Histopathology of the arachnoid granulations and brain in HIV-associated cryptococcal meningitis: correlation with cerebrospinal fluid pressure.

OBJECTIVE: To investigate the histopathology of the arachnoid granulations in patients with HIV-associated cryptococcal meningitis and correlate the findings with clinical data, in particular cerebrospinal fluid (CSF) opening pressure. DESIGN: Case series. METHODS: Postmortems were requested on patients dying during initial hospitalization with HIV-associated cryptococcal meningitis. RESULTS: Five postmortems were performed. Large numbers of cryptococcal cells were seen within the arachnoid granulations. The number of fungal cells correlated with CSF pressure. Inflammatory cell infiltrates and disruption of the normal architecture of the granulations were also observed. CONCLUSION: The study provides the first direct evidence supporting the obstruction to CSF reabsorption at the level of the arachnoid granulations as the main mechanism underlying the development of raised CSF pressure in HIV-associated cryptococcal meningitis.