Objective:To explore the clinical features of death in children with acute encephalopathy associated with influenza and corona virus disease 2019（COVID-19）and to enhance pediatrician's understanding of this disease.Methods:Clinical data of children with influenza and COVID-19-related acute encephalopathy hospitalized in Pediatric Intensive Care Unit of Children's Hospital Affiliated to Soochow University from September 2021 to July 2023 were retrospectively analyzed.The cases were divided into survival group and death group according to outcome.The general condition，clinical manifestations，auxiliary examination and treatment between the two groups were compared and analyzed.Results:A total of 41 pediatric patients were enrolled.In the death group,there were 17 cases,including 15 cases of acute necrotizing encephalopathy (ANE); among them,there were 7 male patients and 10 female patients,with a median age of 3.50 years.Eight patients were infected with influenza A virus,3 with influenza B virus,and 6 with SARS-CoV-2.The survival group comprised 24 cases,including 10 cases of ANE; among them,there were 16 male patients and 8 female patients,with a median age of 4.33 years.Fourteen patients were infected with influenza A virus,4 with influenza B virus,and 6 with SARS-CoV-2.None of the patients in the death group has received influenza and COVID-19 vaccines within 1 year before infection.Common symptoms were fever and disturbance of consciousness in the death group，eight cases had mild cough，seven cases had convulsions ≥three times，one case had two convulsions，nine cases had only one seizure，of which five cases were epileptic status.One case had delirium before convulsions.Seventeen cases began to fall into a coma (6.50±1.50) hours after their first onset of convulsion.Two patients had secondary pulmonary infection.Nine cases showed significantly elevated interleukin-6,while 17 cases had normal cerebrospinal fluid cell counts and 14 cases had elevated protein levels.All 17 cases underwent cranial CT scans,among which 13 showed symmetric necrosis of the bilateral thalami.All patients in the death group underwent glucocorticoid and intravenous immunoglobulin pulse therapy.Eleven patients received continuous renal replacement therapy,ten patients received intrathecal dexamethasone injection,and two patients were treated with tocilizumab.One patient underwent extracorporeal membrane oxygenation.Among the eight influenza patients,neuraminidase inhibitors were first administered 48 hours after the onset of fever.None of the six patients infected with SARS-CoV-2 received nirmatrelvir/ritonavir antiviral treatment.The causes of death in 17 patients included ANE(15 cases) and secondary infections(2 cases).Compared with the survival group,the incidence of brainstem involvement,shock,and low Glasgow coma scores (GCS ≤ 4) were significantly higher in the death group(15/17 vs.2/24， χ 2=26.18， P<0.001；16/17 vs.5/24， χ 2=21.39， P<0.001；14/17 vs.5/24， χ 2=15.15， P<0.001). Conclusion:Acute encephalopathy is primarily characterized by recurrent convulsions and disturbances of consciousness.Influenza and COVID-19 are the main causes.Cranial imaging is helpful for clinical diagnosis.Involvement of the brainstem,occurrence of shock,and GCS≤4 are associated with a higher fatality rate of ANE.

Objective:To explore the clinical features of death in children with acute encephalopathy associated with influenza and corona virus disease 2019（COVID-19）and to enhance pediatrician's understanding of this disease.Methods:Clinical data of children with influenza and COVID-19-related acute encephalopathy hospitalized in Pediatric Intensive Care Unit of Children's Hospital Affiliated to Soochow University from September 2021 to July 2023 were retrospectively analyzed.The cases were divided into survival group and death group according to outcome.The general condition，clinical manifestations，auxiliary examination and treatment between the two groups were compared and analyzed.Results:A total of 41 pediatric patients were enrolled.In the death group,there were 17 cases,including 15 cases of acute necrotizing encephalopathy (ANE); among them,there were 7 male patients and 10 female patients,with a median age of 3.50 years.Eight patients were infected with influenza A virus,3 with influenza B virus,and 6 with SARS-CoV-2.The survival group comprised 24 cases,including 10 cases of ANE; among them,there were 16 male patients and 8 female patients,with a median age of 4.33 years.Fourteen patients were infected with influenza A virus,4 with influenza B virus,and 6 with SARS-CoV-2.None of the patients in the death group has received influenza and COVID-19 vaccines within 1 year before infection.Common symptoms were fever and disturbance of consciousness in the death group，eight cases had mild cough，seven cases had convulsions ≥three times，one case had two convulsions，nine cases had only one seizure，of which five cases were epileptic status.One case had delirium before convulsions.Seventeen cases began to fall into a coma (6.50±1.50) hours after their first onset of convulsion.Two patients had secondary pulmonary infection.Nine cases showed significantly elevated interleukin-6,while 17 cases had normal cerebrospinal fluid cell counts and 14 cases had elevated protein levels.All 17 cases underwent cranial CT scans,among which 13 showed symmetric necrosis of the bilateral thalami.All patients in the death group underwent glucocorticoid and intravenous immunoglobulin pulse therapy.Eleven patients received continuous renal replacement therapy,ten patients received intrathecal dexamethasone injection,and two patients were treated with tocilizumab.One patient underwent extracorporeal membrane oxygenation.Among the eight influenza patients,neuraminidase inhibitors were first administered 48 hours after the onset of fever.None of the six patients infected with SARS-CoV-2 received nirmatrelvir/ritonavir antiviral treatment.The causes of death in 17 patients included ANE(15 cases) and secondary infections(2 cases).Compared with the survival group,the incidence of brainstem involvement,shock,and low Glasgow coma scores (GCS ≤ 4) were significantly higher in the death group(15/17 vs.2/24， χ 2=26.18， P<0.001；16/17 vs.5/24， χ 2=21.39， P<0.001；14/17 vs.5/24， χ 2=15.15， P<0.001). Conclusion:Acute encephalopathy is primarily characterized by recurrent convulsions and disturbances of consciousness.Influenza and COVID-19 are the main causes.Cranial imaging is helpful for clinical diagnosis.Involvement of the brainstem,occurrence of shock,and GCS≤4 are associated with a higher fatality rate of ANE.

Classical immune memory is thought to be possessed by adaptive immune system.It is featured by a specific memory of previous exposure to microbes and enhanced responses to reinfection accordingly in adaptive immune cells.Traditionally, it is believed that innate immunity does not have such characteristics.However, recent researches have raised doubts regarding this view.Studies have found that in mammals and other organisms that lack adaptive immunity, the innate immune system can change the manner and intensity of response to the second infection by certain pathogens, which is a phenomenon referred to innate immune memory.Unlike the antigenic receptor gene rearrangement to produce memory in adaptive immune cells, the training immunity in innate immune cells is mediated by epigenetic reprogramming.Innate immune memory does not always protect the body against infection or stress.It also results in toleranced immunity, which leads to a lowered immune response to pathogens infection and participates in the development of a variety of infectious diseases.Therefore, a tight regulation of innate immune memory may be critical for the therapy of refractory infections caused by sepsis-induced immune paralysis.