Understanding Acute Necrotising Encephalitis
A Rare but serious neurological condition that occurs after a viral infection
What is ane?
Acute necrotizing encephalopathy (ANE) is a rare but serious condition that causes brain damage following a viral infection, most often influenza (the flu). ANE primarily affects children and causes inflammation and swelling in the brain, which can lead to severe neurological symptoms and long-term damage, particularly to the thalamus. The thalamus is a key part of the brain involved in sensation and movement.
While inflammation is a normal response to infection, excessive inflammation can damage tissues, including brain cells. In ANE, viruses aren’t found in the brain or spinal cord, so the damage is more likely caused by the body’s immune reaction to the infection rather than the virus itself.
Because ANE can progress quickly, it’s important to recognize and treat it early for the best possible outcomes.
Causes & Risk Factors
Viral Triggers
While the exact cause is not fully understood, ANE is strongly linked to viral infections, particularly influenza A and influenza B
Genetic Predisposition
In some cases, genetic mutations (like in the RANBP2 gene) may contribute to the development of ANE.
Immune Response
Excessive inflammation due to the body's immune response to the viral infection is thought to play a key role in the development of ANE.
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Fever
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Seizures
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Loss of consciousness
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Behavioural changes
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Paralysis or weakness
Symptoms
Diagnosis
Clinical Presentation
A rapid progression of neurological symptoms after a viral illness is a key indicator
Imaging
Brain imaging (like MRI or CT scans) can reveal characteristic symmetrical lesions, particularly in the thalami.
Cerebrospinal Fluid (CSF) Analysis
Increased CSF protein without pleocytosis can be seen in ANE.
Treatment & Management
There is no specific cure for ANE, but early treatment can reduce the severity of symptoms and complications. Medical approaches include:
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• High-dose corticosteroids
• Intravenous immunoglobulin (IVIG)
• Plasma exchange therapy
• Supportive care (e.g., seizure control, ICU support)
Prognosis
Outcomes vary widely. Some patients recover fully, while others may experience long-term neurological effects. Early diagnosis and treatment significantly improve the chances of recovery. Support from healthcare teams, caregivers, and rare disease networks is vital.
Acute necrotizing encephalopathy (ANE) has a high mortality rate, ranging from 30% to 50%. Even those who survive often experience significant neurological sequelae, with some studies reporting that less than 10% of survivors recover fully
