A Systematic Review on Neurological Aspects of COVID-19: Exploring the Relationship Between COVID-19-Related Olfactory Dysfunction and Neuroinvasion

Abstract

ObjectivesTo identify neurological aspects of Coronavirus disease 2019 (COVID-19) and to investigate COVID-19 infected patients with and without olfactory dysfunction in relation to polymerase chain reaction (PCR) assay results for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in the cerebrospinal fluid (CSF).MethodsPubMed and EMBASE databases were searched until March 26, 2021, for observational studies with COVID-19 patients that had performed CSF PCR assay due to the neurologic symptom and reported anosmia status.ResultsInitially, 2,387 studies were identified;167 studies performed SARS-CoV-2 CSF PCR assay, of which our review comprised 45 observational studies that conducted CSF PCR assay for SARS-CoV-2 in 101 patients and reported anosmia status in 55 of 101 patients. Central and peripheral neurological manifestations observed in COVID-19 patients were diverse. The most common neurological diagnoses were Guillain-Barré syndrome (GBS) and its variants (24%), followed by encephalopathy (21%). The SARS-CoV-2 PCR assay was positive in only four CSF samples, of which two patients had olfactory dysfunction while the others did not.ConclusionsThe neurological spectrum of COVID-19 is diverse, and direct neuroinvasion of SARS-CoV-2 is rare. The neuroprotection against SARS-CoV-2 in COVID-19 patients with anosmia is controversial, as an equal number of patients with and without olfactory dysfunction had positive CSF PCR results for SARS-CoV-2 in our study, and further studies are required to provide more insight into this topic.

Cutaneous vasculitis: Lessons from COVID-19 and COVID-19 vaccination

“…The enveloped RNA virus called Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the etiologic agent, which primarily affects the respiratory tract leading to general symptoms like fever, fatigue, anosmia, and dysgeusia, while respiratory symptoms are variable in severity ranging from cough and rhinorrhea to dyspnea, pneumonia, or acute respiratory distress syndrome. However, evidence about the involvement of other organs and systems is increasing; in fact, knowledge about the neurological, gastrointestinal, and ocular manifestations of SARS-CoV-2 infection is deepening (21,22). Similarly, cutaneous signs of COVID-19 are continuously reported and attempts at classifications are already available in the literature, together with the first prevalence estimations in which dermatologic manifestations would place between 1.8 and 20.4% of the COVID-19 patients (23, 24).…”