Peer-reviewed article
National study on pediatric acute encephalopathy in Japan (April 2020 to October 2023): Insights from the third study.
Omata T, Sakuma H, Nagase H, Abe Y, Kuki I et al. ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This national study tracked 622 cases of acute encephalopathy in Japanese children from 2020 to 2023, covering the COVID-19 period. Researchers found that the most common forms were acute encephalopathy with biphasic seizures (35.1%) and clinically mild encephalitis with splenial lesions (17.8%), with peak cases during COVID-19 and influenza outbreaks. The most common causative pathogens were exanthem subitum, SARS-CoV-2, and influenza. Severe forms including hemorrhagic shock encephalopathy and acute fulminant cerebral edema increased from 1.9% to 9.1% compared to the previous survey period. Treatment primarily involved steroid therapy, mitochondrial cocktails, and targeted temperature management.
Key points
- Highest incidence of acute encephalopathy was in 1-year-old children
- Combined HSES/AFCE rate increased from 1.9% (2014-2017) to 9.1% (2020-2023)
- Most common causative agents were exanthem subitum (16.1%), SARS-CoV-2 (15.9%), and influenza (7.7%)
- Steroid pulse therapy was used in 68.9% of cases, mitochondrial cocktails in 42.5%, and targeted temperature management in 31.0%
- Case numbers peaked during COVID-19 and influenza outbreaks
Limitations
This is a descriptive epidemiological study based on survey responses from hospitals; it does not evaluate treatment effectiveness or compare different therapeutic approaches. The study cannot determine causal relationships between pathogens and encephalopathy outcomes, nor can it assess which treatments are most effective.
Abstract
Background Previous national studies of acute encephalopathy in Japan were conducted in 2007-2010 and 2014-2017. In this third study (April 1, 2020-October 31, 2023), spanning the coronavirus disease 2019 (COVID-19) outbreak, we compared results to assess trends in pediatric viral infections and therapeutic practices. Methods Questionnaires were sent to 430 hospitals of the Japanese Pediatric Society, yielding 241 responses and 1197 cases. A secondary survey to 151 facilities received 110 responses (72.8 %), identifying 622 eligible patients (604 for treatment, 544 for outcome analysis). Data on patient background, syndrome classification, causative virus, treatment, and prognosis were collected. Results Among 622 cases (54.6 % boys), the highest incidence was in 1-year-olds, with case numbers peaking during COVID-19 and influenza outbreaks. The frequency of clinical syndromes was: acute encephalopathy with biphasic seizures and late reduced diffusion, 35.1 %; clinically mild encephalitis/encephalopathy with a reversible splenial lesion, 17.8 %; hemorrhagic shock and encephalopathy syndrome (HSES), 6.9 %; acute encephalitis with refractory, repetitive partial seizures, 3.7 %; acute fulminant cerebral edema (AFCE), 2.2 %; acute necrotizing encephalopathy, 1.6 %; and unclassifiable, 31.4 %. Notably, the combined HSES/AFCE rate increased from 1.9 % in the 2014-2017 survey to 9.1 %, likely due to enhanced diagnosis and COVID-19 impact. Pathogens were exanthem subitum (16.1 %), severe acute respiratory syndrome coronavirus 2 (15.9 %), and influenza (7.7 %). Treatments included steroid pulse therapy (68.9 %), mitochondrial cocktails (42.5 %), and targeted temperature management (31.0 %). Conclusion This study provides a comprehensive overview of pediatric acute encephalopathy during COVID-19 outbreaks, shows increases in the incidence of HSES/AFCE, and presents current treatment.