Infection-triggered encephalopathy syndrome in children: a neuroimaging perspective

Infection-triggered encephalopathy syndrome is a group of acute encephalopathies that develop in temporal association with febrile illnesses. Unlike infectious or autoimmune encephalitis, direct viral invasion or antibody-mediated pathology is usually absent. Instead, excitotoxicity and cytokine storm are considered key mechanisms. The core diagnostic criteria include a preceding febrile illness, presence of neurological symptoms (encephalopathy, seizures), and, most importantly, syndrome-specific magnetic resonance imaging findings. Therefore, neuroimaging is indispensable for confirming infection-triggered encephalopathy syndromes and differentiating them from infectious encephalitis, metabolic disorders, and other acute encephalopathies. Characteristic radiological features-such as the bright tree appearance in acute encephalopathy with biphasic seizures and late reduced diffusion, bithalamic involvement in acute necrotizing encephalopathy, and reversible splenial lesions in mild encephalopathy with reversible splenial lesions-are essential for diagnostic classification and prognostication. Pediatric radiologists must be familiar with these patterns to ensure early recognition and appropriate diagnosis. This review aimed to present the epidemiology, clinical characteristics, and neuroimaging features of infection-triggered encephalopathy syndromes, emphasizing the critical role of magnetic resonance imaging findings in diagnostic criteria.