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.