Characteristics and outcome of influenza-associated encephalopathy/encephalitis among children in China

Influenza-Associated Encephalopathy/Encephalitis (IAE) is characterized by high incidence and poor prognosis. The aim of this study is to describe the clinical features and outcomes of IAE in pediatric patients. We performed a retrospective review of hospitalized cases of laboratory-confirmed influenza infection between January 2018 and December 2021. Demographic, clinical, imaging, treatment and outcome data were collected. Statistical analysis was performed using SPSS software. Of 446 children hospitalized with influenza, 71 cases were identified with a diagnosis of IAE. The median age was 3 years and 46 (64.8 %) were younger than 5 years. Only one patient was vaccinated for seasonal influenza. 46 (64.8 %) patients had abnormal electroencephalogram examination and 47 (66.2 %) had abnormal brain MRI or CT findings. 68 (95.8 %) patients were treated with oseltamivir/peramivir. 12 (16.9 %) patients suffered mortality. Non-survivors were more likely to have lower Glasgow coma score (median 7), longer duration of fever (median 3 days), with underlying medical conditions (P = 0.006), and complications including sepsis (P = 0.003), shock (P < 0.001), respiratory failure (P = 0.006), acute renal failure (P = 0.001), myocardial damage (P < 0.001), coagulation disorders (P = 0.03), electrolyte disturbance (P = 0.001) and hyperlactacidemia (P = 0.003). Non-survivors had higher percentages of corticosteroids (P = 0.003) and immunoglobulin (P = 0.003) treatments compared to survivors. Children with IAE have a high mortality rate. Lower Glasgow coma score, longer duration of fever, with underlying medical conditions and complications pose a great risk to poor prognosis. Influenza vaccination is recommended to all eligible children.