Last Updated on July 31, 2025 by Bertrand Clarke
A Growing Concern for Children’s Health
In the wake of severe flu seasons, a rare and devastating complication is emerging as a critical concern for pediatric healthcare providers across the United States. Acute necrotizing encephalopathy (ANE), a life-threatening brain condition triggered by influenza, is causing alarm due to a noticeable uptick in cases among young children. This fast-moving disorder, which can lead to sudden brain swelling, seizures, and even death, is prompting doctors to urge parents to stay vigilant and prioritize flu prevention. With the 2024-2025 flu season already showing signs of intensity, experts are sounding the alarm to protect vulnerable children from this rare but catastrophic illness.
Understanding Acute Necrotizing Encephalopathy
Acute necrotizing encephalopathy is a rare neurological condition primarily linked to viral infections, with influenza being the most common trigger. Unlike typical flu symptoms—fever, cough, and fatigue—ANE strikes swiftly, causing severe inflammation in the brain that can escalate within hours. The condition is believed to result from an overactive immune response, where the body’s attempt to fight the flu virus goes awry, attacking brain tissue and leading to swelling, seizures, coma, or, in severe cases, death.
Children, particularly those aged 1 to 10, are most at risk, with the median age of affected patients being around 5 years old. Alarmingly, the majority of children diagnosed with ANE have no pre-existing health conditions, making it a silent threat that can strike otherwise healthy kids. According to a recent study led by Stanford Medicine, published in JAMA Neurology in 2025, ANE has a mortality rate of approximately 27%, with 90% of fatal cases resulting from cerebral herniation, where brain tissue is forced through the skull due to extreme swelling.
A Surge in Cases Raises Red Flags
Historically, ANE has been a rare diagnosis, with only a handful of cases reported annually in the U.S. However, the 2024-2025 flu season has seen an unprecedented spike, particularly during January and February 2025. Pediatric neurologists across the country, from Boston Children’s Hospital to Stanford’s Lucille Packard Children’s Hospital, reported an unusual increase in ANE cases, prompting urgent discussions among specialists. “We were reaching out to colleagues nationwide, asking, ‘Are you seeing this too?’” said Dr. Molly Wilson-Murphy, a pediatric neurologist at Boston Children’s Hospital. “The responses came back quickly—many were seeing the same trend.”
The Stanford study, involving 61 researchers from 23 U.S. hospitals, documented 41 cases of ANE over the past two flu seasons, marking it as the largest cohort of ANE cases recorded in the U.S. to date. This surge has raised concerns about whether changes in flu strains, immune responses, or environmental factors could be contributing to the increase. Notably, only 16% of children in the study were vaccinated against the flu, highlighting a potential link between low vaccination rates and severe outcomes.
Symptoms and the Race Against Time
ANE’s rapid progression makes early detection critical. The condition often begins with typical flu symptoms—high fever, body aches, and fatigue—but can quickly escalate to alarming neurological signs. Parents are urged to watch for sudden changes in their child’s behavior, such as extreme drowsiness, confusion, or difficulty staying alert, particularly in the afternoon when children are typically active. Seizures, loss of coordination, or unresponsiveness are red flags that require immediate medical attention.
“The symptoms can develop incredibly quickly,” said Dr. Keith Van Haren, a pediatric neurologist at Stanford Medicine and co-author of the JAMA Neurology study. “A child can go from drowsy to life-threatening in just a couple of hours.” When ANE is suspected, children are typically rushed to intensive care units, where treatments such as high-dose steroids or plasma exchange are used to reduce brain swelling. Despite these interventions, the first week is critical, with survival often hinging on rapid and aggressive treatment.
The Role of Flu Prevention
The rise in ANE cases has reignited discussions about the importance of flu vaccination and early antiviral treatment. The Centers for Disease Control and Prevention (CDC) reported that the 2024-2025 flu season has been particularly severe, with influenza A strains, especially H3N2, dominating hospitalizations. The CDC estimates that flu vaccines reduce the risk of severe outcomes by 40-60% in children, even if they don’t prevent infection entirely. Yet, vaccination rates remain suboptimal, with only about 50% of U.S. children aged 6 months to 17 years receiving the flu shot annually, according to CDC data from 2024.
Antiviral medications like oseltamivir (Tamiflu), when administered within 48 hours of symptom onset, can also reduce the severity of flu infections and potentially lower the risk of complications like ANE. However, public health experts note that awareness of ANE remains low, even among healthcare providers, which can delay diagnosis and treatment. “We need to educate both parents and clinicians about this condition,” Dr. Van Haren emphasized. “Knowing the signs and acting fast can be the difference between life and death.”
A Call for Awareness and Action
The recent spike in ANE cases has prompted pediatric hospitals to launch awareness campaigns targeting parents, schools, and primary care providers. The American Academy of Pediatrics (AAP) issued a statement in July 2025 urging families to prioritize flu vaccinations before the peak of the flu season, typically between December and March. The AAP also recommended that pediatricians screen for neurological symptoms in children with severe flu cases, even if the child appears otherwise healthy.
Public health officials are also exploring whether genetic or environmental factors may predispose certain children to ANE. While some studies suggest a genetic mutation may increase susceptibility in a small subset of patients, most cases occur in children with no known risk factors. Researchers are calling for further studies to understand why ANE cases are rising and whether new flu strains or immune responses are to blame.
Stories of Survival and Loss
For families affected by ANE, the journey is often harrowing. Take the case of 6-year-old Emma, a previously healthy child from Ohio who contracted the flu in January 2025. Within two days, she developed a high fever and became unusually lethargic. Her parents, sensing something was wrong, rushed her to the emergency room, where she was diagnosed with ANE. After a week in the ICU and intensive treatment with steroids, Emma survived but faces a long road to recovery, with ongoing therapy to regain motor skills and cognitive function.
Tragically, not all stories end in recovery. In Texas, a 4-year-old boy succumbed to ANE within 48 hours of showing symptoms, despite aggressive medical intervention. His family, devastated by the loss, is now advocating for greater awareness of the condition and the importance of flu prevention.
Looking Ahead: Protecting the Next Generation
As the 2025-2026 flu season approaches, experts are urging families to take proactive steps to protect children from the flu and its complications. In addition to vaccination, simple measures like frequent handwashing, avoiding sick contacts, and seeking prompt medical care for flu symptoms can make a significant difference. Schools are also being encouraged to reinforce flu prevention strategies, such as sanitizing surfaces and promoting vaccination clinics.
The rise in ANE cases serves as a stark reminder of the flu’s potential to cause far more than a week of discomfort. While the condition remains rare, its devastating impact underscores the need for vigilance and preparedness. “This is a wake-up call,” said Dr. Wilson-Murphy. “We can’t predict which child will develop ANE, but we can take steps to reduce the risk and act quickly when warning signs appear.”
For parents, the message is clear: don’t underestimate the flu. With a rare but deadly complication like ANE on the rise, staying informed and proactive could save a child’s life.
