Acute Encephalopathies in SARS-CoV-2 Infection: A Clinical and Neuroimaging Perspective

Neurological manifestations are frequent in patients with SARS-CoV-2 infection and can be correlated with different pathogenic mechanisms which can be divided into two categories: direct invasion of the central nervous system by the virus and indirect effects deriving from the severity of the systemic infection and by the inflammatory response correlated with cytokine storm. Among the neurological manifestations, acute encephalopathy is very frequent and its nomenclature has recently been updated. The occurrence of a condition of altered mental status, reduced consciousness, delirium up to coma represents an element associated with a greater severity of the infection and mortality both in an Intensive Care Unit setting and in an Emergency Department setting. The tissue damage mechanisms found in COVID-19 patients' encephalopathy and neuroimaging patterns, as well as histopathology, are similar to those described in sepsis-associated encephalopathy, further confirming the role of indirect mechanisms, with no CNS invasion by the virus. The available data have some limitations, notably the underuse of diagnostic neuroimaging techniques in severely affected patients, particularly in the first wave of the pandemic.