Background: The burden that spontaneous bacterial meningitis (SBM) currently represents among HIV-1-infected patients is poorly known.
Methods: We prospectively evaluated 32 episodes of SBM in HIV-1-infected patients from the VACH (VIH-Aplicación de Control Hospitalario) Cohort and compared findings with those of 267 episodes in uninfected persons, matched by age and year of infection. A group of 13,187 HIV-1-infected patients from the VACH Cohort were used to identify predictors for acquiring SBM.
Results: Between 1997 and 2006, we found 32 episodes of SBM among HIV-1-infected patients for an annual incidence rate of 62.0 cases per 100,000 population compared with 3.2 (3.0 to 3.4) per 100,000 population for uninfected patients (P < 0.001). The last CD4 >or=200/mm count was the only predictor for developing SBM. Compared with uninfected, HIV-1-infected patients with SBM had a greater prevalence of primary extrameningeal infection, especially pneumonia (P = 0.02), bacteremia (P = 0.02), focal neurologic signs (P = 0.005), seizures (P = 0.06), a lower cerebrospinal fluid to blood glucose ratio (P = 0.02), and a lower prevalence of nuchal rigidity (P = 0.005). Streptococcus pneumoniae was the most frequent etiologic agent among HIV-1-infected patients. HIV-1-infected patients had neurologic complications more frequently (P = 0.02), a higher overall case fatality rate (P = 0.004), and greater incidence of neurologic sequelae (P = 0.001).
Conclusions: Even in the highly active antiretroviral therapy era, the risk of developing SBM is 19 times higher among HIV-1-infected patients than among uninfected ones. It tends to present in severely immunosuppressed patients not previously vaccinated and off antiretroviral therapy, with a concomitant extrameningeal infection, bacteremia, and focal neurologic signs, and is caused by S. pneumoniae. SBM in HIV-1-infected patients carries a worse prognosis than in uninfected ones both in terms of lethality and sequelae.