The pathogenesis of tuberculous meningitis

Trojan horse strategy and TfR/ LDLR-Mediated transcytosis determine the dissemination of mycobacteria in tuberculous meningoencephalitis

Tuberculous meningoencephalitis (TBM), caused by the Mycobacterium tuberculosis complex, stands as one of the most lethal infections affecting the central nervous system (CNS). The understanding of the mechanisms underlying the neuroinvasion of Mycobacterium bovis (M. bovis) remains limited. Our findings reveal that M. bovis could exploit host transferrin receptor (TfR)- and low-density lipoprotein receptor (LDLR)-mediated transcytosis, while simultaneously utilizing infected macrophages as vectors to traverse the blood-brain barrier (BBB). Infected macrophages accelerate the M. bovis' neuroinvasion and promote its proliferation and dissemination to various organs. Persistent infection disrupts BBB integrity by degrading tight junction proteins and upregulating intercellular cell adhesion molecule-1 (iCAM-1), facilitating macrophage adhesion and migration, which contribute to the pathogen's entry into the brain. This study established a murine TBM model by administering M. bovis through carotid artery injection, accurately mimicking the interactions between the pathogen and the BBB. These findings offer insights into the mechanisms of TBM and serve as a foundation for developing targeted therapeutic strategies.

Headache in infections

PURPOSE OF REVIEW

This review explores the phenomenology, pathogenesis, and nosology of headaches associated with infections, an often-overlooked yet clinically significant symptom. With the increasing recognition of secondary headaches in infections, understanding their clinical patterns, mechanisms, and classifications is crucial for accurate diagnosis and management.

RECENT FINDINGS

Headaches in infections are ubiquitous but vary in presentation, severity, and underlying mechanisms depending on the causative pathogen. Elevated intracranial pressure, meningeal irritation, and activation of the trigeminovascular system are key contributors to headache generation, which varies depending on each pathogen. Pathogen-specific predilection for one of these mechanisms may subtly alter the clinical phenotype of the headache, which can be used to guide management. Emerging evidence highlights postinfectious headache syndromes, particularly following bacterial meningitis and SARS-CoV-2 infection, underscoring the need for long-term follow-up in these patients.

SUMMARY

The diverse presentations of infection-related headaches necessitate a systematic approach to evaluation and management. While the pathophysiology is complex and multifaceted, understanding these mechanisms aids in differentiating primary headaches from those secondary to infections.

Effects of M. tuberculosis and HIV-1 infection on in vitro blood-brain barrier function

BACKGROUND

Tuberculous meningitis is the most severe form of tuberculosis and HIV-1 co-infection worsens the already poor prognosis. However, how Mycobacterium tuberculosis crosses the blood-brain barrier and how HIV-1 influences tuberculous meningitis pathogenesis remains unclear.

METHODS

Using human pericytes, astrocytes, endothelial cells, and microglia alone and combined in an in vitro blood-brain barrier model, we investigated the effect of Mycobacterium tuberculosis +/- HIV-1 co-infection on central nervous system cell entry and function. Cells and the blood-brain barrier model were infected with Mycobacterium tuberculosis and/or HIV-1 and we evaluated the effects of both infection on (i) cells susceptibility to Mycobacterium tuberculosis and its growth in cells by flow cytometry; (ii) modulation of blood-brain barrier permeability and Mycobacterium tuberculosis passage through it; (iii) viral and bacterial cytopathogenicity using the xCELLigence system; (iv) cell metabolic activity and ROS release using colorimetric assays; (v) extracellular glutamate concentration by fluorometric assay; (vi) the inflammatory response by Luminex; and (vii) endoplasmic reticulum stress by quantitative PCR.

RESULTS

We demonstrated that Mycobacterium tuberculosis infects and multiplies in all cell types with HIV-1 increasing entry to astrocytes and pericytes, and growth in HIV-1 positive pericytes and endothelial cells. Mycobacterium tuberculosis also induces an increase of the blood-brain barrier permeability resulting in translocation of bacilli across it. Cytopathic effects include (i) increased markers of cellular stress (mitochondrial metabolic activity, unfolded protein response); (ii) ROS release; (iii) the induction of neurotoxic astrocytes; (iv) and the secretion of the excitotoxic neurotransmitter glutamate. Lastly, we observed distinct cell-type specific production of inflammatory and effector mediators.

CONCLUSION

These results indicate that Mycobacterium tuberculosis can translocate the blood-brain barrier directly to initiate meningitis.

Central nervous system tuberculosis in Western Sydney: a 10-year retrospective cohort study

BACKGROUND

Central nervous system tuberculosis (CNS-TB) is a rare complication of tuberculosis. There is a lack of data surrounding investigation and management of this in Australia.

AIM

To review CNS-TB cases in Western Sydney, Australia, and understand the epidemiology, investigation, diagnosis, management and outcomes in a low-prevalence setting.

METHODS

Retrospective cohort study of all CNS-TB patients managed in Western Sydney from 2013 to 2022. Demographics, risk factors, clinical presentation, investigations and management were reviewed. Clinical outcomes like hospital length-of-stay, adverse drug reactions, paradoxical reactions, functional disability and treatment outcomes, including cure, treatment failure, loss to follow-up and death, were also measured.

RESULTS

Thirty-nine CNS-TB cases were identified, with 16 (41%) confirmed by nucleic acid amplification test or culture of CNS specimens and 23 (59%) diagnosed presumptively without CNS microbiological confirmation. The median age was 32 years. Thirty-seven (95%) were overseas-born; 27 (69%) had no comorbidities. Presenting symptoms included fever (82%), headache (64%) and weight loss (51%). Twenty-five (64%) used fluoroquinolones and nine (23%) used high-dose rifampicin. Steroids were used in all patients. Six (15%) were prescribed aspirin for primary stroke prevention. Twenty-eight (73%) completed treatment, with one requiring re-treatment for presumed treatment failure. Six (15%) were lost to follow-up, and five (13%) died during their treatment course. Twenty-one (54%) experienced an adverse drug reaction.

CONCLUSION

Tuberculosis is an ongoing public health issue in Australia, with CNS-TB being its most devastating form, and all clinicians to be aware of this rare complication. The efficacy of newer treatment options requires further study.

Tuberculosis Related Movement Disorders: A Systematic Scoping Review Highlighting Geographic Disparities, Phenotypic Patterns, Treatment Responses, and Knowledge Gaps in Global Reporting

BACKGROUND

Tuberculosis (TB) of the central nervous system (CNS) is a severe complication of TB, with movement disorders representing an under-recognized yet impactful manifestation. Despite their clinical significance, knowledge gaps persist in epidemiology, pathophysiology, and management of TB-related movement disorders (TBRMDs).

OBJECTIVE

This scoping review synthesizes evidence on TBRMDs, aiming to characterize their spectrum, evaluate diagnostic approaches, and summarize management strategies and outcomes.

METHODS

Following PRISMA-ScR guidelines, a systematic search of PubMed, EMBASE, and Scopus (final search: December 31, 2024) identified studies of all designs and languages reporting movement disorders in CNS TB. Data extraction, quality assessment (Joanna Briggs Institute tools), and thematic synthesis were conducted.

RESULTS

Of 36 included studies (91 cases), tremor (27.5%), chorea (26.4%), and dystonia (16.5%) were most prevalent. Tremor predominated in tuberculous meningitis (48.9%), while chorea was common in tuberculomas (42.3%). Lesion location correlated with phenomenology: basal ganglia lesions linked to chorea/dystonia, cerebellar involvement to ataxia. Pathogenesis included meningitis (54.9%), tuberculomas (32.9%), and vasculitis (8.8%). Treatment with anti-tubercular therapy and corticosteroids resulted in complete resolution in 43.9% of cases, but 32.9% showed no improvement. Geographically, South America (61.8%) and Asia (19.7%) reported most cases, with a temporal surge post-2000.

CONCLUSION

TBRMDs are heterogeneous in presentation, linked to lesion location and pathogenic mechanisms. Early recognition, multimodal management, and neuroimaging are critical. Significant variability in diagnostic and reporting standards highlights the need for consensus criteria and prospective studies, particularly in high-burden regions. This review underscores the need of global collaborations to optimize clinical care and advance research in this neglected domain.

A Case Report of Acute Ischaemic Stroke Associated with T​uberculous Meningitis

Background

Tuberculous meningitis (TBM) is a severe form of tuberculosis (TB) that affects the meninges, frequently causing major neurological problems. Timely diagnosis and care are crucial to avoid unfavourable consequences, particularly in vulnerable populations.

Purpose

This case report aims to highlight the diagnostic problems and management complications of TBM, especially when combined with rare neurological events such as acute ischaemic stroke (AIS).

Methods

An 84-year-old female presented with disorientation, seizures, aphasia and hemiparesis. The initial imaging revealed normotensive hydrocephalus and bilateral delta activity on the electroencephalogram (EEG). Despite anti-fungal treatment, CT imaging revealed widespread inflammatory alterations. Sputum and cerebrospinal fluid (CSF) tests were done and revealed the presence of Mycobacterium tuberculosis. MRI indicated several acute lesions, which are symptomatic of TBM.

Results

The patient developed AIS, a relatively rare complication of TBM. Treatment was initiated with a combination of anti-TB drugs and corticosteroids. While corticosteroids reduced inflammation and mortality risk, their potential to contribute to long-term disability was noted as an area of concern.

Conclusion

This case underscores the critical role of MRI in the early detection of TBM-related complications. Although corticosteroids improve short-term outcomes, their impact on long-term disability necessitates further research. Effective management strategies tailored to vulnerable populations are essential to improve the prognosis of TBM patients.

Tuberculous Meningitis in a Child: A Rare Presentation of Cytotoxic Lesion of the Corpus Callosum

Tuberculous meningitis (TBM) is the most severe form of tuberculosis, disproportionately affecting vulnerable populations such as young children and people living with human immunodeficiency virus (HIV). Major challenges to accurate and early diagnosis of TBM are the non-specific clinical features which overlap with other infectious syndromes and the lack of adequately sensitive tests to detect Mycobacterium tuberculosis in the cerebrospinal fluid (CSF). Diagnosis is, therefore, still dependent on clinical suspicion along with clinical features, cerebrospinal fluid (CSF) characteristics and, where facilities are available, neuroimaging. Typical neuroimaging features of TBM include hydrocephalus, infarcts, tuberculomas and basal exudates; however, less well described are very rare features such as cytotoxic lesion of the corpus callosum (CLOCC), otherwise known as transient splenic lesion. We describe the first case report of a child with confirmed TBM who had a very rare presentation of CLOCC with complete recovery and present a literature review on the pathophysiology and alternative aetiologies where CLOCC is more commonly seen.

Macrophage Differentiation and Metabolic Adaptation in Mycobacterial Infections

The adaptation of macrophages-the most common tissue-resident immune cells-to metabolic and microbial cues with high local variability is essential for the maintenance of organ integrity. In homeostasis, macrophages show largely predictable tissue-specific differentiation, as recently revealed by multidimensional methods. However, chronic infections with human-adapted pathogens substantially contribute to the differentiation complexity of tissue macrophages, which has been only partially resolved. Specifically, the response to mycobacterial species-which range from Mycobacterium tuberculosis (with highest specificity for humans, broad organ tropism, yet tissue-specific disease phenotypes) to environmental mycobacteria with humans as accidental hosts-may serve as a paradigm of tissue macrophage adaptation mechanisms. While mycobacterial species-specific tissue preferences are partially related to the mode of acquisition and pathogen characteristics, evolutionary convergence with macrophages driven by metabolic features of the target organ likely contributes to infection resistance and immunopathology. In this review, we unravel the mechanisms of tissue-specific macrophage differentiation and its limitations in mycobacterial infections.

Are endocranial granular impressions pathognomonic of tuberculous meningitis or a marker of tuberculous infection? An investigation on a medieval osteoarcheological assemblage from Italy

OBJECTIVES

In recent paleopathological literature, granular impressions on the endocranial surface are considered pathognomonic of tuberculous meningitis. This study aims to verify the presence of granular impressions and assess their relationship with tuberculosis in an archeological human skeletal assemblage.

MATERIALS

The study analyzed the endocranial surfaces of 212 skulls (38 non-adults and 174 adults) from the medieval site of Pieve di Pava, Italy.

METHODS

Macroscopic and stereomicroscopic examination of the endocranial surface was conducted to evaluate the presence, location, and manifestation of granular impressions.

RESULTS

Granular impressions affected more than half of the individuals, with no statistical difference between males and females.

CONCLUSIONS

The high frequency of granular impressions challenges their interpretation as pathognomonic of tuberculous meningitis, a rare complication of tuberculosis affecting the central nervous system. Instead, these lesions should be considered indicative of bacteremia, when bacilli reach the central nervous system and form tubercles on the meninges. It cannot be established whether these tubercles were quiescent or had ruptured, leading to tuberculous meningitis.

SIGNIFICANCE

Based on the pathogenic life cycle of M. tuberculosis, as defined in clinical settings, it seems prudent to consider granular impressions as a marker of tuberculosis infection, rather than of active tuberculosis disease or tuberculous meningitis in paleopathology.

LIMITATIONS

Research limitations include the smaller number of non-adults compared to adults.

SUGGESTIONS FOR FURTHER RESEARCH

Screening of granular impressions in other large osteoarcheological assemblages could provide new and more reliable data on the spread of tuberculosis infection across different social contexts, geographical settings, and historical periods.

Development and validation of a liquid chromatography-tandem mass spectrometry assay for the simultaneous analysis of isoniazid and pyrazinamide in cerebrospinal fluid

For the effective treatment of tuberculosis with first-line anti-tubercular drugs, drug concentrations need to be measured at the site of infection to determine drug exposure. To enable the measurement of the anti-tuberculosis drugs isoniazid and pyrazinamide in the nervous system of patients with tuberculous meningitis, an analytical method was developed and validated for the quantification of these drugs in human cerebrospinal fluid. Samples were prepared by solid phase extraction using Strata-X polymeric extraction plates. The analytes were separated by high-performance liquid chromatography on an Atlantis T3, 100 A, 3 µm, 2.1 mm × 100 mm analytical column with gradient elution, employing a mobile phase that consisted of acetonitrile-methanol-formic acid (50:50:0.1, v/v/v), at a flowrate of 0.25 mL/min. The total run time was 4.5 minutes, and the average retention times of isoniazid and pyrazinamide were 1.1 and 1.3 min, respectively. The analytes and their respective deuterated internal standards were detected on a Sciex API4000 triple quadrupole mass spectrometer applying positive electrospray ionization with multiple reaction monitoring as the detection mode. The method was validated according to the FDA and EMA guidelines. The method was demonstrated to be accurate, reproducible, and robust, showing the necessary sensitivity and specificity for the quantification of isoniazid and pyrazinamide in cerebrospinal fluid. The method was successfully applied to analyze clinical samples from the LASER-TBM and TBM-KIDS clinical studies.

Tuberculous meningitis as an underlying cause of rapid neurological deterioration in a patient with a history of psychiatric disorder: Clinical case report

Tuberculous meningitis (TBM), the least common of extrapulmonary tuberculosis presentations, one of the most severe. Highly prevalent in immunosuppressed individuals it is associated with high mortality and significant neurological sequelae. TBM main complications are hydrocephalus, increased intracranial pressure, and compromised blood flow with poor prognosis. The diagnostic approach is complex, as the manifestations of TBM are nonspecific. In the case reported here, the first symptoms of TBM were masked by clinical manifestations of depressive syndrome (previously diagnosed) and its management with antidepressants. The confirmatory diagnosis was based on GenXpert on cerebrospinal fluid and neuroimaging, as in our case, tools frequently delayed. The patient presented sudden neurological deterioration, probably due to dysregulation of the immune system associated with depression and smoking habits. In areas with a high incidence of TB, neurological manifestations, even in patients with psychiatric disorders, should be considered as a differential diagnosis or infectious comorbidity such as TBM.

Stroke thrombolysis in tuberculous meningitis

A woman in her 30s presented with sudden onset right-sided weakness, speech difficulties and transient loss of consciousness. She had a medical history of migraine, hypothyroidism and cervical lymphadenopathy. On examination, her National Institutes of Health Stroke Scale (NIHSS) score was 8 due to dense right-sided hemiparesis. CT brain imaging showed no intracranial haemorrhage but revealed incidental findings of left supraclavicular and cervical lymphadenopathy. CT intracranial angiogram did not show large vessel occlusion. She received thrombolytic treatment for ischaemic stroke. NIHSS improved to 3 with no immediate complications. Following admission, she developed swinging fever, seizures and fluctuating right-sided weakness. Repeat MRI of the head showed leptomeningeal enhancement. Biopsy of the cervical lymph nodes showed histiocytic granulomatous lymphadenitis, which was suggestive of tuberculous meningitis (TBM). She was treated with quadruple antimicrobial therapy and steroids for TBM, as well as aspirin for ischaemic stroke, which resulted in good clinical improvement.

Additive Effects of Glutathione in Improving Antibiotic Efficacy in HIV-M.tb Co-Infection in the Central Nervous System: A Systematic Review

BACKGROUND

HIV and tuberculosis (TB) co-infection poses a significant health challenge, particularly when involving the central nervous system (CNS), where it leads to severe morbidity and mortality. Current treatments face challenges such as drug resistance, immune reconstitution inflammatory syndrome (IRIS), and persistent inflammation. Glutathione (GSH) has the therapeutic potential to enhance treatment outcomes by improving antibiotic efficacy, reducing inflammation, and mitigating immune dysfunction.

METHODS

Relevant studies were identified through systematic searches of PubMed, Elsevier, WHO, and related databases. Inclusion criteria focused on preclinical and clinical research examining GSH or its precursors in HIV, TB, or co-infection, with emphasis on microbial control, immune modulation, and CNS-related outcomes.

RESULTS

Preclinical studies showed that GSH improves macrophage antimicrobial function, reduces oxidative stress, and limits Mycobacterium tuberculosis (M.tb) growth. Animal models demonstrated reduced bacterial burden in the lungs, liver, and spleen with GSH supplementation, along with enhanced granuloma stability. Clinical studies highlighted increased TH1 cytokine production, reduced inflammatory markers, and improved CD4+ T cell counts in HIV-M.tb co-infected patients. N-acetylcysteine (NAC), a GSH precursor, was shown to significantly enhance the efficacy of first-line TB antibiotics and mitigate treatment-associated toxicity.

DISCUSSION

GSH shows promise as an adjunct therapy for HIV-M.tb co-infection, particularly for cases involving the CNS, where it may improve immune recovery and reduce inflammation. However, evidence is limited by small sample sizes and a lack of randomized trials. Future research should focus on developing CNS-directed GSH formulations and evaluating its integration into current treatment protocols to address the dual burden of HIV and TB, ultimately improving patient outcomes.

Clinical Features and Predictors of Treatment Outcome in Patients with Ocular Tuberculosis from the Netherlands and Indonesia: The OculaR TB in Low versus High Endemic Countries (ORTEC) Study

PURPOSE

To describe and compare clinical features, treatment approaches, and treatment outcomes of ocular tuberculosis (OTB) patients in the Netherlands, a low tuberculosis (TB)-endemic country, and Indonesia, a high TB-endemic country. We also aimed to identify predictors of treatment outcomes.

METHODS

A medical chart review of 339 OTB patients (n = 93 from the Netherlands and n = 246 from Indonesia) was performed. The primary outcome was response to treatment, whether with or without anti-tubercular treatment, after six months of treatment initiation (good versus poor responders).

RESULTS

Indonesian OTB patients displayed a higher prevalence of chest radiograph findings indicative of TB infection (p < 0.001) and concurrent active systemic TB (p = 0.011). Indonesian cohort exhibited a more acute and severe disease profile, including uveitis duration ≤ 3 months (p < 0.001), blindness (p < 0.001), anterior chamber (AC) cells ≥ 2+ (p < 0.001), and posterior synechiae (p < 0.001). Overall proportions of good responders to treatment were 67.6% in the Netherlands and 71.5% in Indonesia. Presence of AC cell ≥ 2+ (adjusted odds ratio (aOR): 2.12, 95% CI: 1.09-4.14), choroidal lesions other than serpiginous-like choroiditis (SLC) or tuberculoma (aOR: 4.47, 95% CI: 1.18-16.90), and retinal vasculitis (aOR: 2.32, 95% CI: 1.10-4.90) at baseline were predictors for poor response to treatment.

CONCLUSIONS

Despite a more severe initial clinical presentation in the Indonesian cohort, the overall treatment outcomes of OTB was comparable in both cohorts. Three baseline clinical features were identified as predictors of treatment outcomes.

Diagnostic Challenges of Tuberculous Meningitis Initially Presenting as Otomastoiditis

Background

Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), remains a major global health problem, with one-third of the world's population infected.

Objective

This report presents five cases of tuberculous meningitis with a particular emphasis on the symptoms and signs of otitis media that, in various combinations, should raise suspicion for tuberculous meningitis.

Case presentation

These cases underscore the diagnostic challenges and clinical complexities associated with tuberculous otitis media, particularly when there is concurrent involvement of the central nervous system. It is crucial for physicians to maintain a high index of suspicion for tuberculosis in patients exhibiting chronic otorrhea that does not respond to conventional treatments, especially in endemic regions or in the presence of systemic symptoms. The use of advanced diagnostic tools and a multidisciplinary approach is essential for achieving timely diagnosis and effective management. Early initiation of antituberculous therapy, coupled with surgical interventions when warranted, can lead to favorable clinical outcomes. However, it is important to note that some patients may experience long-term sequelae, which highlights the necessity for prompt diagnosis and treatment to improve prognosis in those presenting with otitis media.

Conclusion

The findings of this case series contribute to a better understanding of the relationship between otitis media and tuberculous meningitis, advocating for increased awareness among healthcare providers to facilitate early recognition and intervention.

Tuberculosis Meningitis in a 9-Month-Old Girl during the COVID-19 Pandemic

Tuberculous meningitis (TBM) is a serious form of TB disease that can result in high morbidity and mortality, particularly if there are delays in diagnosis and treatment. In this case report, a 9-month-old girl was admitted with persistent vomiting and focal seizures. On examination, she was found to have a right-side hemiparesis. Brain imaging showed intense nodular leptomeningeal enhancement, hydrocephalus, a hypolucent lesion in the left basal ganglia, arterial stenosis and vasculitis, and an old ischemic insult. The patient was initially diagnosed with an acute ischemic stroke and was treated with aspirin and antiepileptic drugs. The patient's condition failed to improve despite initial treatment, leading to further diagnostic procedures. The results uncovered a diagnosis of TBM. The case highlights the importance of considering TBM as a possible cause of neurological symptoms, especially during the coronavirus disease 2019 (COVID-19) pandemic where similar symptoms can be present in cases of neurological complications of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and multisystem inflammatory syndrome in children (MIS-C).

Comparative analysis of pediatric pulmonary and extrapulmonary tuberculosis: A single-center retrospective cohort study in Syria

Background

Tuberculosis (TB) is a global public health challenge, contributing significantly to morbidity and mortality worldwide. This research aims to investigate the epidemiology, clinical characteristics, diagnostic methods, and early mortality rate among pediatric patients with pulmonary tuberculosis (PTB) and extrapulmonary tuberculosis (EPTB) who were admitted to a hospital in Syria.

Methods

This retrospective cohort study was conducted at the University Children's Hospital in Syria, involving pediatric patients diagnosed with TB between January 2013 and January 2023. Data were collected from medical records and encompassed socio-demographic characteristics, diagnostic methods, clinical presentation, chest radiography findings, and patient outcomes. Statistical analysis was performed using SPSS version 25.

Results

A total of 129 patients were included in the study, with 26.4 % diagnosed with PTB and 73.6 % with EPTB. The most common types of EPTB were lymphatic (25.6 %) and gastrointestinal (17.1 %). Patients with PTB and EPTB did not differ significantly in terms of age, weight, or gender. Significant cough was more common in PTB cases (67.6 %), while lymphadenopathy was more prevalent in EPTB cases (48.4 %). Chest X-ray abnormalities were found in 58.1 % of patients, with PTB patients more likely to have abnormal findings (97.1 %). Microbiological confirmation was higher in PTB cases (76.5 %) compared to EPTB cases (25.3 %). The overall mortality rate was 14 %, with higher mortality observed in patients with EPTB (16.8 %), particularly in cases of TB meningitis.

Conclusion

Our study highlights the epidemiological challenges of TB among hospitalized children, with a focus on the complexities of diagnosing and managing EPTB. We emphasize the urgent need for enhanced diagnostic and management strategies, particularly in conflict zones like Syria, where TB control efforts face significant obstacles. Prompt solutions are imperative to improve outcomes, given the high occurrence of EPTB and its associated mortality rates. Clinical recommendations stress the need for comprehensive contact histories and awareness of varied clinical presentations in pediatric TB diagnosis.

Distinctive antibody responses to Mycobacterium tuberculosis in pulmonary and brain infection

Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), remains a global health burden. While M. tuberculosis is primarily a respiratory pathogen, it can spread to other organs, including the brain and meninges, causing TB meningitis (TBM). However, little is known about the immunological mechanisms that lead to differential disease across organs. Attention has focused on differences in T cell responses in the control of M. tuberculosis in the lungs, but emerging data point to a role for antibodies, as both biomarkers of disease control and as antimicrobial molecules. Given an increasing appreciation for compartmentalized antibody responses across the blood-brain barrier, here we characterized the antibody profiles across the blood and brain compartments in TBM and determined whether M. tuberculosis-specific humoral immune responses differed between M. tuberculosis infection of the lung (pulmonary TB) and TBM. Using a high throughput systems serology approach, we deeply profiled the antibody responses against 10 different M. tuberculosis antigens, including lipoarabinomannan (LAM) and purified protein derivative (PPD), in HIV-negative adults with pulmonary TB (n = 10) versus TBM (n = 60). Antibody studies included analysis of immunoglobulin isotypes (IgG, IgM, IgA) and subclass levels (IgG1-4) and the capacity of M. tuberculosis-specific antibodies to bind to Fc receptors or C1q and to activate innate immune effector functions (complement and natural killer cell activation; monocyte or neutrophil phagocytosis). Machine learning methods were applied to characterize serum and CSF responses in TBM, identify prognostic factors associated with disease severity, and define the key antibody features that distinguish TBM from pulmonary TB. In individuals with TBM, we identified CSF-specific antibody profiles that marked a unique and compartmentalized humoral response against M. tuberculosis, characterized by an enrichment of M. tuberculosis-specific antibodies able to robustly activate complement and drive phagocytosis by monocytes and neutrophils, all of which were associated with milder TBM severity at presentation. Moreover, individuals with TBM exhibited M. tuberculosis-specific antibodies in the serum with an increased capacity to activate phagocytosis by monocytes, compared with individuals with pulmonary TB, despite having lower IgG titres and Fcγ receptor-binding capacity. Collectively, these data point to functionally divergent humoral responses depending on the site of infection (i.e. lungs versus brain) and demonstrate a highly compartmentalized M. tuberculosis-specific antibody response within the CSF in TBM. Moreover, our results suggest that phagocytosis- and complement-mediating antibodies may promote attenuated neuropathology and milder TBM disease.

From cytokines to chemokines: Understanding inflammatory signaling in bacterial meningitis

Bacterial meningitis is a serious central nervous system (CNS) infection, claiming millions of human lives annually around the globe. The deadly infection involves severe inflammation of the protective sheath of the brain, i.e., meninges, and sometimes also consists of the brain tissue, called meningoencephalitis. Several inflammatory pathways involved in the pathogenesis of meningitis caused by Streptococcus pneumoniae, Neisseria meningitidis, Escherichia coli, Haemophilus influenzae, Mycobacterium tuberculosis, Streptococcus suis, etc. are mentioned in the scientific literature. Many in-vitro and in-vivo analyses have shown that after the disruption of the blood-brain barrier (BBB), these pathogens trigger several inflammatory pathways including Toll-Like Receptor (TLR) signaling in response to Pathogen-Associated Molecular Patterns (PAMPs), Nucleotide oligomerization domain (NOD)-like receptor-mediated signaling, pneumolysin related signaling, NF-κB signaling and many other pathways that lead to pro-inflammatory cascade and subsequent cytokine release including interleukine (IL)-1β, tumor necrosis factor(TNF)-α, IL-6, IL-8, chemokine (C-X-C motif) ligand 1 (CXCL1) along with other mediators, leading to neuroinflammation. The activation of another protein complex, nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome, also takes place resulting in the maturation and release of IL-1β and IL-18, hence potentiating neuroinflammation. This review aims to outline the inflammatory signaling pathways associated with the pathogenesis of bacterial meningitis leading to extensive pathological changes in neurons, astrocytes, oligodendrocytes, and other central nervous system cells.

Outcomes of central nervous system tuberculosis in Saudi Arabia: a multi-center study

OBJECTIVES

Central nervous system tuberculosis (TB) (CNS-TB) can occur in several forms, including intracranial tuberculoma, tuberculous brain abscess, TB meningitis (TBM), and spinal TB. Early treatment can save lives and prevent severe neurological complications. This study aimed to describe the characteristics and post-treatment outcomes of patients with CNS-TB and identify factors associated with poor outcomes. To the best of our knowledge, this is the largest CNS-TB study till date published in Saudi Arabia.

METHODS

This retrospective cohort study included all patients diagnosed with CNS-TB in three tertiary centers in Saudi Arabia (King Abdulaziz Medical City in Jeddah, King Abdulaziz Medical City in Riyadh, and Al-Noor Specialist Hospital in Makkah) between 2009 and 2019. Data of patients' demographics, co-morbidities, presenting symptoms, type of CNS-TB, medical and surgical treatments, and outcome after completion of treatment were obtained from medical records. Treatment outcomes were categorized using the modified Rankin Scale for neurological disability.

RESULTS

A total of 140 participants were included in this study from 2009 to 2019. Good outcomes were achieved in approximately 65% of cases, whereas 35% had poor outcomes based on the modified Rankin Scale. Glasgow Coma Scale score ≤10 at presentation and TBM/tuberculoma were significantly associated with poor outcomes. Moreover, the use of corticosteroids, more than three anti-TB medications, and surgical interventions were not significantly associated with good or poor outcomes.

DISCUSSION

CNS-TB is associated with a high burden of long-term neurological morbidity. Early detection and treatment are crucial to prevent serious complications and decrease morbidity and mortality.

Navigating complex care pathways-healthcare workers' perspectives on health system barriers for children with tuberculous meningitis in Cape Town, South Africa

Tuberculous meningitis (TBM) occurs when tuberculosis (TB) bacilli disseminate and seed into the meninges, triggering a severe inflammatory response that often leads to brain infarction. It is the most severe and debilitating form of childhood TB with high mortality, and children who survive TBM often suffer lifelong physical and neuro-disability resulting in emotional, social, and economic burdens for families. In the early stages the symptoms may be non-specific and so the diagnosis is often made late when the patient already has significant brain injury. To facilitate earlier diagnosis, it is important to understand how patients are evaluated. This study aimed to chart health systems for paediatric TBM care at both primary healthcare (PHC) and hospital level in Cape Town, South Africa. We conducted fourteen in-depth interviews and eight days of semi-structured observations of patient flow across eight healthcare facilities. We found that children with TBM navigate multiple levels of care categorised into pre-admission and primary care, hospital admission and inpatient care, and post-discharge follow-up care. Healthcare workers identified the following health system barriers along the TBM care pathway for children: limited post-training and mentorship opportunities to manage TBM, overburdened facilities, time constraints, lack of recognition of TBM symptoms, delays in referral between PHC and hospital, lack of standardized diagnostic algorithms, limited diagnostic tests and a lack of child-friendly, easy-to-administer treatment. Regular and compulsory training on TB and TBM in children, including continuous mentoring and support to healthcare workers working in child health and TB services in high TB-burden settings, can facilitate early recognition of symptoms and rapid referral for diagnosis. Algorithms outlining referral criteria for patients with possible TBM at both PHC facilities and district level hospitals can guide healthcare providers and facilitate timely referral between different levels of healthcare services. An integrated data system and alert functions could flag multiple healthcare visits and improve communication between different healthcare facilities during diagnosis and treatment. Children and families affected by TBM are an especially vulnerable sub-population requiring high priority attention and support.

Diagnostic Utility of the "Lancet Consensus Scoring System" in Suspected Cases of Tuberculous Meningitis in Patients Attending a Tertiary Care Hospital in Central India

BACKGROUND

Tuberculous meningitis (TBM) is a challenging condition to diagnose, and current laboratory methods have limitations, especially in developing countries. This study evaluated the diagnostic utility of the Lancet consensus scoring (LCS) system in suspected TBM cases at a tertiary care center in India.

METHODS

The clinical manifestations of 75 patients with suspected TBM were prospectively evaluated using the LCS system, which categorizes cases as "definite" (laboratory confirmed), "probable" (>10 points without imaging or > 12 points with imaging), and "possible" (6-9 points without imaging or 6-11 points with imaging). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the LCS system were compared to GeneXpert and mycobacterial growth indicator tube (MGIT) liquid culture, which are considered the gold standard tests.

RESULTS

Out of 75 recruited cases, 11 were confirmed as definite TBM cases. The LCS system correctly identified 8 of these as "probable" and 3 as "possible" cases. Compared to GeneXpert, the LCS system had a specificity of 100%, sensitivity of 54.55%, NPV of 92.7%, and PPV of 100%. Compared to MGIT liquid culture, the LCS system had a specificity of 100%, sensitivity of 81.82%, NPV of 96.97%, and PPV of 100%. The diagnostic accuracy was higher for MGIT liquid culture (97.33%) than GeneXpert (93.33%).

CONCLUSION

The LCS system is a practical and easily applicable tool that can aid the diagnosis of suspected TBM cases, particularly in resource-limited settings. Despite some limitations, the LCS system demonstrated good diagnostic performance, suggesting its potential utility in improving TBM diagnosis and management.

Efficacy and prognostic value of peripheral blood CD4+ T cells and serum IL-6 and IL-8 in tuberculous meningitis

Objective

To investigate the value of peripheral blood clusters of differentiation 4 (CD4+) T-lymphocyte (T cells) count and serum interleukin-6 (IL-6) and interleukin-8 (IL-8) in the treatment and prognosis of tuberculous meningitis (TBM).

Methods

Sixty-five patients with TBM were prospectively included in the observation group. Sixty-five patients with pulmonary TB and a group of 65 healthy individuals served as the control groups. The differences in peripheral blood CD4+ T-cell count, serum IL-6, and IL-8 levels were compared, and changes in these indices after anti-TB treatment in the observation group were analysed. The observation group was divided into effective and ineffective groups based on their response after 24 weeks of anti-TB treatment. The study also evaluated the influence of peripheral blood CD4+ T-cell count, serum IL-6, and IL-8 levels on the adverse prognosis of TBM during anti-TB treatment.

Results

Before treatment, the CD4+ T-cell count in the peripheral blood of the observation group was lower than in both the control and healthy groups, and serum IL-6 and IL-8 levels were higher than in the control group (P < 0.001). After 24 weeks of anti-TB treatment, the CD4+ T-cell count in the peripheral blood of the observation group increased, whereas the levels of IL-6 and IL-8 decreased significantly (P < 0.001). The levels of CD4+ T cells and IL-6 in the peripheral blood of patients before treatment were identified as independent factors influencing the efficacy of anti-TB treatment (odds ratio [OR] = 0.989, 95 % confidence interval [CI]: 0.980-0.997; OR = 1.010, 95 % CI: 1.003-1.017).

Conclusion

In patients with TBM, the CD4+ T-cell count in the peripheral blood is decreased, whereas serum IL-6 and IL-8 are increased. The combination of CD4+ T cells and IL-8 shows a degree of predictive value for the prognosis of anti-TB treatment.

The application value of cerebrospinal fluid immunoglobulin in tuberculous meningitis

This article aims to study the value of cerebrospinal fluid (CSF) immunoglobulin in differential diagnosis, prediction, and prognosis of tuberculous meningitis (TBM). The clinical data of 65 patients with TBM in our hospital were collected, and 65 patients with cryptococcal meningitis (CM) were enrolled in 1:1 matching. Relevant data were collected for comparison. CSFs IgG [331.51 (164.85, 645.00) vs 129.00 (55.05, 251.00) ng/mL], IgM [22.38 (8.52, 40.18) vs 6.08 (2.19, 23.30) ng/mL], and IgA [64.11 (21.44, 115.48) vs 16.55 (4.76, 30.36) ng/mL] in the TBM group were higher than those in the CM group (P < 0.001). In the TBM group, after 24 weeks of treatment, the CSFs IgG, IgM, and IgA were significantly decreased, and the difference was statistically significant (P < 0.05). The predictive results of CSF immunoglobulin for TBM showed that IgG, IgM, and IgA all had some predictive value for TBM, and the combined predictive value of the three was the highest, with an area under the curve of 0.831 (95% CI: 0.774-0.881). Logistic regression analysis of CSF immunoglobulins and TBM prognosis showed that IgG [odds ratio (OR) = 4.796, 95% confidence interval (CI): 2.575-8.864], IgM (OR = 3.456, 95% CI: 2.757-5.754), and IgA (OR = 4.371, 95% CI: 2.731-5.856) were TBM risk factors for poor prognosis in patients. The levels of IgG, IgM, and IgA in CSF were positively correlated with the severity of cranial magnetic resonance imaging (MRI) in TBM patients (R2 = 0.542, F = 65.392, P < 0.05). CSFs IgG, IgM, and IgA can be used as a routine monitoring index for TBM patients, which has a certain reference value in differential diagnosis and efficacy evaluation.

IMPORTANCE

In clinical practice, physicians can determine the physical conditions of patients based on the levels of cerebrospinal fluids (CSFs) IgG, IgM, and IgA. Higher levels of CSFs IgG, IgM, and IgA suggest more possibility of tuberculous meningitis and worse prognosis and magnetic resonance imaging manifestations.

Continuous evaluation of single-dose moxifloxacin concentrations in brain extracellular fluid, cerebrospinal fluid, and plasma: a novel porcine model

BACKGROUND

Knowledge regarding CNS pharmacokinetics of moxifloxacin is limited, with unknown consequences for patients with meningitis caused by bacteria resistant to beta-lactams or caused by TB.

OBJECTIVE

(i) To develop a novel porcine model for continuous investigation of moxifloxacin concentrations within brain extracellular fluid (ECF), CSF and plasma using microdialysis, and (ii) to compare these findings to the pharmacokinetic/pharmacodynamic (PK/PD) target against TB.

METHODS

Six female pigs received an intravenous single dose of moxifloxacin (6 mg/kg) similar to the current oral treatment against TB. Subsequently, moxifloxacin concentrations were determined by microdialysis within five compartments: brain ECF (cortical and subcortical) and CSF (ventricular, cisternal and lumbar) for the following 8 hours. Data were compared to simultaneously obtained plasma samples. Chemical analysis was performed by high pressure liquid chromatography with mass spectrometry. The applied PK/PD target was defined as a maximum drug concentration (Cmax):MIC ratio >8.

RESULTS

We present a novel porcine model for continuous in vivo CNS pharmacokinetics for moxifloxacin. Cmax and AUC0-8h within brain ECF were significantly lower compared to plasma and lumbar CSF, but insignificantly different compared to ventricular and cisternal CSF. Unbound Cmax:MIC ratio across all investigated compartments ranged from 1.9 to 4.3.

CONCLUSION

A single dose of weight-adjusted moxifloxacin administered intravenously did not achieve adequate target site concentrations within the uninflamed porcine brain ECF and CSF to reach the applied TB CNS target.

E3 ubiquitin ligase CBLB regulates innate immune responses and bacterial dissemination during nontuberculous mycobacteria infection

Nontuberculous mycobacteria (NTM) are emerging opportunistic pathogens causing pulmonary infection to fatal disseminated disease. NTM infections are steadily increasing in children and adults, and immune-compromised individuals are at a greater risk of fatal infections. The NTM disease's adverse pathology and resistance to antibiotics have further worsened the therapeutic measures. Innate immune regulators are potential targets for therapeutics to NTM, especially in a T cell-suppressed population, and many ubiquitin ligases modulate pathogenesis and innate immunity during infections, including mycobacterial infections. Here, we investigated the role of an E3 ubiquitin ligase, Casitas B-lineage lymphoma proto-oncogene B (CBLB), in immunocompromised mouse models of NTM infection. We found that CBLB is essential to prevent bacterial growth and dissemination. Cblb deficiency debilitated natural killer cells, inflammatory monocytes, and macrophages in vivo. However, Cblb deficiency in macrophages did not wane its ability to inhibit bacterial growth or production of reactive oxygen species or interferon γ production by natural killer cells in vitro. CBLB restricted NTM growth and dissemination by promoting early granuloma formation in vivo. Our study shows that CBLB bolsters innate immune responses and helps prevent the dissemination of NTM during compromised T cell immunity.

Potential of Neuroinflammation-Modulating Strategies in Tuberculous Meningitis: Targeting Microglia

Tuberculous meningitis (TBM) is the most severe complication of tuberculosis (TB) and is associated with high rates of disability and mortality. Mycobacterium tuberculosis (M. tb), the infectious agent of TB, disseminates from the respiratory epithelium, breaks through the blood-brain barrier, and establishes a primary infection in the meninges. Microglia are the core of the immune network in the central nervous system (CNS) and interact with glial cells and neurons to fight against harmful pathogens and maintain homeostasis in the brain through pleiotropic functions. However, M. tb directly infects microglia and resides in them as the primary host for bacillus infections. Largely, microglial activation slows disease progression. The non-productive inflammatory response that initiates the secretion of pro-inflammatory cytokines and chemokines may be neurotoxic and aggravate tissue injuries based on damages caused by M. tb. Host-directed therapy (HDT) is an emerging strategy for modulating host immune responses against diverse diseases. Recent studies have shown that HDT can control neuroinflammation in TBM and act as an adjunct therapy to antibiotic treatment. In this review, we discuss the diverse roles of microglia in TBM and potential host-directed TB therapies that target microglia to treat TBM. We also discuss the limitations of applying each HDT and suggest a course of action for the near future.

Role of MicroRNAs as post transcription regulators of matrix metalloproteinases and their association in tuberculous meningitis

Matrix metalloproteinases (MMPs) have a role in driving neuroinflammation in infectious as well as non-infectious diseases; however, recent reports have potentiated the role of microRNAs in regulating MMPs at post-transcriptional levels, leading to dysregulation of crucial MMP functions like tissue remodelling, blood brain barrier integrity, etc. In present study, microRNAs regulating MMPs (MMP2 and MMP3) were selected from database search followed by literature support. Expression of these microRNAs i.e., hsa-miR-495-3p, hsa-miR-132-3p and hsa-miR-21-5p was assessed by RT-PCR and the protein levels of MMPs were assessed by ELISA in the cerebrospinal fluid (CSF) of tuberculous meningitis (TBM) patients, healthy controls (HC) and non-infectious neuroinflammatory disease (NID) patients. The expression of hsa-miR-495-3p and hsa-miR-132-3p showed downregulation in TBM while hsa-miR-21-5p was overexpressed as compared to healthy controls. Moreover, MMP levels were found to be deranged with a significant increase in MMP3 levels in the TBM and NID patients compared to HC group. These observations highlight dysregulated microRNAs (hsa-miR-495-3p, hsa-miR-21-5p and hsa-miR-132-3p) levels might impair the levels of MMPs (MMP2 and MMP3) leading to neuroinflammation in TBM and NID population. These findings can further be applied to target these microRNAs for developing newer treatment modalities for better complication management.

Magnetic resonance imaging findings in central nervous system tuberculosis: A pictorial review

Central nervous system (CNS) tuberculosis is a post-primary form of tuberculosis. It has high mortality and morbidity rates despite early diagnosis and treatment. CNS tuberculosis can manifest as subacute/chronic meningitis, parenchymal tuberculous lesions, and spinal tuberculosis. Hematogenous spread of tuberculous bacilli to the brain results in the development of so called "rich foci" on the pial surface, ependyma, and grey-white matter junction. Rupture of these "rich foci" into the subarachnoid space triggers an intense granulomatous inflammatory reaction. Tuberculous meningitis can manifest as leptomeningitis or pachymeningitis. Intracranial parenchymal tuberculous lesions may present as tuberculoma, tuberculous abscess, cerebritis, rhombencephalitis, and encephalopathy, with atypical presentations not uncommon. Complications of CNS tuberculosis encompass hydrocephalus, syrinx formation, vasculitis, infarcts, neuritis, and enduring neurological deficits. Post-contrast 3D fluid-attenuated inversion recovery (FLAIR) and post-contrast T1 spin-echo sequences excel in detecting tuberculous meningitis compared to other conventional magnetic resonance imaging (MRI) sequences. In proton magnetic resonance spectroscopy (PMRS), the presence of a lipid peak at 1.3 ppm is indicative of tuberculous lesions. Magnetization transfer (MT) imaging enhances the detection of tuberculous lesions, as the magnetization transfer ratio (MTR) of tuberculous pathologies, owing to their high lipid content, is lower than that in bacterial or fungal pathologies and higher than that in viral pathologies. This review article delves into the various typical and atypical imaging presentations of CNS tuberculosis in MRI, along with recent advances in imaging techniques.

Comprehensive Therapeutic Approaches to Tuberculous Meningitis: Pharmacokinetics, Combined Dosing, and Advanced Intrathecal Therapies

Tuberculous meningitis (TBM) presents a critical neurologic emergency characterized by high mortality and morbidity rates, necessitating immediate therapeutic intervention, often ahead of definitive microbiological and molecular diagnoses. The primary hurdle in effective TBM treatment is the blood-brain barrier (BBB), which significantly restricts the delivery of anti-tuberculous medications to the central nervous system (CNS), leading to subtherapeutic drug levels and poor treatment outcomes. The standard regimen for initial TBM treatment frequently falls short, followed by adverse side effects, vasculitis, and hydrocephalus, driving the condition toward a refractory state. To overcome this obstacle, intrathecal (IT) sustained release of anti-TB medication emerges as a promising approach. This method enables a steady, uninterrupted, and prolonged release of medication directly into the cerebrospinal fluid (CSF), thus preventing systemic side effects by limiting drug exposure to the rest of the body. Our review diligently investigates the existing literature and treatment methodologies, aiming to highlight their shortcomings. As part of our enhanced strategy for sustained IT anti-TB delivery, we particularly seek to explore the utilization of nanoparticle-infused hydrogels containing isoniazid (INH) and rifampicin (RIF), alongside osmotic pump usage, as innovative treatments for TBM. This comprehensive review delineates an optimized framework for the management of TBM, including an integrated approach that combines pharmacokinetic insights, concomitant drug administration strategies, and the latest advancements in IT and intraventricular (IVT) therapy for CNS infections. By proposing a multifaceted treatment strategy, this analysis aims to enhance the clinical outcomes for TBM patients, highlighting the critical role of targeted drug delivery in overcoming the formidable challenges presented by the blood-brain barrier and the complex pathophysiology of TBM.

A Case of Multiple Brain Tuberculomas in the Subarachnoid Cisterns: Recognition of Radiological Characteristics Regarding the Development of Paradoxical Response during Antituberculosis Treatment

Brain tuberculoma and its occurrence within the subarachnoid cisterns is rare in Japan. Serological and cerebrospinal fluid (CSF) examinations and imaging findings lack specificity; thus, preoperative diagnosis is often challenging. This report presents the case of a 70-year-old woman admitted to our hospital with a one-month history of low-grade fever and altered mental status. Based on the CSF analysis and her history of latent tuberculosis infection seven years ago, she was strongly suspected of suffering from tuberculous meningitis (TBM). Consequently, the patient was enrolled in a clinical trial for antituberculosis treatment (ATT). CSF soluble interleukin-2 receptor level decreased from 2,926 U/mL on day 1 to 225 U/mL 42 days after initiating ATT. Her condition improved after five weeks; however, contrast-enhanced T1-weighted magnetic resonance imaging (MRI) revealed multiple enhanced lesions within the basal subarachnoid cisterns 25 days after admission. As the number and size of these lesions increased, a biopsy confirmed brain tuberculoma diagnosis, and the treatment was continued. In conclusion, when intracisternal scattered mass lesions are identified during TBM treatment, we should consider the possibility of tuberculoma developments arising from a paradoxical response (PR) during the treatment. Serial MRIs are crucial in monitoring PR development in cisternal tuberculomas, an extension of severe TBM. Finally, a PR can be effectively managed by continuing ATT with adjunctive corticosteroids.

Imaging of supra-thoracic tuberculosis

Tuberculosis (TB) typically affects the lungs, but may involve many extra-pulmonary sites; with the latter especially prone in patients with human immunodeficiency virus infection. The clinical features of extra-pulmonary TB are often non-specific, mimicking many different disease entities. Application of the most appropriate imaging modality and knowing the imaging findings with clinical context awareness help initiation of further investigations, diagnosis and early treatment. This pictorial essay highlights the imaging spectrum of extra-pulmonary TB affecting the supra-thoracic region, i.e. brain, neck, and ear, nose and throat.

Urinary metabolic characterization of advanced tuberculous meningitis cases in a South African paediatric population

Tuberculous meningitis (TBM) is a severe form of tuberculosis with high neuro-morbidity and mortality, especially among the paediatric population (aged ≤12 years). Little is known of the associated metabolic changes. This study aimed to identify characteristic metabolic markers that differentiate severe cases of paediatric TBM from controls, through non-invasive urine collection. Urine samples selected for this study were from two paediatric groups. Group 1: controls (n = 44): children without meningitis, no neurological symptoms and from the same geographical region as group 2. Group 2: TBM cases (n = 13): collected from paediatric patients that were admitted to Tygerberg Hospital in South Africa on the suspicion of TBM, mostly severely ill; with a later confirmation of TBM. Untargeted 1H NMR-based metabolomics data of urine were generated, followed by statistical analyses via MetaboAnalyst (v5.0), and the identification of important metabolites. Twenty nine urinary metabolites were identified as characteristic of advanced TBM and categorized in terms of six dysregulated metabolic pathways: 1) upregulated tryptophan catabolism linked to an altered vitamin B metabolism; 2) perturbation of amino acid metabolism; 3) increased energy production-metabolic burst; 4) disrupted gut microbiota metabolism; 5) ketoacidosis; 6) increased nitrogen excretion. We also provide original biological insights into this biosignature of urinary metabolites that can be used to characterize paediatric TBM patients in a South African cohort.

The Role of Oxidative Stress in TB Meningitis and Therapeutic Options

Meningitis is an inflammatory condition affecting the meninges surrounding the brain and spinal cord. Meningitis can be triggered by various factors, including infectious agents like viruses and bacteria and non-infectious contributors such as cancer or head injuries. The impact of meningitis on the central nervous system involves disruptions in the blood-brain barrier, cellular infiltrations, and structural alterations. The clinical features that differentiate between tuberculous meningitis (TBM) and non-tuberculous meningitis (NTM) are discussed in this review and aid in accurate diagnosis. The intricate interplay of reactive oxygen species, ferroptosis, and reactive nitrogen species within the central nervous system reveals a promising field of research for innovative therapeutic strategies tailored to TBM. This review highlights the alternative treatments targeting oxidative stress-induced TBM and ferroptosis, providing potential avenues for intervention in the pathogenesis of this complex condition.

Risk factors for tuberculosis-related death among adults with drug-sensitive pulmonary tuberculosis in Selangor, Malaysia from 2013 to 2019: a retrospective cohort study using surveillance data

OBJECTIVES

Due to the paucity of literature on risk factors for tuberculosis (TB)-related death, we determine the sociodemographic and clinical risk factors associated with TB-related deaths among adult pulmonary TB (PTB) patients on treatment in Selangor, Malaysia.

DESIGN

Retrospective cohort study.

SETTING

Routinely collected primary care data from all government TB clinics in Selangor.

PARTICIPANTS

Data of 24 570 eligible adult PTB patients from 2013 to 2019 were obtained from Selangor's State Health Department surveillance records. We included PTB patients aged at least 15 years old at the time of diagnosis with complete documentation of the dates of diagnosis, treatment initiation, end of treatment/follow-up and treatment outcomes. We excluded patients whose diagnoses were changed to non-TB, post-mortem TB diagnosis and multidrug-resistant TB (MDR-TB) patients.

PRIMARY AND SECONDARY OUTCOME MEASURES

TB-related death, determined from the recorded physicians' consensus during the TB mortality meeting.

RESULTS

TB-related death was significantly associated with far (adjusted HR (aHR) 9.98, 95% CI 4.28 to 23.28) and moderately advanced (aHR 3.23, 95% CI 1.43 to 7.31) radiological findings at diagnosis; concurrent TB meningitis (aHR 7.67, 95% CI 4.53 to 12.98) and miliary TB (aHR 6.32, 95% CI 4.10 to 9.74) involvement; HIV positive at diagnosis (aHR 2.81, 95% CI 2.21 to 3.57); Hulu Selangor (aHR 1.95, 95% CI 1.29 to 2.93), Klang (aHR 1.53, 95% CI 1.18 to 1.98) and Hulu Langat (aHR 1.31, 95% CI 1.03 to 1.68) residing districts; no formal education (aHR 1.70, 95% CI 1.23 to 2.35); unemployment (aHR 1.54, 95% CI 1.29 to 1.84), positive sputum smear acid-fast bacilli (AFB) at diagnosis (aHR 1.51, 95% CI 1.22 to 1.85); rural residency (aHR 1.39, 95% CI 1.13 to 1.72) and advancing age (aHR 1.03, 95% CI 1.02 to 1.03).

CONCLUSIONS

Far and moderately advanced radiological findings, concurrent TB meningitis and miliary TB involvement, HIV positive, Hulu Selangor, Klang and Hulu Langat residing districts, no formal education, unemployment, positive sputum smear AFB, rural residency and advancing age are risk factors of TB-related death. Our findings should assist in identifying high-risk patients requiring interventions against TB-related death.

Neuroinfectious Diseases in Children: Pathophysiology, Outcomes, and Global Challenges

Pathogens with affinity for the central nervous system (CNS) in children are diverse in their mechanisms of infecting and attacking the brain. Infections can reach the CNS via hematogenous routes, transneurally thereby avoiding the blood-brain barrier, and across mucosal or skin surfaces. Once transmission occurs, pathogens can wreak havoc both by direct action on host cells and via an intricate interplay between the protective and pathologic actions of the host's immune system. Pathogen prevalence varies depending on region, and susceptibility differs based on epidemiologic factors such as age, immune status, and genetics. In addition, some infectious diseases are monophasic, whereas others may lie dormant for years, thereby causing a dynamic effect on outcomes. Outcomes in survivors are highly variable for each particular pathogen and depend on the vaccination and immune status of the patient as well as the speed by which the patient receives evidence-based treatments. Given pathogens cause communicable diseases that can cause morbidity and mortality on a population level when spread, the burden is often the greatest and the outcomes the worst in low-resource settings. Here we will focus on the most common infections with a propensity to affect a child's brain, the pathologic mechanisms by which they do so, and what is known about the developmental outcomes in children who are affected by these infections.

The influence of fixation and cryopreservation of cerebrospinal fluid on antigen expression and cell percentages by flow cytometric analysis

The pauci-cellular nature of cerebrospinal (CSF), particularly ventricular CSF, and the rapid cell death following sampling, incumbers the use of flow cytometric analysis of these samples in the investigation of central nervous system (CNS) pathologies. Developing a method that allows long-term storage and batched analysis of CSF samples without compromising cell integrity is highly desirable in clinical research, given that CSF is often sampled after hours creating logistical difficulties for fresh processing. We examined percentages and relative proportion of peripheral and brain-derived immune cells in cryopreserved and transfix-treated CSF, compared to freshly processed CSF. Cell proportions were more comparable between Fresh and Cryopreserved CSF (mean of differences = 3.19), than between fresh and transfix-treated CSF (mean of differences = 14.82). No significant differences in cell percentages were observed in fresh versus cryopreserved CSF; however significantly lower cell percentages were observed in transfix-treated CSF compared to Fresh CSF [(CD11b++ (p = 0.01), CD4+ (p = 0.001), CD8+ (p = 0.007), NK cells (p = 0.04), as well as CD69+ activation marker (p = 0.001)]. Furthermore, loss of marker expression of various lymphocyte sub-populations were observed in transfix-treated CSF. Cryopreservation is a feasible option for long-term storage of ventricular CSF and allows accurate immunophenotyping of peripheral and brain-derived cell populations by flow cytometry.

Recent advances in understanding the human host immune response in tuberculous meningitis

Tuberculous meningitis (TBM), the most severe form of tuberculosis, causes death in approximately 25% cases despite antibiotic therapy, and half of survivors are left with neurological disability. Mortality and morbidity are contributed to by a dysregulated immune response, and adjunctive host-directed therapies are required to modulate this response and improve outcomes. Developing such therapies relies on improved understanding of the host immune response to TBM. The historical challenges in TBM research of limited in vivo and in vitro models have been partially overcome by recent developments in proteomics, transcriptomics, and metabolomics, and the use of these technologies in nested substudies of large clinical trials. We review the current understanding of the human immune response in TBM. We begin with M. tuberculosis entry into the central nervous system (CNS), microglial infection and blood-brain and other CNS barrier dysfunction. We then outline the innate response, including the early cytokine response, role of canonical and non-canonical inflammasomes, eicosanoids and specialised pro-resolving mediators. Next, we review the adaptive response including T cells, microRNAs and B cells, followed by the role of the glutamate-GABA neurotransmitter cycle and the tryptophan pathway. We discuss host genetic immune factors, differences between adults and children, paradoxical reaction, and the impact of HIV-1 co-infection including immune reconstitution inflammatory syndrome. Promising immunomodulatory therapies, research gaps, ongoing challenges and future paths are discussed.

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.

A preclinical model of TB meningitis to determine drug penetration and activity at the sites of disease

Tuberculosis meningitis (TBM) is essentially treated with the first-line regimen used against pulmonary tuberculosis, with a prolonged continuation phase. However, clinical outcomes are poor in comparison, for reasons that are only partially understood, highlighting the need for improved preclinical tools to measure drug distribution and activity at the site of disease. A predictive animal model of TBM would also be of great value to prioritize promising drug regimens to be tested in clinical trials, given the healthy state of the development pipeline for the first time in decades. Here, we report the optimization of a rabbit model of TBM disease induced via inoculation of Mycobacterium tuberculosis into the cisterna magna, recapitulating features typical of clinical TBM: neurological deterioration within months post-infection, acid-fast bacilli in necrotic lesions in the brain and spinal cord, and elevated lactate levels in cerebrospinal fluid (CSF). None of the infected rabbits recovered or controlled the disease. We used young adult rabbits, the size of which allows for spatial drug quantitation in critical compartments of the central nervous system that cannot be collected in clinical studies. To illustrate the translational value of the model, we report the penetration of linezolid from plasma into the CSF, meninges, anatomically distinct brain areas, cervical spine, and lumbar spine. Across animals, we measured the bacterial burden concomitant with neurological deterioration, offering a useful readout for drug efficacy studies. The model thus forms the basis for building a preclinical platform to identify improved regimens and inform clinical trial design.

Central Nervous System Tuberculosis: Risk Factors for Mortality in a Propensity Score-Matched Case-Control Study

Background

Despite advancements in tuberculosis (TB) control and treatment in the United States (US), patients with central nervous system TB (CNS-TB) continue to experience significantly higher mortality rates than those without CNS-TB. This raises concerns regarding clinical management and the need for a deeper understanding of the risk factors contributing to these deaths. This study aimed to determine the predictors of mortality in patients with CNS-TB.

Methods

We conducted a retrospective 1:2 propensity score-matched case-control study. Cases were TB patients diagnosed with TB of the meninges, brain, spinal cord, or peripheral nerves, as documented in the Florida Department of Health (FDOH) TB registry, between 2009 and 2021. Controls were TB patients without CNS-TB, also reported in the FDOH TB registry during the same timeframe. We employed conditional logistic regression models to investigate the factors contributing to mortality in cases compared with controls.

Results

We analyzed data from 116 cases and 232 matched controls. Patients with CNS-TB had a 5.69-fold higher risk of death than those without CNS-TB (adjusted odds ratio [aOR], 5.69 [95% confidence interval {CI}, 2.91-11.6]). Increased risk of death was associated with human immunodeficiency virus (HIV) coinfection (aOR, 1.93 [95% CI, .82-4.37]) and diabetes (aOR, 3.13 [95% CI, 1.28-7.47]). Miliary TB and non-HIV immunosuppression were significantly associated with being a case, while cavitary TB was less likely to be associated with being a case.

Conclusions

Clinical management should prioritize screening and close monitoring of patients with HIV coinfection and diabetes to improve patient outcomes.

Same Pathogen, Different Manifestations: A Case of Extrapulmonary Tuberculosis

Tuberculosis (TB) remains the most prevalent contagious disease worldwide and a significant cause of morbidity, ranking as the second most deadly disease globally. The transmission of the disease occurs through aerosols via the respiratory route, predominantly affecting pulmonary tissue. However, the pathogen can disseminate and infect any organ within the body. Up to 15% of patients exhibit extrapulmonary involvement. The case involves a 59-year-old male who presented to the emergency department complaining of abdominal pain and subfebrile episodes, without any other significant symptoms or findings on physical examination. Laboratory investigations revealed elevated inflammatory markers and abnormal liver biochemistry parameters. A computed tomography (CT) scan showed a neoformative lesion in the liver - a collection with a vascularized, thick, irregular wall. This raised the possibility of a potentially hypervascular hepatic neoformation or an encysted inflammatory lesion. The patient was started on empirical broad-spectrum antibiotics and was admitted to the Internal Medicine ward for further investigation. Later, the patient began to exhibit a decline in overall condition, a slowed and less complex speech pattern, loss of balance, and distal tremors in the upper limbs, as well as a symmetric and distal reduction in strength in all four limbs. A cerebral CT scan revealed no significant abnormalities, and a lumbar puncture yielded no immediate notable findings. Simultaneously, a repeated abdominal CT scan showed the previously known hepatic lesion, albeit with features more indicative of a multiloculated collection. An aspirative biopsy of the hepatic abscess was conducted. From the extensive analysis conducted, a positive PCR result for mycobacterium tuberculosis was identified in both the pus from the hepatic abscess and the cerebrospinal fluid. This led to the conclusion that the case presented was an instance of extrapulmonary TB involving the liver and the central nervous system. Following the identification of the causative agent, the patient commenced antibacterial therapy comprising rifampicin, ethambutol, and isoniazid with adjunctive dexamethasone. Despite targeted treatment and instituted supportive therapy, the patient exhibited an unfavorable progression and eventually succumbed 57 days after diagnosis. This case highlights an unusual manifestation of a patient with disseminated extrapulmonary TB, emphasizing the importance of early diagnostic suspicion for clinicians. The unfavorable disease progression despite appropriate targeted treatment prompts reflection on whether the delay in diagnosis and provision of anti-TB drugs may have played a major role in the prognosis of the patient.

Advancing Diagnosis and Treatment in People Living with HIV and Tuberculosis Meningitis

PURPOSE OF REVIEW

Tuberculous meningitis (TBM) is the most severe form of tuberculosis. Inadequate diagnostic testing and treatment regimens adapted from pulmonary tuberculosis without consideration of the unique nature of TBM are among the potential drivers. This review focuses on the progress being made in relation to both diagnosis and treatment of TBM, emphasizing promising future directions.

RECENT FINDINGS

The molecular assay GeneXpert MTB/Rif Ultra has improved sensitivity but has inadequate negative predictive value to "rule-out" TBM. Evaluations of tests focused on the host response and bacterial components are ongoing. Clinical trials are in progress to explore the roles of rifampin, fluoroquinolones, linezolid, and adjunctive aspirin. Though diagnosis has improved, novel modalities are being explored to improve the rapid diagnosis of TBM. Multiple ongoing clinical trials may change current therapies for TBM in the near future.

The Neuro-Ophthalmology of Tuberculosis

Tuberculosis (TB) is a global health concern and central nervous system (CNS) TB leads to high mortality and morbidity. CNS TB can manifest as tubercular meningitis, tuberculoma, myelitis, and arachnoiditis. Neuro-ophthalmological involvement by TB can lead to permanent blindness, ocular nerve palsies and gaze restriction. Visual impairment is a dreaded complication of tubercular meningitis (TBM), which can result from visual pathway involvement at different levels with varying pathogenesis. Efferent pathway involvement includes cranial nerve palsies and disorders of gaze. The purpose of this review is to outline the various neuro-ophthalmological manifestations of TB along with a description of their unique pathogenesis and management. Optochiasmatic arachnoiditis and tuberculomas are the most common causes of vision loss followed by chronic papilloedema. Abducens nerve palsy is the most commonly seen ocular nerve palsy in TBM. Gaze palsies with deficits in saccades and pursuits can occur due to brainstem tuberculomas. Corticosteroids are the cornerstone in the management of paradoxical reactions, but other immunomodulators such as thalidomide and infliximab are being explored. Toxic optic neuropathy caused by ethambutol necessitates careful monitoring and immediate drug discontinuation. Cerebrospinal fluid diversion through ventriculo-peritoneal shunting may be required in patients with hydrocephalus in stage I and II of TBM to prevent visual impairment. Early diagnosis and prompt management are crucial to prevent permanent disability. Prevention strategies, public health initiatives, regular follow-up and timely intervention are essential in reducing the burden of CNS TB and its neuro-ophthalmological complications.

Possible Mechanisms of Lymphopenia in Severe Tuberculosis

Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis (M. tuberculosis). In lymphopenia, T cells are typically characterized by progressive loss and a decrease in their count results. Lymphopenia can hinder immune responses and lead to systemic immunosuppression, which is strongly associated with mortality. Lymphopenia is a significant immunological abnormality in the majority of patients with severe and advanced TB, and its severity is linked to disease outcomes. However, the underlying mechanism remains unclear. Currently, the research on the pathogenesis of lymphopenia during M. tuberculosis infection mainly focuses on how it affects lymphocyte production, survival, or tissue redistribution. This includes impairing hematopoiesis, inhibiting T-cell proliferation, and inducing lymphocyte apoptosis. In this study, we have compiled the latest research on the possible mechanisms that may cause lymphopenia during M. tuberculosis infection. Lymphopenia may have serious consequences in severe TB patients. Additionally, we discuss in detail potential intervention strategies to prevent lymphopenia, which could help understand TB immunopathogenesis and achieve the goal of preventing and treating severe TB.

LRRC25 Inhibits IFN-γ Secretion by Microglia to Negatively Regulate Anti-Tuberculosis Immunity in Mice

BACKGROUND

Leucine-rich repeat-containing protein-25 (LRRC25) can degrade the ISG15 gene in virus-infected cells and prevent overactivation of the type Ⅰ IFN pathway. However, the role of LRRC25 in bacterial infection is still unclear. In this pursuit, the present study aimed to explore the regulatory role and mechanism of LRRC25 in microglia infected with Mycobacterium tuberculosis in a mouse model.

METHODS

Q-PCR, WB, and cell immunofluorescence were employed to observe the change in LRRC25 in BV2 cells infected by H37Rv. Additionally, siRNA was designed to target the LRRC25 to inhibit its expression in BV2 cells. Flow cytometry and laser confocal imaging were used to observe the infection of BV2 cells after LRRC25 silencing. Q-PCR and ELISA were used to determine the changes in IFN-γ and ISG15 in the culture supernatant of each group.

RESULTS

Following H37Rv infection, it was observed that the expression of LRRC25 was upregulated. Upon silencing LRRC25, the proportion of BV2 cells infected by H37Rv decreased significantly. ELISA analysis showed that IFN-γ and ISG15 levels in cell culture supernatant decreased after H37Rv infection, while they significantly increased after LRRC25 silencing.

CONCLUSIONS

This study provides evidence that LRRC25 is the key negative regulator of microglial anti-Mtb immunity. It exerts its function by degrading free ISG15 and inhibiting the secretion of IFN-γ, thereby improving the anti-Mtb immunity of BV2 cells.