1
|
Al-Chalabi M, Hegde P, Moore SR, Abouainain Y, Keener M, Parvez H, Eid J, Saleem S, Sheikh A. Systematic Review of the Clinical Characteristics and Management of Isaac Syndrome. J Clin Neuromuscul Dis 2023; 25:94-106. [PMID: 37962197 DOI: 10.1097/cnd.0000000000000460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
OBJECTIVES Isaac syndrome (IS) is a condition characterized by peripheral nerve hyperexcitability caused by voltage-gated potassium channel (VGKC)-complex antibodies. Muscle twitching, stiffness, hypertrophy, and dysautonomic characteristics, such as hyperhidrosis, are common manifestations. The syndrome can be autoimmune or paraneoplastic, with thymoma being a common cause of paraneoplastic IS. Furthermore, this condition could be handed down from one generation to another. However, there is limited information regarding outcomes, relapses, associated syndromes, associated malignancies (other than thymoma), and treatment options. Despite its rarity, there remains a need for effective management strategies for patients with IS. To address this gap, we conducted a systematic review to summarize the most common and effective treatments of IS in immunomodulatory agents and symptomatic medications, as well as to describe outcomes, relapses, and associated malignancies. Altogether, this review serves to guide clinical practice recommendations for IS and highlight areas for further research. METHODS We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol to conduct a systematic review of cases reposted through the PubMed and Google Scholar databases. The terms "Isaac Syndrome" and "Acquired Neuromyotonia" were used. The Joanna Briggs Institute's critical appraisal tool was used to evaluate the quality of the included studies. RESULTS We identified 61 case reports and 4 case series, comprising a total of 70 patients with IS (mean age at onset: 42.5 ± 18 years, and 69% were males). Fourteen cases reported relapses. Thymoma was the most common malignancy associated with IS, followed by lymphoma. Among various serum antibodies, voltage-gated potassium channel-complex antibodies were the most reported antibodies elevated in IS (reported in 38 patients and elevated in 21 patients [55.2%]), followed by acetylcholine ganglionic receptor antibodies, which were reported in 30% of patients (n = 21) and were elevated in 5 cases. The most common electromyography findings were myokymic discharges (n = 22), followed by fasciculations (n = 21) and neuromyotonia (n = 19). For treatment, combining anticonvulsants such as carbamazepine with immunotherapy therapy showed the best results in controlling the symptoms. Among immunotherapy therapies, the combination of plasma exchange plus intravenous high-dose steroids achieved the best results in the acute treatment of IS ([n = 6], with improvement noted in 83.3% [n = 5] of cases). Among the symptomatic treatments with anticonvulsants, carbamazepine was the most efficacious anticonvulsant in treatment of IS, with an average effective dosing of 480 mg/day (carbamazepine was used in 32.3% of acute treatment strategies [n = 23], with improvement noted in 73.9% [n = 17] of cases). CONCLUSIONS IS a rare neuromuscular syndrome that tends to affect middle-aged men. These patients should be screened for thymoma and other malignancies such as lymphomas. The management of IS symptoms can be challenging, but based on our review, the combination of multiple immunosuppressives such as IV steroids and plasmapheresis with anticonvulsants such as carbamazepine seems to achieve the best results.
Collapse
Affiliation(s)
| | - Prajwal Hegde
- College of Medicine and Life Sciences, University of Toledo, OH; and
| | - Sara R Moore
- College of Medicine and Life Sciences, University of Toledo, OH; and
| | | | - Myles Keener
- College of Medicine and Life Sciences, University of Toledo, OH; and
| | - Hira Parvez
- Department of Neurology, University of Toledo, Toledo, OH
| | - Jeremy Eid
- College of Medicine and Life Sciences, University of Toledo, OH; and
| | - Sidra Saleem
- Department of Neurology, University of Toledo, Toledo, OH
| | - Ajaz Sheikh
- Department of Neurology, University of Toledo, Toledo, OH
- College of Medicine and Life Sciences, University of Toledo, OH; and
| |
Collapse
|
2
|
Martinez-Velazquez L, Zhou P, López-Font FJ, Hoyek S, Feldman CH, Amato AA, Sobrin L, Patel NA. Retinal Vasculitis in a Patient With Isaacs Syndrome and Inclusion Body Myositis. JOURNAL OF VITREORETINAL DISEASES 2023; 7:165-170. [PMID: 37006658 PMCID: PMC10037760 DOI: 10.1177/24741264221133368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Purpose To report a case of bilateral occlusive retinal vasculitis in a patient with autoimmunity. Methods A case was analyzed and a literature review performed. Results A 55-year-old woman with autoimmune diagnoses of Isaacs syndrome and inclusion body myositis (IBM) reported decreased vision for 3 months. A fundus examination showed peripheral intraretinal hemorrhages in the right eye and an inferotemporal subhyaloid hemorrhage with adjacent intraretinal hemorrhages and preretinal fibrosis in the left eye. Fluorescein angiography showed temporal peripheral leakage and capillary dropout in both eyes, consistent with occlusive vasculitis. Scatter laser treatment to peripheral areas of retinal nonperfusion was followed by an intravitreal bevacizumab injection. Four months later, vision had stabilized at 20/15 in both eyes and the peripheral leakage had resolved. Conclusions This patient developed retinal vasculitis associated with the rare autoimmune neuromuscular disorders of Isaacs syndrome and IBM. An extensive workup showed the most plausible mechanism for the vasculitis was autoimmunity with a history of previously elevated antibodies levels associated with the antiphospholipid syndrome.
Collapse
Affiliation(s)
- Luis Martinez-Velazquez
- Department of Ophthalmology,
Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Paul Zhou
- Department of Ophthalmology,
Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | | | - Sandra Hoyek
- Department of Ophthalmology,
Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Candace H. Feldman
- Division of Rheumatology, Immunology,
and Immunity, Department of Medicine, Harvard Medical School and Brigham and Women's
Hospital, Boston, MA, USA
| | - Anthony A. Amato
- Department of Neurology, Harvard
Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Lucia Sobrin
- Department of Ophthalmology,
Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Nimesh A. Patel
- Department of Ophthalmology,
Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
- Department of Ophthalmology, Bascom
Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL,
USA
| |
Collapse
|
3
|
Posa A, Kornhuber M. EMG-Phänomene peripherer motorisch axonaler
Übererregbarkeit. KLIN NEUROPHYSIOL 2021. [DOI: 10.1055/a-1536-9243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
ZusammenfassungBei der Nadel-Elektromyographie (EMG) besitzen Phänomene der vermehrten
Erregbarkeit von Muskelfasern und von motorischen Axonen Bedeutung für
die Diagnostik neuromuskulärer Erkrankungen. Zur motorisch axonalen
Übererregbarkeit gehören spontane Phänomene wie
Faszikulationen, spontane kontinuierliche Einzelentladungen der motorischen
Einheit (SKEME), Myokymien, neuromyotone Entladungsserien und Krampi. Ferner
gehören dazu reizinduzierte Phänomene wie manche A-Wellen,
reizinduzierte komplex repetitive Entladungen oder tetanischen Spasmen bei
Elektrolytstörungen. In der vorliegenden Übersicht wird der
Kenntnisstand zu den verschiedenen Phänomenen motorisch axonaler
Übererregbarkeit referiert. Ein Schwerpunkt liegt dabei auf den SKEME
als neuem Mitglied der Gruppe spontaner Potenziale aus dem motorischen Axon.
Collapse
Affiliation(s)
- Andreas Posa
- Universitätsklinik für Neurologie,
Martin-Luther-Universität Halle-Wittenberg, Halle (Saale)
| | - Malte Kornhuber
- Universitätsklinik für Neurologie,
Martin-Luther-Universität Halle-Wittenberg, Halle (Saale)
| |
Collapse
|
4
|
Kuttiappan G, Sivakumar S, Thiruvarutchelvan K. Limb Myokymia in Guillain-Barré Syndrome. Neurol India 2020; 68:230-233. [PMID: 32129287 DOI: 10.4103/0028-3886.279682] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Gunasekaran Kuttiappan
- Department of Neurology, Government Mohan Kumaramangalam Medical College Hospital, Salem, Tamil Nadu, India
| | - S Sivakumar
- Department of Neurology, Government Mohan Kumaramangalam Medical College Hospital, Salem, Tamil Nadu, India
| | - K Thiruvarutchelvan
- Department of Neurology, Government Mohan Kumaramangalam Medical College Hospital, Salem, Tamil Nadu, India
| |
Collapse
|
5
|
Xu M, Bennett DLH, Querol LA, Wu LJ, Irani SR, Watson JC, Pittock SJ, Klein CJ. Pain and the immune system: emerging concepts of IgG-mediated autoimmune pain and immunotherapies. J Neurol Neurosurg Psychiatry 2020; 91:177-188. [PMID: 30224548 DOI: 10.1136/jnnp-2018-318556] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 07/18/2018] [Accepted: 07/30/2018] [Indexed: 12/30/2022]
Abstract
The immune system has long been recognised important in pain regulation through inflammatory cytokine modulation of peripheral nociceptive fibres. Recently, cytokine interactions in brain and spinal cord glia as well as dorsal root ganglia satellite glia have been identified important- in pain modulation. The result of these interactions is central and peripheral sensitisation of nociceptive processing. Additionally, new insights and the term 'autoimmune pain' have emerged through discovery of specific IgGs targeting the extracellular domains of antigens at nodal and synaptic structures, causing pain directly without inflammation by enhancing neuronal excitability. Other discovered IgGs heighten pain indirectly by T-cell-mediated inflammation or destruction of targets within the nociceptive pathways. Notable identified IgGs in pain include those against the components of channels and receptors involved in inhibitory or excitatory somatosensory synapses or their pathways: nodal and paranodal proteins (LGI1, CASPR1, CASPR2); glutamate detection (AMPA-R); GABA regulation and release (GAD65, amphiphysin); glycine receptors (GLY-R); water channels (AQP4). These disorders have other neurological manifestations of central/peripheral hyperexcitabability including seizures, encephalopathy, myoclonus, tremor and spasticity, with immunotherapy responsiveness. Other pain disorders, like complex regional pain disorder, have been associated with IgGs against β2-adrenergic receptor, muscarinic-2 receptors, AChR-nicotinic ganglionic α-3 receptors and calcium channels (N and P/Q types), but less consistently with immune treatment response. Here, we outline how the immune system contributes to development and regulation of pain, review specific IgG-mediated pain disorders and summarise recent development in therapy approaches. Biological agents to treat pain (anti-calcitonin gene-related peptide and anti-nerve growth factor) are also discussed.
Collapse
Affiliation(s)
- Min Xu
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Department of Neurology, Xuan wu Hospital Capital Medical University, Beijing, China
| | - David L H Bennett
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Luis Antonio Querol
- Neuromuscular Diseases Unit-Neuromuscular Lab Neurology Department, Universitat Autònoma de Barcelona, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | - Sarosh R Irani
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - James C Watson
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Department of Pain Anesthesiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Sean J Pittock
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Christopher J Klein
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA .,Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| |
Collapse
|
6
|
Huang K, Luo YB, Yang H. Autoimmune Channelopathies at Neuromuscular Junction. Front Neurol 2019; 10:516. [PMID: 31156543 PMCID: PMC6533877 DOI: 10.3389/fneur.2019.00516] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 04/30/2019] [Indexed: 12/22/2022] Open
Abstract
The neuromuscular junction, also called myoneural junction, is a site of chemical communication between a nerve fiber and a muscle cell. There are many types of channels at neuromuscular junction that play indispensable roles in neuromuscular signal transmission, such as voltage-gated calcium channels and voltage-gated potassium channels on presynaptic membrane, and acetylcholine receptors on post-synaptic membrane. Over the last two decades, our understanding of the role that autoantibodies play in neuromuscular junction disorders has been greatly improved. Antibodies against these channels cause a heterogeneous group of diseases, such as Lambert-Eaton syndrome, Isaacs' syndrome and myasthenia gravis. Lambert-Eaton syndrome is characterized by late onset of fatigue, skeletal muscle weakness, and autonomic symptoms. Patients with Isaacs' syndrome demonstrate muscle cramps and fasciculation. Myasthenia gravis is the most common autoimmune neuromuscular junction channelopathy characterized by fluctuation of muscle weakness. All these disorders have a high risk of tumor. Although these channelopathies share some common features, they differ for clinical features, antibodies profile, neurophysiological features, and treatments. The purpose of this review is to give a comprehensive insight on recent advances in autoimmune channelopathies at the neuromuscular junction.
Collapse
Affiliation(s)
- Kun Huang
- Neurology Department, Xiangya Hospital, Central South University, Changsha, China.,Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yue-Bei Luo
- Neurology Department, Xiangya Hospital, Central South University, Changsha, China
| | - Huan Yang
- Neurology Department, Xiangya Hospital, Central South University, Changsha, China
| |
Collapse
|
7
|
|
8
|
Gadoth A, Pittock SJ, Dubey D, McKeon A, Britton JW, Schmeling JE, Smith A, Kotsenas AL, Watson RE, Lachance DH, Flanagan EP, Lennon VA, Klein CJ. Expanded phenotypes and outcomes among 256 LGI1/CASPR2-IgG-positive patients. Ann Neurol 2017. [PMID: 28628235 DOI: 10.1002/ana.24979] [Citation(s) in RCA: 208] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
OBJECTIVE To describe an expanded phenotypic spectrum and longitudinal outcome in 256 LGI1-IgG-seropositive and/or CASPR2-IgG-seropositive patients. METHODS Patients were identified through service neural autoantibody evaluation. Ninety-five had longitudinal follow-up (7-456 months; median = 35). RESULTS Among 3,910 patients tested, 196 were LGI1-IgG positive, 51 were CASPR2-IgG positive, and 9 were dual positive. Cerebrospinal fluid testing was less sensitive than serum testing, detecting only 24 of 38 (63%) LGI1-IgG-positive and 5 of 6 (83%) CASPR2-IgG-positive patients. LGI1-IgG-positive specimens had higher voltage-gated potassium channel-IgG immunoprecipitation values (0.33nmol/l, range = 0.02-5.14) than CASPR2-IgG-positive specimens (0.10nmol/l, range = 0.00-0.45, p < 0.001). Of patients presenting with pain or peripheral nervous system (PNS) manifestations, 39% were LGI1-IgG seropositive (7% had solely neuropathy or pain). Multivariate analysis identified age as the only significant predictor of central nervous system (CNS) versus PNS involvement (>50 years; odds ratio = 15, p < 0.001). Paroxysmal dizziness spells (PDS), a unique LGI1-IgG accompaniment (14% of patients), frequently delayed the diagnosis. T2-mesiotemporal hyperintensity was more common in LGI1-IgG-positive (41%) than in CASPR2-IgG-positive patients (p = 0.033). T1-bright basal ganglia were confined to LGI1-IgG-positive patients with faciobrachial-dystonic seizures (9 of 39, 31%). Cancer was found in 44% of LGI1-IgG/CASPR2-IgG dual seropositive patients (one-third thymoma). Response to initial immunotherapy was favorable in 97%; mean modified Rankin score was 3 (range = 1-5) at onset and 1.74 (range = 0-6) at last follow-up, with 9% having severe refractory disability, 20% being asymptomatic, 28% receiving immunotherapy, and 58% receiving antiepileptic medication. INTERPRETATION Older age is a strong predictor of CNS involvement in patients seropositive for CASPR2-IgG or LGI1-IgG. Pain, peripheral manifestations, and stereotypic paroxysmal dizziness spells are common with LGI1-IgG. Response to initial immunotherapy is often favorable, but some patients remain severely disabled, requiring long-term immunotherapy and/or antiepileptic medications. Ann Neurol 2017;82:79-92.
Collapse
Affiliation(s)
- Avi Gadoth
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Sean J Pittock
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Divyanshu Dubey
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Andrew McKeon
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Jeff W Britton
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - John E Schmeling
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Aurelia Smith
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | | | | | - Daniel H Lachance
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Eoin P Flanagan
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Vanda A Lennon
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Christopher J Klein
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| |
Collapse
|
9
|
Song J, Jing S, Quan C, Lu J, Qiao X, Qiao K, Lu J, Xi J, Zhao C. Isaacs syndrome with CASPR2 antibody: A series of three cases. J Clin Neurosci 2017; 41:63-66. [DOI: 10.1016/j.jocn.2017.02.063] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 02/07/2017] [Indexed: 10/19/2022]
|
10
|
Afterdischarges following M waves in patients with voltage-gated potassium channels antibodies. Clin Neurophysiol Pract 2017; 2:72-75. [PMID: 30214975 PMCID: PMC6123875 DOI: 10.1016/j.cnp.2017.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 02/13/2017] [Accepted: 02/17/2017] [Indexed: 11/20/2022] Open
Abstract
Afterdischarges in patients with VGKC encephalitis. Afterdischarges disappeared in accordance with the clinical improvement. Afterdischarges might be a sensitive indicator of peripheral nerve hyperexcitability.
Objective To explore the correlation between afterdischarges in motor nerve conduction studies and clinical motor hyperexcitability in patients with voltage-gated potassium channels (VGKC) antibodies. Methods Six patients with positive serum antibodies to contactin-associated protein-like 2 (CASPR2) or/and leucine-rich glioma-inactivated protein 1 (LGI1) were recruited, including 5 with autoimmune encephalitis, and 1 with cramp-fasciculation syndrome. Electromyography (EMG), nerve conduction studies (NCS) and F waves were performed, and afterdischarges were assessed. One patient was followed up. Results Five patients had clinical evidence of peripheral motor nerve hyperexcitability (myokymia or cramp), and four of them had abnormal spontaneous firing in concentric needle electromyography (EMG). Prolonged afterdischarges following normal M waves were present in all six patients, including the two patients who had no EMG evidence of peripheral nerve hyperexcitability (PNH). Afterdischarges disappeared after treatment with intravenous immunoglobulin (IVIG). Conclusion The afterdischarges in motor nerve conduction study might be a sensitive indicator of peripheral motor nerve hyperexcitability in patients with VGKC antibodies. Significance Afterdischarges in motor nerve conduction study might be more sensitive than needle electromyography for detecting peripheral motor nerve hyperexcitability, and could disappear gradually in accordance with clinical improvement and reduction of antibodies.
Collapse
|
11
|
Lahoria R, Pittock SJ, Gadoth A, Engelstad JK, Lennon VA, Klein CJ. Clinical-pathologic correlations in voltage-gated Kv1 potassium channel complex-subtyped autoimmune painful polyneuropathy. Muscle Nerve 2017; 55:520-525. [DOI: 10.1002/mus.25371] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 08/03/2016] [Accepted: 08/08/2016] [Indexed: 01/16/2023]
Affiliation(s)
- Rajat Lahoria
- Peripheral Neuropathy Research Laboratory, Mayo Clinic; Rochester Minnesota USA
| | - Sean J. Pittock
- Neuroimmunology Laboratory, Mayo Clinic; 200 First Street SW Rochester Minnesota 55905 USA
| | - Avi Gadoth
- Neuroimmunology Laboratory, Mayo Clinic; 200 First Street SW Rochester Minnesota 55905 USA
| | - Janean K. Engelstad
- Peripheral Neuropathy Research Laboratory, Mayo Clinic; Rochester Minnesota USA
| | - Vanda A. Lennon
- Neuroimmunology Laboratory, Mayo Clinic; 200 First Street SW Rochester Minnesota 55905 USA
| | - Christopher J. Klein
- Peripheral Neuropathy Research Laboratory, Mayo Clinic; Rochester Minnesota USA
- Neuroimmunology Laboratory, Mayo Clinic; 200 First Street SW Rochester Minnesota 55905 USA
| |
Collapse
|
12
|
Nardetto L, Briani C, Fedrigo M, Castellani C, Valente M, Polverino De Laureto P, Santelli L, Angelini A, Giometto B. Isaacs’ syndrome with overlapping myopathy as the first manifestation of AL amyloidosis. J Neurol 2016; 263:2332-2335. [DOI: 10.1007/s00415-016-8264-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 08/07/2016] [Accepted: 08/08/2016] [Indexed: 01/08/2023]
|
13
|
Shimmura M, Maeda N, Kanetou S, Takashima N, Takase KI. [A case of Isaacs' syndrome causing various central nervous symptoms successfully treated with high-dose intravenous methylprednisolone therapy]. Rinsho Shinkeigaku 2015; 55:37-40. [PMID: 25672864 DOI: 10.5692/clinicalneurol.55.37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A 44-year-old man with a bilateral hand tremor suffered from a decline in concentration and abnormal vision for several months. He also complained of easily falling down because of muscle stiffness and cramps in his lower limbs. On admission, he demonstrated lower limb stiffness, muscle cramps, diplopia, hyperhidrosis, left upper limb ataxia and dysesthesia in all limbs. Laboratory examination showed a marked elevation in his serum creatine kinase level (26,890 U/l), and needle electromyography demonstrated myokymic discharges in the muscles of his lower extremities. Isaacs' syndrome was diagnosed based on a positive voltage-gated potassium channel antibody titer of 1,007 pM. Administration of an anticonvulsant (phenytoin, 200 mg/day) did not resolve his symptoms; however, high-dose intravenous methylprednisolone therapy (1 g/day for 3 days) resulted in marked clinical improvement. This case suggests that high-dose intravenous methylprednisolone therapy for Isaacs' syndrome might be as effective as other immunosuppressive therapies such as plasma exchange or intravenous immunoglobulin.
Collapse
|
14
|
Abstract
Isaacs' syndrome is a rare neuromuscular disorder of continuous muscle fibre activity resulting from peripheral nerve hyperexcitability. Symptoms commonly include myokymia (muscle twitching at rest), pseudomyotonia (delayed muscle relaxation), muscle cramps and stiffness. It is caused by voltage-gated potassium channel dysfunction and may be inherited or acquired. Treatment commonly includes anticonvulsants, immunosuppressive therapy and plasma exchange. To date only two cases of Isaacs' syndrome in pregnancy have been reported. We present a case of maternal Isaacs' along with a review of the literature. There are few reports of Isaacs' syndrome in pregnancy, but all are associated with favourable outcomes. Given the autosomal dominant inheritance pattern, genetic counselling of the gravida is recommended. Anticonvulsant may have to be used in pregnancy, and given the potential teratogenicity with several of these agents; preference should be given to newer drugs such as lamotrigine.
Collapse
Affiliation(s)
- Brianna Lide
- Texas A&M University College of Medicine, Bryan, Texas, USA
| | - Jasbir Singh
- North Austin Maternal-Fetal Medicine, Austin, Texas, USA
| | - Sina Haeri
- Department of Obstetrics & Gynecology, Baylor College of Medicine, Houston, Texas, USA
| |
Collapse
|
15
|
Dimitrov AG, Dimitrova NA. Internodal mechanism of pathological afterdischarges in myelinated axons. Muscle Nerve 2013; 49:47-55. [PMID: 23580322 DOI: 10.1002/mus.23874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/05/2013] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Recent optical recordings of transmembrane potentials in the axons of pyramidal neurons have shown that the internodal action potentials (APs) predicted in our previous studies do exist. These novel processes are not well understood. In this study we aim to clarify electrical phenomena in peripheral myelinated axons (MAs). METHODS We used a multi-cable Hodgkin-Huxley-type model to simulate MAs with potassium channels that were either normal or inhibited along a short region of the internodal membrane. A brief stimulus was applied to the first node. RESULTS We demonstrated peculiarities in the internodal APs induced by a saltatory AP: They existed across internodal membranes, were detectable in periaxonal space but not in intracellular space, propagated continuously, collided near the mid-internodes, and produced internodal sources of afterdischarges. CONCLUSIONS These results highlight the importance of the MA internodal regions as new therapeutic targets for avoiding afterdischarges provoked by reduced axonal fast potassium channel expression.
Collapse
Affiliation(s)
- Alexander G Dimitrov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 105, Sofia, 1113, Bulgaria
| | | |
Collapse
|
16
|
Klein CJ, Lennon VA, Aston PA, McKeon A, Pittock SJ. Chronic pain as a manifestation of potassium channel-complex autoimmunity. Neurology 2012; 79:1136-44. [PMID: 22895588 DOI: 10.1212/wnl.0b013e3182698cab] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
OBJECTIVE Autoantibodies targeting voltage-gated potassium channel (VGKC) complexes cause a spectrum of neuronal hyperexcitability disorders. We investigated pain as a manifestation of VGKC-complex autoimmunity. METHODS We reviewed the prevalence and characteristics of pain in VGKC-complex-immunoglobulin G (IgG)-seropositive patients in 25 months of comprehensive service testing for neural autoantibodies, subtyped positive sera for LGI1-IgG and CASPR2-IgG specificities, and reviewed pain prevalence in autoimmune control patients. RESULTS VGKC-complex-IgG was identified in 1,992 patients of 54,853 tested (4%). Of 316 evaluated neurologically at Mayo Clinic, 159 (50%) had pain, in isolation (28%) or with accompanying neurologic manifestations (72%), and not attributable to alternative cause. Pain was subacute in onset, chronic in course, neuropathic, nociceptive, regional, or diffuse and sometimes attributed to fibromyalgia (6%) or psychogenic cause (13%). Most patients had normal peripheral nervous system function, measured by neuropathy impairment scores and nerve conduction. Evidence of neuronal hyperexcitability (hyperhidrosis, quantitative heat-pain hyperalgesia, or electromyographic excitability) was 25-fold more common in pain patients. Pain management required multiple medications in 70% (narcotics, 30%); 13 of 16 patients reported pain relief with immunotherapy. Pain was significantly associated with CASPR2-IgG-positivity (16% positive with pain, 7% without pain; p = 0.014) but not with LGI1-IgG. Less than 10% of 167 patients with neural autoantibodies other than VGKC-complex-IgG reported pain. CONCLUSIONS Chronic idiopathic pain is a syndromic manifestation of VGKC-complex autoimmunity. Hyperexcitability of nociceptive pathways is implicated. CASPR2-IgG significantly associates with pain, but in most patients the antigenic VGKC-complex molecule remains to be determined. VGKC-complex autoimmunity represents an important new direction for pain research and therapy.
Collapse
|
17
|
Altered distribution of juxtaparanodal kv1.2 subunits mediates peripheral nerve hyperexcitability in type 2 diabetes mellitus. J Neurosci 2012; 32:7493-8. [PMID: 22649228 DOI: 10.1523/jneurosci.0719-12.2012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Peripheral nerve hyperexcitability (PNH) is one of the distal peripheral neuropathy phenotypes often present in patients affected by type 2 diabetes mellitus (T2DM). Through in vivo and ex vivo electrophysiological recordings in db/db mice, a model of T2DM, we observed that, in addition to reduced nerve conduction velocity, db/db mice also develop PNH. By using pharmacological inhibitors, we demonstrated that the PNH is mediated by the decreased activity of K(v)1-channels. In agreement with these data, we observed that the diabetic condition led to a reduced presence of the K(v)1.2-subunits in juxtaparanodal regions of peripheral nerves in db/db mice and in nerve biopsies from T2DM patients. Together, these observations indicate that the T2DM condition leads to potassium channel-mediated PNH, thus identifying them as a potential drug target to treat some of the DPN related symptoms.
Collapse
|
18
|
|
19
|
|
20
|
Allen MJ, Lacroix JJ, Ramachandran S, Capone R, Whitlock JL, Ghadge GD, Arnsdorf MF, Roos RP, Lal R. Mutant SOD1 forms ion channel: implications for ALS pathophysiology. Neurobiol Dis 2011; 45:831-8. [PMID: 21930207 DOI: 10.1016/j.nbd.2011.08.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 08/18/2011] [Accepted: 08/31/2011] [Indexed: 10/17/2022] Open
Abstract
Point mutations in the gene encoding copper-zinc superoxide dismutase (SOD1) impart a gain-of-function to this protein that underlies 20-25% of all familial amyotrophic lateral sclerosis (FALS) cases. However, the specific mechanism of mutant SOD1 toxicity has remained elusive. Using the complementary techniques of atomic force microscopy (AFM), electrophysiology, and cell and molecular biology, here we examine the structure and activity of A4VSOD1, a mutant SOD1. AFM of A4VSOD1 reconstituted in lipid membrane shows discrete tetrameric pore-like structure with outer and inner diameters 12.2 and 3.0nm respectively. Electrophysiological recordings show distinct ionic conductances across bilayer for A4VSOD1 and none for wildtype SOD1. Mouse neuroblastoma cells exposed to A4VSOD1 undergo membrane depolarization and increases in intracellular calcium. These results provide compelling new evidence that a mutant SOD1 is capable of disrupting cellular homeostasis via an unregulated ion channel mechanism. Such a "toxic channel" mechanism presents a new therapeutic direction for ALS research.
Collapse
Affiliation(s)
- Michael J Allen
- Center for Nanomedicine and Section of Pulmonary/Critical Care, Department of Medicine, The University of Chicago, Chicago, IL, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Vincent A. Autoimmune channelopathies: well-established and emerging immunotherapy-responsive diseases of the peripheral and central nervous systems. J Clin Immunol 2010; 30 Suppl 1:S97-102. [PMID: 20387102 DOI: 10.1007/s10875-010-9401-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
BACKGROUND The role of antibodies in neuromuscular junction disorders is well established with antibodies to acetylcholine receptor, muscle-specific kinase, and voltage-gated calcium channels. The diseases associated with these antibodies, myasthenia gravis and the Lambert-Eaton myasthenic syndrome, respond well to symptomatic treatments (e.g., cholinesterase inhibitors) and to immunotherapies such as plasma exchange, intravenous immunoglobulin, oral steroids, and steroid-sparing drugs. The role of the antibodies has been established by a variety of in vitro and in vivo approaches. More recently, antibodies to voltage-gated potassium channels have been identified in patients with autoimmune forms of acquired neuromyotonia. Over the last decade, antibodies to CNS membrane receptors or ion channels have begun to be identified and these antibodies define antibody-mediated CNS diseases that also respond to immunotherapies. SUMMARY The paradigms gained from the study of the peripheral conditions has led to a better appreciation of the role of antibodies in neurological disorders and a growing recognition of their role in central nervous system (CNS) diseases.
Collapse
Affiliation(s)
- Angela Vincent
- Department of Clinical Neurology, Level 6 West Wing, John Radcliffe Hospital, University of Oxford, Oxford, UK.
| |
Collapse
|
22
|
|
23
|
Ginsburg G, Forde R, Martyn JAJ, Eikermann M. Increased sensitivity to a nondepolarizing muscle relaxant in a patient with acquired neuromyotonia. Muscle Nerve 2009; 40:139-42. [PMID: 19533664 DOI: 10.1002/mus.21322] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Neuromyotonia is a disorder of hyperexcitability of the peripheral nerve. It has electromyographic features of spontaneous, continuous, irregularly occurring doublets, or multiplets of motor unit potential discharges. Neuromyotonia is characterized by both myokymic and neuromyotonic discharges. To our knowledge, this is the first report in the literature to assess the sensitivity of skeletal muscle to a nondepolarizing muscle relaxant drug, rocuronium, in a woman with acquired neuromyotonia. She had a past medical history notable for prolonged postoperative paralysis following anesthesia. The patient showed increased sensitivity to the neuromuscular effects of rocuronium. This increase in sensitivity may be explained by downregulation of acetylcholine receptors in response to chronic high agonist (acetylcholine) concentrations. If patients with neuromyotonia receive anesthesia, we recommend that smaller doses of a nondepolarizing muscle relaxant be administered, accompanied by monitoring of neuromuscular function, so as to provide optimal muscle relaxation while avoiding overdose and prolonged postoperative recovery.
Collapse
Affiliation(s)
- Greg Ginsburg
- Department of Anesthesia and Critical Care, Massachusetts General Hospital, Shriners Hospital for Children Harvard Medical School, 55 Fruit Street, Boston, Massachusetts 02114, USA
| | | | | | | |
Collapse
|
24
|
Salzer JL, Brophy PJ, Peles E. Molecular domains of myelinated axons in the peripheral nervous system. Glia 2009; 56:1532-1540. [PMID: 18803321 DOI: 10.1002/glia.20750] [Citation(s) in RCA: 159] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Myelinated axons are organized into a series of specialized domains with distinct molecular compositions and functions. These domains, which include the node of Ranvier, the flanking paranodal junctions, the juxtaparanodes, and the internode, form as the result of interactions with myelinating Schwann cells. This domain organization is essential for action potential propagation by saltatory conduction and for the overall function and integrity of the axon.
Collapse
Affiliation(s)
- James L Salzer
- Department of Cell Biology and Neurology, and the Smilow Neuroscience Program, NYU School of Medicine, New York, New York 10016, USA.
| | | | | |
Collapse
|
25
|
Dimitrov AG. A possible mechanism of repetitive firing of myelinated axon. Pflugers Arch 2009; 458:547-61. [DOI: 10.1007/s00424-009-0640-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 12/19/2008] [Accepted: 01/17/2009] [Indexed: 10/21/2022]
|
26
|
Takahashi H, Mori M, Sekiguchi Y, Misawa S, Sawai S, Hattori T, Kuwabara S. Development of Isaacs' syndrome following complete recovery of voltage-gated potassium channel antibody-associated limbic encephalitis. J Neurol Sci 2008; 275:185-7. [DOI: 10.1016/j.jns.2008.07.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2008] [Revised: 07/27/2008] [Accepted: 07/31/2008] [Indexed: 12/29/2022]
|
27
|
Potassium channel antibody-associated encephalitis with hypothalamic lesions and intestinal pseudo-obstruction. J Neurol Sci 2008; 269:176-9. [DOI: 10.1016/j.jns.2007.12.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2007] [Revised: 12/05/2007] [Accepted: 12/14/2007] [Indexed: 11/19/2022]
|
28
|
Takado Y, Shimohata T, Tokunaga J, Kawachi I, Tanaka K, Nishizawa M. [Patient with limbic encephalitis associated with anti-voltage-gated potassium channel antibodies who presented with insomnia and hand tremor]. Rinsho Shinkeigaku 2008; 48:338-342. [PMID: 18540381 DOI: 10.5692/clinicalneurol.48.338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A 65-year-old man presented with bilateral postural hand tremor (3 Hz) followed by memory impairment, which improved spontaneously after admission to our hospital. Two weeks after admission, he had another bout of memory impairment and complained of insomnia. Brain magnetic resonance imaging (MRI) showed a signal intensity change in the medial part of the right temporal lobe, which suggested limbic encephalitis (LE). Serum hyponatremia and absence of cerebrospinal fluid pleocytosis suggested the possibility of anti-voltage-gated potassium channel (VGKC) antibody-associated LE. Serum hyponatremia and hand tremor showed immediate improvement after steroid pulse therapy, and memory impairment and insomnia showed gradual improvement. Brain MRI on day 110 of admission showed partial resolution of medial temporal signal abnormalities with mild bilateral hippocampal atrophy. Serological tests confirmed the clinical diagnosis of anti-VGKC antibody-associated LE. This report may expand the phenotypic profile of anti-VGKC antibody-associated LE, which is characterized by remission and relapse of disease course, insomnia, and hand tremor.
Collapse
Affiliation(s)
- Yuhei Takado
- Department of Neurology, Brain Research Institute, Niigata University
| | | | | | | | | | | |
Collapse
|
29
|
Gonzalez G, Barros G, Russi ME, Nuñez A, Scavone C. Acquired neuromyotonia in childhood: case report and review. Pediatr Neurol 2008; 38:61-3. [PMID: 18054698 DOI: 10.1016/j.pediatrneurol.2007.07.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Revised: 04/06/2007] [Accepted: 07/23/2007] [Indexed: 11/19/2022]
Abstract
Recently characterized as an immune-mediated channelopaty, Isaacs' syndrome (also known as acquired neuromyotonia) was first described in 1961 in two men with persistent, generalized muscle stiffness, in addition to spontaneous, rapid discharges of motor-unit potentials on electromyography. In the peripheral nervous system, antibodies targeted to voltage-gated potassium channels induce hyperexcitability of motor axons, resulting in signs of muscle stiffness or of pseudomyotonia. A spontaneous burst of single motor-unit activity, and myokymic and neuromyotonic discharges, are the most characteristic features found in electromyography studies. This report describes Isaacs' syndrome in a child, in whom the diagnosis was made by clinical features of acquired, spontaneous muscle overactivity and typical electromyographic findings.
Collapse
Affiliation(s)
- Gabriel Gonzalez
- Department of Pediatric Neurology, Pereira Rossell Children's Hospital, Montevideo, Uruguay.
| | | | | | | | | |
Collapse
|
30
|
Kleine BU, Stegeman DF, Drost G, Zwarts MJ. Interspike interval analysis in a patient with peripheral nerve hyperexcitability and potassium channel antibodies. Muscle Nerve 2008; 37:269-74. [PMID: 17636480 DOI: 10.1002/mus.20849] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Neuromyotonia or Isaacs' syndrome is a rare peripheral nerve hyperexcitability disorder caused by antibodies against potassium channels of myelinated axons. We present the high-density surface electromyographic (EMG) recordings of a patient with fasciculations and cramps due to neuromyotonia. To characterize the time course of hyperexcitability, we analyzed the interspike intervals (ISIs) between fasciculation potentials, doublet, and multiplet discharges. ISI duration increased within each burst. The ISI histograms found can be explained by the recovery cycle of the myelinated axon and its dependency on the slow potassium conductance. We conclude that ISI analysis is a useful tool to understand the membrane dynamics underlying abnormal motor unit activity.
Collapse
Affiliation(s)
- Bert U Kleine
- Department of Clinical Neurophysiology, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500HB Nijmegen, The Netherlands.
| | | | | | | |
Collapse
|
31
|
Mazzuca M, Lesage F. [Potassium channels, genetic and acquired diseases]. Rev Med Interne 2007; 28:576-9. [PMID: 17543423 DOI: 10.1016/j.revmed.2007.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Accepted: 04/10/2007] [Indexed: 11/23/2022]
Abstract
INTRODUCTION K(+) channels allow the passive and selective transport of K(+) ions through the membranes. They control K(+) homeostasis, neuronal and muscular excitabilities, and neurotransmitter and hormone release. EXEGESIS K(+) channels are composed of pore-forming subunits associated with regulatory subunits. Many different K(+) channels have been identified. CONCLUSION This diversity is stressed by the growing number of genetic and acquired diseases associated with these channels.
Collapse
Affiliation(s)
- M Mazzuca
- Institut de pharmacologie moléculaire et cellulaire, centre national de la recherche scientifique, Sophia-Antipolis, 660, route des Lucioles, 06560 Valbonne, France
| | | |
Collapse
|
32
|
O'Sullivan SS, Mullins GM, Neligan A, McNamara B, Galvin RJ. Acquired generalised neuromyotonia, cutaneous lupus erythematosus and alopecia areata in a patient with myasthenia gravis. Clin Neurol Neurosurg 2007; 109:374-5. [PMID: 17239529 DOI: 10.1016/j.clineuro.2006.12.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2006] [Revised: 12/18/2006] [Accepted: 12/19/2006] [Indexed: 11/25/2022]
Abstract
We describe a patient with the diagnoses of acquired neuromyotonia, cutaneous lupus erythematosus and alopecia areata, occurring many years after a thymectomy for myasthenia gravis associated with a thymoma. We review the current literature on autoimmune conditions associated with myasthenia gravis and thymectomy. To our knowledge, this combination of multiple autoimmune conditions has not been reported previously.
Collapse
Affiliation(s)
- Sean S O'Sullivan
- Department of Neurology and Neurophysiology, Cork University Hospital, Wilton, Cork, Ireland.
| | | | | | | | | |
Collapse
|
33
|
Myasthenia Gravis and Myasthenic Syndromes. Neurobiol Dis 2007. [DOI: 10.1016/b978-012088592-3/50087-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
34
|
Falace A, Striano P, Manganelli F, Coppola A, Striano S, Minetti C, Zara F. Inherited neuromyotonia: A clinical and genetic study of a family. Neuromuscul Disord 2007; 17:23-7. [PMID: 17140792 DOI: 10.1016/j.nmd.2006.09.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 09/11/2006] [Accepted: 09/20/2006] [Indexed: 10/23/2022]
Abstract
Neuromyotonia is a disorder of peripheral nerve hyperexcitability characterized by myokymia, muscle cramps and stiffness, delayed muscle relaxation after contraction (pseudomyotonia), and hyperhidrosis, associated with well described spontaneous electromyographic features. It is usually an acquired disorder associated with autoantibodies against neuronal voltage-gated potassium channels. However, mutations of KCNA1, encoding the K(+) channel subunit hKv1.1, have been reported in rare families with neuromyotonia, and mutations in KCNQ2, encoding voltage-gated potassium M channel subunit, in families with benign neonatal seizures and myokymia. We report a three-generation family with inherited neuromyotonia without evidence of immunological involvement. Genetic study excluded mutations in KCNA1, KCNA2, KCNA6 and KCNQ2 genes. Our study does not completely exclude the involvement of other genes encoding ion channels subunits in the pathogenesis of this disorder. Further studies of familial cases will shed light on the molecular basis of inherited neuromyotonia.
Collapse
Affiliation(s)
- Antonio Falace
- Neuromuscular and Neurodegenerative Disease Unit, University of Genova, G Gaslini Institute, Genova, Italy
| | | | | | | | | | | | | |
Collapse
|
35
|
Fukushima K, Sato T, Mitsuhashi S, Kaneko K, Yazaki M, Matsuda M, Hashimoto T, Hamanaka K, Yoshida K, Ikeda SI. Isaacs' syndrome associated with myasthenia gravis, showing remission after cytoreductive surgery of pleural recurrence of thymoma. Neuromuscul Disord 2006; 16:763-5. [PMID: 16934467 DOI: 10.1016/j.nmd.2006.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Revised: 06/15/2006] [Accepted: 07/03/2006] [Indexed: 11/27/2022]
Abstract
We report a patient with Isaacs' syndrome associated with myasthenia gravis and pleural recurrence of thymoma, who showed severe limb pain attributed to hyperexcitability of sensory nerves. Myokymia and severe pain were successfully treated with cytoreductive surgery and intraoperative hyperthermic intrathoracic perfusion chemotherapy, but neither pharmacotherapy nor plasma exchange showed obvious clinical effects. Pleural thymoma in our patient may have caused Isaacs' syndrome, probably by unconfirmed humoral immune mechanisms. Cytoreductive treatment for recurrent thymoma should be actively considered as a potent therapeutic option in refractory patients with disabling neuromyotonia symptoms.
Collapse
Affiliation(s)
- Kazuhiro Fukushima
- Department of Internal Medicine (Neurology and Rheumatology), Shinshu University School of Medicine, Matsumoto 390-8621, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Wilson RK, Murinson BB. Sudden spasms following gradual lordosis—the stiff-person syndrome. ACTA ACUST UNITED AC 2006; 2:455-9; quiz 460. [PMID: 16932604 DOI: 10.1038/ncpneuro0259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Accepted: 05/19/2006] [Indexed: 11/08/2022]
Abstract
BACKGROUND A 28-year-old woman presented to hospital after an episode of severe lower back spasms that occurred during a stressful family gathering. She had a history of progressive difficulty bending forward and increasing lumbar lordosis. INVESTIGATIONS Physical examination, spine MRI scan, abdominal and pelvic ultrasound, electromyogram, nerve conduction studies, cerebrospinal fluid analysis, breast examination, Pap smear, transabdominal and endovaginal ultrasound. DIAGNOSIS Stiff-person syndrome with high titer of antibodies against glutamic acid decarboxylase. TREATMENT Benzodiazepines and intravenous immunoglobulins.
Collapse
Affiliation(s)
- Robin K Wilson
- Johns Hopkins Adult Hydrocephalus Program, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | | |
Collapse
|
37
|
Kurono A, Arimura K, Watanabe O, Tomimitsu H, Nagado T, Sonoda Y, Kameyama M, Osame M. IgM-containing fraction suppressed voltage-gated potassium channels in acquired neuromyotonia. Acta Neurol Scand 2006; 113:185-8. [PMID: 16441249 DOI: 10.1111/j.1600-0404.2005.00569.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Acquired neuromyotonia (ANM) is an autoimmune disorder caused by antibodies to voltage-gated potassium channels (VGKC). Previously, we reported a patient with immunoglobulin M (IgM), instead of immunoglobulin G (IgG), anti-VGKC antibody. The purpose of this study was to determine the function of IgM-containing fraction in ANM patients. MATERIALS AND METHODS We determined whether anti-VGKC antibodies in the IgG or IgM-containing fractions suppressed outward potassium current (OKC) using the patch clamp method in three patients with ANM. Whole sera from all patients suppressed OKCs. RESULT Only the purified IgG, not the IgM-containing fractions from two patients suppressed VGKCs, whereas in a patient with IgM anti-VGKC antibody, only the IgM-containing fractions, not the IgG-containing fractions suppressed VGKCs. CONCLUSION Anti-VGKC antibodies belonging to the IgM subclass should be determined in seronegative ANM patients.
Collapse
Affiliation(s)
- A Kurono
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medicine and Dental Sciences, Kagoshima, Japan
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Abstract
A patient with Isaacs' syndrome had generalized muscle spasms, twitching, and progressive muscle stiffness for 21 years. Electrodiagnostic study showed continuous spontaneous motor-unit activity and the presence of M-wave afterdischarges. He responded dramatically to treatment with carbamazepine but developed a drug rash; his treatment was changed to gabapentin with continued improvement. Subsequent nerve conduction studies showed decreased amplitude and later an absence of M-wave afterdischarges. Gabapentin thus appears to be an effective treatment for Isaacs' syndrome.
Collapse
Affiliation(s)
- Upinder K Dhand
- Department of Neurology, University of Missouri, M178, Columbia, Missouri 65212, USA.
| |
Collapse
|
39
|
Jamora RDG, Umapathi T, Tan LCS. Finger flexion resembling focal dystonia in Isaacs' syndrome. Parkinsonism Relat Disord 2006; 12:61-3. [PMID: 16337423 DOI: 10.1016/j.parkreldis.2005.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Revised: 08/22/2005] [Accepted: 08/22/2005] [Indexed: 10/25/2022]
Abstract
We describe a patient with a 5-month history of gradually progressive painless flexion of the left ring finger associated with cramps in both thighs. She has severe chronic obstructive pulmonary disease and was on salbutamol. Serum anti-voltage-gated potassium channel antibodies was positive. Electromyography showed generalized neuromyotonia and myokymic discharges. The cramps were partially relieved by phenytoin. We would like to highlight that finger flexion resembling dystonia can be a presenting sign of Isaacs' syndrome.
Collapse
Affiliation(s)
- Roland Dominic G Jamora
- Department of Neurology, National Neuroscience Institute, TTSH Campus, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore
| | | | | |
Collapse
|
40
|
Arimura K, Arimura Y, Ng A, Uehara A, Nakae M, Osame M, Stålberg E. The origin of spontaneous discharges in acquired neuromyotonia. A Macro EMG study. Clin Neurophysiol 2005; 116:1835-9. [PMID: 15979405 DOI: 10.1016/j.clinph.2005.03.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2004] [Revised: 03/23/2005] [Accepted: 03/24/2005] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To study the generator sites of spontaneous discharges in patients with immune-mediated neuromyotonia. METHODS Macro EMGs triggered by both spontaneously and voluntarily activated single action potentials were recorded and the mean peak-to-peak amplitude and area of the macro motor unit potentials were compared in two patients with typical acquired neuromyotonia having positive antibodies against voltage-gated potassium channels. RESULTS Mean peak-to-peak amplitude and area of Macro EMG motor unit potentials (macro MUPs) triggered by spontaneous discharges were significantly smaller than those triggered by voluntary activation in both patients. However, a few macro MUPs triggered by spontaneous discharges resembled those triggered by voluntary activation. CONCLUSIONS Spontaneous discharges in two patients with immune-mediated neuromyotonia seem to be mostly generated at sites distal to the terminal axon branching points. SIGNIFICANCE This finding may provide a new insight in the understanding of spontaneous discharges in immune-mediated neuromyotonia.
Collapse
Affiliation(s)
- Kimiyoshi Arimura
- Department of Neurology and Geriatrics, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, 8-35-1 Kagoshima, Japan.
| | | | | | | | | | | | | |
Collapse
|
41
|
Brooke RE, Moores TS, Morris NP, Parson SH, Deuchars J. Kv3 voltage-gated potassium channels regulate neurotransmitter release from mouse motor nerve terminals. Eur J Neurosci 2004; 20:3313-21. [PMID: 15610163 DOI: 10.1111/j.1460-9568.2004.03730.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Voltage-gated potassium (Kv) channels are critical to regulation of neurotransmitter release throughout the nervous system but the roles and identity of the subtypes involved remain unclear. Here we show that Kv3 channels regulate transmitter release at the mouse neuromuscular junction (NMJ). Light- and electron-microscopic immunohistochemistry revealed Kv3.3 and Kv3.4 subunits within all motor nerve terminals of muscles examined [transversus abdominus, lumbrical and flexor digitorum brevis (FDB)]. To determine the roles of these Kv3 subunits, intracellular recordings were made of end-plate potentials (EPPs) in FDB muscle fibres evoked by electrical stimulation of tibial nerve. Tetraethylammonium (TEA) applied at low concentrations (0.05-0.5 mM), which blocks only a few known potassium channels including Kv3 channels, did not affect muscle fibre resting potential but significantly increased the amplitude of all EPPs tested. Significantly, this effect of TEA was still observed in the presence of the large-conductance calcium-activated potassium channel blockers iberiotoxin (25-150 nM) and Penitrem A (100 nM), suggesting a selective action on Kv3 subunits. Consistent with this, 15-microM 4-aminopyridine, which blocks Kv3 but not large-conductance calcium-activated potassium channels, enhanced evoked EPP amplitude. Unexpectedly, blood-depressing substance-I, a toxin selective for Kv3.4 subunits, had no effect at 0.05-1 microM. The combined presynaptic localization of Kv3 subunits and pharmacological enhancement of EPP amplitude indicate that Kv3 channels regulate neurotransmitter release from presynaptic terminals at the NMJ.
Collapse
Affiliation(s)
- Ruth E Brooke
- School of Biomedical Sciences, University of Leeds, Leeds, LS2 9NQ, United Kingdom
| | | | | | | | | |
Collapse
|
42
|
Löscher WN, Wanschitz J, Reiners K, Quasthoff S. Morvan's syndrome: clinical, laboratory, and in vitro electrophysiological studies. Muscle Nerve 2004; 30:157-63. [PMID: 15266630 DOI: 10.1002/mus.20081] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Morvan's syndrome is a rare disorder characterized by neuromyotonia, hyperhidrosis, and central nervous system dysfunction. We report a patient with features of this syndrome, but who initially presented with breathing difficulties. Concentric needle electromyography showed an abundance of myokymic and neuromyotonic discharges. Exercise tests and repetitive nerve stimulation showed a decrement-increment response of compound muscle action potentials. Antibodies against voltage-gated potassium channels were not detected on repeated testing, but the presence of oligoclonal bands in the cerebrospinal fluid (CSF) suggested an autoimmune etiology. At follow-up over 3 years, no cancer was found. Electrophysiological in vitro studies of effects of patient serum and CSF on rat nerves provided no evidence of altered voltage-gated sodium or potassium conductances. We conclude that putative humoral factors do not block ion channels acutely but may cause channel dysfunction with chronic exposure.
Collapse
Affiliation(s)
- Wolfgang N Löscher
- Department of Neurology, University of Innsbruck, Anichstrasse 35, A-6020 Innsbruck, Innsbruck, Austria.
| | | | | | | |
Collapse
|
43
|
Shahar E, Raviv R. Sporadic major hyperekplexia in neonates and infants: clinical manifestations and outcome. Pediatr Neurol 2004; 31:30-4. [PMID: 15246489 DOI: 10.1016/j.pediatrneurol.2003.12.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2003] [Accepted: 12/08/2003] [Indexed: 10/26/2022]
Abstract
The aim of the present study is to report on the syndrome of sporadic major hyperekplexia during the neonatal period and early infancy, diagnosed in 39 patients at an average age of 3.3 months, the most severely affected during the first month of life. The patients mainly presented with marked irritability and recurrent startles in response to handling or even minute sounds, accompanied by rhythmic jerky movements and occasionally breath-holding episodes. Family history was negative for hyperekplexia, although eight parents reported jerky leg movements during sleep. The hallmark of hyperekplexia consisted of a hyper-alert gaze and an exaggerated startle with delayed habituation, also elicited by nose tapping and air blowing on the face accompanied by increasing rigidity. Nine severely affected infants, presenting with relentless startles, marked stiffness, violent rhythmic jerks, and breath-holding episodes were treated with oral low doses of clonazepam and completely recovered. Overall, the debilitating symptoms of hyperekplexia gradually resolved in all 39 infants, and their developmental assessment by 2 years of age was within the normal range. Therefore a prompt diagnosis of hyperekplexia during the neonatal period and early infancy, and then treatment if required with benzodiazepines to alleviate the debilitating symptoms, may prevent life-threatening events and enable better feeding and handling. Establishing the diagnosis of such a relatively benign disorder with a favorable developmental outcome may avoid unjustified extensive investigations or unnecessary treatment, suspecting an ominous progressive neurologic disorder.
Collapse
Affiliation(s)
- Eli Shahar
- Child Neurology Unit and Epilepsy Service, Meyer Children Hospital, Rambam Medical Center, Rappaport School of Medicine, Haifa, Israel
| | | |
Collapse
|
44
|
Abstract
The entire length of myelinated axons is organized into a series of polarized domains that center around nodes of Ranvier. These domains, which are crucial for normal saltatory conduction, consist of distinct multiprotein complexes of cell adhesion molecules, ion channels, and scaffolding molecules; they also differ in their diameter, organelle content, and rates of axonal transport. Juxtacrine signals from myelinating glia direct their sequential assembly. The composition, mechanisms of assembly, and function of these molecular domains will be reviewed. I also discuss similarities of this domain organization to that of polarized epithelia and present emerging evidence that disorders of domain organization and function contribute to the axonopathies of myelin and other neurologic disorders.
Collapse
Affiliation(s)
- James L Salzer
- Department of Cell Biology and Neurology, Program in Molecular Neurobiology, Skirball Institute of Biomedical Research, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA.
| |
Collapse
|