Deciphering changes in the incidence of the Guillain-Barré syndrome during the COVID-19 pandemic: a nationwide time-series correlation study.

Background: Postinfectious autoimmunity is a hallmark of Guillain-Barré syndrome (GBS), and GBS incidence closely parallels that of its immune triggers. Sociobehavioural interventions implemented during the COVID-19 pandemic have altered the infectious disease landscape. Methods: This nationwide time-series correlation study analysed GBS incidence, sentinel surveillance and SARS-CoV-2 vaccination data from January 2017 to December 2021 in the National Health Insurance Service and Korean Disease Control and Prevention Agency databases. The incidence of GBS and sentinel gastrointestinal and respiratory infectious diseases during the pandemic (2020-2021) was estimated and compared with both prepandemic (2017-2019) and incidence predicted in a time-series forecasting model. Time-series correlation analysis was used to examine the temporal association between GBS, infectious triggers and SARS-CoV-2 vaccination. Results: During the pandemic, the total crude cumulative incidence rate was 2.1 per 100 000 population, which is lower than the prepandemic incidence, especially in age groups of less than 60 years. Seasonality was briefly interrupted during the winter of 2021. The majority of respiratory and some gastrointestinal conditions had a lower-than-expected incidence during the pandemic. Compared with the prepandemic state, during the pandemic period a higher number of gastrointestinal pathogens (Escherichia coli, Campylobacter spp., Clostridium perfringens, Yersinia enterocolitica and enteric adenovirus) had significant, moderate-to-strong positive temporal associations with GBS. The temporal association between SARS-CoV-2 infection and GBS was not significant, but SARS-CoV-2 vaccination exhibited a strong positive temporal association with GBS in 2021. Conclusion: The incidence of GBS and sentinel infectious diseases decreased to below-expected levels during the pandemic, with the former attributable to the decreased incidence of non-COVID-19 respiratory and gastrointestinal infections. The evolving incidence of autoimmune postinfectious phenomena following the pandemic needs attention.

Prevalence and Impact of Venous and Arterial Thromboembolism in Patients With Embolic Stroke of Undetermined Source With or Without Active Cancer.

Background An increased risk of acute ischemic stroke is recognized among patients with cancer. However, the mechanism behind cancer-related stroke is unclear. In this study, we determined the presence of associated venous thromboembolism and arterial thromboembolism and their clinical impact on patients with cancer-related stroke. Methods and Results Patients with embolic stroke of undetermined source with or without cancer were evaluated for venous thromboembolism (deep vein thrombosis [DVT] and/or pulmonary embolism) and arterial thromboembolism by using Doppler sonography to determine the presence of lower-extremity DVT and the microembolic signal of the symptomatic cerebral circulation, respectively. Infarct volume was determined by diffusion-weighted magnetic resonance imaging. The multivariable linear regression and Cox proportional hazard analysis were used to investigate the effect of DVT and microembolic signal on infarct volume and 1-year survival, respectively. Of 142 screened patients, 118 were included (37 with, 81 without cancer). Those with cancer had a higher prevalence of DVT or microembolic signal than did the noncancer group (62.2% versus 19.8%; P<0.001). Among patients with cancer-related stroke, DVT was associated with a greater infarct volume in magnetic resonance imaging (beta, 13.14; 95% CI, 1.62-24.66; P=0.028). Presence of DVT (hazard ratio, 16.79; 95% CI, 2.05-137.75; P=0.009) and microembolic signal (hazard ratio, 8.16; 95% CI, 1.36-48.85; P=0.022) were independent predictors of poor 1-year survival. Conclusions Patients with cancer-associated embolic stroke of undetermined source have an elevated risk of associated venous thromboembolism and arterial thromboembolism, both of which have a significant negative impact on 1-year survival. The results of this study may enhance our understanding of cancer-associated stroke and improve risk stratification of patients with this disease. Clinical Trial Registration URL: https://www.clinicaltrials.gov/.Unique identifier: NCT02212496.

Anti-CV2/CRMP5 Paraneoplastic Chorea Effectively Managed with Intravenous Amantadine.

Background: Paraneoplastic chorea is typically a subacute progressive hyperkinetic movement disorder. The mainstay of treatment is managing the underlying neoplasm. However, the clinical course may be variable, and effective symptomatic management can precede the start of cancer treatment. Case report: A 63-year-old man presented with insidious onset, slowly progressive generalized chorea for 1 year, later diagnosed as anti-CV2/CRMP5 autoantibody positive paraneoplastic chorea. His chorea was markedly improved with intravenous amantadine. Discussion: In patients with anti-CV2/CRMP5 autoantibody-related chorea, sequential follow-up of brain magnetic resonance imaging reveals progression from active inflammation to atrophy. Our report highlights the efficacy of intravenous amantadine in paraneoplastic chorea.