The Environmental Neurology Specialty Group (ENSG) of the World Federation of Neurology (WFN) has published a report that details current understanding of the neurologic impacts of coronavirus disease 2019 (COVID-19). The report, published in the Journal of Neurological Sciences, describes various cases across the world of COVID-19 and the associated incidence of several different neurological complications, including headache, cerebrovascular disease, Guillain-Barré syndrome (GBS), and Miller Fisher syndrome.
Involvement of Central Nervous System (CNS) Symptoms and Diseases
In studies from Wuhan, China, the geographic center where cases of COVID-19 were first reported, investigators found an association between the infection and headache. Additionally, the researchers also found a substantially higher proportion of patients who experienced early alteration of consciousness or impaired consciousness because of severe disease.
Although the data did not determine whether these conditions were concurrent or if they were induced by the virus, the ENSG-WFN suggested that early onset of headache and decreased responsiveness may be indicators of possible neurologic involvement in COVID-19.
According to current evidence and real-world data, common CNS symptoms associated with COVID-19 include anosmia and dysgeusia, or the impaired ability to smell or taste normally, respectively. The presence of anosmia may be associated with the coronaviruses’ potential to invade the brain, the ENSG-WFN wrote.
There are some data to suggest patients with COVID-19 are at an increased risk for cerebrovascular disease, including venous and arterial thromboembolism and stroke. Advanced age as well as the presence of underlying vascular risk factors are thought to increase this risk.
Hospitals in Denmark have reported a high incidence of thrombotic complications as a result of COVID-19, including in some patients with stroke. Venous thrombosis occurred more often than arterial thromboses, according to reports, yet pulmonary embolism represented the most frequent thrombotic complication in these reports.
In a report of 3 patients with COVID-19 between the ages of 65 and 70 years, severe COVID-19 infection was associated with the development of multiple arterial thromboses. Another case report of a 65-year-old woman with COVID-19 noted the development of progressive thrombocytopenia, in addition to lower-extremity purpura and epistaxis.
Acute hemorrhagic necrotizing encephalopathy, a rare parainfectious disease, was found in a case study of a patient with COVID-19 infection in the United States. This condition is thought to be caused by a cytokine storm and associated with an increase in proinflammatory cytokines.
Other case reports have found an association between meningitis, encephalitis, and seizures with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the coronavirus strain responsible for COVID-19. In some instances, these conditions were treated successfully, and the patients were discharged. In others, particularly in elderly patients, the conditions may have complicated prognosis and led to respiratory failure.
Respiratory failure, a leading cause of mortality in COVID-19, may have a neurogenic origin, resulting in the viral invasion of cranial nerve 1. This may ultimately lead into the rhinencephalon and brainstem respiratory center, according to the ENSG-WFN.
Peripheral Nervous System (PNS) and Muscle Involvement
The literature on PNS and muscle involvement in COVID-19 is limited, but some case reports do provide some insight. A case study from China reported an incidence of GBS in a 61-year-old woman who had returned to Shanghai from Wuhan, China, with COVID-19 based on oropharyngeal swab testing.
In a 54-year-old patient in the United States with confirmed COVID-19, the patient was eventually diagnosed with GBS after complaining of weakness and demonstrating diminished reflexes in the extremities. Other reports from Italy found an association between COVID-19 and GBS.
Case reports have also highlighted an association between COVID-19 and the development of myelitis and myopathies. Other case reports have described associations between COVID-19 and the development of Miller Fisher syndrome, polyneuritis cranialis, and neurosensory hearing loss.
Based on the paucity of available literature, the ENSG-WFN emphasizes the need for greater epidemiological research initiatives to produce better data on total number of COVID-19 cases as well as information on risk factors for severe outcomes. Additionally, the group wrote that there is currently an unmet yet urgent need to understand SARS-CoV-2 and its neurotropic potential, in addition to the frequency of neurological complications associated with the virus.
To address these needs, the ENSG-WFN recently issued an appeal to global neurological societies, asking these organizations to initiate neuroepidemiological databanks specific to COVID-19. According to the ENSG-WFN, the creation of these national and regional databases may “encourage much needed peer-reviewed publications on the neurology COVID-19.”
Román GC, Spencer PS, Reis J, et al; WFN Environmental Neurology Specialty Group. The neurology of COVID-19 revisited: A proposal from the Environmental Neurology Specialty Group of the World Federation of Neurology to implement international neurological registries [published online May 7, 2020]. J Neurol Sci. doi: 10.1016/j.jns.2020.116884.