Chronic meningitis.

Chronic meningitis is a clinical syndrome that is characterized by persistent or progressive signs and symptoms of meningitis associated with cerebrospinal fluid pleocytosis and elevated protein concentrations, lasting for a duration of at least 4 weeks without improvement. A large number of infectious and noninfectious diseases, many of which are difficult to diagnose, can cause chronic meningitis. Careful attention to exposure and travel history, physical examination findings, and certain patterns of CSF parameters, coupled with other specific laboratory evaluations, all play important roles in trying to identify the etiologic agent causing the chronic meningitis.