Journal of Neuroinfectious Diseases
Open Access

Acute Necrotizing Encephalopathy (ANE) is a rare, rapidly progressive neurological disorder characterized by multiple, symmetrical brain lesions, primarily affecting the thalami, brainstem, cerebellum, and cerebral white matter. First described in 1995 in Japan, ANE is most commonly seen in children following viral infections, particularly influenza and human herpesvirus 6. The condition is associated with high morbidity and mortality, making early recognition and intervention crucial. ANE is distinct from other forms of encephalopathy due to its unique radiological findings and often severe systemic involvement, including hepatic dysfunction and coagulopathy. Understanding the pathogenesis, clinical features, and management strategies is vital for improving patient outcomes [1,2].

Discussion

ANE typically presents with acute onset of high fever, seizures, altered consciousness, and rapid neurological deterioration, often within days of a preceding viral illness. The exact pathophysiology is not fully understood, but it is widely believed to result from an excessive inflammatory response or “cytokine storm” rather than direct viral invasion of the central nervous system. Elevated levels of pro-inflammatory cytokines, such as interleukin-6, interleukin-10, and tumor necrosis factor-alpha, have been documented in patients, leading to blood–brain barrier disruption, brain edema, and necrotic lesions. Genetic predisposition plays a role in some cases; mutations in the RANBP2 gene have been linked to familial or recurrent forms of ANE, known as ANE1 [3-6].

Epidemiologically, ANE is most frequently reported in East Asia, especially Japan and Taiwan, though sporadic cases have been documented worldwide. While it predominantly affects children under five years of age, adults can also be affected. Mortality rates range from 30% to 50%, and survivors often experience long-term neurological sequelae, including motor deficits, cognitive impairment, and epilepsy. Early identification is therefore essential [7-10].

Diagnosis of ANE relies on a combination of clinical suspicion, neuroimaging, and laboratory findings. Magnetic resonance imaging (MRI) is the cornerstone, revealing symmetrical lesions in the thalami, brainstem, cerebellum, and occasionally the cerebral hemispheres. Laboratory tests often show elevated liver enzymes, thrombocytopenia, and coagulopathy, reflecting systemic involvement. Cerebrospinal fluid analysis may reveal mild protein elevation, but pleocytosis is uncommon, helping differentiate ANE from infectious encephalitis.

Conclusion

Acute Necrotizing Encephalopathy is a rare but life-threatening neurological disorder, often triggered by viral infections and characterized by rapid onset, severe brain injury, and high mortality. Early recognition through clinical assessment and MRI, combined with prompt supportive care and immunomodulatory therapy, is crucial to improving outcomes. Genetic predisposition in some cases highlights the need for awareness among clinicians regarding familial forms. As research continues into the pathogenesis and treatment of ANE, prevention of viral infections through vaccination and early medical intervention remains a key strategy in reducing the burden of this devastating condition.

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