Influenza-Associated Encephalopathy and Neurological Complications

Influenza-associated encephalopathy encompasses a spectrum of central nervous system dysfunction that arises in the context of seasonal or pandemic influenza infection. Clinically, presentations range from transient confusion and seizures to severe forms such as acute necrotizing encephalopathy, which carries high rates of morbidity and mortality. Although children account for the majority of cases, adults—particularly those with comorbidities—are also at risk. The underlying pathophysiology reflects a combination of direct viral effects on cerebral endothelium and parenchyma, dysregulated host immune responses with cytokine overproduction, and secondary metabolic disturbances. Neuroimaging frequently reveals diffuse or bilateral symmetric lesions, while cerebrospinal fluid findings may be unremarkable despite significant neurological involvement. Early recognition and intervention—antiviral therapy, immunomodulation and supportive care—are essential to mitigate long-term sequelae. Ongoing research seeks to clarify viral entry mechanisms, host genetic predispositions and optimal therapeutic windows, with the ultimate aim of reducing the global burden of this rare but devastating complication of influenza.

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Influenza-Associated Encephalopathy and Neurological Complications publication trend

The graph below shows the total number of articles in influenza-associated encephalopathy and neurological complications across all publications each year (not limited to Nature Index journals).

Technical terms

Encephalopathy: Diffuse brain dysfunction presenting with altered consciousness, seizures or focal neurological deficits.

Acute necrotizing encephalopathy (ANE): A rapidly progressive encephalopathy marked by symmetric brain necrosis, often following viral febrile illness.

Blood–brain barrier: A specialised endothelial interface that regulates molecular and cellular trafficking between blood and central nervous system.

Cytokine storm: An excessive, uncontrolled release of pro-inflammatory cytokines causing widespread tissue injury.

Astrocyte: A glial cell that supports neuronal function, regulates extracellular ion balance and maintains blood–brain barrier integrity.

References

1. Viral entry and translation in brain endothelia provoke influenza-associated encephalopathy. Acta Neuropathologica (2024).
2. Severe A(H1N1)pdm09 influenza acute encephalopathy outbreak in children in Tuscany, Italy, December 2023 to January 2024. Eurosurveillance (2024).
3. Clinical Manifestations and Pathogenesis of Acute Necrotizing Encephalopathy: The Interface Between Systemic Infection and Neurologic Injury. Frontiers in Neurology (2022).