Histoplasma meningitis: diagnostic value of cerebrospinal fluid serology.

Two patients with culture-negative chronic meningitis were diagnosed as having Histoplasma capsulatum meningitis based on serial serologic studies; both had antibody in the cerebrospinal fluid as well as the serum. The patients were treated successfully with amphotericin B and had favorable clinical responses. Three control patients with active histoplasmosis and positive serum serologic tests, but without meningeal involvement, did not have antibody in the cerebrospinal fluid. Patients with chronic meningitis of obscure cause should have serial serum and cerebrospinal fluid antibody studies for H. capsulatum.