Management and outcome in viral meningo-encephalitis

Viruses are the most common infectious cause of meningitis and encephalitis. There are a large number of viruses which may cause meningo-encephalitis either through primary infection or through secondary immune-mediated processes. The presentation of both viral meningitis and encephalitis is described along with features which may help identify the aetiology. Viral meningitis is most commonly caused by enteroviruses notably coxsackie viruses and usually follows a self-limiting course with significantly better outcomes than encephalitis. The most common form of viral encephalitis in the developed world is Herpes simplex encephalitis. This carries a poor prognosis particularly if treatment is delayed, with mortality rates of 70% if left untreated. The importance of testing for Herpes simplex virus on two separate occasions separated by at least 72 h is highlighted, alongside the importance of prompt initiation of intravenous aciclovir and a guide as to when it is appropriate to stop aciclovir. A comprehensive description of neuroimaging findings and management of other viral aetiologies is also included.