[A case of acute necrotizing encephalopathy and acute encephalopathy with biphasic seizures and late reduced diffusion].

Acute necrotizing encephalopathy (ANE) has a characteristic imagimg finding of bilateral symmetrical thalamic lesions. Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is characterized by biphasic clinical course and high intensity of subcortical white matter in MRI diffusion images appearing around the late seizure. We herein report a case of an 8-month-old girl who presented with fever and status epilepticus associated with human herpes 6 infection. Although MRI first demonstrated images of ANE, typical AESD images were observed several days after the onset. We therefore concluded that this case had a combination of ANE and AESD. A proper therapeutic strategy should be established, and acute encephalopathy needs to be better clarified by identifying diagnostic markers and improving the genetical analysis.