Putative autoimmune mechanisms for Acute Disseminated Encephalomyelitis (ADEM) and Guillain-Barré Syndrome (GBS) associated with SARS-CoV-2 infection

The novel coronavirus severe acute respiratory syndrome coronavirus 2, SARS-CoV-2, responsible for the ongoing COVID-19 pandemic, is associated with a broad manifestation of neurological disease, including Acute Disseminated Encephalomyelitis (ADEM) and Guillain-Barré Syndrome (GBS), amongst other forms of autoimmune encephalitis, stroke, encephalopathy, delirium, and cranial neuropathies. These phenomena are not limited to human coronaviruses but are also seen in a minority of patients in response to other viral infection. There is good evidence that an autoimmune mechanism hypothesis is likely. The final pathology is probably the culmination of mixed mechanisms such as vascular and immune dysregulation as well as direct viral invasion of neurons – though there is little if any evidence of viral invasion in the literature to date. The aim of this review is to elucidate the emerging evidence about this subset of COVID-19-associated neurological disease. This unique opportunity to study the interactions between virus and host immune and central nervous system (CNS) to gain novel insights applicable to other probable autoimmune neurological disease. I have conducted a literature search as well as drawn on my own observations from the COVID-19 and encephalitis multidisciplinary meetings at Queen Square National Hospital for Neurology and Neurosurgery, London, UK.