Though COVID-19 has most notably affected the respiratory system, case studies with related neurological disease began trickling in soon after the pandemic started.
Those reports have continued to grow, including cases of central and peripheral nervous system disorders. The exact injury mechanism, however, has been elusive. A new multidisciplinary study out of the United Kingdom takes one of the deepest dives yet into the many ways COVID-19 wreaks havoc on the nervous system.
In early March 2020, it started to become apparent that COVID-19 was linked to the development of certain neurological conditions, including encephalopathy, stroke, and Guillain-Barré Syndrome (GBS).
“There were a lot of neurologic presentations that ended up being COVID-positive patients,” Dr. Elaine Jones, a neurologist who does telehealth in ERs across the country, told us. “We are still working through that data to see what it was. Some of it, we think, was inflammation of the vessels. Some we think were hypercoagulable. They certainly had both microclots and microbleeds in their lungs and that was affecting their brains as well. Sometimes their brains were affected first.”
In response to this growing concern, researchers from multiple UK institutions formed an official study group to look at the neurological implications of COVID-19. The results of their work were published in the July 2020 issue of Brain: A Journal of Neurology.
The authors, who were affiliated with no less than 18 institutions in and around London, collaborated and shared data via weekly virtual meetings. Between April and May they gathered retrospective clinical, pathological, radiological, and laboratory data from 43 severely impacted patients. These patients were either diagnosed as confirmed COVID-19 positive (29), probable (8), or possible (6), based on World Health Organization criteria.
Five major categories of neurological disease related to COVID-19 emerged:
- Encephalopathies with delirium/psychosis
- Inflammatory CNS syndromes
- Ischemic strokes
- Peripheral neurological disorders
- Other miscellaneous central disorders
Within these categories, patients were diagnosed with a large variety of neurological conditions. They included encephalitis, brain hemorrhage, necrosis, myelitis, thromboembolism (often both in the brain and lungs), and Guillain-Barré syndrome. In their resultant open-access paper, the authors presented several case studies in detail to illuminate these disease presentations, treatments, and progression.
Interestingly, the authors did not find evidence of direct infection of the nervous system by the coronavirus.
“None of the eight patients tested for SARS-CoV-2 PCR in CSF were positive,” they write, “and none of the autoantibodies seen in autoimmune forms of encephalitis (NMDAR, LGI1) or encephalomyelitis (AQP4, MOG) were detected in serum or CSF samples.”
They did, however, find evidence that the neurological syndromes were linked to secondary effects. These include hypercoagulability and, to some extent, inflammation. Patients from all five categories, not just the ones who suffered strokes, had elevated D-dimers, an indicator of blood clot degradation. There were indications that corticosteroids could be effective in treating patients with inflammatory CNS diseases, though the follow-up period for this study was short.
In its detail and thorough reporting, this paper adds significantly to the growing effort to untangle the relationship between COVID-19 and neurological disease. This will be increasingly important to neurologists. It’s becoming clear they will be playing an increasingly important role in the days, months and even years to come in the fight against this virus.