International Journal of Brain Disorders and Treatment Int J Brain Disord Treat 10.23937/2469-5866 2469-5866 ClinMed International Library Wilmington, USA 10.23937 SARS-Cov-2 Neurological Infection: Implications and Possible Mechanisms Schlindwein MAM 10.23937/2469-5866/1410035 COVID-19 is an emergent disease with reported neurotropism and neuroinvasion, although its pathophysiology is not yet understood. We present the newly discoveries and hypothesis for SARS-Cov-2 neurological infection. Commentary 6 1 OPEN ACCESS 10.23937/2469-5866/1410035 SARS-Cov-2 Neurological Infection: Implications and Possible Mechanisms Marco Antônio Machado Schlindwein Department of Medicine, University of the Region of Joinville, Santa Catarina, Brazil Letícia Caroline Breis Department of Medicine, University of the Region of Joinville, Santa Catarina, Brazil Isabelle Pastor Bandeira Department of Medicine, University of the Region of Joinville, Santa Catarina, Brazil Marcus Vinicius Magno Gonçalves Department of Medicine, University of the Region of Joinville, Santa Catarina, Brazil Letícia Caroline Breis
Student, Department of Medicine, University of the Region of Joinville, Rua Ministro Calógeras, 439, Bucarein, Joinville, Santa Catarina, Brazil, 89202-207, Tel: +5547991760101
16 April 2020 Schlindwein MAM 2020 SARS-Cov-2 Neurological Infection: Implications and Possible Mechanisms Int J Brain Disord Treat 10.23937/2469-5866/1410035 2020 Schlindwein MAM © This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

COVID-19 is an emergent disease with reported neurotropism and neuroinvasion, although its pathophysiology is not yet understood. We present the newly discoveries and hypothesis for SARS-Cov-2 neurological infection.

SARS-Cov-2, COVID-19, Anosmia, Hypogeusia, ACE2

Neurotropism is a well established characteristic in coronaviruses infections in humans and animals [1-3]. With the emergence of the new coronavirus SARS-CoV-2, its neurotrophic activities begin to attract attention, with a study proposing an effect in the respiratory distress caused by neuroinvasion [4].

A study proposed two possible neurotrophic paths for the SARS-CoV-2 -- gaining access to the central neural system (CNS) via general circulation disrupting the blood brain barrier [5] or via the olfactory bulb that intimately related with the cribriform plate and so giving the virus access to the CNS [5]. The last one is a common route for respiratory virus to enter the CNS [2] and is possibly related to hyposmia in an early state of the disease (Figure 1) [5].

These assumption correlates with clinical findings in a study conducted by Mao, et al. that presents 218 confirmed patients with SARS-CoV-2 infection - 53 (24.8%) of those who had CNS involvement were related to more severe disease and laboratory differences, especially lower lymphocytes count, compared to patients without CNS involvement [6]. A similar correlation showing lower lymphocytes count was found in children with neurological human CoV infection compared to respiratory human CoV patients [7].

Patients with peripheral nervous system (PNS) symptoms had hyposmia and hypogeusia and presented no laboratory differences compared to patients without PNS involvement [6], indicating that these symptoms can be prodrome of a more serious neurological involvement - although more data is needed - or the low lymphocytes and immune dysfunction are needed for a CNS infection.

Recently, the first case of encephalopathy associated with SARS-COV2 infection described was published. The patient rapidly progressed from fever and cough to an altered mental status, headache and unresponsive to verbal commands, with no alterations in the liquor, suggesting that the blood brain barrier was not affected in the patient [8].

In conclusion, SARS-Cov-2 infection is an emergent disease whose pathophysiology is not yet understood, but neurological involvement is already established. Hyposmia and hypogeusia have been related in patients with COVID-19 and must be considered as symptoms of SARS-Cov-2 infection, even if patients with those symptoms were previously considered asymptomatics.

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The image represents the SARS-CoV-2 gaining access to the olfactory bulb and then, via transsynaptic transfer, accessing the Central Nervous System (CNS), especially in patients with lower lymphocytes count [4,6]. It progresses with CNS symptoms, infecting neurons by binding in Angiotensin conversion enzyme 2 receptor (ACE2) [5]. Images acquired at: http://smart.servier.com/. https://www.clinmedjournals.org/articles/ijbdt/ijbdt-6-035-001.jpg
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