Flu-Associated Brain Swelling in Children Shows 27% Mortality Rate Despite Aggressive Treatment
核心洞察
A multicenter study of 41 U.S. children with influenza-associated acute necrotizing encephalopathy (ANE) revealed a 27% mortality rate, with most deaths occurring within three days of symptom onset.
Only 16% of affected children had received age-appropriate seasonal influenza vaccination, suggesting vaccination could prevent many cases of this rare but devastating complication.
Survivors faced significant long-term disability, with 63% experiencing at least moderate impairment at 90-day follow-up despite intensive immunomodulatory treatments.
A comprehensive analysis of influenza-associated acute necrotizing encephalopathy (ANE) in U.S. children has revealed alarming mortality rates and highlighted critical gaps in vaccination coverage, according to research published in the Journal of the American Medical Association.
The multicenter case series, led by Andrew Silverman from Stanford University, examined 41 cases of influenza-associated ANE from 23 U.S. hospitals between 2023 and 2025. The condition, characterized by rapid-onset brain swelling and immune system dysfunction, claimed the lives of 11 children (27%) at a median of three days from symptom onset.
High-Risk Population and Clinical Presentation
The study revealed that 76% of affected children (31 of 41 cases) had no significant medical history, with an average age of 5 years. Most cases (39 of 41) involved influenza A virus, while two were associated with influenza B.
Clinical presentation was consistent across cases, with fever occurring in 93% of patients, encephalopathy in 100%, and seizures in 68%. All patients experienced brain swelling as the condition progressed, creating a medical emergency requiring intensive intervention.
"It's similar to the sepsis response, this massive burst of inflammation that becomes its own problem," explained co-senior author Dr. Thomas LaRocca, a pediatric critical care medicine specialist at Stanford Medicine. "It's like the immune system is going into a panic attack."
Genetic Risk Factors and Vaccination Status
Genetic testing revealed potential risk factors in nearly half of tested patients. Of 32 patients who underwent genetic analysis, 15 (47%) carried genetic risk alleles potentially related to ANE susceptibility, including 11 (34%) with RANBP2 (搜索) variants.
Perhaps most concerning was the vaccination data: only six of 38 patients (16%) with available vaccination history had received age-appropriate seasonal influenza vaccination, suggesting that many cases might have been preventable through routine immunization.
Treatment Approaches and Outcomes
Healthcare teams employed aggressive, multi-modal treatment strategies. Most patients received multiple immunomodulatory treatments, including methylprednisolone (95%), intravenous immunoglobulin (66%), tocilizumab (51%), plasmapheresis (32%), anakinra (5%), and intrathecal methylprednisolone (5%).
The intensity of care was reflected in hospital stays, with a median intensive care unit duration of 11 days and median total hospitalization of 22 days. Among the 11 fatalities, 91% resulted from cerebral herniation, with eight deaths occurring within eight days of hospitalization.
Long-Term Disability Among Survivors
Survival did not guarantee full recovery. Among the 27 survivors with 90-day follow-up data, 63% experienced at least moderate disability. However, functional outcomes varied significantly: 19 patients could sit up independently three months after illness onset, 16 could stand independently, and 13 could walk independently.
"We identified ANE patients with a wide range of outcomes, from no residual neurological deficits to, unfortunately, fatal complications," LaRocca noted. "We saw that critical-care management of brain swelling, along with immune modulating therapies such as plasma exchange and intravenous immunoglobin, appeared helpful for patients who recovered."
Clinical Implications and Prevention
The research emphasizes the critical importance of early recognition and aggressive treatment. Co-senior author Dr. Keith Van Haren, a pediatric neurologist at Lucile Packard Children's Hospital Stanford, stressed that outcomes were better than traditionally expected for this condition.
"The number of kids who had pretty good outcomes surprised me; it was better than I thought it would be," Van Haren said. "For clinicians, the takeaway from our report is that early, intensive management of brain swelling and the immune response really seemed to help children with this condition recover."
The study's findings underscore vaccination as the primary prevention strategy. "For doctors, our message is that these kids can recover remarkably well, even if they appear gravely ill early in their course. Don't give up. And for parents, it's: Vaccinate!" Van Haren emphasized.
The research team noted that ANE represents "the most severe flu complication" but stressed that influenza causes numerous other serious complications, including pneumonia and respiratory failure, all of which can be prevented through vaccination.
LaRocca concluded that prompt identification is essential "to ensure that these children can receive rapid, intensive care at hospitals that offer advanced neurocritical care and have experts familiar with immunomodulating medications."