Cerebrospinal Fluid Lactate as a Prognostic Marker of Disease Severity and Mortality in Cryptococcal Meningitis.

BACKGROUND: Cerebrospinal fluid (CSF) lactate levels can be used to differentiate between bacterial and viral meningitis. We measured CSF lactate in individuals with cryptococcal meningitis to determine its clinical significance. METHODS: We measured point-of-care CSF lactate at the bedside of 319 Ugandan adults living with human immunodeficiency virus at diagnosis of cryptococcal meningitis. We summarized demographic variables and clinical characteristics by CSF lactate tertiles. We evaluated the association of CSF lactate with clinical characteristics and survival. RESULTS: Individuals with high CSF lactate >5 mmol/L at cryptococcal diagnosis more likely presented with altered mental status (P < .0001), seizures (P = .0005), elevated intracranial opening pressure (P = .03), higher CSF white cells (P = .007), and lower CSF glucose (P = .0003) compared with those with mid-range (3.1 to 5 mmol/L) or low (≤3 mmol/L) CSF lactate levels. Two-week mortality was higher among individuals with high baseline CSF lactate >5 mmol/L (35%; 38 of 109) compared with individuals with mid-range (22%; 25 of 112) or low CSF lactate (9%; 9 of 97; P =<.0001). After multivariate adjustment, CSF lactate >5 mmol/L remained independently associated with excess mortality (adjusted hazard ratio = 3.41; 95% confidence interval, 1.55-7.51; P = .002). We found no correlation between baseline CSF lactate levels and blood capillary lactate levels. CONCLUSIONS: Baseline point-of-care CSF lactate levels are a prognostic marker of disease severity and mortality in cryptococcal meningitis. Individuals with an elevated baseline CSF lactate level are more likely to present with altered mental status, seizures, and elevated CSF opening pressure and are at a greater risk of death. Future studies are needed to determine targeted therapeutic management strategies in persons with high CSF lactate.

Cerebrospinal Fluid Bacillary Load by Xpert MTB/RIF Ultra Polymerase Chain Reaction Cycle Threshold Value Predicts 2-Week Mortality in Human Immunodeficiency Virus-Associated Tuberculous Meningitis.

BACKGROUND: The World Health Organization recommends GeneXpert MTB/RIF Ultra (Xpert Ultra), a fully automated polymerase chain reaction (PCR) assay, as the initial tuberculous meningitis (TBM) diagnostic test. The assay's PCR cycle threshold (Ct) values represent the number of PCR cycles required for probe signal to be detected (low Ct value = high bacillary load) and may approximate tuberculosis (TB) bacillary load. We measured the relationship between cerebrospinal fluid (CSF) TB bacillary load with mortality. METHODS: We prospectively enrolled 102 human immunodeficiency virus (HIV)-positive Ugandans with probable or definite TBM from April 2015 to August 2019. Xpert Ultra Ct tertiles and semi-quantitative categories were separately analyzed as predictors of 2-week mortality. We investigated associations between Ct and baseline clinical and CSF parameters. RESULTS: Subjects with Ct values in the low tertile (ie, high bacillary load) had 57% 2-week mortality-worse than the intermediate (17%) and high (25%) Ct tertiles and Xpert Ultra-negative (30%) probable TBM cases (P = .01). In contrast, the reported semi-quantitative Xpert Ultra categorization was less precise; with the medium to low category trending toward worse 2-week survival (42%) compared with very low (28%), trace (26%), and negative (30%) categories (P = .48). Ct tertile was significantly associated with baseline CSF lactate (P = .03). CONCLUSIONS: High CSF TB bacillary load, as measured by Xpert Ultra Ct tertile, is associated with an almost 2-fold higher 2-week mortality in HIV-associated TBM and is a better predictor than the reported Xpert Ultra semi-quantitative category. Xpert Ultra Ct values could identify TBM patients at increased risk of death who may benefit from enhanced supportive care.

Evaluation of the Diagnostic Performance of a Semiquantitative Cryptococcal Antigen Point-of-Care Assay among HIV-Infected Persons with Cryptococcal Meningitis.

A newly developed cryptococcal antigen (CrAg) semiquantitative (SQ) lateral flow assay (LFA) provides a semiquantitative result in a rapid one-step test instead of performing serial dilutions to determine CrAg titer. We prospectively compared the diagnostic performance of the CrAgSQ assay (IMMY) with the CrAg LFA (IMMY) on cerebrospinal fluid (CSF) samples collected from persons with HIV-associated meningitis. The CrAgSQ grades (1+ to 5+) were compared with CrAg LFA titers and quantitative CSF fungal cultures. Among 87 participants screened for HIV-associated meningitis, 60 had cryptococcal meningitis (59 CrAg positive [CrAg+] by LFA and 1 false negative due to prozone with CrAg LFA titer of 1:1,310,000 and culture positivity), and 27 had no cryptococcal meningitis by CrAg LFA or culture. The CrAgSQ on CSF had 100% (60/60) sensitivity and 100% specificity (27/27). CSF CrAg titers ranged from 1:5 to 1:42 million. CrAgSQ grades of 1+, 2+, 3+, 4+, and 5+ corresponded to median CrAg LFA titers of 1:<10, 1:60, 1:7,680, 1:81,920, and 1:1,474,000, respectively. CSF CrAgSQ grades 3+ or higher were always CSF culture positive. Mortality at 14 days for those with low CrAgSQ grade (1+ to 3+) was 5% (1/22) versus 21% (8/38) with high CrAgSQ grades (4+ to 5+) (P = 0.084). The CrAgSQ demonstrates excellent diagnostic performance, maintaining both the sensitivity and specificity of the CrAg LFA, and counters false-negative prozone effects. The CrAgSQ assay reading is more complex but does provide useful clinical information about disease burden and probability of culture positivity in a single rapid diagnostic test.

Integrated management of cryptococcal meningitis and concurrent opportunistic infections to improve outcomes in advanced HIV disease: a randomised strategy trial.

Background: Mortality associated with HIV-associated cryptococcal meningitis remains high even in the context of clinical trials (24-45% at 10 weeks); mortality at 12-months is up to 78% in resource limited settings. Co-prevalent tuberculosis (TB) is common and preventable, and likely contributes to poor patient outcomes. Innovative strategies to increase TB preventative therapy (TPT) provision and uptake within this high-risk group are needed. Protocol: The IMPROVE trial (Integrated management of cryptococcal meningitis and concurrent opportunistic infections to improve outcomes in advanced HIV disease) is a nested open label, two arm, randomised controlled strategy trial to evaluate the safety (adverse events) and feasibility (adherence and tolerability) of two ultra-short course TPT strategies, in the context of recent diagnosis and treatment for cryptococcal meningitis. We will enrol 205 adults with HIV-associated cryptococcal meningitis from three hospitals in Uganda. Participants will be randomised to either inpatient initiation (early) or outpatient initiation (standard, week 6) of 1HP (one month of isoniazid and rifapentine). Participant follow-up is to include TB screening, 1HP pill counts and tolerability reviews on alternate weeks until week-18. The trial primary endpoint is TB-disease free 1HP treatment completion at 18-weeks, secondary endpoints: 1HP treatment completion, 1HP discontinuation, grade ≥3 adverse events and serious adverse events, drug-induced liver injury, incident active TB, 18-week survival; rifapentine, fluconazole and dolutegravir concentrations will be measured with intensive sampling in a pharmacokinetic sub-study of 15 eligible participants. Discussion: The IMPROVE trial will provide preliminary safety and feasibility data to inform 1HP TPT strategies for adults with advanced HIV disease and cryptococcal meningitis. The potential impact of demonstrating that inpatient initiation of 1HP TPT is safe and feasible amongst this high-risk subpopulation with advanced HIV disease, would be to expand the range of clinical encounters in which clinicians can feasibly provide 1HP, and therefore increase the reach of TPT as a preventative intervention. ISRCTN registration: ISRCTN18437550 (05/11/2021).

Cytomegalovirus viremia as a risk factor for mortality in HIV-associated cryptococcal and tuberculous meningitis.

OBJECTIVES: CMV viremia is associated with increased mortality in persons with HIV. We previously demonstrated that CMV viremia was a risk factor for 10-week mortality in antiretroviral therapy (ART)-naïve persons with cryptococcal meningitis. We investigated whether similar observations existed over a broader cohort of patients with HIV-associated meningitis at 18 weeks. METHODS: We prospectively enrolled Ugandans with cryptococcal or TB meningitis into clinical trials in 2015-2019. We quantified CMV DNA concentrations from stored baseline plasma or serum samples from 340 participants. We compared 18-week survival between those with and without CMV viremia. RESULTS: We included 308 persons with cryptococcal meningitis and 32 with TB meningitis, of whom 121 (36%) had detectable CMV DNA. Baseline CD4+ T-cell counts (14 vs. 24 cells/µl; P = 0.07) and antiretroviral exposure (47% vs. 45%; P = 0.68) did not differ between persons with and without CMV viremia. The 18-week mortality was 50% (61/121) in those with CMV viremia versus 34% (74/219) in those without (P = 0.003). Detectable CMV viremia (adjusted hazard ratio [aHR] 1.60; 95% confidence interval [CI] 1.13-2.25; P = 0.008) and greater viral load (aHR 1.22 per log10 IU/ml increase; 95% CI 1.09-1.35; P <0.001) were positively associated with all-cause mortality through 18 weeks. CONCLUSION: CMV viremia at baseline was associated with a higher risk of death at 18 weeks among persons with HIV-associated cryptococcal or TB meningitis, and the risk increased as the CMV viral load increased. Further investigation is warranted to determine whether CMV is a modifiable risk contributing to deaths in HIV-associated meningitis or is a biomarker of immune dysfunction.

Standardized Urine-Based Tuberculosis (TB) Screening With TB-Lipoarabinomannan and Xpert MTB/RIF Ultra in Ugandan Adults With Advanced Human Immunodeficiency Virus Disease and Suspected Meningitis.

BACKGROUND: Diagnosis of extrapulmonary tuberculosis (TB) remains challenging. We sought to determine the prevalence of disseminated TB by testing urine with TB-lipoarabinomannan (TB-LAM) lateral flow assay and Xpert MTB/RIF Ultra (Ultra) in hospitalized adults. METHODS: We prospectively enrolled human immunodeficiency virus (HIV)-positive adults with suspected meningitis in Uganda during 2018-2020. Participants underwent standardized urine-based TB screening. Urine (60 mcL) was tested with TB-LAM (Alere), and remaining urine was centrifuged with the cell pellet resuspended in 2 mL of urine for Xpert Ultra testing. RESULTS: We enrolled 348 HIV-positive inpatients with median CD4 of 37 cells/mcL (interquartile range, 13-102 cells/mcL). Overall, 26% (90 of 348; 95% confidence interval [CI], 21%-30%) had evidence of disseminated TB by either urine assay. Of 243 participants with both urine TB-LAM and Ultra results, 20% (48 of 243) were TB-LAM-positive, 12% (29 of 243) were Ultra-positive, and 6% (14 of 243) were positive by both assays. In definite and probable TB meningitis, 37% (14 of 38) were TB-LAM-positive and 41% (15 of 37) were Ultra-positive. In cryptococcal meningitis, 22% (40 of 183) were TB-LAM-positive and 4.4% (6 of 135) were Ultra-positive. Mortality trended higher in those with evidence of disseminated TB by either assay (odds ratio = 1.44; 95% CI, 0.83-2.49; P = .19) and was 6-fold higher in those with definite TB meningitis who were urine Ultra-positive (odds ratio = 5.67; 95% CI, 1.13-28.5; P = .04). CONCLUSIONS: In hospitalized Ugandans with advanced HIV disease and suspected meningitis, systematic screening with urine TB-LAM and Ultra found a high prevalence of urine TB test positivity (26%). In those with TB meningitis, urine tests were positive in over one third. There was little concordance between Ultra and TB-LAM, which warrants further investigation.

Cerebral Oximetry for Detecting High-mortality Risk Patients with Cryptococcal Meningitis.

BACKGROUND: Cryptococcus is the commonest cause of adult meningitis in Africa, with 50%-70% experiencing increased intracranial pressure. Cerebral oximetry is a noninvasive near-infrared spectroscopy technology to monitor percent regional cerebral tissue oxygenation (rSO2). We assessed if cerebral oximetry predicts meningitis mortality. METHODS: We performed cerebral oximetry within 14 days of cryptococcal meningitis diagnosis on 121 Ugandans from April 2016 to September 2017. We evaluated baseline rSO2 association with mortality by multivariable logistic regression and correlation with other clinical factors. We compared groups formed by initial rSO2 <30% vs ≥30% for longitudinal change with mixed effects models. We measured change in %rSO2 before and after lumbar puncture (LP). RESULTS: The median initial rSO2 (interquartile range) was 36% (29%-42%), and it was <30% in 29% (35/121). For 30-day mortality, the unadjusted odds ratio (per 5% increase in rSO2) was 0.73 (95% confidence interval [CI], 0.58 to 0.91; P = .005). Those with initial rSO2 <30% had 3.4 (95% CI, 1.5 to 8.0) higher odds of 30-day mortality than those with initial rSO2 ≥30%. Hemoglobin correlated with initial rSO2 (rho = .54; P < .001), but rSO2 did not correlate with pulse oximetry, intracranial pressure, cerebral perfusion pressure, or quantitative cerebrospinal fluid culture, and rSO2 was unchanged pre/post-lumbar punctures. The longitudinal rSO2 measurements change was 15% (95% CI, 12% to 18%) lower in the group with initial rSO2 <30%. CONCLUSIONS: Individuals with cryptococcal meningitis and low cerebral oximetry (rSO2 < 30%) have high mortality. Cerebral oximetry may be useful as a prognostic marker of mortality. Targeted interventions to improve rSO2 should be tested in trials to try to decrease mortality in meningitis.