Neurological Involvement in Multisystem Inflammatory Syndrome in Children: Clinical, Electroencephalographic and Magnetic Resonance Imaging Peculiarities and Therapeutic Implications. An Italian Single-Center Experience.

ABSTRACT

Objective: To describe neurological involvement in multisystem inflammatory syndrome in children (MIS-C) and to evaluate whether neurological manifestations are related to the degree of multiorgan involvement and inflammation. Methods: The authors conducted a retrospective analysis of clinical, electroencephalographic (EEG), neuroradiological (MRI), and CSF parameters in 62 children with MIS-C (45 M, age 8 months-17 years, mean age 9 years) hospitalized between October 1, 2020 and March 31, 2022. Results: Neurological involvement was documented in 58/62 (93.5%) patients. Altered mental status was observed in 29 (46.7%), focal neurological signs in 22 (35.4%), and non-specific symptoms in 54 (87%). EEG was performed in 26/62 children 20 showed EEG slowing, diffuse or predominantly over the posterior regions. Ten patients underwent brain MRI three showed a cytotoxic lesion of the corpus callosum. CSF analysis, performed in six patients, was normal. On the basis of the clinical and EEG findings, two profiles of neurological involvement were identified 16/62 (26%) patients presented encephalitis with rapid-onset encephalopathy, focal neurological signs, and EEG slowing; 42/62 (68%) showed mild neurological involvement with mild or non-specific neurological signs. All patients received intravenous immunoglobulin and methylprednisolone (MTP), low-molecular-weight heparin, and therapeutic-dose anticoagulant treatment. Children with severe encephalopathy received intravenous MTP at 30 mg/kg/day for 3 days, obtaining rapid clinical and EEG improvement. Neurological assessment at discharge was normal in all cases. Children with encephalitis were younger than those without (median age 5 and 10 years, respectively); no differences between the two groups were found in the other parameters comorbidities, fever, number of organs and systems involved, shock, hospitalization, pediatric intensive care unit admission, non-invasive ventilation, inotropic support, laboratory data. Conclusion: Neurological involvement in MIS-C is frequent but not serious in most cases around two thirds of the affected children had mild and short-lasting symptoms. It seems to be related to age, but not to the degree of multiorgan involvement and inflammation. In children with acute immune-mediated encephalitis, the clinical picture was dominated by encephalopathy that disappeared with immunomodulatory therapy. Neurological assessment allowed timely diagnosis and treatment.