[A patient with HHV-6 encephalopathy showing a cluster of convulsions during the eruptive stage and hyperperfusion of the cerebral hemisphere during the acute phase].

: We report a case of "HHV-6 encephalopathy with cluster of convulsions during eruptive stage" (HECCES) that showed hyperperfusion in the cerebral hemisphere by single photon emission computed tomography (SPECT) during the acute phase. There are several reports that described brain hypoperfusion of HECCES by SPECT, but all of these descriptions involved the chronic phase. In contrast, our patient showed hyperpefusion on the day of seizure cluster. Since the prognosis for HECCES is sometimes poor, it is important to clarify the etiology and to develop a treatment. The description of this case is significant for these points.