Indirect Confirmation of a COVID-19 Encephalitis Case

A 58-year-old man was admitted to the hospital with acute neurological manifestations of encephalitis 15 days after a previous upper respiratory COVID-19 illness. On presentation, he was confused with altered mental status, aggressive behavior, and a Glasgow coma scale score of 10/15. Laboratory investigation, brain computed tomography (CT), and brain magnetic resonance imaging (MRI) were unremarkable with normal results. Although the cerebrospinal fluid (CSF) polymerase chain reaction (PCR) for SARS-CoV-2 was negative, we found increased concentrations of positive immunoglobulin (Ig) A and IgG antibodies in CSF, suggesting acute central nervous system (CNS) infection and indirect confirmation of virus neuroinvasion. There was no evidence of humoral auto-reactivity, and we rejected the hypothesis of autoimmune encephalitis with known autoantibodies. On the fifth day of hospitalization, myoclonic jerks emerged as a new neurological sign until the added levetiracetam led to total remission. The patient achieved full recovery after antiviral and corticosteroid therapy implementation of 10 days in the hospital. This case report emphasizes the importance of the presence of CSF IgA and IgG antibodies to diagnose encephalitis in COVID-19 patients as an indirect confirmation of CNS infection.