Disease spectrum and prognostic factors in patients treated for tuberculous meningitis in Shaanxi province, China

Background

Tuberculous meningitis (TBM) is the most severe form of tuberculosis (TB) and can be difficult to diagnose and treat. We aimed to describe the clinical presentation, diagnosis, disease spectrum, outcome, and prognostic factors of patients treated for TBM in China.

Methods

A multicenter retrospective study was conducted from 2009 to 2019 enrolling all presumptive TBM patients referred to Xijing tertiary Hospital from 27 referral centers in and around Shaanxi province, China. Patients with clinical features suggestive of TBM (abnormal CSF parameters) were included in the study if they had adequate baseline information to be classified as "confirmed," "probable," or "possible" TBM according to international consensus TBM criteria and remained in follow-up. Patients with a confirmed alternative diagnosis or severe immune compromise were excluded. Clinical presentation, central nervous system imaging, cerebrospinal fluid (CSF) results, TBM score, and outcome-assessed using the modified Barthel disability index-were recorded and compared.

Findings

A total of 341 presumptive TBM patients met selection criteria; 63 confirmed TBM (25 culture positive, 42 Xpert-MTB/RIF positive), 66 probable TBM, 163 possible TBM, and 49 "not TBM." Death was associated with BMRC grade III (OR = 5.172; 95%CI: 2.298-11.641), TBM score ≥ 15 (OR = 3.843; 95%CI: 1.372-10.761), age > 60 years (OR = 3.566; 95%CI: 1.022-12.442), and CSF neutrophil ratio ≥ 25% (OR = 2.298; 95%CI: 1.027-5.139). Among those with confirmed TBM, nearly one-third (17/63, 27.0%) had a TBM score < 12; these patients exhibited less classic meningitis symptoms and signs and had better outcomes compared with those with a TBM score ≥ 12. In this group, signs of disseminated/miliary TB (OR = 12.427; 95%CI: 1.138-135.758) and a higher TBM score (≥15, OR = 8.437; 95%CI: 1.328-53.585) were most strongly associated with death.

Conclusion

TBM patients who are older (>60 years) have higher TBM scores or CSF neutrophil ratios, have signs of disseminated/miliary TB, and are at greatest risk of death. In general, more effort needs to be done to improve early diagnosis and treatment outcome in TBM patients.

Neurotuberculosis: A mystery seeking it's answers in pulmonary tuberculosis

Neurotuberculosis remains a mystery and presents a formidable challenge in diagnosis and management. While pulmonary tuberculosis has a well understood pathophysiology and well researched management strategies, CNS tuberculosis still has plenty of unanswered questions. The purpose of this review is to highlight the debatable issues in the current understanding of the clinical, diagnostic, and therapeutic aspects of Neurotuberculosis.

Development and validation of a new model for the early diagnosis of tuberculous meningitis in adults based on simple clinical and laboratory parameters

BACKGROUND

The differential diagnosis between tuberculous meningitis (TBM) and viral meningitis (VM) or bacterial meningitis (BM) remains challenging in clinical practice, particularly in resource-limited settings. This study aimed to establish a diagnostic model that can accurately and early distinguish TBM from both VM and BM in adults based on simple clinical and laboratory parameters.

METHODS

Patients diagnosed with TBM or non-TBM (VM or BM) between January 2012 and October 2021 were retrospectively enrolled from the General Hospital (derivation cohort) and Branch Hospital (validation cohort) of Ningxia Medical University. Demographic characteristics, clinical symptoms, concomitant diseases, and cerebrospinal fluid (CSF) parameters were collated. Univariable logistic analysis was performed in the derivation cohort to identify significant variables (P < 0.05). A multivariable logistic regression model was constructed using these variables. We verified the performance including discrimination, calibration, and applicability of the model in both derivation and validation cohorts.

RESULTS

A total of 222 patients (70 TBM and 152 non-TBM [75 BM and 77 VM]) and 100 patients (32 TBM and 68 non-TBM [31 BM and 37 VM]) were enrolled as derivation and validation cohorts, respectively. The multivariable logistic regression model showed that disturbance of consciousness for > 5 days, weight loss > 5% of the original weight within 6 months, CSF lymphocyte ratio > 50%, CSF glucose concentration < 2.2 mmol/L, and secondary cerebral infarction were independently correlated with the diagnosis of TBM (P < 0.05). The nomogram model showed excellent discrimination (area under the curve 0.959 vs. 0.962) and great calibration (P-value in the Hosmer-Lemeshow test 0.128 vs. 0.863) in both derivation and validation cohorts. Clinical decision curve analysis showed that the model had good applicability in clinical practice and may benefit the entire population.

CONCLUSIONS

This multivariable diagnostic model may help clinicians in the early discrimination of TBM from VM and BM in adults based on simple clinical and laboratory parameters.

Incidence and Risk Factors of Cranial Nerve Palsy in Patients with Tuberculous Meningitis: A Retrospective Evaluation

Objective

Tuberculous meningitis (TBM) is a common form of central nervous system (CNS) tuberculosis (TB). Cranial nerve palsy is a serious complication of TBM. Literature regarding this subject is still limited in China. This study evaluated the incidence of cranial nerve palsy in patients with TBM in South China, its association with the clinical forms of TB, and other patient characteristics.

Methods

A retrospective chart review of patients with a diagnosis of TBM between January 2004 and December 2019 was conducted, and the demographic characteristics, clinical characteristics, and laboratory results of 114 patients were collected and followed up for 3 months. A multivariate logistic regression analysis model was used to explore the risk factors of cranial nerve palsy in patients with TBM.

Results

A total of 114 patients were enrolled in this study. Cranial nerve palsy was observed in approximately 38 (33.3%) of TBM patients. Among them, 13 (28.3%) had optic nerve palsy, 24 (52.2%) had oculomotor nerve palsy, 5 (10.9%) had abducens nerve palsy, 2 (4.3%) had auditory nerve palsy, 1 (2.2%) had glossopharyngeal nerve palsy, and 1 (2.2%) had vagus nerve palsy. Using logistic regression analysis, focal neurological deficit, extracranial TB and cerebrospinal fluid (CSF) total white cell count (WCC) were shown to be risk factors for cranial nerve palsy.

Conclusion

The prevalence rate of cranial nerve palsy was 33.3% in patients with TBM. Focal neurological deficits, extracranial TB and CSF total WCC are important predictors of cranial nerve palsy in patients with TBM.

Exploration of the Risk Factors of Anemia in Patients with Tuberculous Meningitis in South China

OBJECTIVE

Central nervous system (CNS) infection has a high incidence and mortality worldwide. Tuberculous meningitis (TBM) accounts for approximately 5-6% of all extrapulmonary tuberculosis (TB), and is considered an extremely lethal form of CNS TB, which has become an important threat to human health. Anemia is a common symptom of TB, and its prevalence is generally higher in patients with TBM than in other meningitis patients and healthy individuals. Anemia can increase a person's susceptibility to common infectious diseases, including TB, by compromising the immune system. Information regarding anemia during the hospitalization of TBM is still scarce in China. This study aimed to describe in detail the prevalence of anemia in patients with TBM in Southern China and its association with the clinical forms of TB, as well as other characteristics of these patients.

METHODS

We conducted a retrospective analysis of patients diagnosed with TBM at two tertiary hospitals in southern China. The demographic characteristics, clinical characteristics, and laboratory results of 114 patients with TBM were collected. Multivariate logistic regression analysis was performed to explore the risk factors for anemia in patients with TBM.

RESULTS

Electronic medical record data of adult patients diagnosed with TBM from January 2004 to December 2019 were reviewed. Among 134 patients with TBM, 20 were excluded and 114 were analyzed, of whom 33 had anemic, the prevalence rate of anemia was 28.9%. Among patients with anemia, 51.5% had hypochromic microcytic anemia, 33.3% had normochromic normocytic anemia, and 15.2% had macrocytic anemia. Fever duration, TBM grade III and ESR were found to be independent predictors of anemia.

CONCLUSION

Anemia was highly prevalent in patients with TBM, mainly hypochromic microcytic anemia. Besides, Fever duration, TBM grade III and ESR are predictors of anemia in patients with TBM.

Scrub Typhus Meningoencephalitis: An Overlooked Entity

Scrub typhus is common in rural parts of Nepal, but its diagnosis remains difficult due to a lack of clinical suspicion and poor diagnostic resources. The absence of common clinical features further complicates this problem. Acute kidney injury (AKI), myocarditis, rhabdomyolysis, hepatitis, acute respiratory distress syndrome, and meningoencephalitis are complications of the disease associated with high mortality. Overlap findings can be noted in scrub typhus meningoencephalitis and other tropical infections. This makes diagnosing the disease more challenging, especially in areas where the burden of infectious diseases is high. We report three cases of scrub typhus meningoencephalitis. All three patients were treated successfully with doxycycline. Because patients with scrub typhus have an excellent response to treatment, delay in treatment and rate of complications can be prevented with high clinical suspicion of the condition.

10-Year Retrospective Review of the Etiologies for Meningitis With Elevated Adenosine Deaminase in Cerebrospinal Fluid: Etiologies Other Than TB

Purpose

An elevated adenosine deaminase (ADA) level in the cerebrospinal fluid (CSF) is considered a reliable marker of tuberculous meningitis (TBM). However, CSF-ADA levels can also be elevated in other diseases. We aimed to find the most common diagnosis of patients with elevated CSF-ADA levels for the last 10 years.

Methods

We retrospectively investigated the diagnoses of all patients with elevated CSF-ADA (ADA ≥ 10 IU/L) levels between 2010 and 2019 at the Samsung Medical Center. Definite TBM was defined based on microbiological evidence. Clinical TBM was defined based on the brain imaging and response to the standard TB treatment. We compared the laboratory characteristics of the three most common diagnoses.

Results

CSF-ADA levels were elevated in 137 (5.6%) of 2,600 patients. The most common diagnoses included hematologic malignancy (HM; n = 36, 26.2%), TBM (n = 26, 19.0%), and viral meningitis (VM; n = 25, 18.2%). CSF-ADA levels did not differ significantly between TBM [median (interquartile range (IQR)), 20.2 IU/L (13.8–29.3)] and HM [16.5 (12.8–24.0)]. However, CSF-ADA levels were lower in VM [14.0 (11.0–16.1)] than in TBM (p = 0.027). Lymphocyte-dominant pleocytosis was more common in VM [77.0% (70.8–81.5)] than in TBM [16.0 (3.0–51.0), p = 0.015] or HM [36.0 (10.0–72.0); p = 0.032]. Interestingly, the CSF characteristics of clinical TBM were similar to those of VM but not definite TBM.

Conclusion

The most common diagnoses with elevated CSF-ADA levels were HM, followed by TBM and VM. Clinicians should carefully consider the differential diagnoses in patients with elevated CSF-ADA levels, especially those in the early stage of meningitis without microbiological evidence for TBM.

Improving Technology to Diagnose Tuberculous Meningitis: Are We There Yet?

Diagnosis of tuberculous meningitis (TBM) remains challenging due to a paucity of high-performance diagnostics. Even those that have reasonable sensitivity are not adequate to 'rule out' TBM. Therefore, a combination of clinical factors alongside microbiological, molecular, and radiological investigations are utilized, depending on availability. A low threshold for starting empiric therapy in the appropriate clinical scenario remains crucial for good outcomes in many cases. Herein, we review the current TBM diagnostics landscape with a focus on limitations frequently encountered, such as diagnostic test performance, cost, laboratory infrastructure, and clinical expertise. Though molecular technologies, particularly GeneXpert MTB/Rif Ultra, have been a step forward, diagnosis of TBM remains difficult. We also provide an overview of promising technologies, such as cerebrospinal fluid (CSF) lactate, a new lipoarabinomannan test (FujiLAM), metagenomic next-generation sequencing, and transcriptomics that may further improve our TBM diagnostic capacity and lead to better outcomes.

Diagnostic Accuracy of Interferon-Gamma Release Assays for Tuberculous Meningitis: A Systematic Review and Meta-Analysis

Background

In this study, we evaluated and compared the accuracy of blood and cerebrospinal fluid (CSF) interferon release tests [interferon-gamma release assays (IGRAs)] in the diagnosis of tuberculous meningitis (TBM) by a meta-analysis of the relevant literature.

Methods

We searched for studies published before 2021 in Medline, Embase, the Cochrane database, and Chinese databases. All studies used the QuantiFERON-TB Gold In-Tube and/or T-SPOT.TB method. Blood and/or CSF tests that met the guidelines for the quality assessment of studies with diagnostic accuracy were included. We used the revised diagnostic accuracy study quality assessment to assess the quality of the included studies. Begg’s funnel plots were used to assess publication bias in the meta-analysis of the diagnostic studies, and statistical analyses were performed by using Stata (Version 12) software.

Results

A total of 12 blood and/or CSF IGRA studies were included in this meta-analysis, with 376 patients and 493 controls. The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the summary receiver operating characteristic curve (SROC) of the blood IGRAs in the pooled data from 12 studies were 74% (95% CI: 0.65-0.82), 78% (95% CI: 0.68-0.86), 3.38 (95% CI 2.26-5.06), 0.33 (95% CI: 0.23-0.46), 10.25 (95% CI: 5.46-19.25), and 0.83 (95% CI: 0.79-0.86), respectively. For CSF IGRAs, these values for the pooled data from the 10 studies included were 79% (95% CI: 0.71-0.85), 95% (95% CI: 0.88-0.98), 16.30 (95% CI 6.5-40.83), 0.22 (95% CI: 0.16-0.31), 57.93 (95% CI: 22.56-148.78), and 0.91 (95% CI: 0.88-0.93), respectively.

Conclusion

CSF IGRAs exhibited a better diagnostic accuracy than blood IGRAs in diagnosing TBM.

The challenge of differentiating tuberculous meningitis from bacterial meningitis

Tuberculous meningitis (TBM) is a rare but important differential diagnosis in patients with impaired consciousness. Here, we describe a case of TBM in an 83-year-old Japanese woman who presented to a local hospital with fever and decreased consciousness of 20 days' duration (from day -40). She was started on treatment for bacterial meningitis due to an increased cerebrospinal fluid cell count, but her condition did not improve. She was transferred to a second hospital on suspicion for cholecystitis, then to a university hospital when consciousness did not improve and finally to us at a fourth hospital. On day -2, diffuse granulation was seen in both lung fields on chest computed tomography, sputum Mycobacterium test was positive and adenosine deaminase was elevated in spinal fluid. We diagnosed TBM secondary to miliary tuberculosis and started treatment with steroids and anti-tuberculous drugs (day 0). However, her level of consciousness did not improve and she died at a sanatorium on day 178. Delayed treatment of TBM has a prognostic impact and should be kept in mind as a differential diagnosis for impaired consciousness.

Study of cerebrospinal fluid levels of lactate, lactate dehydrogenase and adenosine deaminase in the diagnosis and outcome of acute meningitis

BACKGROUND

Meningitis is a serious clinical health issue in most developing countries. Late diagnosis and treatment result in significant morbidity and mortality. This research aims to study the utility of CSF lactate, lactate dehydrogenase (LDH), and adenosine deaminase (ADA) as diagnostic markers in acute meningitis, and to differentiate among varied aetiologies of acute meningitis and their outcomes.

METHOD

A cross-sectional observational case-control study was conducted in 30 patients of suspected meningitis of varied aetiologies and 30 controls without any pre-existing neurological disorder and who underwent lumbar puncture during spinal anesthesia. A fresh CSF sample was collected in a heparinized vial following an aseptic lumbar puncture. The levels of lactate, LDH and ADA were estimated and recorded.

RESULT

CSF lactate was significantly elevated in bacterial meningitis (BM) and cryptococcal meningitis, with 100% sensitivity when compared to controls. Elevated LDH was found only in BM, hence elevated LDH levels may strongly signify bacterial etiology. Significantly elevated ADA levels were noted in tuberculous meningitis. Significantly elevated levels of lactate and ADA were suggestive of slower clinical recovery and a prolonged hospital stay (p < 0.001).

CONCLUSION

Estimation of CSF lactate, LDH, and ADA levels is a rapid, inexpensive and simple procedure and can play a major role in the early differentiation of bacterial, viral, tuberculous, and fungal meningitis. This would facilitate the initiation of appropriate treatment as early as possible, thereby decreasing mortality and complications.

Evaluation of CSF pyrosequencing to diagnose tuberculous meningitis: A retrospective diagnostic accuracy study

BACKGROUND

We evaluated the performance of pyrosequencing, a genotypic test which detects TB and XDR-defining mutations within 6 h, directly on CSF samples for diagnosing TB meningitis(TBM).

METHODS

This retrospective, diagnostic accuracy study was conducted in Hinduja hospital, Mumbai from May-2017 to May-2019. 107 consecutive patients with physician-suspected TBM for whom CSF pyrosequencing was requested were screened. Seven patients with incomplete data were excluded. Diagnostic accuracy of pyrosequencing was compared with Xpert MTB/Rif and TBMGIT (TB Mycobacterial Growth Indicator Tube) culture against the uniform case definition of definite or probable TBM. Susceptibility concordance rate of pyrosequencing with TBMGIT culture and Xpert MTB/Rif was determined.

RESULTS

The study cohort comprised of 100 patients[Definite(n = 33), Probable(n = 20), Possible(n = 30), Alternative(n = 17)] with 50% males[median age(years):38(Range:2-87)]. Against the uniform case definition, pyrosequencing had 98·11%(95%CI 89·93-99·95; n = 52/53) sensitivity and 97·79%(86·31-99·67; n = 44/45) negative predictive value(NPV) compared with 43.39%(29·83-57·72; n = 23/53,p < 0.0001) sensitivity and 61.04%(55·31-66·48; n = 47/77) NPV for Xpert MTB/Rif and 45·28%(31·56-59·55; n = 24/53,p < 0.0001) sensitivity and 61·84%(55·92-67·43; n = 47/76) NPV for TBMGIT culture. Susceptibility concordance rate of pyrosequencing with phenotypic Drug Susceptibility Testing was 91.3%(n = 21/23) and with Xpert MTB/Rif was 95·45%(n = 21/22).

CONCLUSION

CSF pyrosequencing is significantly more sensitive than Xpert MTB/Rif and TBMGIT culture for diagnosing TBM. Additionally, it facilitates early therapeutic decision-making by providing information on XDR-defining mutations.

Advances in tuberculous meningitis diagnosis

Introduction: Tuberculous meningitis (TBM) is the most devastating form of central nervous system tuberculosis (TB) and causes high mortality worldwide. Nonspecific clinical manifestations and limited sensitivity of existing laboratory methods make the diagnosis elusive due to the paucibacillary nature of the infection. Areas Covered: We reviewed current literature on the adequacy and limitations of globally existing laboratory methods for diagnosing TBM. Expert opinion: TBM is deadliest among all TB forms, as the outcome may lead to death in 50% of cases, and survivors undergo irreversible neurological disorders. Therefore, early diagnosis and prompt treatment are cornerstones of effective disease management. Conventional microscopy and culture are widely used modalities but remain inadequate in most TBM cases. Although expanded use of rapid molecular tests such as real-time PCR and Xpert Ultra, even in resource-limited settings, hold promising results for TB diagnosis but need optimization for early detection of TBM. Moreover, CSF IGRA is also used but unable to differentiate between active and latent TB. Overall no single test for diagnosing TBM has adequate accuracy so, there is an urgent need to devise a point-of-care test.

Methods for rapid diagnosis of meningitis etiology in adults

Infectious meningitis can be caused by viral, bacterial or fungal pathogens. Despite widely available treatments, many types of infectious meningitis are still associated with significant morbidity and mortality. Delay in diagnosis contributes to poor outcomes. Cerebrospinal fluid cultures have been used traditionally but are time intensive and sensitivity is decreased by empiric treatment prior to culture. More rapid techniques such as the cryptococcal lateral flow assay (IMMY), GeneXpert MTB/Rif Ultra (Cepheid) and FilmArray multiplex-PCR (Biofire) are three examples that have drastically changed meningitis diagnostics. This review will discuss a holistic approach to diagnosing bacterial, mycobacterial, viral and fungal meningitis.

Advances in the Diagnosis and Management of Tubercular Meningitis in Children

Tubercular meningitis (TBM) continues to be a common cause of neuromorbidity in children. There is no single diagnostic method that can rapidly detect Mycobacterium tuberculosis (M.tb) in TBM patients with high sensitivity and specificity. Newer diagnostic modalities like Xpert/RIF assay and Loop mediated isothermal amplification assay (LAMP) have gained an essential stand in molecular diagnostics due to their high specificity, modest sensitivity in cerebrospinal fluid (CSF) and quick availability of results. Intensified drug regimens using high dose rifampicin, fluoroquinolone and aspirin appear to be useful adjunct therapy but more pediatric clinical trials on large scale are needed to determine their appropriate place in pediatric TBM. The emergence of multi and extreme drug resistant M.tb strains further challenges the standard therapy. In this review authors summarize challenges of the currently used diagnostic methods and treatment for TBM and discuss the recent advances.

Review of literature on disseminated tuberculosis with emphasis on the focused diagnostic workup

Disseminated tuberculosis (TB) is a life-threatening disease resulting from the hematogenous spread of Mycobacterium tuberculosis. The diagnosis is challenging owing to its subtle nonspecific clinical presentation, which usually reflects the underlying organ involved. Besides, tools for confirmatory laboratory diagnosis are limited. Therefore, a high index of suspicion is required for early diagnosis. Miliary pattern on chest radiography is a common finding that has an important role in the early detection of the disease. Nevertheless, approximately 10%-15% of patients have normal chest radiography. Although abnormalities are present, basic hematologic and biochemical tests as well as tuberculin skin test are nonspecific for the diagnosis. Imaging studies are helpful adjunct tools for disseminated TB as they can help determine the involved sites and guide technicians to obtain appropriate specimens for diagnosis. Clinical confirmation of the diagnosis of disseminated TB is usually based on bacteriological or histological evidence. Response to first-line anti-TB drugs is good as evidenced by many reports. This review aims to present a current update on disseminated TB with emphasis on the diagnostic workup of this devastating condition.

Potential of Host Serum Protein Biomarkers in the Diagnosis of Tuberculous Meningitis in Children

Background: Tuberculous meningitis (TBM) is the most severe form of tuberculosis and results in high morbidity and mortality in children. Diagnostic delay contributes to the poor outcome. There is an urgent need for new tools for the rapid diagnosis of TBM, especially in children. Methods: We collected serum samples from children in whom TBM was suspected at a tertiary hospital in Cape Town, South Africa. Children were subsequently classified as having TBM or no TBM using a published uniform research case-definition. Using a multiplex cytokine array platform, we investigated the concentrations of serum biomarkers comprising biomarkers that were previously found to be of value in the diagnosis of adult pulmonary TB (CRP, SAA, CFH, IFN-γ, IP-10, Apo-AI, and transthyretin) plus other potentially useful host biomarkers as diagnostic candidates for TBM. Findings: Out of 47 children included in the study, 23 (48.9%) had a final diagnosis of TBM and six were HIV infected. A modified version of the adult 7-marker biosignature in which transthyretin was replaced by NCAM1, diagnosed TBM in children with AUC of 0.80 (95% CI, 0.67-0.92), sensitivity of 73.9% (95% CI, 51.6-89.8%) and specificity of 66.7% (95% CI, 44.7-84.4%), with the other six proteins in the signature (CRP, IFN-γ, IP-10, CFH, Apo-A1, and SAA) only achieving and AUC of 0.75 (95% CI, 0.61-0.90) when used in combination. A new childhood TBM specific 3-marker biosignature (adipsin, Aβ42, and IL-10) showed potential in the diagnosis of TBM, with AUC of 0.84 (95% CI, 0.73-0.96), sensitivity of 82.6% (95 CI, 61.2-95.0%) and specificity of 75.0% (95% CI, 53.3-90.2%) after leave-one-out cross validation. Conclusion: A previously described adult 7-marker serum protein biosignature showed potential in the diagnosis of TBM in children. However, a smaller childhood TBM-specific 3-marker signature demonstrated improved performance characteristics. Our data indicates that blood-based biomarkers may be useful in the diagnosis of childhood TBM and requires further validation in larger cohort studies.

Delta-like 1 protein, vitamin D binding protein and fetuin for detection of Mycobacterium tuberculosis meningitis

AIM

Tuberculosis meningitis (TBM) diagnosis is difficult, new biomarkers are needed. We evaluated the diagnostic utility of delta-like 1 protein (DLL1), vitamin D binding protein (VDBP) and fetuin.

METHODS

Biomarker concentrations were measured by ELISA in cryopreserved cerebrospinal fluid from 139 HIV-infected Ugandans with suspected meningitis. TBM was diagnosed by GeneXpert MTB/Rif or culture. Cohort diagnoses included TBM (n = 22), cryptococcal (n = 71), or aseptic meningitis (n = 16) and no meningitis (n = 30).

RESULTS

DLL1 (cut-off value 1150 pg/ml) provided 32% sensitivity and 98% specificity. Adding fetuin, cryptococcal antigen and IFN-γ resulted in sensitivities of 36, 63 and 76% with specificities of 98, 90 and 92%, respectively. VDBP (cut-off value 2.0 μg/ml) provided 81% sensitivity and 68% specificity while fetuin (cut-off value 2 μg/ml) provided a sensitivity of 86% and specificity of 68%.

CONCLUSION

CSF DLL1, VDBP and fetuin exhibited fair diagnostic performance for TBM diagnosis.

Rapid Accurate Identification of Tuberculous Meningitis Among South African Children Using a Novel Clinical Decision Tool

BACKGROUND

Early diagnosis of tuberculous meningitis (TBM) is crucial to achieve optimum outcomes. There is no effective rapid diagnostic test for use in children. We aimed to develop a clinical decision tool to facilitate the early diagnosis of childhood TBM.

METHODS

Retrospective case-control study was performed across 7 hospitals in KwaZulu-Natal, South Africa (2010-2014). We identified the variables most predictive of microbiologically confirmed TBM in children (3 months to 15 years) by univariate analysis. These variables were modelled into a clinical decision tool and performance tested on an independent sample group.

RESULTS

Of 865 children with suspected TBM, 3% (25) were identified with microbiologically confirmed TBM. Clinical information was retrieved for 22 microbiologically confirmed cases of TBM and compared with 66 controls matched for age, ethnicity, sex and geographical origin. The 9 most predictive variables among the confirmed cases were used to develop a clinical decision tool (CHILD TB LP): altered Consciousness; caregiver HIV infected; Illness length >7 days; Lethargy; focal neurologic Deficit; failure to Thrive; Blood/serum sodium <132 mmol/L; CSF >10 Lymphocytes ×10/L; CSF Protein >0.65 g/L. This tool successfully classified an independent sample of 7 cases and 21 controls with a sensitivity of 100% and specificity of 90%.

CONCLUSIONS

The CHILD TB LP decision tool accurately classified microbiologically confirmed TBM. We propose that CHILD TB LP is prospectively evaluated as a novel rapid diagnostic tool for use in the initial evaluation of children with suspected neurologic infection presenting to hospitals in similar settings.

Microbiological diagnosis of adult tuberculous meningitis in a ten-year cohort in Indonesia

We evaluated microbiological diagnosis of tuberculous (TB) meningitis in a referral hospital in Indonesia. Over a ten-year period, we examined cerebrospinal fluid (CSF) samples of 1180 adult meningitis suspects. Sensitivity of different methods was compared, and results were stratified for HIV status, disease severity, and CSF volume. TB meningitis was bacteriologically confirmed in 501 patients. Using clinical diagnosis as reference standard (n = 713), sensitivity of different methods was 12.2% (86/703) for microscopy, 42% (73/174) for Xpert MTB/RIF, 46.0% (163/354) for solid culture, 48.8% (332/680) for liquid culture, and 64.0% (212/331) for in-house PCR. Head to head comparisons in 654 patients showed a higher yield of in-house PCR (32.3%) compared to culture (15.6%, P < 0.01). Microscopic observation of drug susceptibility (MODS) culture more rapidly became positive compared to other culture methods. Yield of culture was lower in HIV-infected (39/105) than in HIV-negative patients (N = 316/585; P < 0.01). Molecular and culture methods gave higher yields in patients with more severe disease (P < 0.01). CSF volume of ≥6 ml increased the yield of culture (42.8% versus 12.1% for CSF <6 ml, P < 0.01) and ZN-microscopy (18.3% versus 1.9% for CSF <6 ml, P < 0.01). CSF centrifugation had no clear effect on sensitivity of Xpert MTB/RIF. ZN-microscopy lacks sensitivity for diagnosis of TB meningitis. For molecular assays, in-house IS6110-PCR is more sensitive than Xpert MTB/RIF. MODS culture has a clear advantage in terms of speed. Large CSF volumes are necessary for all tests. The effect of CSF processing for Xpert MTB/RIF needs further study.

Other central nervous system infections: cytomegalovirus, Mycobacterium tuberculosis, and Treponema pallidum

Human immunodeficiency virus (HIV)-infected individuals are particularly susceptible to several central nervous system infections: human cytomegalovirus, which may cause encephalitis, ventriculitis, polyradiculitis, or polyradiculomyelitis; Mycobacterium tuberculosis, which can cause meningitis or space-occupying lesions; and Treponema pallidum subspecies pallidum (T. pallidum), which affects the meninges, cerebrospinal fluid, cranial nerves, and vasculature in early neurosyphilis, and additionally the brain and spinal cord parenchyma in late neurosyphilis. Central nervous system cytomegalovirus infection is seen in HIV-infected individuals with very advanced immunosuppression. Its prognosis is poor and optimal therapy has not been determined. Tuberculous meningitis has a high mortality in those also infected with HIV, especially in the developing world, and better therapies are urgently needed. As the rates of syphilis increase in the developed world, neurosyphilis and in particular ocular syphilis are increasingly reported. The likelihood of all three of these central nervous system infections is decreased in individuals who receive potent antiretroviral therapy.

Tuberculous tales: an East London experience

Tuberculous meningitis presents a diagnostic and therapeutic challenge, and considering its long history and increasing global incidence, the evidence base for its treatment is relatively scanty. Many UK neurologists will have little first-hand experience of this deadly condition, and if faced with a patient with possible tuberculous meningitis will find decision making less than straightforward. In parts of East London (UK) the rates of tuberculosis and tuberculous meningitis are among the highest in Western Europe, and so the neurologists and respiratory physicians at the Royal London Hospital have encountered many such patients over the years. We have found experience to be a valuable teacher and so would like to share five cases that illustrate the complexities of diagnosis and management of the disease, and complications of its treatment.

Tuberculosis in Infants and Children

One million children develop tuberculosis disease each year, and 210,000 die from complications of tuberculosis. Childhood tuberculosis is very different from adult tuberculosis in epidemiology, clinical and radiographic presentation, and treatment. This review highlights the many unique features of childhood tuberculosis, with special emphasis on very young children and adolescents, who are most likely to develop disease after infection has occurred.

Diagnostic test accuracy of adenosine deaminase for tuberculous meningitis: A systematic review and meta-analysis

INTRODUCTION

The measurement of adenosine deaminase (ADA) level in cerebrospinal fluid (CSF) has generated as a suitable test for tuberculous meningitis (TBM) diagnosis. The main objective in the present meta-analysis focused on analyzing the ADA test accuracy in order to diagnose TBM.

METHODS

We searched several databases including Medline, Embase and Cochrane databases to identify studies addressing the diagnosis of TBM. The quality of included reports were assessed by RevMan5 software (via QUADS2 checklist). Accuracy measures of ADA test (sensitivity, specificity and others) pooled with random effects models. In addition, the data was elicited by using midas and metan packages in stata (version 12).

RESULT

Twenty studies were eligible for inclusion within the meta-analysis. The pooled sensitivity and specificity for TBM diagnosis hallmarks were 89% (95% CI: 0.84-0.92) and 91% (95% CI: 0.87-0.93), respectively. The positive likelihood ratio was 9.4 (95% CI: 7-12.8), negative likelihood ratio was 0.12 (95% CI: 0.09-0.17), and diagnostic odds ratio was 77 (95% CI: 45-132). Indeed, the area under the summary receiver operating characteristic (SROC) was 0.96.

CONCLUSION

It was magnificently attained that ADA test had a relatively high accuracy for TBM diagnosis.

Clinical Features and Outcome in Adult Cases of Tuberculous Meningitis in Tertiary Care Hospital in Antananarivo, Madagascar

Purpose. We aimed to describe and to assess prognosis factors in tuberculous meningitis in adult patients. Methods. We performed a retrospective study of case records of adult patients. Patients classified as definite, probable, or possible tuberculous meningitis according to standardized definition criteria were included and assessed in the study. Results. Seventy-five patients were included in the study. Tuberculous meningitis was classified as definite in 8 (10.7%), probable in 44 (58.7%), and possible in 23 patients (30.6%). HIV was found in 3% of patients. Patients were in advanced stages at admission in 82.7%. Median duration of symptoms prior to admission was 3 weeks (IQR: 2–5). Median time to diagnosis following admission was 5 days (IQR: 3–8). Median CSF WCC was 75 per mm³ with lymphocytic predominance in 38 cases (52.8%). Median CSF glucose level was 1.48 mmol/L and median CSF protein level was 1 g/L. Mortality rate was 28%. Age ≥ 35 years (aOR: 4.06; 95% CI: 1.16–14.26) and coma (aOR: 12.98; 95% CI: 1.13–149.16) predicted inpatient mortality. Conclusion. Most of the patients experienced more than 3 weeks of diagnostic delay prior to admission. Mortality was high and occurred early after admission. Age and coma were identified as independent prognosis factors.

Mir-29a expressions in peripheral blood mononuclear cell and cerebrospinal fluid: Diagnostic value in patients with pediatric tuberculous meningitis

To evaluate the value of miR-29a expression in peripheral blood mononuclear cell (PBMC) and cerebrospinal fluid (CSF) in the diagnosis of pediatric tuberculous meningitis (TBM). Our study enrolled 112 children with TBM and 130 healthy children, from which PBMC and CSF were collected. The quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure the expression of miR-29a in PBMC and CSF, and then analyze the diagnostic value. Compared with control group, the miR-29a expressions in PBMC and CSF were increased in TBM children (both P<0.05), and the expressions were associated with following factors: intracranial hypertension, conscious disturbance, focal cerebral symptoms, meningeal irritation, hydrocrania, abnormal electroencephalogram and extra-cerebral tuberculous (all P<0.05). The receiver operating characteristic (ROC) curve showed that the sensitivity, specificity and area under the curve (AUC) of miR-29a in PBMC was 67.20%, 88.50% and 0.852, respectively, and that in CSF was 81.10%, 90.00% and 0.890, respectively, and that in combination of PBMC and CSF was 84.40%, 95.38% and 0.934, respectively. miR-29a expression in PBMC and CSF may provide a reference for the diagnosis of pediatric TBM.

Tuberculous meningitis is a major cause of mortality and morbidity in adults with central nervous system infections in Kota Kinabalu, Sabah, Malaysia: an observational study

BACKGROUND

Central nervous system (CNS) infections are a significant contributor to morbidity and mortality globally. However, most published studies have been conducted in developed countries where the epidemiology and aetiology differ significantly from less developed areas. Additionally, there may be regional differences due to variation in the socio-economic levels, public health services and vaccination policies. Currently, no prospective studies have been conducted in Sabah, East Malaysia to define the epidemiology and aetiology of CNS infections. A better understanding of these is essential for the development of local guidelines for diagnosis and management.

METHODS

We conducted a prospective observational cohort study in patients aged 12 years and older with suspected central nervous system infections at Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia between February 2012 and March 2013. Cerebrospinal fluid was sent for microscopy, biochemistry, bacterial and mycobacterial cultures, Mycobacterium tuberculosis polymerase chain reaction (PCR), and multiplex and MassCode PCR for various viral and bacterial pathogens.

RESULTS

A total of 84 patients with clinically suspected meningitis and encephalitis were enrolled. An aetiological agent was confirmed in 37/84 (44 %) of the patients. The most common diagnoses were tuberculous meningitis (TBM) (41/84, 48.8 %) and cryptococcal meningoencephalitis (14/84, 16.6 %). Mycobacterium tuberculosis was confirmed in 13/41 (31.7 %) clinically diagnosed TBM patients by cerebrospinal fluid PCR or culture. The acute case fatality rate during hospital admission was 16/84 (19 %) in all patients, 4/43 (9 %) in non-TBM, and 12/41 (29 %) in TBM patients respectively (p = 0.02).

CONCLUSION

TBM is the most common cause of CNS infection in patients aged 12 years or older in Kota Kinabalu, Sabah, Malaysia and is associated with high mortality and morbidity. Further studies are required to improve the management and outcome of TBM.

Linezolid is Associated with Improved Early Outcomes of Childhood Tuberculous Meningitis

BACKGROUND

Linezolid serves as an important component for the treatment of drug-resistant tuberculosis although there is little published data about linezolid use in children, especially in childhood tuberculous meningitis (TBM).

METHODS

In this study, we retrospectively reviewed records of childhood TBM patients who started treatment between January 2012 and August 2014. A total of 86 childhood TBM patients younger than 15 years old were enrolled. Out of 86 children, 36 (41.9%) received the regimen containing linezolid.

RESULTS

Thirty-two (88.9%) of 36 linezolid-treated cases had favorable outcomes, and 35 (70.0%) cases were successfully treated in the control group. The frequency of favorable outcome of linezolid group was significantly higher than that of control group (P = 0.037). In addition, compared with cases with fever clearance time of <1 week, the control group had more cases with fever clearance time of 1-4 weeks (P = 0.010) and >4 weeks (P = 0.000) than linezolid group. Furthermore, there was no significant difference in the frequency of adverse events between the two regimens (P = 0.896). In addition, the patients with adverse events were more likely to have treatment failure, the P value of which was 0.008.

CONCLUSIONS

Our data demonstrate that linezolid improves early outcome of childhood TBM. The low frequency of linezolid-associated adverse effects highlights the promising prospects of its use for treatment of childhood TBM.

GeneXpert MTB/Rif to Diagnose Tuberculous Meningitis: Perhaps the First Test but not the Last

Tuberculous meningitis (TBM) is the most severe form of tuberculous with substantial mortality. In May 2015, 54 researchers from 10 countries met in Da Lat, Vietnam, to discuss advances in TBM. Among the attendees were researchers involved in pivotal studies on the use of Xpert MTB/Rif for TBM diagnosis. Attendees discussed the 2014 World Health Organization strong recommendation favoring the use of Xpert "in preference to conventional microscopy and culture as the initial diagnostic test for cerebrospinal fluid (CSF) if the sample volume is low or if additional specimens cannot be obtained to make a quick diagnosis." Attendees were concerned that the limitations of Xpert testing for TBM are not emphasized. Clear guidance is needed for the investigational pathway for TBM, including recommendations on the diagnostic package of investigations, which does not stop with Xpert testing. Second, emphasis on the large CSF volumes (ideally 8-10 mL) needed for Xpert testing is required. Guidelines should also emphasize that TBM is a medical emergency and early treatment reduces mortality.

Evaluation of host Hsp(s) as potential biomarkers for the diagnosis of tuberculous meningitis

OBJECTIVES

Diagnosis of tuberculosis meningitis (TBM) remains challenging in tuberculosis (TB) endemic countries. The need for TB biomarkers arises, in part, from the difficulty of accurately diagnosing TBM with the available methods.

PATIENTS AND METHODS

To explore the potential of host Hsps (Hsp 25, Hsp 60, Hsp 70 and Hsp 90) as an alternative marker in TBM diagnosis, we evaluated cerebrospinal fluid (CSF) sample of TBM (n=49), Pyogenic Meningitis (PM) (n=20), Viral Meningitis (VM) (n=09), Fungal Meningitis (FM) (n=04) and non infectious control (n=79) patients using indirect ELISA.

RESULTS

Out of four Hsps, Hsp 70 and Hsp 90 yields 89% & 88% sensitivity and 82% & 89% specificity, respectively. The positive (PPV) and negative (NPV) predictive values yielded in TBM group for Hsp 70 was 86.27% (73.74-94.27) and 93.51% (85.48-97.83), respectively. For Hsp 90 the obtained PPV was 89.36% (76.88-96.41) and NPV was 91.36% (82.99-96.44). In 86% of TBM patients all the four Hsps were found to be positive and none of the patient was found to be negative for all Hsps in the same group.

CONCLUSIONS

The data presented in the study indicate that host Hsp 70 and Hsp 90 shows good sensitivity and specificity and have potential in the diagnosis of TBM disease. The combined use of all Hsps (Hsp 25, Hsp 60, Hsp 70 and Hsp 90) effectively distinguishes patients with TBM from other disease controls.

The diagnostic value of cerebrospinal fluid chemistry results in childhood tuberculous meningitis

PURPOSE

Cerebrospinal fluid (CSF) hypoglycorrhachia and elevated protein is well-described in bacterial meningitis, but evidence for its differential diagnostic value in tuberculous meningitis (TBM) is lacking. We aimed to assess the diagnostic utility of CSF glucose, CSF to serum glucose ratio and CSF protein in children with suspected TBM.

METHODS

We describe CSF glucose and protein values as well as CSF to serum glucose ratios in a prospective evaluation of TBM suspects seen at Tygerberg Children's Hospital, Cape Town, South Africa, from January 1985 to January 2014.

RESULTS

Of 615 TBM suspects, 88 (14%) had microbiologically confirmed TBM, 381 (62%) 'probable' TBM and 146 (24%) 'non-TBM'. Mean absolute CSF glucose concentration was significantly lower in the microbiologically confirmed (1.87 ± 1.15 mmol/L) and 'probable' TBM (1.82 ± 1.19 mmol/L) groups compared to non-TBM (3.66 ± 0.88 mmol/L). A CSF glucose concentration of <2.2 mmol/L diagnosed TBM with sensitivity 0.68 and specificity 0.96. Sensitivity using a CSF to serum glucose ratio of <0.5 was 0.90. Mean CSF protein was significantly elevated in the microbiologically confirmed TBM (1.91 ± 1.44 g/L) and 'probable' TBM (2.01 ± 1.49 g/L) groups compared to the non-TBM (0.31 ± 0.31 g/L). A CSF protein >1 g/L diagnosed TBM with sensitivity 0.78 and specificity 0.94.

CONCLUSION

Absolute CSF glucose values of <2.2 mmol/L and protein values of >1 g/L differentiated between TBM and non-bacterial meningitis with good specificity, although sensitivity was poor. A CSF to serum glucose ratio is more informative than the absolute value.

Methods of rapid diagnosis for the etiology of meningitis in adults

Infectious meningitis may be due to bacterial, mycobacterial, fungal or viral agents. Diagnosis of meningitis must take into account numerous items of patient history and symptomatology along with regional epidemiology and basic cerebrospinal fluid testing (protein, etc.) to allow the clinician to stratify the likelihood of etiology possibilities and rationally select additional diagnostic tests. Culture is the mainstay for diagnosis in many cases, but technology is evolving to provide more rapid, reliable diagnosis. The cryptococcal antigen lateral flow assay (Immuno-Mycologics) has revolutionized diagnosis of cryptococcosis and automated nucleic acid amplification assays hold promise for improving diagnosis of bacterial and mycobacterial meningitis. This review will focus on a holistic approach to diagnosis of meningitis as well as recent technological advances.

Accuracy of Lipoarabinomannan and Xpert MTB/RIF Testing in Cerebrospinal Fluid To Diagnose Tuberculous Meningitis in an Autopsy Cohort of HIV-Infected Adults

Point-of-care tests for tuberculous meningitis (TBM) are needed. We studied the diagnostic accuracy of the lipoarabinomannan (LAM) lateral flow assay (LFA), LAM enzyme-linked immunosorbent assay (ELISA), and Xpert MTB/RIF in cerebrospinal fluid (CSF) in an autopsy cohort of Ugandan HIV-infected adults. We obtained written informed consent postmortem from the next of kin. A complete autopsy was done and CSF obtained. We performed LAM LFA (on unprepared and supernatant CSF after heating and spinning), LAM ELISA, and Xpert MTB/RIF on the CSF samples. Accuracy parameters were calculated for histopathological TBM and also for the composite standard, including Xpert MTB/RIF-positive cases. We tested CSF of 91 patients. LAM LFA had a sensitivity of 75% for definite histopathological TBM, ELISA a sensitivity of 43%, and Xpert MTB/RIF a sensitivity of 100% and specificities of 87%, 91%, and 87%, respectively. LAM LFA had a sensitivity of 50% for definite and probable histopathological TBM, ELISA a sensitivity of 38%, and Xpert MTB/RIF a sensitivity of 86% and specificities of 70%, 91%, and 87%, respectively. LAM LFA had a sensitivity of 68% for the composite standard and ELISA a sensitivity of 48% and specificities of 78% and 98%, respectively. The rapid diagnostic tests detected TBM in 22% to 78% of patients not on anti-TB treatment. Point-of-care tests have high accuracy in diagnosis of TBM in deceased HIV-infected adults. LAM LFA in CSF is a useful additional diagnostic tool.

Tuberculous meningitis: advances in diagnosis and treatment

INTRODUCTION

Tuberculous meningitis (TBM) is the most severe form of infection caused by Mycobacterium tuberculosis, causing death or disability in more than half of those affected. The aim of this review is to examine recent advances in our understanding of TBM, focussing on the diagnosis and treatment of this devastating condition.

SOURCES OF DATA

Papers on TBM published between 1891 and 2014 and indexed in the NCBI Pubmed. The following search terms were used: TBM, diagnosis, treatment and outcome.

AREAS OF AGREEMENT

The diagnosis of TBM remains difficult as its presentation is non-specific and may mimic other causes of chronic meningoencephalitis. Rapid recognition of TBM is crucial, however, as delays in initiating treatment are associated with poor outcome. The laboratory diagnosis of TBM is hampered by the low sensitivity of cerebrospinal fluid microscopy and the slow growth of M. tuberculosis in conventional culture systems. The current therapy of TBM is based on the treatment of pulmonary tuberculosis, which may not be ideal. The combination of TBM and HIV infection poses additional management challenges because of the need to treat both infections and the complications associated with them.

AREAS OF CONTROVERSY

The pathogenesis of TBM remains incompletely understood limiting the development of interventions to improve outcome. The optimal therapy of TBM has not been established in clinical trials, and increasing antimicrobial resistance threatens successful treatment of this condition. The use of adjunctive anti-inflammatory agents remains controversial, and their mechanism of action remains incompletely understood. The role of surgical intervention is uncertain and may not be available in areas where TBM is common.

GROWING POINTS

Laboratory methods to improve the rapid diagnosis of TBM are urgently required. Clinical trials of examining the use of high-dose rifampicin and/or fluoroquinolones are likely to report in the near future.

AREAS TIMELY FOR DEVELOPING RESEARCH

The use of biomarkers to improve the rapid diagnosis of TBM warrants further investigation. The role of novel antituberculosis drugs, such as bedaquiline and PA-824, in the treatment of TBM remains to be explored. Human genetic polymorphisms may explain the heterogeneity of response to anti-inflammatory therapies and could potentially be used to tailor therapy.

A hypothetical astrocyte-microglia lactate shuttle derived from a 1H NMR metabolomics analysis of cerebrospinal fluid from a cohort of South African children with tuberculous meningitis

Tuberculosis meningitis (TBM) is the most severe form of extra-pulmonary tuberculosis and is particularly intense in small children; there is no universally accepted algorithm for the diagnosis and substantiation of TB infection, which can lead to delayed intervention, a high risk factor for morbidity and mortality. In this study a proton magnetic resonance (¹H NMR)-based metabolomics analysis and several chemometric methods were applied to data generated from lumber cerebrospinal fluid (CSF) samples from three experimental groups: (1) South African infants and children with confirmed TBM, (2) non-meningitis South African infants and children as controls, and (3) neurological controls from the Netherlands. A total of 16 NMR-derived CSF metabolites were identified, which clearly differentiated between the controls and TBM cases under investigation. The defining metabolites were the combination of perturbed glucose and highly elevated lactate, common to some other neurological disorders. The remaining 14 metabolites of the host's response to TBM were likewise mainly energy-associated indicators. We subsequently generated a hypothesis expressed as an "astrocyte-microglia lactate shuttle" (AMLS) based on the host's response, which emerged from the NMR-metabolomics information. Activation of microglia, as implied by the AMLS hypothesis, does not, however, present a uniform process and involves intricate interactions and feedback loops between the microglia, astrocytes and neurons that hamper attempts to construct basic and linear cascades of cause and effect; TBM involves a complex integration of the responses from the various cell types present within the CNS, with microglia and the astrocytes as main players.

When smear and molecular diagnostics fail: identification of tuberculosis in advanced HIV infection using the newly developed urine lipoarabinomannan lateral-flow assay

In HIV infection, progression of immunodeficiency is associated with increased risk of paucibacillary and disseminated forms of tuberculosis (TB). As a result, the clinical presentation may be atypical and the conventional diagnostic assays often unreliable, resulting in significant treatment delays. Here, we report a case of HIV-associated immune reconstitution inflammatory syndrome and TB meningitis. Although the smear and molecular assays were negative, Mycobacterium tuberculosis was identified in our patient using the new Determine-lipoarabinomannan (LAM) lateral-flow urine 'dip-stick' assay. This case report illustrates the clinical value of this assay for the diagnosis of TB in a subgroup of HIV-infected patients with advanced immunodeficiency. Also, although two recent studies have evaluated the use of the Determine TB-LAM assay in clinical settings, to the best of our knowledge, this is the first case report of TB diagnosed using this novel assay.

Commercial nucleic acid amplification tests in tuberculous meningitis--a meta-analysis

Although nucleic acid amplification tests (NAATs) promise a rapid, definitive diagnosis of tuberculous meningitis, the performance of first-generation NAATs was suboptimal and variable. We conducted a meta-analysis of studies published between 2003 and 2013, using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool to evaluate methodological quality. The diagnostic accuracy of newer commercial NAATs was assessed. Pooled estimates of diagnostic accuracy for commercial NAATs measured against a cerebrospinal fluid Mycobacterium tuberculosis culture-positive gold standard were sensitivity 0.64, specificity 0.98, and diagnostic odds ratio 64.0. Heterogeneity was limited; P value = 0.147 and I(2) = 33.85%. The Xpert MTB/RIF® test was evaluated in 1 retrospective study and 4 prospective studies, with pooled sensitivity 0.70 and specificity 0.97. The QUADAS-2 tool revealed low risk of bias, as well as low concerns regarding applicability. Heterogeneity was pronounced among studies of in-house tests. Commercial NAATs proved to be highly specific with greatly reduced heterogeneity compared to in-house tests. Sub-optimal sensitivity remains a limitation.

Evaluation of GeneXpert MTB/RIF for diagnosis of tuberculous meningitis

Tuberculous meningitis (TBM) is the most severe form of tuberculosis. Microbiological confirmation is rare, and treatment is often delayed, increasing mortality and morbidity. The GeneXpert MTB/RIF test was evaluated in a large cohort of patients with suspected tuberculous meningitis. Three hundred seventy-nine patients presenting with suspected tuberculous meningitis to the Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam, between 17 April 2011 and 31 December 2012 were included in the study. Cerebrospinal fluid samples were tested by Ziehl-Neelsen smear, mycobacterial growth indicator tube (MGIT) culture, and Xpert MTB/RIF. Rifampin (RIF) resistance results by Xpert were confirmed by an MTBDR-Plus line probe assay and all positive cultures were tested by phenotypic MGIT drug susceptibility testing. Overall, 182/379 included patients (48.0%) were diagnosed with tuberculous meningitis. Sensitivities of Xpert, smear, and MGIT culture among patients diagnosed with TBM were 59.3% (108/182 [95% confidence interval {CI}, 51.8 to 66.5%]), 78.6% (143/182 [95% CI, 71.9 to 84.3%]) and 66.5% (121/182 [95% CI, 59.1 to 73.3%]), respectively. There was one false-positive Xpert MTB/RIF test (99.5% specificity). Four cases of RIF resistance (4/109; 3.7%) were identified by Xpert, of which 3 were confirmed to be multidrug-resistant (MDR) TBM and one was culture negative. Xpert MTB/RIF is a rapid and specific test for the diagnosis of tuberculous meningitis. The addition of a vortexing step to sample processing increased sensitivity for confirmed TBM by 20% (P = 0.04). Meticulous examination of a smear from a large volume of cerebrospinal fluid (CSF) remains the most sensitive technique but is not practical in most laboratories. The Xpert MTB/RIF represents a significant advance in the early diagnosis of this devastating condition.