Muscle-specific tyrosine kinase-antibody-positive myasthenic crisis with detailed electrophysiologic studies.

A 69-year-old male who presented in a coma due to sudden respiratory arrest was transferred to our hospital. After endotracheal intubation with manual ventilation, he became alert and his neurologic findings were within the normal range, except for palsy of the respiratory muscles. Biochemical analyses of the blood and brain computed tomography failed to indicate the cause of the respiratory arrest. An edrophonium test did not improve the respiratory arrest. An urgent electromyogram at the dorsal interossei, biceps, and sternocleidomastoideus muscle and a repetitive nerve stimulation test at the trapezius and deltoid muscle were also negative on the first hospital day. However, on the 16th day in the hospital, a repetitive nerve stimulation test at the levator labii superioris alaeque nasi showed a waning phenomenon. This result indicated a diagnosis of myasthenia gravis. Anti.muscle-specific tyrosine kinase antibody was found to be positive. After treatment with plasmapheresis and prednisolone, he regained normal respiratory function. Anti.muscle-specific tyrosine kinase (MuSK)-antibodypositive myasthenia gravis (MG) (MuSK-MG) tends to be associated with a lower incidence of a positive edrophonium test, a lower incidence of a positive electrophysiologic study excluding the face, and a higher incidence of respiratory failure in comparison to anti.acetylcholine receptors (AchR)-antibody-positive MG (AchR-MG). Respiratory failure is curable with treatment. Accordingly, in addition to obtaining a precise diagnosis, an emergency physician should recommend an electrophysiologic study including the face to make a differential diagnosis for respiratory arrest when biochemical and radiologic studies fail to indicate the cause of the respiratory arrest

Multifocal Motor Neuropathy

Objective: Our objective was to do an epidemiologic survey of patients with multifocal motor neuropathy (MMN) in comparison with those with amyotrophic lateral sclerosis (ALS) in Japan. Methods: In this retrospective study, we examined 46 patients with MMN and 1,051 patients with ALS from major neuromuscular centers in Japan from 2005 to 2009. Diagnosis was based on the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) and the revised El Escorial criteria. The efficacy of intravenous immunoglobulin (IVIg) was also taken into consideration in the diagnosis of MMN. Results: The ratio of MMN to ALS patients (0-0.10) varied among the centers, but mostly converged to 0.05. The prevalence was estimated to be 0.29 MMN patients and 6.63 ALS patients per 100,000 population. Conclusions: The frequency of MMN patients was around 1 out of 20 ALS patients, and MMN was possibly underdiagnosed in some centers

発症早期ALS患者に対する超高用量メチルコバラミンの有効性・安全性について : ランダム化比較試験

Importance: Post hoc analysis in a phase 2/3 trial indicated ultra-high dose methylcobalamin slowed decline of the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) total score at week 16 as well as at week 182, without increase of adverse events, in patients with amyotrophic lateral sclerosis (ALS) who were enrolled within 1 year from onset. Objective: To validate the efficacy and safety of ultra-high dose methylcobalamin for patients with ALS enrolled within 1 year of onset. Design: A multicenter, placebo-controlled, double-blind, randomized phase 3 trial with 12-week observation and 16-week randomized period, conducted from October 2017 to September 2019. Setting: Twenty-five neurology centers in Japan. Participants: Patients with ALS diagnosed within 1 year of onset by the updated Awaji criteria were initially enrolled. Of those, patients fulfilling the following criteria after 12-week observation were eligible for randomization: 1- or 2-point decrease in ALSFRS-R total score, a percent forced vital capacity over 60%, no history of noninvasive respiratory support and tracheostomy, and being ambulant. The target number was 64 in both methylcobalamin and placebo groups. Of 203 patients enrolled in the observation, 130 patients (age, 61.0 ± 11.7 years; female, 56) met the criteria and were randomly assigned through an electronic web-response system to methylcobalamin or placebo (65 for each). Of these, 129 patients were eligible for the full analysis set, and 126 completed the double-blind stage. Interventions: Intramuscular injection of methylcobalamin 50 mg or placebo twice weekly for 16 weeks. Main outcomes and measures: The primary endpoint was change in ALSFRS-R total score from baseline to week 16 in the full analysis set. Results: The least-squares mean difference in ALSFRS-R total score at week 16 of the randomized period was 1.97 points greater with methylcobalamin than placebo (−2.66 versus −4.63; 95% CI, 0.44–3.50; P = 0.012). The incidence of adverse events was similar between the two groups. Conclusions and relevance: Ultra-high dose methylcobalamin was efficacious in slowing functional decline and safe in the 16-week treatment period in ALS patients in the early stage and with moderate progression rate. Trial registration: UMIN-CTR Identifier: UMIN000029588 (umin.ac.jp/ctr); ClinicalTrials.gov Identifier: NCT03548311 (clinicaltrials.gov

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Amyotrophic lateral sclerosis with a sudden-onset history

Objective: We report on two patients with amyotrophic lateral sclerosis (ALS) complaining of sudden-onset difficulty in finger elevation. Case report: A 65-year-old man (the first patient) and a 66-year-old man (the second patient) suddenly became aware of difficulty in finger elevation of one hand. They were not aware of any other symptoms prior to the onset. In the first patient, cerebral infarction at the precentral gyrus was initially suspected. In the second patient, cervical spondylosis was initially suspected, and cervical spine surgery was planned. However, needle EMG revealed widespread neurogenic changes and abundant fasciculation potentials for both patients. Widespread weakness emerged in time and relentlessly progressed, and finally the diagnosis of ALS was made. In both cases, notable weakness in the extensor digitorum (ED) muscle with relatively mild weakness in the other muscles in the affected limb was a characteristic finding. Loss of one motor unit in ED that has already enlarged due to reinnervation must have caused sudden awareness of the weakness. Significance: Clinicians should recognize the presence of ALS patients with a sudden-onset history because the risk of initial misdiagnosis is high for such patients. Keywords: Amyotrophic lateral sclerosis, Sudden-onset, Finger elevation, Needle electromyography, Manual muscle testin