Histoplasma Capsulatum Infections of the Central Nervous System. A Clinical Review

Central nervous system manifestations occur in 10 to 20% of patients with disseminated histoplasmosis. Additionally, histoplasmosis may be the cause of cases of chronic meningitis in patients with no other evidence for dissemination. Histoplasmosis may also cause cerebral or spinal cord mass lesions resembling neoplasms or abscesses, and encephalitis. Diagnosis of chronic meningitis or mass lesions caused by H. capsulatum may be difficult and involves careful analysis of serologic tests for antibodies, cultures and tests for HPA in body fluids. Amphotericin B remains the treatment of choice, but relapses occur in half of cases despite total courses of at least 35 mg/kg. Accordingly, careful long-term follow-up is required to identify patients with relapsing infection. Newer antifungal agents which cross the blood brain barrier are needed. A trial of amphotericin B treatment without surgical excision can be justified in patients with cerebral or spinal cord histoplasmomas, in view of the apparent success of such treatment in a few cases. Progression of clinical abnormalities or persistence of the lesion following completion of treatment would support the need for surgical excision.