Successful treatment of acute encephalitis and hepatitis in a child with COVID-19 infection.

We present the case of a 6-year-old Taiwanese boy with a fulminant course of COVID-19 manifesting as high fever, acute consciousness changes, and status epilepticus. Brain MRI showed restricted diffusion in the bilateral hemisphere. Electroencephalogram showed diffuse slow waves with few spikes. CSF study was clear without evidence of common pathogens. He received treatment with antiviral agents, corticosteroids, intravenous immunoglobulins, and anti-IL-6 monoclonal antibodies. However, progressive fulminant hepatitis, hyperammonaemia, and disseminated intravascular coagulopathy developed. Rescue therapy with hybrid continuous renal replacement therapy and plasma exchange were performed in the first 11 days. The patient improved and was extubated on the 11th day. After physical therapy, his neurological function improved significantly. The patient was discharged under rehabilitation after 1 month of hospitalization. Viral sequencing confirmed infection with the Omicron BA.2.3 variant, one of the dominant strains in Taiwan and Hong Kong. Whole-exome sequencing revealed heterozygous uncertain significance variants in <I>TICAM-1, RNF 31</I>, and mitochondrial <I>MT-RNR1</I>, which provide additional support for the fulminant course. To the best of our knowledge, this is the first reported case of COVID-19 in a child with a fulminant course of acute encephalitis and hepatitis who successfully recovered by hybrid continuous renal replacement therapy and plasma exchange.