Does COVID-19 affect the brain?

EAN 2020

Does COVID-19 affect the brain?

1920 1080 Anne Carter, MA (Cantab)

With EAN going virtual this year, the global SARS-CoV2 pandemic was never far from the attendees’ minds. After a brief overview of the putative mechanisms for SARS-CoV2 accessing the brain, Renaud Du Pasquier (Service of Neurology, Department of Clinical Neuroscience, CHUV, Lausanne, Switzerland) used three clinical cases to illustrate potential neurological consequences of COVID-19.

Can COVID-19 cause meningoencephalitis?

Prof. Du Pasquier shared, “It has been suspected that some of the ICU severe COVID-19 patients had respiratory insufficiency not only explained by their pulmonary problems, but maybe some central cause.” It may be that the respiratory centre in the brainstem is affected by the virus. Potential consequences of this were illustrated in his first case, of a 64-year-old woman with no psychiatric history, who developed acute psychotic symptoms and tonic–clonic seizures. The diagnosis was meningoencephalitis likely related to COVID-19, “although we could not prove it,” as Prof. Du Pasquier noted.

Prof. Du Pasquier presented two possible mechanisms for this. First, the virus may enter the brain through the olfactory bulb (hence the symptoms of anosmia) and migrate through axons to the thalamus and brainstem.1 However, while several cases of meningoencephalitis have been reported, very few of these describe SARS-CoV2 in the cerebrospinal fluid (CSF). This may be due to polymerase chain reaction (PCR) not being sensitive or accurate enough in this compartment, or due to direct infection not being the primary cause of meningoencephalitis – the massive inflammatory response triggered by the virus may instead be the main cause. As Prof. Du Pasquier summed up, “This is clearly a field that we will need to study in more details, in particular to study in detail the CSF of those patients.”

Does COVID-19 have a role in stroke?

There is “clearly a trend to a pro-coagulable state” in patients with COVID-19, Prof. Du Pasquier shared. His second clinical case was of a man with COVID-19 pneumonia and no cerebrovascular risk factors who experienced a massive stroke. He also presented results from a series of autopsies in patients with COVID-19, showing most had deep venous thrombosis that was diagnosed while alive.2 Coupled with a study showing that SARS-CoV2 is present in endothelial cells,3 Prof. Du Pasquier explained, “If the virus targets the endothelial cells, then it can explain why so many organs can be affected.”

An unsurprising consequence of COVID-19?

Prof. Du Pasquier’s final case was diagnosed with severe Guillain–Barré syndrome (type acute inflammatory demyelinating polyneuropathy [AIDP]) in the wake of COVID-19. As Guillain–Barré syndrome can occur following other viral infections, this potential consequence of COVID-19 was not a surprise to Prof. Du Pasquier. The suggested mechanism is molecular mimicry.

What can neurologists do?

Prof. Du Pasquier noted that while neurologists are not at the forefront of managing patients with COVID-19, they have a valuable role to play in the longer term. For instance, there may be as yet unknown neuropsychological consequences of COVID-19, and there may be a burst of neurodegenerative disease similar to that seen after the 1918 Spanish flu pandemic.

As Prof. Du Pasquier noted throughout his presentation, further study is needed to fully understand the neurological implications of SARS-CoV2. While case studies such as those presented are important, he ended by endorsing the EAN initiative to collect a registry of patients and their neurological complications, encouraging listeners to contribute to this if they are able.

For more coverage from EAN 2020, click here.


References

1. Bohmwald K et al. Front Cell Neurosci. 2018;12:386
2. Wichmann D et al. Ann Intern Med. 2020; Epub ahead of print. Doi: 10.7326/M20-2003
3. Varga Z et al. Lancet. 2020;395:1417–8

Brainwork is supported by unrestricted grants from: