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Lee SK, Lee MS. Ocular neuromyotonia: a review of diagnosis and treatment. Curr Opin Ophthalmol 2022; 33:465-470. [PMID: 35980029 DOI: 10.1097/icu.0000000000000894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE OF REVIEW The current review will cover the clinical presentation, causes, epidemiology, differential diagnoses, workup, and treatment of ocular neuromyotonia (ONM) in detail. RECENT FINDINGS While ONM largely remains a unilateral eye movement disease affecting adults with a history of sellar radiation, recent case reports highlight an expansion of this presentation to include bilateral, pediatric, and congenital cases. SUMMARY ONM is a rare but recognizable ocular motility disorder involving sustained contraction of the extraocular muscle, commonly resulting in intermittent diplopia. Diagnosis of ONM relies upon a thorough history and clinical exam, with particular attention to history of radiotherapy and eccentric gaze testing. Treatment with carbamazepine remains first-line therapy, although other membrane stabilizing agents and surgical interventions can be effective.
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Affiliation(s)
| | - Michael S Lee
- Departments of Ophthalmology, Neurology, and Neurosurgery, University of Minnesota, Minneapolis, Minnesota, USA
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Abstract
Ocular neuromyotonia is a rare disorder of the oculomotor nerves caused by chronic damage to the nerve, usually secondary to previous irradiation or longstanding compression. We present the case of a 40-year-old man who had received proton beam therapy for a right cavernous sinus chondrosarcoma 15 years earlier. He developed intermittent episodes of self-limited horizontal diplopia, which occurred over the course of 1 year. At its peak, the deviation reached 20Δ in primary gaze and 25Δ in right gaze. Signs included right upper lid retraction and right medial rectus muscle absence of relaxation after sustained left gaze, with mild deficit of elevation and depression but no pupillary involvement. Full recovery occurred after he closed his eyes. Ocular neuromyotonia of the right oculomotor nerve was diagnosed after recurrence of primary disease relapse was ruled out. Symptoms remitted completely under oxcarbazepine.
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Affiliation(s)
- Rafel Alcubierre
- Department of Ophthalmology, Hospital Moisès Broggi Sant Joan Despi, Consorci Sanitari Integral, Barcelona, Spain.
| | - Aida Alejaldre
- Department of Neurology, Hospital Moisès Broggi Sant Joan Despi, Consorci Sanitari Integral, Barcelona, Spain
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Rogatko CP, Glass EN, Kent M, Hammond JJ, de Lahunta A. Use of botulinum toxin type A for the treatment of radiation therapy-induced myokymia and neuromyotonia in a dog. J Am Vet Med Assoc 2016; 248:532-7. [PMID: 26885596 DOI: 10.2460/javma.248.5.532] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
CASE DESCRIPTION A 5-year-old castrated male Maltese was evaluated for intermittent clinical signs of muscle cramping and abnormal movements of the skin of the right pelvic limb at the site where an infiltrative lipoma had twice been resected. After the second surgery, the surgical field was treated with radiation therapy (RT). The clinical signs developed approximately 14 months after completion of RT. CLINICAL FINDINGS When clinical signs were present, the right biceps femoris and semitendinosus muscles in the area that received RT were firm and had frequently visible contractions, and the skin overlying those muscles had episodic vermiform movements. Electromyography of those muscles revealed abnormal spontaneous activity with characteristics consistent with myokymic discharges and neuromyotonia. Magnetic resonance imaging of the affected leg revealed no evidence of tumor regrowth. The myokymia and neuromyotonia were considered secondary to RT. TREATMENT AND OUTCOME 4 U of Clostridium botulinum toxin type A (BoNT-A) neurotoxin complex was injected into the affected muscles at each of 6 sites twice during a 24-hour period (ie, 48 U of BoNT-A were administered). The clinical signs were completely resolved 10 days after BoNT-A treatment and were controlled by repeated BoNT-A treatment every 3 to 4 months for > 1 year. CLINICAL RELEVANCE To our knowledge, this is the first report of myokymia and neuromyotonia secondary to RT in a dog. For the dog of this report, injection of BoNT-A into the affected muscles was safe, effective, and easy to perform.
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Abstract
A 27-year-old woman noticed diplopia when gazing left and paresthesia of the left face and headache of the left side for 8 months. Abduction and supraduction of the left eye were moderately restricted. Hypoesthesia of the face innervated by the ophthalmic branch of the left trigeminal nerve was detected. Visual disturbance due to optic neuropathy developed 5 months later. MRI with gadolinium revealed a mass lesion extending from the left cavernous sinus to the orbital apex. Ocular neuromyotonia and corresponding diplopia were induced by sustained right gaze. Such episodes occurred almost every day on awaking in the morning. Prednisolone (60 mg/day) was given and the headache and visual disturbance ameliorated in two days. The diplopia disappeared in 4 days. The patient remains free from these symptoms after 6 months. This is the first report of ocular neuromyotonia associated with Tolosa-Hunt syndrome.
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Affiliation(s)
- Akihiko Oohira
- Department of Ophthalmology, Tokyo Women's Medical University School of Medicine
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Hayashi Y, Kimura A, Watanabe N, Yamada M, Sakurai T, Tanaka Y, Hozumi I, Inuzuka T. Serial monitoring of basal metabolic rate for therapeutic evaluation in an Isaacs' syndrome patient with chronic fluctuating symptoms. Intern Med 2010; 49:475-7. [PMID: 20190487 DOI: 10.2169/internalmedicine.49.2865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A 52-year-old man presented with hyperhydrosis, painful pseudomyotonia and gait disturbance. The condition was diagnosed as Isaacs' syndrome on the basis of characteristic findings noted on an electromyogram. Carbamazepine treatment was only partially and transiently effective. Intravenous immunoglobulin therapy was effective. The basal metabolic rate (BMR) was serially monitored using an automatic integrated system for breath analysis. Serial monitoring of the BMR facilitates therapeutic evaluation in an Isaacs' syndrome patient with chronic fluctuating symptoms.
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Affiliation(s)
- Yuichi Hayashi
- Department of Neurology and Geriatrics, Gifu University, Graduate School of Medicine.
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Kuroda M, Isozaki E, Matsubara S, Yoshida H, Hayashi H. [Case of ocular neuromyotonia with transient and gaze-induced diplopia]. Rinsho Shinkeigaku 2007; 47:344-7. [PMID: 17633107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A 71-year-old man had recurrent spells of transient diplopia for about four years. Vertical diplopia were induced by downward gaze, mostly to the lower-left, and lasted for about ten seconds. During the spells, limitation in elevation of the left eye was observed. Other neurological examinations were normal except for a minor paresis of the left trochlear nerve revealed only by detailed neuroophthalmological examination. The patient was treated with carbamazepine 200 mg daily, which abolished the spells. He was diagnosed to have idiopathic ocular neuromyotonia of the left third or fourth nerve. Ocular neuromyotonia is a rare disturbance of ocular motility, characterized by paroxysmal monocular involuntary spasms of one or more extraocular muscles supplied by the third, fourth or sixth cranial nerves. Past studies showed that most patients had radiation therapy to the parasellar or sellar regions. Slight injury to the peripheral nerves such as one caused by radiation may have an important role in the development of ocular neuromyotonia. Furthermore, patients with ocular neuromyotonia often benefit from the use of carbamazepine, a membrane-stabilizing agent. We report a case of idiopathic ocular neuromyotonia without history of damage to the cranial nerves. It is the first report in Japan.
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Affiliation(s)
- Masatoshi Kuroda
- Department of Neurology, Tokyo Metropolitan Neurological Hospital
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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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Affiliation(s)
- Sean S O'Sullivan
- Department of Neurology and Neurophysiology, Cork University Hospital, Wilton, Cork, Ireland.
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Sukajintanakarn D, Mitrabhakdi E, Phanthumchinda K. Acquired neuromyotonia (Isaacs' syndrome): a case report with autonomic physiologic studies. J Med Assoc Thai 2006; 89:1308-12. [PMID: 17048446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Acquired neuromyotonia (Isaacs' syndrome) is a rare disorder characterized by hyperexcitability of peripheral motor nerves. The cardinal features consist of myokymia, pseudomyotonia and contracture of hands and feet. The diagnosis of Isaacs' syndrome is based on the clinical features and classic electromyographic findings. Serum antibodies against Voltage-Gated Potassium Channels (VGKCs) are detected in some cases. The authors report a 17 year-old man presented with difficulty in walking, writing and respiratory discomfort for 7 months. His body weight had decreased from 120 to 70 kilograms during that period. Physical examination was remarkable for profound sweating. Muscles were in a state of contraction, action myotonia without percussion myotonia, myokymia and carpopedal spasm. Electromyography showed classical neuromyotonic and myokymic discharges. The investigations for conditions associated with Isaacs' syndrome were unrevealing. VGKCs antibody were not performed. Treatment with carbamazepine resulted in substantial improvement of the symptoms within 7 days.
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Affiliation(s)
- Damrongvit Sukajintanakarn
- Division of Neurology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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Affiliation(s)
- Maud Jacob
- Unité de Neuro-Ophtalmologie, Hôpital Neurologique, Hospices Civils de Lyon, Université Claude Bernard Lyon I, Bron, France
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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.
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Affiliation(s)
- Upinder K Dhand
- Department of Neurology, University of Missouri, M178, Columbia, Missouri 65212, USA.
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Abstract
BACKGROUND Ocular neuromyotonia is a rare ocular motility disorder characterized by involuntary contractions of one or several ocular motor muscles. In this report a typical case is presented. PATIENT AND METHODS A 61-year-old female patient was referred with persistent diplopia despite previous surgical treatment for right 6 (th) nerve palsy. The palsy was caused by a meningeoma of the petrous bone, which had been incompletely resected. Subsequently, the patient had received radiation therapy. Strabismological and neuroophthalmological examinations were performed. The results coincide with data collected in our department from three other patients with ocular neuromyotonia (2 cranial nerve VI, 1 cranial nerve IV), over the past three years. RESULTS The patient showed orthophoria at distance (5 m) and an exophoria of 6 degrees at near vision. The abduction and adduction of the right eye were restricted to 40 degrees and 35 degrees , respectively. After several seconds of eccentric gaze to the right, the right eye remained in an abducted position of approximately 25 degrees . The gaze to the left led to a retraction instead of an adduction of the right eye. The spasm of the lateral rectus muscle resolved after some seconds, returning to the aforementioned right eye motility. Under oral treatment with carbamazepine, initially 200 mg, later increasing to 400 mg per day, the symptoms improved significantly, did not resolve entirely, however. CONCLUSIONS These typical findings permit the diagnosis of ocular neuromyotonia. The characteristic symptoms of ocular neuromyotonia and the typical history of a previous intracranial tumor, treated neurosurgically with adjuvant radiotherapy, lead to the hypothesis that ephaptic transmission in the cranial nerve is the underlying pathophysiological mechanism in the development of ocular neuromyotonia. Hereby, efferent impulses from non-twitch motoneurons could activate neighbouring axons, and spread both peripherally and centrally. Beside other mechanisms discussed, an involvement of proprioceptive elements and their reafference is also a possible cause for the prolonged muscle contraction.
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Affiliation(s)
- G Koop
- Zentrum für Augenheilkunde der Justus-Liebig-Universität Giessen.
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Abstract
A 6-year-old spayed female domestic shorthair cat was examined because of a 2-week history of rhythmic muscle movements. Physical examination revealed thoracic limb rigidity, contracture of the carpi, generalized muscle atrophy, and rhythmic rippling of the muscles of all 4 limbs. Results of a CBC and serum biochemistry profile were unremarkable other than high creatine kinase activity. Electromyography revealed unique high-frequency discharges, including rhythmic bursts of single motor unit potentials appearing as doublets (myokymia) and more prolonged bursts of nonrhythmic motor unit potentials with characteristic waning amplitudes (neuromyotonia). Histologic examination of muscle biopsy specimens revealed noninflammatory necrotizing myopathy with regeneration. The cat did not respond to treatment with carbamazepine or prednisone but improved rapidly after treatment with phenytoin was initiated. Six months after initial examination, electromyography revealed a substantial decrease in the amount of spontaneous activity in previously affected muscles. However, the myokymic and neuromyotonic discharges were still present, albeit with a substantial decrease in frequency.
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Affiliation(s)
- Heather R Galano
- Veterinary Teaching Hospital, College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA
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Taylor PW. Isaacs' syndrome (autoimmune neuromyotonia) in a patient with systemic lupus erythematosus. J Rheumatol 2005; 32:757-8. [PMID: 15801039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Patients with systemic lupus erythematosus (SLE) often produce autoantibodies against a large number of antigens. A case of SLE is presented in which muscle twitching and muscle cramps were associated with an autoantibody directed against the voltage-gated potassium channel of peripheral nerves (Isaacs' syndrome).
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Affiliation(s)
- Philip W Taylor
- Cape Girardeau Physician Associates, Cape Girardeau, Missouri 63703, USA
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Abstract
Ocular neuromyotonia is a rare clinical entity, which is characterized by spontaneous spasm of ocular muscles resulting in paroxysmal diplopia and strabismus. Inappropriate discharges from ocular motor neurons or axons with unstable cell membranes may cause the sustained contraction of their respective ocular muscles. In most cases, ocular neuromyotonia resulted from radiation therapy to the parasellar and sellar regions or compressive lesions on ocular motor nerves. Among 30 patients reported in the literatür only six patients were accepted as idiopathic. Here, we reported a patient with third nerve myotonia representing with spells of diplopia. No lesion was found and she was accepted as idiopathic ocular neuromyotonia.
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Affiliation(s)
- Betigül Yürüten
- Department of Neurology, School of Medicine, Selçuk University, 42080 Konya, Turkey.
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Tindle HA. Why etiology matters. Med Econ 2002; 79:130, 135, 139. [PMID: 11989155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
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Abstract
Malfunction in ion channels, due to mutations in genes encoding channel proteins or the presence of autoantibodies, are increasing being implicated in causing disease conditions, termed channelopathies. Dysfunction of potassium (K(+)) channels has been associated with the pathophysiology of a number of neurological, as well as peripheral, disorders (e.g., episodic ataxia, epilepsy, neuromyotonia, Parkinson's disease, congenital deafness, long QT syndrome). K(+) channels, which demonstrate a high degree of diversity and ubiquity, are fundamental in the control of membrane depolarisation and cell excitability. A common feature of K(+) channelopathies is a reduction or loss of membrane potential repolarisation. The identification of K(+) channel subtype specific openers will allow the recovery of the mechanism(s) responsible for counteraction of uncontrolled cellular depolarisation. Synthetic agents that demonstrate K(+) channel opening properties are available for a variety of K(+) channel subtypes (e.g., K(ATP), BK(Ca), GIRK and M-channel). This study reviews the realistic therapeutic potential that may be gained in a broad spectrum of clinical conditions by K(+) channel openers. K(+) channel openers would therefore identify dysfunctional K(+) channel as therapeutic targets for clinical benefit, in addition being able to modulate normally functioning K(+) channels to gain clinical management of pathophysiological events irrespective of the cause.
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Affiliation(s)
- K Lawson
- Biomedical Research Centre, Sheffield Hallam University, School of Science and Mathematics, City Campus, Sheffield, S1 1WB, UK.
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Abstract
Neuromyotonia is characterized by spontaneous and continuous muscle fibre activity leading to muscle cramps, pseudomyotonia, myokymia and weakness. Electromyographic recordings show typical findings. An auto-immune mechanism has been suggested in at least a subset of patients. Various therapies have been tried with different outcome. A patient with neuromyotonia responding well to high-dose immunoglobulin treatment is presented.
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Affiliation(s)
- G Alessi
- Department of Neurology, University Hospital Ghent, De Pintelaan, 185 Ghent, Belgium
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Abstract
The purpose of this study was to further characterize neuromyotonia in mice with deletions and point mutations of myelin protein genes. Clinical observation showed irregular stretching of the hindlimbs, tremor and generalized myokymia in mice with targeted deletions of the genes encoding myelin protein zero (P0-/-) or peripheral myelin protein 22 (Pmp22-/-), and Trembler mice, which carry a point mutation of Pmp22. By electromyography (EMG), we found irregular high-frequency bursts of spontaneous motor unit activity and rhythmic doublet or multiplet discharges of motor units in these mouse models of human hereditary neuropathies. The EMG signs are typical for neuromyotonia and myokymia, respectively. The activity persisted after a proximal nerve section in many cases, localizing the generator to the peripheral nerve or the muscle. We now show that blocking neuromuscular transmission with suxamethonium abolished the spontaneous activity, ruling out a muscle origin. Phenytoin ameliorated the motor behavior. Taken together, our study shows that neuromyotonia develops in different mouse models of hereditary myelinopathies. This indicates that spontaneous motor unit activity may underlie neuromyotonia, which is occasionally observed in Charcot-Marie-Tooth disease. These animal models will be useful to study the pathogenesis of neuromyotonia.
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Affiliation(s)
- J Zielasek
- Department of Neurology, Julius-Maximilians-University, Josef-Schneider-Str. 11, D-97080 Würzburg, Germany.
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Montero Homs J, Barraquer Bordas L, Martínez Matos JA, Peres Serra J. [Congenital neuromyotonia. Retrospective study of 4 cases]. Neurologia 1999; 14:328-37. [PMID: 10570619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
BACKGROUND Fasciculation, double discharge, myokymia and neuromyotonia are different kinds of involuntary muscular activity that originate in ectopic discharges of the motor axons. Electrophysiological studies are needed in all cases for the diagnosis. Non rigorous electrophysiological studies in some cases is the cause of the historically unclear nosological delimitation of the neuromyotonic syndromes. OBJECTIVE To report the clinical picture and electrophysiological findings in patients with congenital neuromyotonia. PATIENTS AND METHODS Four patients with congenital neuromyotonia were studied. Electrophysiological exam included nerve conduction measurements, study of the after-discharges and conventional EMG. Spontaneous discharges were displayed after applying a low pass filter, signal trigger and delay line. RESULTS In one case positive motor features predominate (continuous muscle fiber activity). On the contrary, two cases, showed neuropathic deficitary signs with a Charcot-Marie-Tooth type II disease phenotype; neuromyotonia was, in both cases, an electrophysiological feature. In the last patient, motor signs were limited to the facial muscles but electrophysiological study discovered generalized neuromyotonia. Treatment with carbamazepine or oxcarbazepine was useful in the four cases. CONCLUSION Congenital neuromyotonia is a clinically heterogeneous syndrome with uniform electrophysiological features that permit its qualification.
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Affiliation(s)
- J Montero Homs
- Servicio de Neurología de la CSUB, L'Hospitalet de Llobregat, Barcelona.
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van den Berg JS, van Engelen BG, Boerman RH, de Baets MH. Acquired neuromyotonia: superiority of plasma exchange over high-dose intravenous human immunoglobulin. J Neurol 1999; 246:623-5. [PMID: 10463372 DOI: 10.1007/s004150050419] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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