[HHV-6 encephalopathy].

Primary human herpesvirus 6(HHV-6) and HHV-7 infections cause exanthem subitum. The disease is common febrile illness in infants, indeed these viruses rarely cause encephalopathy. Recently, various types of encephalopathy have been reported in the patient with HHV-6. Therefore, appropriate treatment should be developed for each type of the encephalitis. Recent data suggest that HHV-6 reactivation is associated with encephalitis, which occurred in immunocompromised patients. Typical clinical features of HHV-6 encephalitis in transplant recipients were amnesia and MRI findings in the hippocampus. Thus, HHV-6 is considered to be etiological agent for post-transplant acute limbic encephalitis. It has been suggested that either ganciclovir or foscarnet has anti-viral effect against HHV-6 in vitro. Therefore either of the two anti-viral drugs might be useful for treatment of HHV-6 encephalitis.