Diagnostic Approach to Chronic Meningitis.

Chronic meningitis is defined as cerebrospinal fluid pleocytosis that persists for at least 4 weeks without spontaneous resolution. The differential diagnosis of chronic meningitis is broad, encompassing 4 main categories, including infectious, autoimmune, neoplastic, and idiopathic. Up to one-third of cases have no discernible cause, making chronic meningitis a diagnostic dilemma for many clinicians. This article suggests a diagnostic approach to chronic meningitis using clinical history, key examination findings, selective advanced testing, and neuroimaging. Case presentations demonstrate application of a diagnostic algorithm, followed by a brief discussion on common infectious pathogens, autoimmune conditions, and neoplastic disease with selected treatment regimens.