Viral infections of the CNS with special emphasis on herpes simplex infections

Abstract

Within the past decade the management of acute HSV I encephalitis has been improved dramatically by the advent of the polymerase chain reaction (PCR), a method which has become the gold standard of diagnosis of HSV I encephalitis, replacing diagnostic uncertainties and, avoiding, in particular, invasive brain biopsy. Early detection of HSV II in the neonate is mandatory; however, prevention by Caesarean section and/or prenatal therapy of the mother are for this the best option. Very recently the causative agent of Mollaret's meningitis has proved to be, at least in part, HSV I or II. So far prospective randomized therapeutic trials are awaited for the treatment of Mollaret's meningitis using intravenous acyclovir or the more modern oral forms of virostatics (famciclovir, valaci-clovir). For decades the causative agent of facial palsy (Bell's palsy) has been sought; only with the advent of PCR has this question been answered. Although one single study indicates the superiority of a combination of acyclovir plus prednisone, this finding has to be confirmed by a large scale prospective randomised double blind study. Nevertheless, if other causes for the clinical/neurological syndrome of peripheral facial palsy have been excluded, a combination therapy with acyclovir plus prednisone seems to be indicated in a patient with Bell's palsy.