Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The virus causes a pneumonia syndrome, with specific and already well-described symptoms, and fatal outcome in a subset of patients. The lungs are the organs most affected by COVID-19 because the virus accesses host cells via the enzyme angiotensin-converting enzyme 2 (ACE2), which is most abundant in the type II alveolar cells of the lungs. Of note, glial cells and neurons of the central nervous system have been reported to express ACE2 receptors, rendering the brain a potential target of COVID-19 (1). Evidence for transneuronal transport of severe acute respiratory syndrome (SARS)-CoV through the olfactory bulb provides support for this hypothesis (2). Yet, whether viral invasion of the olfactory bulbs is the neurobiological background for smell and taste disorders reported by some of the patients remains to be elucidated (3). In a commentary from the UK Encephalitis Society, there is a report about a 56-year-old male in China who developed COVID-19 and in whom the virus was detected in cerebrospinal fluid (CSF). There are no clinical details outlined beyond the information that this patient recovered and was discharged from hospital (4). The concern that reports of patients with neuroinvasive disease and atypical CNS manifestations will be just a matter of time is supported by a case of COVID-19 associated acute necrotizing encephalopathy (5). Moreover, the neuroinvasive potential of SARS-CoV2 may play a role in the respiratory failure of COVID-19 patients as coronaviruses were shown to reach the brainstem via a synapse‐connected route from the lung and airways (6). Neurologists should also keep the potential risk for parainfectious disorders following COVID-19 infection in mind since there were cases of acute disseminated encephalomyelitis, vasculopathy and Guillain-Barré syndrome in association with the Middle East Respiratory Syndrome (MERS)-CoV (7).
References
- https://pubs.acs.org/doi/10.1021/acschemneuro.0c00122
- https://jvi.asm.org/content/82/15/7264.long
- https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa330/5811989
- https://www.encephalitis.info/blog/coronavirus
- https://pubs.rsna.org/doi/10.1148/radiol.2020201187
- https://onlinelibrary.wiley.com/doi/full/10.1002/jmv.25728
- https://www.ncbi.nlm.nih.gov/pubmed/30416428
- https://www.frontiersin.org/articles/10.3389/fncel.2018.00386/full
1. Specific challenges at present regarding Covid-19 and how these are being addressed
1. The potential clinical and radiological spectrum of CNS neuroinvasive and postinfectious disease needs to be characterized: well-documented studies are required
2. Physicians should be aware of neurological complications as a cause of clinical deterioration: neurologists need to be involved in the care of COVID-19 patients
3. Diagnosis, management and risk factors for neurological manifestations of COVID-19 infection are unclear: concerted efforts to perform clinical trials and set up registries is recommended
4. Currently ethical issues in the setting of limited health care resources cannot be answered: the prognosis of neurological manifestations needs to be clarified.
2. Unanswered questions
1. Pathogenesis of infectious/parainfectious neurological complications
2. Impact of infectious/parainfectious neurological complications on outcome
3. Preventive strategies and risk factors for the development of infectious/parainfectious complications, e.g. relevance of neurological comorbidities
3. What you see as the most important next steps to deal with coronavirus across Europe.
1. Concerted action to collect valid data
2. Early involvement of neurologists in the care of COVID-19 patients
3. Platform to discuss emerging findings in the field, e.g. EANcore
*EAN Expert Panel
Johann Sellner, MD FAAN FANA FEAN
Co-Chair EAN Scientific Panel Infectious diseases
Professor of Neurology
Chair of the Department of Neurology and Multiple Sclerosis Center, Landesklinikum Mistelbach-Gänserndorf, Mistelbach, Austria
Pille Taba, MD PhD FEAN
Co-Chair EAN Scientific Panel Infectious diseases
Professor of Neurology
Consultant neurologist at the Department of Neurology and Neurosurgery, Institute of Clinical Medicine
University of Tartu, Estonia
