The rare (and potentially fatal) influenza complication docs need to know about ASAP
Industry Buzz
“Acute necrotizing encephalopathy is the most severe flu complication, but it’s only the tip of the iceberg for what flu can do.” — Keith Van Haren, MD, press release
“This can affect them lifelong, in terms of their educational attainment, where they end up economically, and their future prospects.” — Dean Blumberg, MD, Chief of Pediatric Infectious Diseases at UC Davis
Rapid identification and treatment for swelling in the brain and an extreme immune response could be the key for survival of influenza-associated acute necrotizing encephalopathy (ANE) in children. []
Research published late last month in JAMA found that rapid and targeted care in a pediatric ICU gave children a greater chance of recovery. []
“Acute necrotizing encephalopathy is the most severe flu complication, but it’s only the tip of the iceberg for what flu can do,” said Keith Van Haren, MD, co-senior author of the study, in a press statement. “Flu causes all kinds of complications, including other forms of brain swelling, as well as pneumonia and respiratory failure. Vaccines really do help protect wonderfully against all those complications.” []
A new development
The understanding of influenza-associated ANE has been a recent development.
“It's only in the past couple of years that this has been more widely recognized and reported, and so now, for example, the authors had a case definition. Having the case definition allows further research to be done, which could lead to better management,” Dean Blumberg, MD, Chief of Pediatric Infectious Diseases at UC Davis, tells MDLinx.
The rare but potentially fatal complication causes swelling in the brain as well as a runaway immune response. []
The researchers examined 41 cases of ANE in the US between 2023 and 2025. Of the children studied, 27% died. Among the survivors, 63% had a moderate to severe disability at three months from symptom onset. []
“Fortunately, it is a rare event, but once it occurs, it’s terrible … the tissue of the brain is actually destroyed, and that’s what makes it so terrible,” William Schaffner, MD, an infectious disease expert at Vanderbilt University, tells MDLinx.
Outcomes variable among children
Of the children studied, the median age was five. Of the 41 children studied, 39 were infected with influenza A, and two of them had influenza B. The majority of the children had been healthy, without a significant medical history, before they became ill with influenza. []
All of the children had brain swelling at the onset of the illness, 95% had a fever, and 68% experienced seizures. The outcomes among the children were variable. []
“We identified ANE patients with a wide range of outcomes, from no residual neurological deficits to, unfortunately, fatal complications,” Thomas LaRocca, MD, PhD, co-senior author of the study, said in a press statement. “We saw that critical-care management of brain swelling, along with immune modulating therapies such as plasma exchange and intravenous [immunoglobulin], appeared helpful for patients who recovered.” []
Of the children who survived, several still experienced neurologic symptoms at follow-up, including spasticity and dystonia.
The researchers say it is essential clinicians react early in detecting ANE and provide intensive management of the condition to save lives and improve long-term outcomes. []
Related: The first at-home flu vaccine is now available—here’s what physicians thinkVaccination is key
Dr. Schaffner argues that the research reinforces the importance of the influenza vaccine, which greatly reduces the odds of children becoming seriously ill from the flu.
“About half the children in the United States receive influenza vaccine each year. So this should be a further message, both to pediatricians and family doctors, to be more persuasive and for parents to be more accepting,” he says.
Dr. Blumberg says the research provides further valuable insight into how outcomes could be improved for children who become seriously ill with flu.
“One of the things that parents really care about is their children's neurologic and intellectual outcomes. This can affect them lifelong, in terms of their educational attainment, where they end up economically, and their future prospects. So I think it's really important to try to understand this as much as we can,” he says.