To describe the epidemiology and outcomes of patients with chronic meningitis (CM).

CM can be caused by infectious, autoimmune, and neoplastic conditions. The diagnosis of a precise underlying etiology of CM can be challenging and time-consuming, demanding significant resources and delaying proper treatment.

An observational retrospective analysis was performed on all cases of CM presenting between January 1, 2014 and July 31, 2018 at Geisinger Health System. Initial patient selection was based on ICD 9 and 10 codes, then, the charts of all identified patients were reviewed to ensure that each subject had a cerebrospinal fluid (CSF) pleocytosis (>5 cells) plus symptoms of CM including headache, fever, neck stiffness, and visual symptoms for at least four weeks, or two separate documentations of CSF pleocytosis separated by at least four weeks.

127 cases of CM were identified and categorized as infectious (46%), neoplastic (36%), and idiopathic (17%), and autoimmune (12%). Epidemiological data including demographics, comorbidities, and mortality was reviewed for each etiology of CM. Infectious CM was most frequency caused by Lyme disease, Cryptococcus, and Candida, for which Cryptococcal meningitis had a 44% mortality rate and Lyme meningitis resulted in no mortality. Neoplastic CM had a mortality of 78% when caused by lymphoma and 94% when caused by metastatic disease. Idiopathic cases were either classified as aseptic meningitis or undiagnosed. Idiopathic CM had a 29% mortality rate.

The epidemiology of CM in our cohort, with a breakdown of demographic and mortality data for infectious, autoimmune, neoplastic, and idiopathic CM, demonstrates the need for prompt recognition and treatment of CM. This demographic and outcome data could aid in risk-stratification of patients undergoing workup. Patients suspected of having CM due to a cause with high mortality should undergo early expedited and definitive testing.