Chronic meningitis: still a diagnostic challenge.

Chronic meningitis is characterized by a progressive, subacute onset of lepomeningeal disease and persisting cerebrospinal fluid (CSF) abnormalities such as elevated protein level and pleocytosis for at least one month. The array of aetiologies is very wide comprising non-infectious (carcinomatous, systemic disease, toxic) and infectious (classic and opportunistic pathogens). The evaluation encompasses a careful history, complete physical examination and laboratory tests. The specific diagnosis may remain a challenge in some cases. Algorithms for the differential diagnosis are provided for both immunocompetent and immunocompromised patients.