Acute and recurrent viral meningitis.

Acute viral meningitis is the most common infection of the central nervous system. Most cases occur in children and young adults and are due to enteroviruses. Although the common causes of acute viral meningitis still lack treatment with an effective antiviral agent, management of patients is changing because of better and more rapid diagnostic tests to determine the exact viral etiology. These tests reduce the cost of workups and shorten hospitalizations. Recurrent meningitis is less common, with most cases caused by herpes simplex virus 2 in young adults. Early administration of antiviral drugs such as acyclovir, valaciclovir, or famciclovir can shorten the duration of an episode of aseptic meningitis. Daily prophylactic administration of any of these medicines also reduces the frequency of future episodes.