One of the first and most commonly reported neurological symptoms of mild-to-moderate Covid-19 are olfactory (smell) and gustatory (taste) dysfunctions (Mercante et al., 2020). Increasing evidence of the neurological manifestations of Covid-19 indicate the complexity of the disease (for review: Majid et al, 2020, Felice et al., 2020, Ellul et al., 2020). Though the prevalence of neurological symptoms is still unknown, they have been reported in Covid-19 patients ranging from alerted mental states such as agitation and confusion to headaches, strokes, brain haemorrhages, seizures, disturbances of consciousness and brain inflammation depending on the severity of the disease (for review: Majid et al, 2020, Felice et al., 2020, Ellul et al., 2020; Mao et al., 2020; Helms et al., 2020).
Some patients experienced such severe cases of brain and spinal cord inflammation that they developed symptoms resembling multiple sclerosis (Zanin et al., 2020). This spectrum of neurological symptoms makes treatment even more challenging.
“The exact effect of the virus on the central nervous system (CNS) is unclear.“
The exact effect of the virus on the central nervous system (CNS) is unclear. The literature suggests that neurological complications are most likely immune-mediated (Wu et al., 2020, Fotuhi et al., 2020). Covid-19 can lead to the formation of blood clots that can obstruct the blood and oxygen flow to the brain, causing an ischaemic stroke (Fotuhi et al., 2020). Further, the cytokine storm (a hyperactive inflammatory response) can potentially damage the blood-brain barrier, allowing the viral particles or other pathogenic bacteria in the bloodstream to enter the brain which can lead to secondary intracranial infections (Fotuhi et al., 2020, Wu et al., 2020).
“Neuropsychological and neuropsychiatric assessments of Covid-19 survivors can assist in further evaluation of cognitive and psychological effects of the disease.”
Fortunately there are important initiatives being considered. The Fernanda G De Felice group, for example, plans to create a biobank of samples of the convalescents treated in intensive care units in order to evaluate the long-term impact of Covid-19 (based on Marshall, 2020). This can potentially help in evaluating the extent of damage to the CNS. Neuropsychological and neuropsychiatric assessments of Covid-19 survivors can assist in further evaluation of cognitive and psychological effects of the disease. It will also contribute to the development of Covid-19-specific neuro-rehabilitation and treatments.
Nevertheless, the impact of Covid-19 on the CNS can be devastating because there are currently no treatment options for brain recovery. Even the mildest neurological complication of Covid-19 can cause significant distress and impact quality of life long-lasting effect. Fernanda G De Felice group, This ultimately translates into significant economic effects in the post-pandemic world. Our need to understand and address neuro – covid 19 complications lies at the heart of comprehensive and effective recovery worldwide.
17 August 2020
By Adriana Michalak
Public Health Pathways team member. PhD student in the Sleep and Brain Unit, Faculty of Medicine and Health Sciences, University of East Anglia.
