Blood-CSF-barrier permeability in tuberculous meningitis and its association with clinical, MRI and inflammatory cytokines

Blood -cerebrospinal fluid-barrier (BCB) disruption in tuberculous meningitis (TBM) may be mediated by inflammatory cytokines, and may determine clinico-radiological severity and outcome. We report BCB permeability in TBM and its relationship with inflammatory cytokines (TNF-α, IL-1β and IL-6), clinical severity, MRI changes and outcome. 55 TBM patients with a median age of 26 years were included. Their clinical, cerebrospinal fluid (CSF) and MRI findings were noted. The severity of meningitis was graded into stages I to III. Cranial MRI was done, and the presence of exudates, granuloma, hydrocephalus and infarctions was noted. BCB permeability was assessed by a ratio of CSF albumin to serum albumin (Q_alb). The concentration of TNF-α, IL-1β and IL-6 in CSF were measured by cytokine bead array. The Q_alb in the patients was more than the mean + 2.5 SD of controls. In TBM, Q_alb correlated with TNF- α (r = 0.47; p = 0.01), CSF cells (r = 0.29; p = 0.02) and exudate on MRI (0.18 ± 0.009 Vs 0.13 ± 0.008; p = 0.04). There was however no association of Q_alb with demographic variables, stage, tuberculoma, infarction and hydrocephalus. At 6 months, 11(20%) died, 10(18.2%) had poor and 34(61.8%) had a good recovery. BCB permeability in TBM correlated with TNF-α, CSF pleocytosis and exudates but not with severity of meningitis and outcome.

Attainment of target rifampicin concentrations in cerebrospinal fluid during treatment of tuberculous meningitis

Objective:

There is considerable uncertainty regarding the optimal use of rifampicin for the treatment of tuberculous (TB) meningitis. A pharmacokinetic modeling and simulation study of rifampicin concentrations in cerebrospinal fluid (CSF) during TB meningitis treatment was performed in this study.

Methods:

Parameters for rifampicin pharmacokinetics in CSF were estimated using individual-level rifampicin pharmacokinetic data, and the model was externally validated in three separate patient cohorts. Monte Carlo simulations of rifampicin serum and CSF concentrations were performed. The area under the rifampicin CSF concentration-versus-time curve during 24 h (AUC_0–24) relative to the minimum inhibitory concentration (MIC) served as the pharmacodynamic target.

Results:

Across all simulated patients on the first treatment day, 85% attained the target AUC_0–24/MIC ratio of 30 under a weight-based dosing scheme approximating 10 mg/kg. At the rifampicin MIC of 0.5 mg/l, the probability of AUC_0–24/MIC target attainment was 26%. With an intensified dosing strategy corresponding to 20 mg/kg, target attainment increased to 99%, including 93% with a MIC of 0.5 mg/l.

Conclusions:

Under standard dosing guidelines, few TB meningitis patients would be expected to attain therapeutic rifampicin exposures in CSF when the MIC is ≤0.5 mg/l. Either downward adjustment of the rifampicin MIC breakpoint in the context of TB meningitis, or intensified rifampicin dosing upwards of 20 mg/kg/day, would reflect the likelihood of pharmacodynamic target attainment in CSF.

Comparison of Clinical Features and Prognostic Factors of Cryptococcal Meningitis Caused by Cryptococcus neoformans in Patients With and Without Pulmonary Nodules

Whether the clinical features of cryptococcal meningitis (CM) patients vary with the coexistence of pulmonary nodules is not clear. This study aimed to compare the clinical features of CM in patients with and without pulmonary nodules detected by chest computed tomography (CT). The medical records of CM patients hospitalized in Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology from January 1, 2010, to December 31, 2016, were retrospectively reviewed. Baseline demographics, laboratory and radiographic findings, clinical managements, and outcomes were analyzed. A total of 90 CM patients were enrolled. Forty (44.4%) patients had pulmonary nodules (PN-positive), and 50 (55.6%) patients had no pulmonary nodules (PN-negative). Compared with PN-negative patients, PN-positive patients had higher cerebrospinal fluid (CSF)/serum albumin ratios, higher rates of CSF protein > 1000 mg/L, CSF glucose < 2.5 mmol/L, worse overall treatment response, higher rates of abnormal head CT and magnetic resonance imaging manifestations, and more unfavorable clinical outcomes. Multivariate analysis showed that immunocompromise (p = 0.037) and CSF glucose < 2.5 mmol/L (p = 0.044) indicated poor outcome in PN-positive patients, while CSF glucose < 2.5 mmol/L (p = 0.025) also indicated poor outcome in PN-negative patients. Amphotericin B in the initial therapy was a protective factor for PN-negative patients (p = 0.008). Certain clinical features showed significant differences between CM patients with and without pulmonary nodules, and several independent contributing factors impacted the clinical outcomes for CM patients. Future studies should be performed to further examine these factors.

Different characteristics of cryptococcal meningitis between HIV-infected and HIV-uninfected patients in the Southwest of China

Cryptococcus is the major pathogen that causes fungal meningitis. In the People's Republic of China, especially in the Southwest area, cryptococcal meningitis (CM) in HIV-uninfected patients is more common than in HIV-infected patients. We compared clinical features and laboratory data pertaining to CM in patients with different immunological statuses. Demographic data, clinical manifestations, and laboratory data from inpatients in West China Hospital Sichuan University were collected from June 2009 to June 2014. Patients were grouped according to HIV status. Continuous variables were evaluated by Student t-test or Wilcoxon rank sum tests. Categorical variables were analyzed by χ2 test. Among 85 patients with CM were identified, 53 (62.4%) were HIV-uninfected patients. CM occurred more frequently in males in the HIV-infected group. Compared with HIV-infected patients, HIV-uninfected patients had more leukocytes in their blood and more leukocytes and protein in cerebrospinal fluid. More HIV-uninfected patients had increased cerebrospinal fluid (CSF)/serum albumin ratios, while intrathecal immunoglobulin G (IgG) synthesis was significantly increased. The rate of in-hospital mortality of HIV-infected CM patients was higher. Clinical signs are similar between HIV-uninfected and HIV-infected CM patients. Fewer leukocytes and protein was detected in the CSF and lower local synthesis of IgG in the central nervous system in HIV-infected patients, which reflects their diminished immune response. These characteristics should be noted in order to avoid misdiagnosis. Meningeal enhancement and intrathecal IgG synthesis in the HIV-uninfected group was significantly higher, that may be performance of aggressive inflammatory response and might contribute to a better outcome.