Uniform research case definition criteria differentiate tuberculous and bacterial meningitis in children

MRI advances in the imaging diagnosis of tuberculous meningitis: opportunities and innovations

Tuberculous meningitis (TBM) is not only one of the most fatal forms of tuberculosis, but also a major public health concern worldwide, presenting grave clinical challenges due to its nonspecific symptoms and the urgent need for timely intervention. The severity and the rapid progression of TBM underscore the necessity of early and accurate diagnosis to prevent irreversible neurological deficits and reduce mortality rates. Traditional diagnostic methods, reliant primarily on clinical findings and cerebrospinal fluid analysis, often falter in delivering timely and conclusive results. Moreover, such methods struggle to distinguish TBM from other forms of neuroinfections, making it critical to seek advanced diagnostic solutions. Against this backdrop, magnetic resonance imaging (MRI) has emerged as an indispensable modality in diagnostics, owing to its unique advantages. This review provides an overview of the advancements in MRI technology, specifically emphasizing its crucial applications in the early detection and identification of complex pathological changes in TBM. The integration of artificial intelligence (AI) has further enhanced the transformative impact of MRI on TBM diagnostic imaging. When these cutting-edge technologies synergize with deep learning algorithms, they substantially improve diagnostic precision and efficiency. Currently, the field of TBM imaging diagnosis is undergoing a phase of technological amalgamation. The melding of MRI and AI technologies unquestionably signals new opportunities in this specialized area.

Development of clinical-based scoring system to diagnose tuberculous meningitis in children

OBJECTIVE

Diagnosing tuberculous meningitis (TBM) in children is challenging due to the low sensitivity with time delay of bacterial culture techniques and the lack of brain imaging facilities in many low- and middle-income settings. This study aims to establish and test a scoring system consisting of clinical manifestations on history and examination for diagnosing TBM in children.

DESIGN

A retrospective study was conducted using a diagnostic multivariable prediction model.

PARTICIPANTS

167 children diagnosed with meningitis (tuberculous, bacterial, viral and others) aged 3 months to 18 years who were hospitalised from July 2011 until November 2021 in a national tertiary hospital in Indonesia.

RESULTS

Eight out of the 10 statistically significant clinical characteristics were used to develop a predictive model. These resulted in good discrimination and calibration variables, which divided into systemic features with a cut-off score of ≥3 (sensitivity 78.8%; specificity 86.6%; the area under the curve (AUC) value 0.89 (95% CI 0.85 to 0.95; p<0.001)) and neurological features with a cut-off score of ≥2 (sensitivity 61.2%; specificity 75.2%; the AUC value 0.73 (95% CI 0.66 to 0.81; p<0.001)). Combined together, this scoring system predicted the diagnosis of TBM with a sensitivity, specificity and positive predictive value of 47.1%, 95.1% and 90.9%, respectively.

CONCLUSION

The clinical scoring system consisting of systemic and neurological features can be used to predict the diagnosis of TBM in children with limited resource setting. The scoring system should be assessed in a prospective cohort.

A New Scoring System to Differentially Diagnose and Distinguish Tuberculous Meningitis and Bacterial Meningitis in South China

Background

Tuberculous meningitis (TBM) is the most serious form of extrapulmonary tuberculosis caused by Mycobacterium tuberculosis, and is characterized by high morbidity and mortality. Unfortunately, it is difficult to distinguish TBM from bacterial meningitis (BM) based on clinical features alone. The latest diagnostic tests and neuroimaging methods are still not available in many developing countries. This study aimed to develop a simple diagnostic algorithm based on clinical and laboratory test results as an early predictor of TBM in South China.

Methods

A retrospective study was conducted to compare the clinical and laboratory characteristics of 114 patients with TBM and 47 with BM. Multivariate logistic regression analysis was performed on the characteristics of independently predicted TBM to develop a new diagnostic rule.

Results

Five characteristics were predictive of a diagnosis of TBM: duration of symptoms before admission; tuberculous symptoms; white blood cell (WBC) count, total cerebrospinal fluid WBC count, and cerebrospinal fluid chloride concentration. The sensitivity and specificity of the new scoring system developed in this study were 81.6 and 93.6%, respectively.

Conclusion

The new scoring system proposed in this study can help physicians empirically diagnose TBM and can be used in countries and regions with limited microbial and radiological resources.

The diagnostic challenge of atypical tuberculous meningitis in children from rural area

Tuberculous meningitis (TBM) is a severe form of Mycobacterium tuberculosis infection, while its diagnosis is still a challenge in children. Here, six children with atypical TBM were retrospectively reviewed and the main findings were displayed as follows. The enrolled cases exhibited non-specific symptoms on admission, mainly including fever ( n = 5), headache ( n = 3), vomiting ( n = 5), and drowsiness ( n = 3), but no typical symptoms of TB infection. Two of them exhibited progressive symptoms under routine treatment. Cerebrospinal fluid (CSF) examinations revealed increased white blood cells and proteins, as well as decreased glucose and chloride in all cases. Chest imaging identified the possibly of pulmonary tuberculous in 2 cases. Cranial CT and MRI revealed neuroimaging abnormality in 1 and 3 cases, respectively. In addition, next-generation sequencing directly supported the diagnosis of TBM in case 5. To sum up, TBM should be highly suspected in children with central nervous system infection, when there are no improvements under routine treatment and/or the presence of progressive symptoms. Timely rechecking of CSF combined with cranial imaging is feasible and valuable for the diagnosis of TBM.

A Diagnostic Scoring System for Distinguishing between Tuberculous and Bacterial Meningitis Based on Clinical and Laboratory Findings

It is very difficult to diagnose and distinguish tuberculous meningitis, and the current laboratory methods are unsubstantial in developing countries. The study is aimed at creating a scoring system on the basis of basic laboratory and clinical achievements that could be used as diagnostic aid for tuberculous meningitis for Chinese patients. A retrospective study of cases was conducted for comparison between clinical characteristics and laboratory features of 241 patients on admission who conformed to inclusion criteria of tuberculous meningitis (n = 141) or bacterial meningitis (n = 100). Logistic regression was employed to establish a diagnostic formula to distinguish between tuberculous meningitis and bacterial meningitis. The receiver operating characteristic curve analysis was applied to determine the best diagnostic critical point of the diagnostic formula. It was found that five variables (disease course, white blood cell count, serum sodium, total white cell count of cerebrospinal fluid, and neutrophil proportion in cerebrospinal fluid) were independently associated with tuberculous meningitis. The 87% sensitivity and 94% specificity were included in the diagnostic scoring system derived from these variables. Especially in the case of limited microbial resources, doctors can use this diagnostic scoring system to distinguish tuberculous meningitis from bacterial meningitis.

Mullen Scales of Early Learning Adaptation for Assessment of Indian Children and Application to Tuberculous Meningitis

INTRODUCTION

Tuberculous meningitis (TBM) results in significant morbidity and mortality among children worldwide. Associated neurocognitive complications are common but not well characterized. The Mullen Scales of Early Learning (MSEL), a well-established measure for assessment of neurodevelopment, has not yet been adapted for use in India. This study's goal was to adapt the MSEL for local language and culture to assess neurocognition among children in India, and apply the adapted measure for assessment of children with TBM.

METHODS

Administration of MSEL domains was culturally adapted. Robust translation procedures for instructions took place for three local languages: Marathi, Hindi and Tamil. Multilingual staff compared instructions against the original version for accuracy. The MSEL stimuli and instructions were reviewed by psychologists and pediatricians in India to identify items concerning for cultural bias.

RESULTS

MSEL stimuli unfamiliar to children in this setting were identified and modified within Visual Reception, Fine-Motor, Receptive Language and Expressive Language Scales. Item category was maintained for adaptations of items visually or linguistically different from those observed in daily life. Adjusted items were administered to six typically developing children to determine modification utility. Two children diagnosed with confirmed TBM (ages 11 and 29 months) were evaluated with the adapted MSEL before receiving study medications. Skills were below age-expectation across visual reception, fine motor and expressive language domains.

CONCLUSIONS

This is the first study to assess children with TBM using the MSEL adapted for use in India. Future studies in larger groups of Indian children are warranted to validate the adapted measure.

Pooled analysis of the Xpert MTB/RIF assay for diagnosing tuberculous meningitis

BACKGROUND

Tuberculous meningitis (TBM) is one of the most serious types of extrapulmonary tuberculosis. However, low sensitivity of culture of cerebrospinal fluid (CSF) increases the difficulty in clinical diagnosis, leading to diagnostic delay, and misdiagnosis. Xpert MTB/RIF assay is a rapid and simple method to detect tuberculosis. However, the efficacy of this technique in diagnosing TBM remains unclear. Therefore, a meta-analysis was conducted to evaluate the diagnostic efficacy of Xpert MTB/RIF for TBM, which may enhance the development of early diagnosis of TBM.

METHODS

Relevant studies in the PubMed, Embase, and Web of Science databases were retrieved using the keywords 'Xpert MTB/RIF', 'tuberculous meningitis (TBM)'. The pooled sensitivity, pooled specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, summary receiver operator characteristic curve, and area under the curve (AUC) of Xpert MTB/RIF were determined and analyzed.

RESULTS

A total of 162 studies were enrolled and only 14 met the criteria for meta-analysis. The overall pooled sensitivity of Xpert MTB/RIF was 63% [95% confidence interval (CI), 59-66%], while the overall pooled specificity was 98.1% (95% CI, 97.5-98.5%). The pooled values of positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 20.91% (12.71-52.82%), 0.40% (0.32-0.50%), and 71.49% (32.64-156.56%), respectively. The AUC was 0.76.

CONCLUSIONS

Xpert MTB/RIF exhibited high specificity in diagnosing TBM in CSF samples, but its sensitivity was relatively low. It is necessary to combine other high-sensitive detection methods for the early diagnosis of TBM. Moreover, the centrifugation of CSF samples was found to be beneficial in improving the sensitivity.

Tuberculous Meningitis: Pathogenesis, Immune Responses, Diagnostic Challenges, and the Potential of Biomarker-Based Approaches

Tuberculous meningitis (TBM) is the most devastating form of tuberculosis (TB), causing high mortality or disability. Clinical management of the disease is challenging due to limitations of the existing diagnostic approaches. Our knowledge on the immunology and pathogenesis of the disease is currently limited. More research is urgently needed to enhance our understanding of the immunopathogenesis of the disease and guide us toward the identification of targets that may be useful for vaccines or host-directed therapeutics.

Tuberculous meningitis (TBM) is the most devastating form of tuberculosis (TB), causing high mortality or disability. Clinical management of the disease is challenging due to limitations of the existing diagnostic approaches. Our knowledge on the immunology and pathogenesis of the disease is currently limited. More research is urgently needed to enhance our understanding of the immunopathogenesis of the disease and guide us toward the identification of targets that may be useful for vaccines or host-directed therapeutics. In this review, we summarize the current knowledge about the immunology and pathogenesis of TBM and summarize the literature on existing and new, especially biomarker-based, approaches that may be useful in the management of TBM. We identify research gaps and provide directions for research which may lead to the development of new tools for the control of the disease in the near future.

Clinical Profile, Yield of Cartridge-based Nucleic Acid Amplification Test (GeneXpert), and Outcome in Children with Tubercular Meningitis

Background:

GeneXpert MTB/RIF is a test for early, rapid diagnosis of tubercular meningitis (TBM).

Aim:

The aim of this article was to study the clinical profile, radiological features, yield of GeneXpert, neurosurgical interventions, and outcome of TBM in children.

Settings and Design:

This was a retrospective and prospective observational study.

Materials and Methods:

Diagnosis was based on the uniform research definition criteria and was staged according to the British Medical Research Council. Mantoux test, analysis of cerebrospinal fluid (CSF), CSF GeneXpert, and radiological investigations were performed.

Results:

Of 36 patients, 50% were aged 1–5 years. Fever (100%), headache (82%), altered sensorium (80%), and vomiting (66%) were common features. Twelve (33%) had contact with active case of tuberculosis; 32 received Bacille Calmette Guarin vaccination. Neurological features included severe deterioration in sensorium (Glasgow Coma Scale < 8) (38%), mild and moderate deficit in sensorium (31%), hemiparesis (41%), and involvement of sixth (25%) and seventh (22%) cranial nerves. Cerebral vision impairment (25%), papilledema (25%), and dystonia (22%) were other findings. CSF GeneXpert was positive in 37% (12/33) patients. Hydrocephalus and basal exudates (75%) were noted on neuro-imaging. Surgical intervention was performed in children with hydrocephalus (13/27). Omayya reservoir was placed in seven children, of which five needed conversion to ventriculoperitoneal (VP) shunt; direct VP shunt was carried out in six (6/13). Good outcome was noted in 78% at discharge. Stage III TBM (P = 0.0001), cerebral infarcts (P = 0.0006), and motor deficits (P = 0.03) were associated with poor outcome. Sequelae included learning difficulties with poor scholastic performance (31.5%).

Conclusion:

GeneXpert has high diagnostic specificity, but negative results do not rule out TBM. CSF GeneXpert provided quick results. Placement of Ommaya reservoir in TBM stage II and III with hydrocephalus was not successful. Hydrocephalus was managed conservatively with success (53%).

Machine-Learning-Based Approach to Differential Diagnosis in Tuberculous and Viral Meningitis

Background

Tuberculous meningitis (TBM) is the most severe form of tuberculosis, but differentiating between the diagnosis of TBM and viral meningitis (VM) is difficult. Thus, we have developed machine-learning modules for differentiating TBM from VM.

Material and Methods

For the training data, confirmed or probable TBM and confirmed VM cases were retrospectively collected from five teaching hospitals in Korea between January 2000 - July 2018. Various machine-learning algorithms were used for training. The machine-learning algorithms were tested by the leave-one-out cross-validation. Four residents and two infectious disease specialists were tested using the summarized medical information.

Results

The training study comprised data from 60 patients with confirmed or probable TBM and 143 patients with confirmed VM. Older age, longer symptom duration before the visit, lower serum sodium, lower cerebrospinal fluid (CSF) glucose, higher CSF protein, and CSF adenosine deaminase were found in the TBM patients. Among the various machine-learning algorithms, the area under the curve (AUC) of the receiver operating characteristics of artificial neural network (ANN) with ImperativeImputer for matrix completion (0.85; 95% confidence interval 0.79 - 0.89) was found to be the highest. The AUC of the ANN model was statistically higher than those of all the residents (range 0.67 - 0.72, P <0.001) and an infectious disease specialist (AUC 0.76; P = 0.03).

Conclusion

The machine-learning techniques may play a role in differentiating between TBM and VM. Specifically, the ANN model seems to have better diagnostic performance than the non-expert clinician.

The immunological architecture of granulomatous inflammation in central nervous system tuberculosis

Of all tuberculosis (TB) cases, 1% affects the central nervous system (CNS), with a mortality rate of up to 60%. Our aim is to fill the 'key gap' in TBM research by analyzing brain specimens in a unique historical cohort of 84 patients, focusing on granuloma formation. We describe three different types: non-necrotizing, necrotizing gummatous, and necrotizing abscess type granuloma. Our hypothesis is that these different types of granuloma are developmental stages of the same pathological process. All types were present in each patient and were mainly localized in the leptomeninges. Intra-parenchymal granulomas were less abundant than the leptomeningeal ones and mainly located close to the cerebrospinal fluid (subpial and subependymal). We found that most of the intraparenchymal granulomas are an extension of leptomeningeal lesions which is the opposite of the classical Rich focus theory. We present a 3D-model to facilitate further understanding of the topographic relation of granulomas with leptomeninges, brain parenchyma and blood vessels. We describe innate and adaptive immune responses during granuloma formation including the cytokine profiles. We emphasize the presence of leptomeningeal B-cell aggregates as tertiary lymphoid structures. Our study forms a basis for further research in neuroinflammation and infectious diseases of the CNS, especially TB.

Drug resistant TB spine in a two year old child: A case report

Spinal tuberculosis (TB) is a disease of high morbidity that is associated with deformity and neurological sequelae, especially in growing children. Children diagnosed with spinal TB need to be monitored closely for clinical improvements. Previous history of antituberculous therapy (ATT), poor adherence to previous ATT, contact with persons having known drug-resistant (DR) TB, or clinical worsening despite regular ATT are strong indicators for the diagnosis of DR TB of the spine. We report a case of spinal DRTB in a two year old child with no previous history of ATT and contact with a person on irregular treatment for drug sensitive TB that did not show regression of the spinal lesions despite standard ATT.

Patients with tuberculous meningitis and hepatitis B co-infection have increased risk for antituberculosis drug-induced liver injury and poor outcomes

BACKGROUND

Tuberculous meningitis (TBM) is one of the most severe forms of tuberculosis. Previous studies reported that hepatitis B virus (HBV) infection could increase the risk of antituberculosis drug-induced liver injury (ATB-DILI) in pulmonary tuberculosis patients. To date, only a few studies exist on the effect of HBV on TBM.

METHODS

This inpatient study retrospectively analyzed the medical records of patients who were diagnosed with TBM between June 2002 and June 2018. Statistical analysis was used to reveal the difference between the HBV and non-HBV groups. Univariate analysis and multivariate regression analysis were performed on data to determine the prognostic factors of TBM.

RESULTS

A total of 386 patients were enrolled in our study, 57 of whom were included in the HBV group and 329 in the non-HBV group. The HBV group showed a higher frequency of ATB-DILI (HBV group: 14.0% versus non-HBV group: 3.3%, p < .001) and a higher risk of poor outcomes (i.e. death during inpatient period or neurological deficit at discharge, HBV group: 31.6% versus non-HBV group: 19.8%, p = .045) than the non-HBV group. The multivariate regression analysis identified ATB-DILI, scores of 3-8 on the Glasgow Coma Scale and hydrocephalus as independent predictors of poor outcomes in TBM patients.

CONCLUSIONS

Our study demonstrated that HBV co-infection could increase the incidence of ATB-DILI and the risk of poor outcomes as identified by three predictors in TBM patients.

Establishing the cascade of care for patients with tuberculous meningitis

Meningitis is a relatively rare form of tuberculosis, but it carries a high mortality rate, reaching 50% in some settings, with higher rates among patients with HIV co-infection and those with drug-resistant disease. Most studies of tuberculosis meningitis (TBM) tend to focus on better diagnosis, drug treatment and supportive care for patients in hospital. However, there is significant variability in mortality between settings, which may be due to specific variation in the availability and quality of health care services, both prior to, during, and after hospitalization. Such variations have not been studied thoroughly, and we therefore present a theoretical framework that may help to identify where efforts should be focused in providing optimal services for TBM patients. As a first step, we propose an adjusted cascade of care for TBM and patient pathway studies that might help identify factors that account for losses and delays across the cascade. Many of the possible gaps in the TBM cascade are related to health systems factors; we have selected nine domains and provide relevant examples of systems factors for TBM for each of these domains that could be the basis for a health needs assessment to address such gaps. Finally, we suggest some immediate action that could be taken to help make improvements in services. Our theoretical framework will hopefully lead to more health system research and improved care for patients suffering from this most dangerous form of tuberculosis.

Establishing the cascade of care for patients with tuberculous meningitis

Meningitis is a relatively rare form of tuberculosis, but it carries a high mortality rate, reaching 50% in some settings, with higher rates among patients with HIV co-infection and those with drug-resistant disease. Most studies of tuberculosis meningitis (TBM) tend to focus on better diagnosis, drug treatment and supportive care for patients in hospital. However, there is significant variability in mortality between settings, which may be due to specific variation in the availability and quality of health care services, both prior to, during, and after hospitalization. Such variations have not been studied thoroughly, and we therefore present a theoretical framework that may help to identify where efforts should be focused in providing optimal services for TBM patients. As a first step, we propose an adjusted cascade of care for TBM and patient pathway studies that might help identify factors that account for losses and delays across the cascade. Many of the possible gaps in the TBM cascade are related to health systems factors; we have selected nine domains and provide relevant examples of systems factors for TBM for each of these domains that could be the basis for a health needs assessment to address such gaps. Finally, we suggest some immediate action that could be taken to help make improvements in services. Our theoretical framework will hopefully lead to more health system research and improved care for patients suffering from this most dangerous form of tuberculosis.

Tuberculous meningitis in children: Clinical management & outcome

Although the occurrence of tuberculous meningitis (TBM) in children is relatively rare, but it is associated with higher rates of mortality and severe morbidity. The peak incidence of TBM occurs in younger children who are less than five years of age, and most children present with late-stage disease. Confirmation of diagnosis is often difficult, and other infectious causes such as bacterial, viral and fungal causes must be ruled out. Bacteriological confirmation of diagnosis is ideal but is often difficult because of its paucibacillary nature as well as decreased sensitivity and specificity of diagnostic tests. Early diagnosis and management of the disease, though difficult, is essential to avoid death or neurologic disability. Hence, a high degree of suspicion and a combined battery of tests including clinical, bacteriological and neuroimaging help in diagnosis of TBM. Children diagnosed with TBM should be managed with antituberculosis therapy (ATT) and steroids. There are studies reporting low concentrations of ATT, especially of rifampicin and ethambutol in cerebrospinal fluid (CSF), and very young children are at higher risk of low ATT drug concentrations. Further studies are needed to identify appropriate regimens with adequate dosing of ATT for the management of paediatric TBM to improve treatment outcomes. This review describes the clinical presentation, investigations, management and outcome of TBM in children and also discusses various studies conducted among children with TBM.

Validation of the Uniform Case Definition Criteria for Differentiating Tuberculous Meningitis, Viral Meningitis, and Bacterial Meningitis in Adults

We validated the uniform case definition for differentiating tuberculous meningitis (TBM) from both viral meningitis (VM) and bacterial meningitis (BM) in adults from South Korea, a country with an intermediate TB-burden. ‘Probable’ TBM differentiated ‘definite’ TBM with a sensitivity of 81% and specificity of 98%. ‘Possible TBM’ criteria identified ‘definite’ TBM with a sensitivity of 100% and specificity of 60%. Despite the usefulness of the uniform case definition criteria, there was substantial overlaps among VM, BM, and ‘possible’ TBM, especially in severe cases of VM and indolent cases of BM.

Clinical presentations, diagnosis, mortality and prognostic markers of tuberculous meningitis in Vietnamese children: a prospective descriptive study

BACKGROUND

Tuberculous meningitis in adults is well characterized in Vietnam, but there are no data on the disease in children. We present a prospective descriptive study of Vietnamese children with TBM to define the presentation, course and characteristics associated with poor outcome.

METHODS

A prospective descriptive study of 100 consecutively admitted children with TBM at Pham Ngoc Thach Hospital, Ho Chi Minh City. Cox and logistic regression were used to identify factors associated with risk of death and a combined endpoint of death or disability at treatment completion.

RESULTS

The study enrolled from October 2009 to March 2011. Median age was 32.5 months; sex distribution was equal. Median duration of symptoms was 18.5 days and time from admission to treatment initiation was 11 days. Fifteen of 100 children died, 4 were lost to follow-up, and 27/81 (33 %) of survivors had intermediate or severe disability upon treatment completion. Microbiological confirmation of disease was made in 6 %. Baseline characteristics associated with death included convulsions (HR 3.46, 95CI 1.19-10.13, p = 0.02), decreased consciousness (HR 22.9, 95CI 3.01-174.3, p < 0.001), focal neurological deficits (HR 15.7, 95CI 1.67-2075, p = 0.01), Blantyre Coma Score (HR 3.75, 95CI 0.99-14.2, p < 0.001) and CSF protein, lactate and glucose levels. Neck stiffness, MRC grade (children aged >5 years) and hydrocephalus were also associated with the combined endpoint of death or disability.

CONCLUSIONS

Tuberculous meningitis in Vietnamese children has significant mortality and morbidity. There is significant delay in diagnosis; interventions that increase the speed of diagnosis and treatment initiation are likely to improve outcomes.

Diagnostic usefulness of T-cell based assays for tuberculous meningitis in HIV-uninfected patients

OBJECTIVES

Early diagnosis and treatment of tuberculous meningitis (TBM) is essential for a positive outcome, but sensitive, specific, and rapid diagnostic tests for TBM are lacking. We evaluated the diagnostic utility of enzyme-linked immunosorbent spot (ELISPOT) assays in HIV-uninfected patients with suspected TBM.

METHODS

All HIV-uninfected patients with suspected TBM were prospectively enrolled at a tertiary care hospital in an intermediate TB-burden country, during a 6-year period. ELISPOT assays were performed on peripheral blood mononuclear cells (PBMC) and cerebrospinal fluid-mononuclear cells (CSF-MC).

RESULTS

Of the 276 evaluable patients, 90 (33%) were classified as having TBM (30 definite cases, 19 probable, and 41 possible), and 186 (67%) as having non-TBM. When comparing definite TBM versus non-TBM, the sensitivity and specificity of the PBMC ELISPOT assay (≥6 spots; manufacturer's recommended cut-off) for diagnosing TBM were 96% (95% CI, 82-100) and 58% (95% CI, 50-66), respectively. The CSF-MC ELISPOT assay (≥38 spots; receiver operating characteristic [ROC]-derived cut-off) was a useful rule-in test with specificity of 95% (96% CI, 90-98). Its sensitivity was 68% (95% CI, 45-86), which was superior those of AFB smear microscopy (14%; P < 0.001) and CSF Mycobacterium tuberculosis PCR (41%; P = 0.07). Combining this assay with M. tuberculosis PCR, clinical score, and both together increased sensitivity to 86%, 91%, and 95%, respectively, while retaining about 95% specificity.

CONCLUSIONS

The CSF-MC ELISPOT assay appears to be a rapid and accurate rule-in test for the diagnosis of TBM and a useful adjunct for diagnosing TBM in HIV-uninfected patients.

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.