Probable Neuropsychological and Cognitive Complications Due to Cytokine Storm in Patients With COVID-19

Abstract

Introduction: COVID-19 (coronavirus disease 2019) was identified in China in December 2019 for the first time and is rapidly spreading throughout the world as a pandemic. As COVID-19 causes mild to severe acute respiratory syndrome, most studies in this context have focused on pathogenesis primarily in the respiratory system. However, evidence shows that the central nervous system (CNS) may also be affected by COVID-19. Since COVID-19 is spreading, it is imperative to study its possible cognitive effects in patients suffering and recovering from COVID-19. Methods: The articles used in this study were searched by keywords such as Cytokine storm and covid-19, covid-19 and executive dysfunction, cognitive disorder and covid-19, CNS and covid 19, Coronavirus, Neuroinvasion in science direct, Scopus, PubMed, Embase, and Web of Science databases based on Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) checklist. The study will assess all observational studies published between December 2019 and April 2021 in peer-reviewed journals, including cross-sectional, cohort, case-control studies, case reports and case series. The search result was 106 articles, of which 73 articles related to Covid-19, the stages of infection by this virus, its effect on the nervous system and neurological symptoms, the cytokine storm caused by this infection, and the possible cognitive consequences caused by this virus in patients, has been reviewed. Other articles were not checked due to their limited relevance to the topic under discussion. Results: Studies show that neurons may be directly affected by SARS-CoV-1 and SARS-CoV-2. Furthermore, various studies indicate that systemic inflammation (so-called "cytokine storm") is also responsible for brain damage induced by infection with SARS-CoV-1 and SARS-CoV-2. Such a way that this patients showed elevated levels of interleukin (IL-), 6, 8, and 10 and of tumor necrosis factor-alpha (TNF- α) in their blood. Conclusion: Various cognitive defects following an increase level of cytokines such as TNF-α and IL-6,8 have been observed. Therefore, due to the increase level of these pro-inflammatory factors in the brains of these patients, cognitive deficits can be expected, which need further investigation.