[Dramatic improvement of urinary retention and the left lower limb paresis with methylprednisolone in a case of regional encephalitis following varicella zoster infection].

We report a previously well 14-year-old male who developed left-sided hemiconvulsion, urinary retention and hemiplegia 1 months after varicella-zoster virus (VZV) infection. Brain T2-weighted MRI showed hyperintensity in medial fronto-parietal area including cyngulate gyrus, foot division of the motor cortex, para-central lobule and corpus callosum with right predominance, which corresponded to hyperperfusion area in SPECT study. MR angiography revealed no occlusion or narrowing of vessels. Cerebrospinal fluid (CSF) showed mononuclear pleocytosis. After methylprednisolone pulse tharapy under diagnosis of regional encephalitis, the patient recovered completely. Although polymerase chain reaction(PCR) could not detect VZV-DNA in CSF, antecedent VZV infection might be closely related to pathomechanism of the regional encephalitis. Dramatic response to steroid, rapid recovery on MRI and good prognosis supported that the underlying pathology was mainly vasogenic edema rather than cytotoxic edema.