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How COVID-19 Affects The Brain

Author: Brittany Alexander


Graphic of coronavirus with COVID-19 text overlay.
Image Credit: Martin Sanchez (Unsplash)

COVID-19 has impacted people from every continent around the world. Parallel to the diverse amount of people the virus impacts, patients’ brains are being affected in a variety of ways (Hosein, (n.d.); Marshall, 2020). Some patients are experiencing confusion, encephalitis, and a loss of taste and smell (Marshall, 2020; Weir, 2020). These issues are known to appear early and late in the course of the illness (Davies, 2020). There are also reports of COVID-19 patients experiencing strokes (Marshall, 2020; Stevens, (n.d.). Patients from ages 30 to 50 are suffering from life-altering neurological issues due to COVID-19 induced strokes (Marshall, 2020; Stevens, (n.d.). It’s proposed that the virus triggers an inflammatory response, which in turn induces the formation of stroke-causing blood clots. (Weir, 2020). COVID-19 may also cause a cytokine storm, which can damage the blood-brain barrier and cause inflammation by allowing the entry of inflammatory cells, molecules, and viral particles into the brain (Weir, 2020).


In a June paper, neurologist Benedict Michael and his team analyzed 125 people in the UK with COVID-19 who reported neurological effects (Marshall, 2020). 62% were found to have damage to the brain’s blood supply, finding things like hemorrhages, and 31% had altered mental states, exhibiting symptoms such as confusion (Marshall, 2020). In addition, ten of the analyzed patients with altered mental states suffered psychosis (Marshall, 2020).


It is unknown how exactly COVID-19 is able to infiltrate the patient’s brains (Marshall, 2020; Stevens, (n.d.). Viruses are able to infect the brain, but it is not known whether COVID-19 does so to an extent significant enough to cause these widespread neurological issues among COVID-19 patients (Marshall, 2020; Stevens, (n.d.). Additionally, it’s unknown exactly how COVID-19 is able to infiltrate the brain, possibly because brain infections tend to cluster around blood vessels and are hard to detect (Marshall, 2020, Stevens, (n.d.)). What is known is that overstimulation of the immune system can also cause these kinds of widespread problems (Stevens, (n.d.)). Polymerase chain reaction tests do not commonly detect COVID-19 in the brain even though they are highly sensitive, and only a handful of studies have found any virus particles in patients’ cerebrospinal fluid (Marshall, 2020; Weir, 2020). The ACE2 receptor, which is on human cells and allows the virus entry into cells, is not expressed much in brain cells and may be why studies commonly fail to find virus particles in cerebrospinal fluid (Marshall, 2020). In China, doctors have documented brain inflammation in a COVID-19 patient and did find that his cerebrospinal fluid contained COVID-19 (Hosein, (n.d.)). Also, there are more cases than this one patient in which COVID-19 was detected in the cerebrospinal fluid, referencing the possible significance of this finding (Weir, 2020).


Looking at symptoms affecting the brain, it was found that neurological issues became more common as the severity of the disease increased (Mundell, 2000). It was found that in a number of cases that typical COVID-19 symptoms were not present when neurological issues were (Mundell, 2000). So far, the neurophysiological outcomes of people with COVID-19 remain unknown (Weir, 2020).


References


Davies, N. (2020, July 08). The Neurological Symptoms of COVID-19: Practitioner Views. Retrieved from https://www.neurologyadvisor.com/topics/general-neurology/the-neurological-symptoms-of-covid-19-practitioner-views/


Hosein, S. R. (n.d.). The brain and nerves in COVID-19. Retrieved from https://www.catie.ca/en/treatmentupdate/treatmentupdate-236/covid-19/brain-and-nerves-covid-19


Marshall, M. (2020, September 15). How COVID-19 can damage the brain. Retrieved from https://www.nature.com/articles/d41586-020-02599-5


Mundell, E. J. (2020, April 10). Brain Affected in 1 in 3 Cases of Severe COVID-19. Retrieved from https://www.webmd.com/lung/news/20200410/brain-affected-in-1-in-3-cases-of-severe-covid-19


Stevens, R. (n.d.). How Does Coronavirus Affect the Brain? Retrieved from https://www.hopkinsmedicine.org/health/conditions-and-diseases/coronavirus/how-does-coronavirus-affect-the-brain


Weir, K. (2020, November 1). How COVID-19 attacks the brain. Retrieved from https://www.apa.org/monitor/2020/11/attacks-brain

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