ABSTRACT
Acute encephalopathy is classified into multiple syndromes, such as acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) and acute necrotizing encephalopathy (ANE), characterized radiologically by lesions in the cerebral subcortical white matter, splenium of the corpus callosum and bilateral thalami, respectively. We described a previously healthy 8-year-old boy who had febrile and biphasic seizures, and encephalopathy. MRI showed abnormal signal intensity in the corpus callosum on day 2 and cerebral subcortical white matter and bilateral thalamic lesions on day 8. This is the first case of acute encephalopathy in which callosal, subcortical and thalamic lesions co-existed. The clinical course of this case was typical for AESD, atypical for MERS, and different from that of ANE.