COVID-19-associated meningoencephalitis treated with intravenous immunoglobulin.

A 40-year-old man presented with altered mental status after a recenthospitalisation for COVID-19 pneumonia. Cerebrospinal fluid (CSF) analysis showed lymphocytosis concerning for viral infection. The CSF PCR for SARS-CoV-2 was negative, yet this could not exclude COVID-19 meningoencephalitis. During hospitalisation, the patient's mentation deteriorated further requiring admission to the intensive care unit (ICU). Brain imaging and electroencephalogram (EEG) were unremarkable. He was, thus, treated with intravenous immunoglobulin (IVIg) for 5 days with clinical improvement back to baseline. This case illustrates the importance of considering COVID-19's impact on the central nervous system (CNS). Haematogenous, retrograde axonal transport, and the effects of cytokine storm are the main implicated mechanisms of CNS entry of SARS-CoV-2. While guidelines remain unclear, IVIg may be of potential benefit in the treatment of COVID-19-associated meningoencephalitis.