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Internal Medicine (Tokyo, Japan) Aug 2021We herein report a 48-year-old woman receiving eribulin mesylate for breast cancer who presented with gait disorder, distal limb paresthesia, and weakness progressing...
We herein report a 48-year-old woman receiving eribulin mesylate for breast cancer who presented with gait disorder, distal limb paresthesia, and weakness progressing monthly. A nerve conduction study indicated demyelination with multifocal conduction block. Considering the immune-mediated pathology of her condition, she was administered intravenous immunoglobulin. Her neurological symptoms improved promptly after intravenous immunoglobulin therapy and eribulin withdrawal. Furthermore, the limb myokymia seen at the time of admission disappeared. Her symptoms continued to improve without additional treatment. We conclude that eribulin was a rare cause of demyelinating neuropathy with multifocal conduction block derived from immune-mediated pathology.
Topics: Breast Neoplasms; Female; Furans; Humans; Ketones; Middle Aged; Myokymia; Neural Conduction
PubMed: 33678744
DOI: 10.2169/internalmedicine.6780-20 -
Brain Circulation 2020Neurocysticercosis (NCC) is a specific form of cysticercosis that affects the central nervous system. It is caused by the tapeworm , which is often found in pigs. NCC is... (Review)
Review
Neurocysticercosis (NCC) is a specific form of cysticercosis that affects the central nervous system. It is caused by the tapeworm , which is often found in pigs. NCC is considered one of the "great simulator/mimickers" of other diseases. In this context, movement disorders (MDs) can occur in a small percentage of individuals with NCC. This review aims to evaluate the clinicoepidemiological profile, pathological mechanisms, and historical features of NCC-associated MD. Relevant reports in six databases were identified and assessed by two reviewers without language restriction. A total of 71 reports containing 148 individuals who developed an MD related to NCC were identified. NCC-associated MD included parkinsonism ( = 47), ataxia ( = 32), chorea ( = 18), dystonia ( = 13), tremor ( = 8), myokymia ( = 6), myoclonus ( = 4), ballism ( = 1), tics ( = 1), and others ( = 18). The mean and median ages were 36.58 (standard deviation: 20.51) and 35 years (age range: 1-88 years), respectively. There was a slight predominance of female sex (52.17%). On follow-up, 58.90% of the individuals had a full recovery; two deaths were reported. We believe that the majority of cases reported were only diagnosed because patients had classical clinical manifestations generally investigated by neuroimaging, resulting in incidental findings suggestive of NCC, which were later supported by laboratory examinations. Therefore, the association between NCC and MD is probably underreported. Clinicians should be wary of this association, mainly in endemic areas for cysticercosis.
PubMed: 33506145
DOI: 10.4103/bc.bc_48_20 -
Clinical Neurophysiology Practice 2021We report a case of sustained atypical myokymia associated with short bursts of neuromyotonic discharges involving the abductor pollicis brevis (APB) muscle and describe...
OBJECTIVE
We report a case of sustained atypical myokymia associated with short bursts of neuromyotonic discharges involving the abductor pollicis brevis (APB) muscle and describe a useful way of detecting a focal slowing involving a small number of median nerve motor fibers with a concentric needle using the filter setting for single fiber electromyography (EMG).
METHODS AND RESULTS
A 62-year-old woman developed right thumb twitches at regular interval of 1.7-3.3 s (0.6-0.3 Hz), which continued for more than four months. Muscle twitches remained the same during altered hand position, psychological stress, or sleep. A concentric needle inserted in the active zone of the APB muscle revealed myokymic bursts with a characteristic of neuromyotonic discharges. Inching study, stimulating at 5 mm increment along the median nerve and recording with a concentric needle using a filter setting for single fiber EMG, revealed a focal slowing of the motor fibers at a point 5-10 mm distal from the distal crease of the wrist, an entrapment site occasionally seen in the carpal tunnel syndrome. One injection of botulinum toxin type A eliminated the myokymia, which then recurred two and a half years later, showing less prominent muscle twitches.
CONCLUSIONS
Sustained atypical myokymia seen in our case represented bursts of neuromyotonic discharges originated from a focal demyelinating lesion involving a few median nerve motor fibers.
PubMed: 33490741
DOI: 10.1016/j.cnp.2020.11.003 -
Biomedicines Jan 2021The gene encodes the α subunit of the voltage-gated Kv1.1 potassium channel that critically regulates neuronal excitability in the central and peripheral nervous...
The gene encodes the α subunit of the voltage-gated Kv1.1 potassium channel that critically regulates neuronal excitability in the central and peripheral nervous systems. Mutations in have been classically associated with episodic ataxia type 1 (EA1), a movement disorder triggered by physical and emotional stress. Additional features variably reported in recent years include epilepsy, myokymia, migraine, paroxysmal dyskinesia, hyperthermia, hypomagnesemia, and cataplexy. Interestingly, a few individuals with neuromyotonia, either isolated or associated with skeletal deformities, have been reported carrying variants in the S2-S3 transmembrane segments of Kv1.1 channels in the absence of any other symptoms. Here, we have identified by whole-exome sequencing a novel de novo variant, T268K, in in a boy displaying recurrent episodes of neuromyotonia, muscle hypertrophy, and skeletal deformities. Through functional analysis in heterologous cells and structural modeling, we show that the mutation, located at the extracellular end of the S3 helix, causes deleterious effects, disrupting Kv1.1 function by altering the voltage dependence of activation and kinetics of deactivation, likely due to abnormal interactions with the voltage sensor in the S4 segment. Our study supports previous evidence suggesting that specific residues within the S2 and S3 segments of Kv1.1 result in a distinctive phenotype with predominant musculoskeletal presentation.
PubMed: 33466780
DOI: 10.3390/biomedicines9010075 -
Clinical Case Reports Nov 2020Facial myokymia is a clinical sign that can occur as a manifestation of demyelinating lesions. As seen in our patient with multiple sclerosis, acute-onset continuous...
Facial myokymia is a clinical sign that can occur as a manifestation of demyelinating lesions. As seen in our patient with multiple sclerosis, acute-onset continuous facial myokymia can be indicative of an active lesion and can have localizing value.
PubMed: 33235796
DOI: 10.1002/ccr3.3135 -
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 -
International Journal of Molecular... Oct 2020(1) Background: Episodic ataxia type 1 is caused by mutations in the gene encoding for the voltage-gated potassium channel Kv1.1. There have been many mutations in...
(1) Background: Episodic ataxia type 1 is caused by mutations in the gene encoding for the voltage-gated potassium channel Kv1.1. There have been many mutations in Kv1.1 linked to episodic ataxia reported and typically investigated by themselves or in small groups. The aim of this article is to determine whether we can define a functional parameter common to all Kv1.1 mutants that have been linked to episodic ataxia. (2) Methods: We introduced the disease mutations linked to episodic ataxia in the drosophila analog of Kv1.1, the Shaker Kv channel, and expressed the channels in Xenopus oocytes. Using the cut-open oocyte technique, we characterized the gating and ionic currents. (3) Results: We found that the episodic ataxia mutations variably altered the different gating mechanisms described for Kv channels. The common characteristic was a conductance voltage relationship and inactivation shifted to less polarized potentials. (4) Conclusions: We suggest that a combination of a prolonged action potential and slowed and incomplete inactivation leads to development of ataxia when Kv channels cannot follow or adapt to high firing rates.
Topics: Animals; Ataxia; Humans; Ion Channel Gating; Kv1.1 Potassium Channel; Mutation; Myokymia; Xenopus
PubMed: 33066705
DOI: 10.3390/ijms21207602 -
Journal of Clinical Neurology (Seoul,... Oct 2020
PubMed: 33029979
DOI: 10.3988/jcn.2020.16.4.699 -
Journal of Clinical Medicine Sep 2020Paroxysmal symptoms are well-recognized manifestations of multiple sclerosis (MS). These are characterized by multiple, brief, sudden onset, and stereotyped episodes.... (Review)
Review
Paroxysmal symptoms are well-recognized manifestations of multiple sclerosis (MS). These are characterized by multiple, brief, sudden onset, and stereotyped episodes. They manifest as motor, sensory, visual, brainstem, and autonomic symptoms. When occurring in the setting of an established MS, the diagnosis is relatively straightforward. Conversely, the diagnosis is significantly more challenging when they occur as the initial manifestation of MS. The aim of this review is to summarize the various forms of paroxysmal symptoms reported in MS, with emphasis on the clinical features, radiological findings and treatment options.
PubMed: 32992918
DOI: 10.3390/jcm9103100 -
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