Trending Clinical Topic: COVID Brain Fog

Ryan Syrek


February 26, 2021

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Symptoms associated with so-called "long COVID" have been a growing concern. A recent research letter has identified a potential origin for some associated neurologic issues. These findings, combined with news about guidelines in development and information about a new database dedicated to neurologic effects, resulted in our top trending clinical topic of the week.

A report published in JAMA Neurology points to the presence of large cells in cortical capillaries, found during the autopsies of patients who died with COVID-19, as a possible cause of "brain fog" (see Infographic below). The authors state that, to their knowledge, megakaryocytes had not been identified previously in the brain. By occluding the flow through individual capillaries, these cells could cause ischemic alteration in a distinct pattern, potentially resulting in an atypical form of neurologic impairment, the investigators suggest.

This brain fog is just one of many symptoms associated with COVID "long-hauler" syndrome. Experts say that to be considered post–COVID-19 syndrome, symptoms should persist for at least 4 weeks after acute SARS-CoV-2 infection. However, many patients experience symptoms that last 2-6 months or longer. Fatigue appears to be most common, followed by dyspnea and other pulmonary complications. Neurologic symptoms, particularly brain fog and numbness or tingling throughout the body, have also been reported.

The World Health Organization recently issued updated treatment guidance for COVID-19, including for people with persistent symptoms. The Centers for Disease Control and Prevention is currently working on guidelines for diagnosis and management of people with post-COVID syndrome, and the National Institutes of Health (NIH) has also shown interest in developing protocols. Given the large number of unknowns about long COVID and how vaccines may factor in, the development of clear guidance may still be at least 6 months away.

To help advance this work, the NIH has launched a database to track neurologic issues related to COVID-19, including brain fog. The database will catalog symptoms, complications, and outcomes as well as the effects of the virus on preexisting neurologic conditions. The COVID-19 Neuro Databank/Biobank (NeuroCOVID) is funded by the National Institute of Neurological Disorders and Stroke. It was created and will be maintained by researchers at NYU Langone Health in New York City. Researchers interested in using data and biosamples from the database may submit requests to the NeuroCOVID Steering Committee. More information is available on the NeuroCOVID website.

Long COVID cases are on the rise, with as many as 1 in 10 patients with COVID-19 reporting that their symptoms have continued for weeks and months after the initial diagnosis. Some research has shown that the condition may actually be as many as four different syndromes. Older patients with COVID-19 in particular have described battling brain fog, weakness, and other cognitive dysfunction even after initial recovery from acute infection. The work of investigators to find potential causes and create guidance for clinicians is understandably of great interest, as evidenced by COVID brain fog becoming this week's top trending clinical topic.

Read more about the clinical presentation of COVID-19.


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