key: cord-0817838-gn1xk09n
authors: F, Sarubbo; Haji K, El; Vidal-Balle, A.; J, Bargay
title: Neurological consequences of COVID-19 and brain related pathogenic mechanisms: A new challenge for neuroscience
date: 2021-11-30
journal: Brain Behav Immun Health
DOI: 10.1016/j.bbih.2021.100399
sha: 723396ae1a85b571e325fa79c5fed74f4688a596
doc_id: 817838
cord_uid: gn1xk09n

Due to the infection by the SARS-CoV-2 virus (COVID-19) there were also reported neurological symptoms, being the most frequent and best cited those that affect the cerebrovascular, sensorial, cognitive and motor functions, together with the neurological diffuse symptoms as for examples headache or dizziness. Besides, some of them behave high risk of mortality. Consequently, it is crucial to elucidate the mechanisms of action in brain of SARS-CoV-2 virus in order to create new therapeutic targets to fight against this new disease. Since now the mechanisms of arrival to the brain seems to be related with the following processes: blood brain barrier (BBB) disruption together with nervous or axonal transport of the virus by the trigeminal nerve, the vagus nerve, or the brain-gut-axis. Being two the mechanisms of brain affectation most cited: a direct affectation of the virus in the brain through neuroinvasion and an indirect mechanism of action due to the effects of the systemic infection. Both processes include the triggering of inflammation, hypoxia and the increased likelihood of secondary infections. This topic supposes a major novel challenge for neuroscience. Therefore, the aim of this review is to provide summarized information about the neurological symptomatology and the brain pathogenic mechanisms involved and reported in COVID-19.

bleeding diathesis (Gao et al., 2020)(C. Wu et al., 2020) (Yang et al., 2020) . Therefore, 272 the plausible mechanism that causes these ischemic processes is the so called "sepsis- 307 Although the motor symptomatology is less frequent than other neurological symptoms 308 in COVID-19 illness, some symptoms were detected, such as the neuropathic pain In severe patients the cognitive impairment seems to be more present, so in a study about 394 COVID-19 adults who survived after being hospitalized in an ICU, it was described that problems caused by the SARS-CoV-2 infection in moderated or asymptomatic patients. 398 Therefore, frequency of cognitive decline is not well known, but authors link the cognitive 399 impairment with the so call "long-COVID-19", defined as an infection by SARSR-CoV-400 2 not recovered for several weeks or months following the start of symptoms that were 401 suggestive of COVID-19, whether the patient was tested or not (Nabavi, 2020). Long-402 COVID-19, also is described as a profound fatigue, including cough, breathlessness, 403 muscle and body aches, and chest heaviness or pressure, but also skin rashes, palpitations, The olfactory route is the most cited brain front door for the SARS-CoV-2 virus (Fig. 2) . 455 Once virus enters in contact with the olfactory epithelium, the cilia, projected from the 

The pulmonary affectation caused by the SARS-CoV-2 could induce also brain hypoxia 631 due to the loss of supply of oxygen to the brain. Therefore, hypoxia is another potential were also found in COVID-19 infection, having a multifactorial etiology that should be studied, because it is a factor risk causative of morbidity and mortality. In brain biopsies 647 of some COVID-19 patients affected by cerebrovascular problems there were found signs 648 of thrombotic microangiopathy and endothelial injury, suggesting that endothelial 649 disruption is the primary mechanism of damage. There were also found thrombotic 

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