Results from a study suggest that the effects of the virus on the brain may be more profound than respiratory symptoms.
The more we learn about COVID-19, the more mysterious the disease caused by SARS-CoV-2 becomes.
For example, analysis published on October 5 by the Annals of Clinical and Translational Neurology focuses on the neurologic complications associated with the virus. And, based on the findings, it appears they may be even more troublesome than the virus’ effects on the respiratory tract.
In an assessment of 509 patients admitted to Chicago-area hospitals, the authors found that neurologic manifestations of COVID-19 were present at disease onset in 42.2%, at hospitalization in 62.7%, and at any time during the disease course in 82.3%. In comparison, severe respiratory disease requiring mechanical ventilation was observed in only 26.3% of the patients.
Overall, patients with severe COVID-19 had a 4-fold higher risk than others for developing neurologic complications, and the risk was 98% higher in younger patients with the disease. This latter point is significant, given that older age has been seen as a key driver of risk in infected patients since the start of the pandemic.
“Only 9 months into the pandemic, the long‐term effects of COVID‐19 on the nervous system remain uncertain,” wrote the authors, from Northwestern University. “Prospective cognitive and neurologic‐focused evaluations through specialized clinics dedicated to further diagnostic assessment and tailored rehabilitation needs could play a significant role in recovery from this pandemic.”
Among the patients in the study, the most frequent neurologic manifestations were myalgias (44.8%), headaches (37.7%), encephalopathy (31.8%), dizziness (29.7%), dysgeusia (15.9%), and anosmia (11.4%). In all, 71.1% of the study patients had a favorable functional outcome at discharge (based on modified Rankin Scale score). However, encephalopathy was associated with worse functional outcome and higher mortality within 30 days of hospitalization. Among patients who developed encephalopathy, 21.7% (n=35) died, compared with 3.2% (n=11) of those who didn’t.
“Our results suggest that, of all neurologic manifestations, encephalopathy is associated with a worse functional outcome in hospitalized patients with COVID‐19, and may have lasting effects,” the researchers wrote. “Long‐term follow‐up is necessary to assess the true burden of encephalopathy in these patients. Whether milder forms occur in non‐hospitalized individuals with COVID‐19 who complain of protracted inability to concentrate or decreased short term memory (referred to as ‘brain fog’) warrants further evaluation.”
Unlike other neurologic manifestations of the disease such as myalgia, headache, or dizziness, though, encephalopathy was more frequently found in older patients, particularly those with severe disease and a history of any neurological disorder or chronic kidney disease. They also found that encephalopathy in COVID‐19 was associated with significantly longer hospital stays (17 days vs 5 days).
Although they were unable to determine the cause of encephalopathy in these patients, given the lack of extensive diagnostic neurologic testing due to ongoing pandemic restrictions, they attribute the complication to the systemic nature of the disease and the multisystem inflammation associated with it as well as coagulopathy, direct neuroinvasion by the virus, endotheliitis, and intensive care unit delirium.
“Broad recognition and screening for encephalopathy as a contributor to disease severity in COVID‐19 may have utility in resource allocation and potential to improve patient outcomes,” they wrote. “Furthermore, our findings emphasize the broader need to develop interventions that target encephalopathy as a component of multi‐organ system medical illness.”