A different phenomenon
The manifestations of neuroPASC are heterogeneous and can include confusion, cognitive dysfunction, headache, encephalitis, and other impairments. Neurologic symptoms occur during acute SARS-CoV2 infections, but neuroPASC appears to be a different phenomenon. These symptoms, which develop after the initial respiratory disease has resolved, were attributed by Dr. Spatola to persistent inflammation that is not necessarily directly related to ongoing infection.
“The reason why some patients develop neuroPASC is unknown, but I think the evidence has pointed to a role for the immune system rather than the virus itself,” Dr. Spatola said.
Currently, neuroPASC is a clinical diagnosis but Dr. Spatola and her coinvestigators are conducting research to identify biomarkers. A viable diagnostic test is not expected imminently. They have identified 150 different features with potential relevance to neuroPASC.
In their comparison of those who did relative to those who did not develop neuroPASC, the initial studies were undertaken 2-4 months after the acute COVID-19 symptoms had resolved. The patients with neuroPASC and those without neurologic sequelae have now been followed for 6-8 months, which Dr. Spatola said was too short to draw firm conclusions about outcomes.
An evolving concept
Despite the small sample size of this study, these are “very interesting data” for considering the pathogenesis of neuroPASC, which is “a concept that is still evolving,” according to Natalia S. Rost, MD, chief of the stroke division, department of neurology, Massachusetts General Hospital, Boston.
Applied to SARS-CoV2, the concept of original antigenic sin “is new” but Dr. Rost said that it might help differentiate neuroPASC from acute neurologic symptoms of COVID-19, which include stroke. She indicated that the work performed by Dr. Spatola and others might eventually explain the pathology while leading to treatment strategies. She cautioned that the concepts explored in this study “need to be further developed” through larger sample sizes and the exploration of other variables that support the hypothesis.
Dr. Spatola and Dr. Rost report no potential conflicts of interest.