To describe the etiologies, mortality, and comorbidities of patients with chronic meningitis.

Knowledge about the most common etiologies of chronic meningitis and comorbidities may aid in earlier diagnosis and more effective management. There are few recent studies in the literature regarding the common etiologies and their morbidity in populations who are not immunosuppressed or hailing from regions where tuberculosis is endemic.

This was a retrospective chart review of all patients diagnosed with chronic meningitis at Geisinger Medical Center from 2002 to 2018. Chronic meningitis was defined as the presence of CSF WBC pleocytosis greater than 5 cells/mm3 on two occasions at least 4 weeks apart.

We identified 59 infectious cases of chronic meningitis. The most common etiologies were Lyme disease (37%), cryptococcus (27%), and candida (10%), followed by herpes simplex (5%), varicella zoster (3%), and pneumococcus (3%). Of these, 0% of Lyme cases, 44% of Cryptococcus cases, and 17% of Candida cases resulted in mortality.  Comorbidities amongst infectious causes of chronic meningitis included alcohol use (25%), type 2 diabetes (22%), immunotherapy or chemotherapy (20%), chronic kidney disease (10%), and being a transplant recipient (5%). The majority of patients with the comorbidities of chemotherapy/immunotherapy (7/9) and being a transplant recipient (2/3) were those with cryptococcus.

The most common etiologies of chronic meningitis were Lyme disease, cryptococcus, and candida. Prior studies have shown 15% of lyme patients have neurologic involvement, but our data suggests Lyme is a prominent cause of chronic meningitis in endemic regions of the US but has a good prognosis. Also in contrast to existing studies, there was only 1 case of tuberculosis, reflecting declining incidence in the United States and earlier detection preventing chronic neurological disease. Our findings suggested that cases of chronic cryptococcal meningitis have a high mortality rate and were more likely to have predisposing comorbidities.