LAUSR

Acute necrotizing encephalopathy of childhood (ANEC) is a rare syndrome often observed after a viral disease in East Asian children, although it has been sporadically reported worldwide [1]. Hoshino et al. recognized the diagnostic criteria for four syndromes of acute encephalopathy (AE) including acute necrotizing encephalopathy of childhood (ANEC), acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS), and finally hemorrhagic shock and encephalopathy syndrome (HSES) [2]. More than 40% of the patients continue to be unclassified into these specific syndromes [3]. Despite prior viral infections, ANEC is not an inflammatory encephalitis. Cerebrospinal fluid (CSF) pleocytosis is usually absent in patients with ANEC. The hallmark of neuroradiological manifestations of ANEC is multifocal, symmetrical bilateral thalamic lesions [1]. We report a 22-month-old child with ANEC triggered by HHV-6. With this case report, we aim to promote ANEC as a rare, often underdiagnosed syndrome and an important differential diagnosis of AE. Case report