows precise study of the microphysiology of the human motor unit under normal conditions. The physiological parameters that can be quantified include impulse transmission along the intramuscular axon collaterals, pre- and post synaptic events at the neuromuscular junction, and muscle fiber membrane properties. This chapter illustrates some of the advantages of SFEMG in studies of neuromuscular fatigue in normal muscle, as well as in disorders of neuromuscular transmission, and conditions associated with disturbed muscle fiber depolarization-repolarization.
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Affiliation(s)
- J V Trontelj
- University Institute of Clinical Neurophysiology, University Medical Center of Ljubljana, Slovenia
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89
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Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 32-1994. A 61-year-old man with muscular weakness. N Engl J Med 1994; 331:528-35. [PMID: 8041421 DOI: 10.1056/nejm199408253310809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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90
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91
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Abstract
A patient with procainamide-induced "pseudo" myasthenia gravis is presented. This clinical entity is discussed in terms of its clinical features, diagnosis, and treatment. Attention is directed to the importance of role of the ophthalmologist in making the diagnosis.
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Affiliation(s)
- C L Blanton
- Department of Ophthalmology, Naval Hospital San Diego 92134-5000
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92
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Gutmann L, Weidman D, Gutiérrez A. Lambert-Eaton myasthenic syndrome with prominent postexercise exhaustion. Muscle Nerve 1993; 16:716-9. [PMID: 8389419 DOI: 10.1002/mus.880160705] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A 66-year-old man with Lambert-Eaton myasthenic syndrome, polyneuropathy, and small cell lung cancer, developed profound muscle weakness with a prolonged period of ventilatory dependency. Electrophysiological studies demonstrated very small compound muscle action potentials in response to supramaximal nerve stimulation, limited tetanic and postexercise facilitation, and prolonged prominent postexercise exhaustion (40-60% of baseline value) persisting up to 20 minutes. It is hypothesized that these changes may reflect both a severe defect in acetylcholine release and decreased availability of releasible acetylcholine from the terminal axon.
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Affiliation(s)
- L Gutmann
- Department of Neurology, West Virginia University Health Sciences Center, Morgantown 26506
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93
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Kennett RP, Fawcett PR. Repetitive nerve stimulation of anconeus in the assessment of neuromuscular transmission disorders. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1993; 89:170-6. [PMID: 7686849 DOI: 10.1016/0168-5597(93)90130-h] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Repetitive nerve stimulation of the anconeus muscle is described. Control studies showed the test to be reliable and well tolerated over a range of stimulus frequencies and train lengths. Sixty-one patients with primary disorders of neuromuscular transmission were tested. Repetitive nerve stimulation of anconeus was abnormal in 2 of 21 patients with ocular myasthenia, but showed a significant decrementing response in 16 of 30 patients with generalized myasthenia gravis. In comparison with other muscles, repetitive nerve stimulation of anconeus was more sensitive than abductor digiti minimi, but equally sensitive as deltoid. The test may also be used to help characterize other disorders of neuromuscular transmission such as congenital myasthenia or the Lambert-Eaton myasthenic syndrome. Compared with single fibre EMG on extensor digitorum communis, repetitive stimulation of anconeus was usually, but not always, a less sensitive method of detecting a neuromuscular transmission disorder.
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Affiliation(s)
- R P Kennett
- Department of Clinical Neurophysiology, Newcastle General Hospital, Newcastle upon Tyne, UK
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94
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Abstract
Paraneoplastic phenomena associated with primary lung cancer have diverse initial manifestations and epitomize the systemic nature of human malignant disease. The spectrum of clinical features in patients with paraneoplastic syndromes ranges from mild systemic or cutaneous disease to hypercoagulability and severe neuromyopathic disorders. Although the diagnosis is often one of exclusion, an improved understanding of the pathogenesis involved in some of these syndromes has provided another means of recognizing the disorders and perhaps treating the affected patients. Proposed mechanisms of paraneoplastic processes include the aberrant release of humoral mediators such as hormones and hormone-like peptides, cytokines, and antibodies. In this update, we review the potential mechanisms, diagnosis, and treatment of paraneoplastic syndromes associated with lung cancer.
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Affiliation(s)
- A M Patel
- Division of Thoracic Diseases and Internal Medicine, Mayo Clinic, Rochester, MN 55905
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95
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Abstract
This rare myasthenic disorder is the first neurologic disease found to be caused by antibodies against an ion channel complex. It presents an unusual opportunity to clarify the pathobiology of so-called receptor diseases, as well as to gain better understanding of the normal biology of acetylcholine release and its effect on neuromuscular junctions.
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Affiliation(s)
- R G Smith
- Department of Neurology, Baylor College of Medicine, Houston
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96
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Oguro-Okano M, Griesmann GE, Wieben ED, Slaymaker SJ, Snutch TP, Lennon VA. Molecular diversity of neuronal-type calcium channels identified in small cell lung carcinoma. Mayo Clin Proc 1992; 67:1150-9. [PMID: 1335101 DOI: 10.1016/s0025-6196(12)61144-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Using the polymerase chain reaction (PCR), we identified RNA transcripts for two distinct classes of neuronal-type voltage-gated Ca2+ channels (VGCC) in a prototypic small cell lung carcinoma (SCLC) cell line, SCC-9. Oligonucleotide primers were designed to encode amino acid sequences common to alpha 1-subunits of known neuronal VGCC classes. Sequencing of complementary DNA (cDNA) clones derived from two independent PCR products revealed that one corresponded to a brain class A VGCC fragment predicted to encode a P-type VGCC (insensitive to dihydropyridines and omega-conotoxin) characteristic of cerebellar Purkinje cells but not previously identified in humans. The second PCR product was identical (except for one conservative nucleotide difference) to a fragment of the class D VGCC of neurons and neuroendocrine cells, which encodes an L-type VGCC (sensitive to dihydropyridines). By Northern blot analyses, both cDNAs hybridized to messenger RNAs (mRNAs) obtained from SCC-9; class D hybridized additionally to human cerebral cortical mRNA, but neither hybridized to mRNA from the skeletal muscle cell line TE671. Although no cDNA corresponding to class B VGCC (N-type) was identified, SCLCs are known to express VGCC that are sensitive to omega-conotoxin and coprecipitate with 125I-labeled-omega-conotoxin when complexed with serum IgG from patients with the Lambert-Eaton myasthenic syndrome. The multiple classes of neuronal-type VGCC expressed in SCLC could conceivably have both unique and related antigenic determinants that may give rise to antineuronal autoimmune responses. This would account for a spectrum of paraneoplastic neurologic disorders including the Lambert-Eaton syndrome and subacute cerebellar degeneration.
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Affiliation(s)
- M Oguro-Okano
- Department of Immunology, Mayo Clinic, Rochester, MN 55905
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97
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Ma DM. Recording of Nerve and Muscle Action Potentials. Phys Med Rehabil Clin N Am 1990. [DOI: 10.1016/s1047-9651(18)30743-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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98
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Lööf Y. Improving electromyographic jitter measurements by analysis of the firing pattern. IEEE Trans Biomed Eng 1990; 37:1105-14. [PMID: 2177447 DOI: 10.1109/10.61036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A new model for predicting the jitter from the firing pattern is presented. The jitter is decomposed into two components: 1) variation explained by the firing pattern, 2) random variation. The first component reflects the velocity recovery function of the muscle fiber. The second component reflects the neuromuscular transmission. Two methods are deduced from the model. Method I predicts the jitter from the most recent discharge. Method II can take any period of firing pattern into consideration. Model parameters can be given a physiological interpretation. Measures describing the velocity recovery function are derived. An improved estimate of the neuromuscular jitter is obtained compared to traditional jitter measures under simulated conditions.
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Affiliation(s)
- Y Lööf
- Department of Clinical Neurophysiology, Region Hospital, Orebro, Sweden
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99
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Chapman J, Rabinowitz R, Korczyn AD, Michaelson DM. Rats immunized with cholinergic synaptosomes: a model for Lambert-Eaton syndrome. Muscle Nerve 1990; 13:726-33. [PMID: 2385259 DOI: 10.1002/mus.880130811] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disorder characterized by reduced acetylcholine release at the neuromuscular junction. We report a model of the disease developed by active immunization of rats with purely cholinergic nerve terminals (synaptosomes) isolated from the Torpedo electric organ. Electromyographic studies of neuromuscular transmission in these rats showed a weak initial response followed by a pronounced incremental response to paired supramaximal stimuli (8 msec apart). There was no such response in control rats. There was no evidence of a postsynaptic transmission deficit in the synaptosomes immunized rats. We conclude that immunizing rats with Torpedo cholinergic nerve terminals causes a specific presynaptic dysfunction and may serve as a model for the study of LEMS.
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Affiliation(s)
- J Chapman
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Israel
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100
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Abstract
Neuroendocrine carcinomas of the larynx are uncommon tumors of considerable scientific interest and clinical importance. They include typical carcinoid tumors, atypical carcinoid tumors, and small cell neuroendocrine carcinomas. This paper considers these neoplasms from a personal experience and reviews the relevant medical literature. About 200 cases of neuroendocrine carcinomas of the larynx have been reported. The diagnosis is based on light microscopy and is confirmed by ultrastructural evidence of neurosecretory granules. Histochemical and immunocytochemical investigations may support it. Paraneoplastic syndromes associated with laryngeal neuroendocrine carcinomas have been reported occasionally. The histogenesis, treatment, and prognosis of these lesions also are discussed.
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Affiliation(s)
- A Ferlito
- Department of Otolaryngology, Padua-University, Italy
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