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Neurology. Clinical Practice Jun 2021Morvan syndrome is characterized by central, autonomic, and peripheral hyperexcitability due to contactin-associated protein 2 (CASPR2) antibody. Our objective was to...
OBJECTIVE
Morvan syndrome is characterized by central, autonomic, and peripheral hyperexcitability due to contactin-associated protein 2 (CASPR2) antibody. Our objective was to study the clinical spectrum, electrophysiologic, autonomic, polysomnographic, and neuropsychological profile in patients with CASPR2-related Morvan syndrome.
METHODS
Serum and CSF samples that were CASPR2 antibody positive from 2016 to 2019 were assessed. Among them, patients with Morvan syndrome diagnosed based on clinical and electrophysiologic basis were included.
RESULTS
Fourteen (M:F = 10:4) patients with Morvan syndrome were included with age at onset of 37.1 ± 17.5 years. The clinical features were muscle twitching (12), insomnia (12), pain (11), paresthesias (9), hyperhidrosis (7), hypersalivation (6), double incontinence (3), spastic speech (2), dysphagia (2), behavioral disturbances (2), seizures (1), and cold intolerance (1). Neurologic examination revealed myokymia (12), hyperactive tendon reflexes (10), and tremor (6). EMG revealed neuromyotonia (12) and increased spontaneous activity (7). Autonomic function tests conducted in 8 patients revealed definite autonomic dysfunction (4), orthostatic hypotension (2), early dysfunction (1), and postural orthostatic tachycardia syndrome (1). Polysomnography findings in 6 patients revealed insomnia (3), absence of deep sleep (1), high-frequency beta activity (1), REM behavior disorder (1), and periodic leg movements (1). Neuropsychological evaluation showed subtle involvement of the left frontal and temporal lobe. Malignancy workup was negative. All patients were treated with steroids. There was complete neurologic resolution in follow-up with persistent neuropathic pain in 5 patients.
CONCLUSIONS
This study has contributed to the growing knowledge on CASPR2-related Morvan syndrome. It is important for an increased awareness and early recognition as it is potentially treatable by immunotherapy.
PubMed: 34484901
DOI: 10.1212/CPJ.0000000000000978 -
European Neurology 2020Although multifocal motor neuropathy (MMN) is now recognized as a distinct, albeit rare, neurological condition, the path to its recognition was long and winding. This...
Although multifocal motor neuropathy (MMN) is now recognized as a distinct, albeit rare, neurological condition, the path to its recognition was long and winding. This article provides an insight into the medical history of MMN "patient zero" and the first scientific publication that led to the recognition of MMN by the medical community. Multifocal motor neuropathy is nowadays recognized as a disease that produces asymmetric muscle weakness and cramping, with spontaneous motor unit activity (fasciculations and myokymia) but without sensory disorder. From an electrophysiological point of view, the neuropathy is characterized by persistent conduction blocks that usually initially affect the proximal upper extremity. The path to recognizing this rare entity was long and winding. In this article, we describe the first known patient suffering from this disease and the scientific context of its emergence, leading to the first publication on the subject, written by Gérard Roth (1923-2006) and his colleagues at the Neurology Department of Geneva University Hospital (Switzerland) [Eur Neurol. 1986;25(6):416-23].
Topics: Adult; Humans; Male; Demyelinating Diseases; History, 20th Century; Motor Neuron Disease; Neural Conduction; Polyneuropathies; Switzerland
PubMed: 33176310
DOI: 10.1159/000511732 -
Neurology India 2020
Topics: Deglutition Disorders; Electromyography; Facial Nerve Diseases; Guillain-Barre Syndrome; Humans; Lower Extremity; Male; Middle Aged; Myokymia; Neural Conduction; Neurologic Examination
PubMed: 32129287
DOI: 10.4103/0028-3886.279682 -
Tremor and Other Hyperkinetic Movements... 2021Hemifacial spasm is diagnosed on a clinical base, with certain atypical features alerting the physician for mimics.
BACKGROUND
Hemifacial spasm is diagnosed on a clinical base, with certain atypical features alerting the physician for mimics.
PHENOMENOLOGY SHOWN
Hemifacial neuromyotonia/myokymia characterized by tonic hemifacial contraction followed by multifocal undulating hemifacial twitches.
EDUCATIONAL VALUE
These features are a red flag for (post-irradiation) facial neuromyotonia/myokymia which generally responds well to low dose carbamazepine.
Topics: Carbamazepine; Facial Nerve Diseases; Hemifacial Spasm; Humans; Isaacs Syndrome; Myokymia
PubMed: 34692229
DOI: 10.5334/tohm.653 -
Clinical Ophthalmology (Auckland, N.Z.) 2020Eyelid myokymia, commonly referred to as "eyelid twitching", is a common, benign condition that resolves in most individuals within hours to days; however, chronic cases...
Eyelid myokymia, commonly referred to as "eyelid twitching", is a common, benign condition that resolves in most individuals within hours to days; however, chronic cases can persist for several weeks to months, prompting the search for home remedies that may reduce the frequency or duration of symptoms. In this article, we discuss the proposed pathophysiologic mechanism and safety concerns surrounding tonic water as a treatment for eyelid myokymia.
PubMed: 32184555
DOI: 10.2147/OPTH.S235895 -
The Journal of Pharmacology and... Jun 2020Loss of function of voltage-gated potassium (Kv) channels is linked to a range of lethal or debilitating channelopathies. New pharmacological approaches are warranted to...
Loss of function of voltage-gated potassium (Kv) channels is linked to a range of lethal or debilitating channelopathies. New pharmacological approaches are warranted to isoform-selectively activate specific Kv channels. One example is KCNA1 Potassium Voltage-Gated Channel Subfamily A Member 1 (KCNA1) (Kv1.1), an archetypal -type Kv channel, in which loss-of-function mutations cause episodic ataxia type 1 (EA1). EA1 causes constant myokomia and episodic bouts of ataxia and may associate with epilepsy and other disorders. We previously found that the inhibitory neurotransmitter -aminobutyric acid and modified versions of glycine directly activate Kv channels within the KCNQ subfamily, a characteristic favored by strong negative electrostatic surface potential near the neurotransmitter carbonyl group. Here, we report that adjusting the number and positioning of fluorine atoms within the fluorophenyl ring of glycine derivatives produces isoform-selective KCNA1 channel openers that are inactive against KCNQ2/3 channels, or even KCNA2, the closest relative of KCNA1. The findings refine our understanding of the molecular basis for KCNQ versus KCNA1 activation and isoform selectivity and constitute, to our knowledge, the first reported isoform-selective KCNA1 opener. SIGNIFICANCE STATEMENT: Inherited loss-of-function gene sequence variants in , which encodes the KCNA1 (Kv1.1) voltage-gated potassium channel, cause episodic ataxia type 1 (EA1), a movement disorder also linked to epilepsy and developmental delay. We have discovered several isoform-specific KCNA1-activating small molecules, addressing a notable gap in the field and providing possible lead compounds and a novel chemical space for the development of potential future therapeutic drugs for EA1.
Topics: Animals; Ataxia; Epilepsy; Glycine; Humans; Kv1.1 Potassium Channel; Mutation; Myokymia; Protein Isoforms; Xenopus laevis
PubMed: 32217768
DOI: 10.1124/jpet.119.264507 -
Annals of Indian Academy of Neurology 2022Myokymia is a rare neuromuscular disorder and limb involvement is not common in this disease. To the best of our knowledge, isolated peroneus longus muscle myokymia was...
Myokymia is a rare neuromuscular disorder and limb involvement is not common in this disease. To the best of our knowledge, isolated peroneus longus muscle myokymia was not reported before in the literature; and for that reason treatment protocols were not established. Botulinum toxin type A (BoNT-A), which is used in the treatment of a variety of neurologic disorders, was also defined as a treatment option in myokymia. Herein, we will report three cases of peroneus longus muscle myokymia in children in the absence of any other neurological findings, and the successful results of treatment with local BoNT-A injections. BoNT-A is a safe and effective treatment in myokymia when administered by an experienced clinician and should always be considered when the disorder is persistent and affecting the life of the patient.
PubMed: 36561037
DOI: 10.4103/aian.aian_293_22 -
Arquivos de Neuro-psiquiatria May 2020Neurophysiological studies are ancillary tools to better understand the features and nature of movement disorders. Electromyography (EMG), together with...
BACKGROUND
Neurophysiological studies are ancillary tools to better understand the features and nature of movement disorders. Electromyography (EMG), together with electroencephalography (EEG) and accelerometer, can be used to evaluate a hypo and hyperkinetic spectrum of movements. Specific techniques can be applied to better characterize the phenomenology, help distinguish functional from organic origin and assess the most probable site of the movement generator in the nervous system.
OBJECTIVE
We intend to provide an update for clinicians on helpful neurophysiological tools to assess movement disorders in clinical practice.
METHODS
Non-systematic review of the literature published up to June 2019.
RESULTS
A diversity of protocols was found and described. These include EMG analyses to define dystonia, myoclonus, myokymia, myorhythmia, and painful legs moving toes pattern; EMG in combination with accelerometer to study tremor; and EEG-EMG to study myoclonus. Also, indirect measures of cortical and brainstem excitability help to describe and diagnose abnormal physiology in Parkinson's disease, atypical parkinsonism, dystonia, and myoclonus.
CONCLUSION
These studies can be helpful for the diagnosis and are usually underutilized in neurological practice.
Topics: Dystonia; Electroencephalography; Electromyography; Humans; Movement Disorders; Myoclonus; Neurophysiology; Tremor
PubMed: 32901697
DOI: 10.1590/0004-282X20190195 -
Cerebellum & Ataxias 2019Friedreich ataxia (FRDA) is the most common familial ataxia syndrome in Central and Southern Europe but rare in Scandinavia. Biallelic mutations in SH3 domain and...
BACKGROUND
Friedreich ataxia (FRDA) is the most common familial ataxia syndrome in Central and Southern Europe but rare in Scandinavia. Biallelic mutations in SH3 domain and tetratricopeptide repeats 2 ( cause Charcot-Marie-Tooth disease type 4C (CMT4C), one of the most common autosomal recessive polyneuropathies associated with early onset, slow disease progression and scoliosis. Beyond nystagmus reported in some patients, neither ataxia nor cerebellar atrophy has been documented as part of the CMT4C phenotype.
METHODS
Here we describe a single centre CMT4C cohort. All patients underwent a comprehensive characterization that included physical examination, neurophysiological studies, neuroimaging and genetic testing. In a patient with cerebellar features, an evaluation of the vestibular system was performed.
RESULTS
All five patients in this cohort harbored the R954X mutation in suggesting a founder effect Two patients had been diagnosed as FRDA. One of them, an 80-year-old woman had onset of unsteadiness during childhood leading to gradual loss of mobility. She also had scoliosis and hearing loss. On examination she had generalized muscle atrophy, leg flaccidity, pes cavus, facial myokymia, limb dysmetria, dysarthria and gaze-evoked nystagmus. She exhibited bilateral vestibular areflexia. Neuroimaging demonstrated atrophy in the frontoparietal regions and cerebellar hemispheres.
CONCLUSIONS
CMTC4A may present with a cerebellar phenotype and mimic a flaccid-ataxic form of FRDA. Absence of cardiomyopathy or endocrine abnormalities and lack of pathological dentate iron accumulation in CMT4C distinguish it from FRDA.
PubMed: 31346473
DOI: 10.1186/s40673-019-0103-8 -
JA Clinical Reports Feb 2020Isaacs' syndrome is a peripheral nerve hyperexcitability syndrome and rare acquired channel disease. The symptoms (myokymia, neuromyotonia, and muscle spasm) emerge even...
BACKGROUND
Isaacs' syndrome is a peripheral nerve hyperexcitability syndrome and rare acquired channel disease. The symptoms (myokymia, neuromyotonia, and muscle spasm) emerge even during sleep. This report describes the anesthetic management, especially neuromuscular blocking drugs and postoperative pain, in a case of Isaacs' syndrome.
CASE PRESENTATION
A 63-year-old woman with Isaacs' syndrome underwent elective laparoscopic distal gastrectomy under general anesthesia without epidural anesthesia. She received double filtration plasmapheresis four times to alleviate symptoms before surgery. To avoid a prolonged neuromuscular blockade, we performed total intravenous anesthesia and titrated muscle relaxant with neuromuscular monitoring. Anesthetic management was performed without any problems. However, pain management after surgery proved difficult as she experienced severe pain due to myokymia.
CONCLUSIONS
Despite attempts to minimize symptoms, severe postoperative pain associated with myokymia occurred. Continuous regional anesthesia should be considered to treat pain from abnormal discharge in the central nervous system in Isaacs' syndrome.
PubMed: 32062811
DOI: 10.1186/s40981-020-00321-y