Clinical characteristics and outcomes of COVID-19-Associated acute encephalopathy in pediatric patients during the Omicron wave in beijing: a single-center prospective study

Abstract

Background: The Omicron variant has become the predominant strain globally, yet pediatric data on COVID-19-associated acute encephalopathy (AE) remain scarce. This study aimed to characterize the clinical features and outcomes of Omicron-related AE in a PICU cohort.

Methods: We prospectively analyzed 10 pediatric patients (aged ≤ 18 years) diagnosed with COVID-19-associated AE at Capital Center of Children's health Capital Medical University from December 2022 to January 2023. AE diagnosis followed the Japanese Society of Child Neurology criteria. Demographic, clinical, laboratory, radiological, and outcome data were collected.

Results: Median page was 35 months (IQR 17.0-62.5), with 80% ≤4 years old. All patients presented with fever and altered mental status; 40% had seizures. Cranial MRI revealed symmetric brain lesions in all cases: 70% acute necrotizing encephalopathy (ANE), 10% encephalitis with splenial lesions (MERS), and 10% acute encephalopathy with subcortical demyelination (AESD). Elevated inflammatory markers (procalcitonin 31.27 ng/mL [IQR 23.8-38.7], IL-6 21.6 pg/mL [IQR 12.3-34.9]) and CSF pleocytosis were common. Six patients (60%) died within 48 h of PICU admission, all unvaccinated and ≤ 4 years old. Survivors exhibited long-term neurological sequelae (quadriparesis, hypotonia).

Conclusions: Omicron-associated AE in young children is characterized by rapidly progressive neurological deterioration, with 60% mortality in this cohort and persistent deficits in survivors. Symmetric MRI lesions, elevated procalcitonin, and CSF cytokine elevation may serve as early diagnostic indicators. Vaccination gaps and innate immune dysregulation likely contribute to severe outcomes.

Keywords: COVID-19; Critical care; Neuroinflammation; Omicron variant; Pediatric acute encephalopathy.

Fig. 1

Imaging Characteristics of ANE: patient 4 on day 1, bilateral and symmetrical low signal in thalamus on axial T1-weighted (A), high signal on T2-weighted (B) and FLAIR (C) images, and abnormal low signal on ADC (D) revealed thalamus cytotoxic edema. The same MRI signal pattern can also be seen in bilateral cerebellum, cerebellar and dorsal brain stem on T1-weighted (E), T2-weighted (F), FLAIR (G), and ADC (H) images. ANE acute necrotizing encephalopathy, MRI magnetic resonance imaging, DW diffusion-weighted images, FLAIR fluid-attenuated inversion recovery, ADC apparent diffusion coefficient

Fig. 2

Imaging Characteristics of AESD: patient 10 on day 4 of onset, axial MRI T1-weighted (A), T2-weighted (B) images showed subtle changes in cortex and subcortical white matter. However, DWI (C) showed bilateral subcortical white matter predominance high signal (bright tree appearance), ADC (D) revealed cytotoxic edema. AESD acute encephalopathy with biphasic seizures and reduced diffusion, MRI magnetic resonance imaging, DWI diffusion-weighted images, FLAIR fluid-attenuated inversion recovery, ADC apparent diffusion coefficient

Fig. 3

Imaging Characteristics of MERS: patient 8 on day 1, axial MRI T1-weighted (A), T2-weighted (B), FLAIR (C) and DWI (D) images showed subtle abnormal signa in splenium of the corpus callosum. MERS mild encephalitis/reversible splenic lesion, DWI diffusion-weighted images, FLAIR fluid-attenuated inversion recovery