Covid-19 is associated with neurological and neuropsychiatric illness and in a number of cases the neurological disorder was the first and main presentation, according to new research.
The study published in Brain, found that neurological complications of Covid-19 can include delirium, brain inflammation, stroke and nerve damage and researchers identified one rare and sometimes fatal inflammatory condition, known as ADEM, which appears to be increasing in prevalence due to the pandemic.
Some patients in the study conducted by University College London, did not experience severe respiratory symptoms.
Joint senior author Dr Michael Zandi, UCL Queen Square Institute of Neurology and University College London Hospitals NHS Foundation Trust, said: "We identified a higher than expected number of people with neurological conditions such as brain inflammation, which did not always correlate with the severity of respiratory symptoms.
"We should be vigilant and look out for these complications in people who have had Covid-19. Whether we will see an epidemic on a large scale of brain damage linked to the pandemic - perhaps similar to the encephalitis lethargica outbreak in the 1920s and 1930s after the 1918 influenza pandemic - remains to be seen."
The study provides a detailed account of neurological symptoms of 43 people (aged 16-85) treated at the National Hospital for Neurology and Neurosurgery, UCLH, who had either confirmed or suspected Covid-19.
Brain inflammation and immune response to the disease
The researchers identified 10 cases of transient encephalopathies (temporary brain dysfunction) with delirium, which corresponds with other studies finding evidence of delirium with agitation. There were also 12 cases of brain inflammation, eight cases of strokes, and eight others with nerve damage, mainly Guillain-Barré syndrome (which usually occurs after a respiratory or gastrointestinal infection).
The virus causing Covid-19, SARS-CoV-2, was not detected in the cerebrospinal brain fluid of any of the patients tested, suggesting the virus did not directly attack the brain to cause the neurological illness. Further research is needed to identify why patients were developing these complications.
In some patients, the researchers found evidence that the brain inflammation was likely caused by an immune response to the disease, suggesting that some neurological complications of Covid-19 might come from the immune response rather than the virus itself.
Joint senior author Dr Hadi Manji said: "Our study amalgamates, for the first time, the clinical presentations of patients with Covid-19 neurological disease with MRI and laboratory features including, in one case, a brain biopsy.
"This now sets up a template for other researchers around the world, facilitating coordinated research to optimise the diagnosis and treatments of these complications, which to date, has proved difficult. In addition, patients are going to require long term follow up."
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