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Clinical manifestations and diagnosis of Cryptococcus neoformans meningoencephalitis in HIV-seronegative patients

Gary M Cox, MD
John R Perfect, MD
Section Editor
Carol A Kauffman, MD
Deputy Editor
Jennifer Mitty, MD, MPH


Cryptococcus neoformans meningoencephalitis is the most frequently encountered manifestation of cryptococcosis. The term "meningoencephalitis" is more appropriate than "meningitis" since histopathological examination has demonstrated that the brain parenchyma is almost always involved.

Cryptococcal meningoencephalitis is an important opportunistic infection in immunosuppressed patients. Issues related to patients with HIV are discussed in detail separately. (See "Epidemiology, clinical manifestations, and diagnosis of Cryptococcus neoformans meningoencephalitis in HIV-infected patients" and "Treatment of Cryptococcus neoformans meningoencephalitis in HIV-infected patients" and "Clinical management and monitoring during antifungal therapy of the HIV-infected patient with cryptococcal meningoencephalitis".)

The pathogenesis, clinical manifestations, and diagnosis of cryptococcal meningoencephalitis in HIV-seronegative patients will be reviewed here. Other issues related to C. neoformans infection are discussed separately. Cryptococcus gattii infection is also presented separately. (See "Microbiology and epidemiology of Cryptococcus neoformans infection" and "Cryptococcus neoformans: Treatment of meningoencephalitis and disseminated infection in HIV seronegative patients" and "Cryptococcus neoformans infection outside the central nervous system" and "Cryptococcus gattii infection: Microbiology, epidemiology, and pathogenesis" and "Cryptococcus gattii infection: Clinical features and diagnosis" and "Cryptococcus gattii infection: Treatment".)


C. neoformans causes infection following inhalation through the respiratory tract. The organism disseminates hematogenously and has a propensity to localize to the central nervous system (CNS). The basis for the tropism for the CNS is uncertain, but a number of hypotheses have been proposed:

The cerebrospinal fluid (CSF) is a favorable growth medium for the organism as it lacks the factors present in serum that inhibit cryptococcal growth [1]. In the serum, the organism activates the alternative complement pathway, but complement activity in the CSF is very low [2].

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Literature review current through: Nov 2017. | This topic last updated: Jun 07, 2016.
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