COVID-19-associated immune-mediated encephalitis mimicking acute-onset Creutzfeldt-Jakob disease

Abstract

We report a subtype of immune-mediated encephalitis associated with COVID-19, which closely mimics acute-onset sporadic Creutzfeldt-Jakob disease. A 64-year-old man presented with confusion, aphasia, myoclonus, and a silent interstitial pneumonia. He tested positive for SARS-CoV-2. Cognition and myoclonus rapidly deteriorated, EEG evolved to generalized periodic discharges and brain MRI showed multiple cortical DWI hyperintensities. CSF analysis was normal, except for a positive 14-3-3 protein. RT-QuIC analysis was negative. High levels of pro-inflammatory cytokines were present in the CSF and serum. Treatment with steroids and intravenous immunoglobulins produced EEG and clinical improvement, with a good neurological outcome at a 6-month follow-up.

Figure 1

Representative EEG epochs showing left‐sided lateralized periodic discharges with associated myoclonus on day 1 (A) and generalized periodic discharges on day 7 (B). EMG = right flexor carpi surface electromyography electrode.

Figure 2

Representative MRI images showing coronal DWI, ADC, and FLAIR sequences of the same slice and axial FLAIR sequence, performed in the subacute phase (day 10; (A) and post‐acute phase (day 50; (B). Abnormal cortical areas are indicated by arrows. Notably, ADC map does not show commensurate hypointensity in the anterior cingulate and insula, where the DWI and FLAIR cortical hyperintensity was present. ADC, apparent diffusion coefficient; DWI, diffusion‐weighted imaging; FLAIR, fluid‐attenuated inversion recovery.