[Acute viral meningitis].

Viral meningitis are the most frequent cause of clear cerebrospinal fluid (CSF) meningitis and are usually benign. The viral nature is suggested by clinical arguments (context, associated manifestations) and particularly the analysis of CSF, typically lymphocytic. However, problems of CSF interpretation may occur during the polymorphonuclear reaction at the beginning of such meningitis and after elevated protein or low glucose concentration. The main differential diagnosis are: partially treated bacterial meningitis, the beginning of meningococcal meningitis, listeriosis or tuberculous meningitis which need and urgent and specific treatment. The most common agents are the enteroviruses. The etiology can only be detected through careful virological investigations. These studies may be useful in outbreaks or in epidemiological studies.