Coagulant and fibrinolytic status in tuberculous meningitis

Host-directed therapies in pulmonary tuberculosis: Updates on anti-inflammatory drugs

Tuberculosis (TB) is a lethal disease and remains one of the top ten causes of mortality by an infectious disease worldwide. It can also result in significant morbidity related to persistent inflammation and tissue damage. Pulmonary TB treatment depends on the prolonged use of multiple drugs ranging from 6 months for drug-susceptible TB to 6-20 months in cases of multi-drug resistant disease, with limited patient tolerance resulting from side effects. Treatment success rates remain low and thus represent a barrier to TB control. Adjunct host-directed therapy (HDT) is an emerging strategy in TB treatment that aims to target the host immune response to Mycobacterium tuberculosis in addition to antimycobacterial drugs. Combined multi-drug treatment with HDT could potentially result in more effective therapies by shortening treatment duration, improving cure success rates and reducing residual tissue damage. This review explores the rationale and challenges to the development and implementation of HDTs through a succinct report of the medications that have completed or are currently being evaluated in ongoing clinical trials.

Neutrophil-Mediated Immunopathology and Matrix Metalloproteinases in Central Nervous System - Tuberculosis

Tuberculosis (TB) remains one of the leading infectious killers in the world, infecting approximately a quarter of the world’s population with the causative organism Mycobacterium tuberculosis (M. tb). Central nervous system tuberculosis (CNS-TB) is the most severe form of TB, with high mortality and residual neurological sequelae even with effective TB treatment. In CNS-TB, recruited neutrophils infiltrate into the brain to carry out its antimicrobial functions of degranulation, phagocytosis and NETosis. However, neutrophils also mediate inflammation, tissue destruction and immunopathology in the CNS. Neutrophils release key mediators including matrix metalloproteinase (MMPs) which degrade brain extracellular matrix (ECM), tumor necrosis factor (TNF)-α which may drive inflammation, reactive oxygen species (ROS) that drive cellular necrosis and neutrophil extracellular traps (NETs), interacting with platelets to form thrombi that may lead to ischemic stroke. Host-directed therapies (HDTs) targeting these key mediators are potentially exciting, but currently remain of unproven effectiveness. This article reviews the key role of neutrophils and neutrophil-derived mediators in driving CNS-TB immunopathology.

Host Directed Therapies for Tuberculous Meningitis

A dysregulated host immune response significantly contributes to morbidity and mortality in tuberculous meningitis (TBM). Effective host directed therapies (HDTs) are critical to improve survival and clinical outcomes. Currently only one HDT, dexamethasone, is proven to improve mortality. However, there is no evidence dexamethasone reduces morbidity, how it reduces mortality is uncertain, and it has no proven benefit in HIV co-infected individuals. Further research on these aspects of its use, as well as alternative HDTs such as aspirin, thalidomide and other immunomodulatory drugs is needed. Based on new knowledge from pathogenesis studies, repurposed therapeutics which act upon small molecule drug targets may also have a role in TBM. Here we review existing literature investigating HDTs in TBM, and propose new rationale for the use of novel and repurposed drugs. We also discuss host variable responses and evidence to support a personalised approach to HDTs in TBM.

Host Directed Therapies for Tuberculous Meningitis

A dysregulated host immune response significantly contributes to morbidity and mortality in tuberculous meningitis (TBM). Effective host directed therapies (HDTs) are critical to improve survival and clinical outcomes. Currently only one HDT, dexamethasone, is proven to improve mortality. However, there is no evidence dexamethasone reduces morbidity, how it reduces mortality is uncertain, and it has no proven benefit in HIV co-infected individuals. Further research on these aspects of its use, as well as alternative HDTs such as aspirin, thalidomide and other immunomodulatory drugs is needed. Based on new knowledge from pathogenesis studies, repurposed therapeutics which act upon small molecule drug targets may also have a role in TBM. Here we review existing literature investigating HDTs in TBM, and propose new rationale for the use of novel and repurposed drugs. We also discuss host variable responses and evidence to support a personalised approach to HDTs in TBM.

Efficacy and safety of aspirin as an adjunctive therapy in tubercular meningitis: A systematic review and meta-analysis

BACKGROUND

Tubercular meningitis (TBM) is associated with high mortality and stroke with chronic neurological sequelae even with best of care and antitubercular therapy. Studies have shown that aspirin as an adjunctive therapy might play some role in management of TBM. This systematic review and meta-analysis has been planned to evaluate the efficacy and safety of aspirin as an adjunctive therapy in TBM patients.

METHODS

We conducted a systematic search of randomized controlled trials in patients with tubercular meningitis published till October 2019 in all major clinical journals. Study was registered with PROSPERO with registration number: CRD42019136689. Articles were tested for eligibility and assessed for quality and various bias. Data synthesis and analysis was done using Review manager 5.3. The primary end point for assessment of efficacy was mortality at three months. The secondary end point was stroke or composite outcome of stroke and mortality at three months. Adverse effects were also assessed as secondary safety end point.

FINDINGS

Overall, three eligible randomized controlled trials with 365 participants were included that provided quantitative data for this meta-analysis. The analysis of primary and secondary end points was done using fixed effect model. There was not significant reduction in mortality [hazard ratio 0.78 (95% CI 0.45-1.35, p = 0.37)] and composite outcome of mortality and new onset stroke [hazard ratio 0.86 (95% CI 0.60-1.24, p = 0.43)] in aspirin group as compared to placebo. However, aspirin as compared to placebo significantly reduced new onset stroke [hazard ratio of 0.51 (95% CI 0.29-0.87, p = 0.01)].

INTERPRETATION

We did not find significant reduction in mortality and composite outcome (mortality and new onset stroke) with aspirin as compared to placebo but there was significant reduction in new onset stroke in aspirin group as compared to placebo with Number Needed to Treat (NNT) = 10, which might be of clinical importance since stroke is responsible for high mortality and morbidity in these subset of patients. However, a large well conducted randomized controlled trial is required to put more light on the available evidence.

Mechanism, spectrum, consequences and management of hyponatremia in tuberculous meningitis

Hyponatremia is the commonest electrolyte abnormality in hospitalized patients and is associated with poor outcome. Hyponatremia is categorized on the basis of serum sodium into severe (< 120 mEq/L), moderate (120-129 mEq/L) and mild (130-134mEq/L) groups. Serum sodium has an important role in maintaining serum osmolality, which is maintained by the action of antidiuretic hormone (ADH) secreted from the posterior pituitary, and natriuretic peptides such as atrial natriuretic peptide and brain natriuretic peptide. These peptides act on kidney tubules via the renin angiotensin aldosterone system. Hyponatremia <120mEq/L or a rapid decline in serum sodium can result in neurological manifestations, ranging from confusion to coma and seizure. Cerebral salt wasting (CSW) and syndrome of inappropriate secretion of ADH (SIADH) are important causes of hyponatremia in tuberculosis meningitis (TBM). CSW is more common than SIADH. The differentiation between CSW and SIADH is important because treatment of one may be detrimental for the other; evidence of hypovolemia in CSW and euvolemia or hypervolemia in SIADH is used for differentiation. In addition, evidence of dehydration, polyuria, negative fluid balance as assessed by intake output chart, weight loss, laboratory evidence and sometimes central venous pressure are helpful in the diagnosis of these disorders. Volume contraction in CSW may be more protracted than hyponatremia and may contribute to border zone infarctions in TBM. Hyponatremia should be promptly and carefully treated by saline and oral salt, while 3% saline should be used in severe hyponatremia with coma and seizure. In refractory patients with hyponatremia, fludrocortisone helps in early normalization of serum sodium without affecting polyuria or functional outcome. In SIADH, V2 receptor antagonist conivaptan or tolvaptan may be used if the patient is not responding to fluid restriction. Fluid restriction in SIADH has not been found to be beneficial in TBM and should be avoided.

The New Frontier of Host-Directed Therapies for Mycobacterium avium Complex

Mycobacterium avium complex (MAC) is an increasingly important cause of morbidity and mortality, and is responsible for pulmonary infection in patients with underlying lung disease and disseminated disease in patients with AIDS. MAC has evolved various virulence strategies to subvert immune responses and persist in the infected host. Current treatment for MAC is challenging, requiring a combination of multiple antibiotics given over a long time period (for at least 12 months after negative sputum culture conversion). Moreover, even after eradication of infection, many patients are left with residual lung dysfunction. In order to address similar challenges facing the management of patients with tuberculosis, recent attention has focused on the development of novel adjunctive, host-directed therapies (HDTs), with the goal of accelerating the clearance of mycobacteria by immune defenses and reducing or reversing mycobacterial-induced lung damage. In this review, we will summarize the evidence supporting specific adjunctive, HDTs for MAC, with a focus on the repurposing of existing immune-modulatory agents targeting a variety of different cellular pathways. We also highlight areas meriting further investigation.

Child with tuberculous meningitis and COVID-19 coinfection complicated by extensive cerebral sinus venous thrombosis

We herein report a case of a child with tuberculous meningitis and COVID-19 coinfection complicated by hydrocephalus, arterial ischaemic stroke and extensive cerebral sinus venous thrombosis. Both conditions induce a proinflammatory cytokine drive resulting, among others, in a prothrombotic state. The disruption of the coagulation system in this case was supported by elevated D-dimers, fibrinogen and ferritin levels, consistent with thrombotic complications reported in some adult patients infected with COVID-19. The child also exhibited prolonged viral shedding that suggests severe disease.

Platelet dysfunction and coagulation assessment in patients of tuberculous meningitis

INTRODUCTION

Tuberculous meningitis (TBM) is the most severe form of tuberculosis. As reported in various studies, stroke is common among patients with TBM, with a prevalence of 17-54%. The present study assessed platelet dysfunction and coagulation abnormality in patients with TBM.

METHODS

This was a prospective observational study that included 123 consecutive patients with TBM. In addition to clinical and radiological parameters, the complete platelet function and coagulation function were studied. The patients were followed up to 6 months.

RESULTS

A significant correlation between platelet abnormality and stroke in patients with TBM was reported in this study. Results of the univariate analysis revealed that haematological parameters such as mean platelet volume (MPV) (p < 0.001), platelet distribution width (PDW)(p < 0.001), platelet-large cell ratio (P-LCR) (p < 0.001), and platelet aggregometry (PAg) (p < 0.001) were significantly associated with infarct. However, other haematological parameters such as bleeding time (p = 0.712), clotting time (p = 0.362), activated partial thromboplastin time (p = 0.094), INR (p = 0.420), protein C (p = 0.988), and protein S (p = 0.579) were not significantly associated with infarct. During follow-up at 3 and 6 months, parameters such as MPV (p < 0.001), PDW (p < 0.001), and P-LCR (p < 0.001) were significantly associated with infarct.

CONCLUSION

The present study concluded that platelet abnormalities in patients with TBM contribute to infarct and are associated with poor clinical outcomes. This study suggested the role of antiplatelet agents in preventing stroke in patients with TBM.

Mechanism, spectrum, consequences and management of hyponatremia in tuberculous meningitis

Hyponatremia is the commonest electrolyte abnormality in hospitalized patients and is associated with poor outcome. Hyponatremia is categorized on the basis of serum sodium into severe (< 120 mEq/L), moderate (120-129 mEq/L) and mild (130-134mEq/L) groups. Serum sodium has an important role in maintaining serum osmolality, which is maintained by the action of antidiuretic hormone (ADH) secreted from the posterior pituitary, and natriuretic peptides such as atrial natriuretic peptide and brain natriuretic peptide. These peptides act on kidney tubules via the renin angiotensin aldosterone system. Hyponatremia <120mEq/L or a rapid decline in serum sodium can result in neurological manifestations, ranging from confusion to coma and seizure. Cerebral salt wasting (CSW) and syndrome of inappropriate secretion of ADH (SIADH) are important causes of hyponatremia in tuberculosis meningitis (TBM). CSW is more common than SIADH. The differentiation between CSW and SIADH is important because treatment of one may be detrimental for the other; evidence of hypovolemia in CSW and euvolemia or hypervolemia in SIADH is used for differentiation. In addition, evidence of dehydration, polyuria, negative fluid balance as assessed by intake output chart, weight loss, laboratory evidence and sometimes central venous pressure are helpful in the diagnosis of these disorders. Volume contraction in CSW may be more protracted than hyponatremia and may contribute to border zone infarctions in TBM. Hyponatremia should be promptly and carefully treated by saline and oral salt, while 3% saline should be used in severe hyponatremia with coma and seizure. In refractory patients with hyponatremia, fludrocortisone helps in early normalization of serum sodium without affecting polyuria or functional outcome. In SIADH, V2 receptor antagonist conivaptan or tolvaptan may be used if the patient is not responding to fluid restriction. Fluid restriction in SIADH has not been found to be beneficial in TBM and should be avoided.

A Child with Tuberculous Meningitis Complicated by Cortical Venous and Cerebral Sino-Venous Thrombosis

Stroke is common in tuberculous meningitis. Stroke commonly affects the tubercular zone, comprising the anterior part of the thalamus, caudate and the internal capsule (anterior limb and genu). Stroke, in tuberculous meningitis is predominantly arterial ischemic stroke, and is due to infiltrative, proliferative or necrotizing arteritis. Rarely, aneurysm formation and mycotic aneurysms have also been described. The authors describe the clinical and autopsy findings of a 27-mo-old boy with tuberculous meningitis whose course was complicated by arterial and venous strokes, and nonresponse to adequate and appropriate antitubercular therapy.

Frequency and Impact of Cerebral Infarctions in Patients With Tuberculous Meningitis

Background and Purpose—

Cerebral infarctions complicate a variable proportion of tuberculous meningitis (TBM) cases and adversely affect outcomes. The objective of this study was to evaluate the predictors of cerebral infarcts in patients with TBM and to assess their impact on mortality.

Methods—

The study was based on a retrospective chart review of all patients with TBM admitted to a tertiary care hospital between 2002 and 2013. Data were collected on basic demographics, conventional vascular risk factors, radiological findings, severity of TBM, and neurological outcomes. Data were analyzed using SPSS version 19.0. Binary logistic regression was done to determine the factors predictive of cerebral infarcts and of mortality in patients with TBM.

Results—

A total of 559 patients were admitted with TBM during the study period. Mean age was 41.9 years (SD, 17.7 years), and 47% were women. A quarter of the patients had stage III disease. One hundred forty-four (25.8%) patients had cerebral infarcts on brain imaging of which 3 quarters were acute or subacute. Those with cerebral infarcts were more likely to be >40 years of age (adjusted odds ratio [AOR], 1.7; 95% CI, 1.1–2.7) and to have hypertension (AOR, 1.8; 95% CI, 1.1–2.8), dyslipidemia (AOR, 9.7; 95% CI, 3.8–24.8), and diabetes mellitus (AOR, 2.2; 95% CI, 1.3–3.6). Presence of cerebral infarction was an independent predictor of mortality among patients with TBM (AOR, 2.1; 95% CI, 1.22–3.5).

Conclusions—

Cerebral infarcts complicate a substantial proportion of TBM cases. Conventional vascular risk factors are the most important predictors of infarction, and future efforts need to focus on these high-risk patients with TBM to reduce morbidity and mortality.

Hypovolemia due to cerebral salt wasting may contribute to stroke in tuberculous meningitis

BACKGROUND

Both stroke and cerebral salt wasting (CSW) are common in tuberculous meningitis (TBM), but there is paucity of studies evaluating their combined effect.

AIM

The present study has been undertaken to evaluate the spectrum of stroke in TBM and its relation to CSW.

DESIGN

Hospital-based prospective cohort study.

METHODS

Eighty-one patients with TBM diagnosed on the basis of clinical, cerebrospinal fluid and magnetic resonance imaging (MRI) criteria were prospectively included. Stroke was diagnosed on the basis of clinical, MRI findings or both. Stroke risk factors were noted. Patients with hyponatremia were categorized into CSW and other causes. Three and 6 months outcome was defined using modified Rankin Scale (mRS) as good (<2) or poor (≥2).

RESULTS

Out of 81 patients with TBM, 32 (39.5%) had ischemic stroke. CSW was the commonest cause of hyponatremia and occurred in 34 (42%) patients. Stroke occurred in tubercular zone in 10, ischemic zone in 15 and both in 7 patients. The patients with ischemic zone infarction were older and had stroke risk factors such as diabetes mellitus, hypertension and hyperlipidemia. Out of 16 (47%) patients with CSW, 10 (62.5%) had stroke during the polyuric phase. The patients with CSW had more frequent deep white matter infarcts (P = 0.01) which were in internal border zone in 4 (40%).

CONCLUSION

In TBM, stroke occurred in 39.5% of the patients, 50% of whom had CSW. Volume contraction due to CSW may contribute to stroke.

A Beneficial Effect of Low-Dose Aspirin in a Murine Model of Active Tuberculosis

An excessive, non-productive host-immune response is detrimental in active, chronic tuberculosis (TB) disease as it typically leads to tissue damage. Given their anti-inflammatory effect, non-steroidal anti-inflammatory drugs can potentially attenuate excessive inflammation in active TB disease. As such, we investigated the prophylactic and therapeutic effect of low-dose aspirin (LDA) (3 mg/kg/day), either alone or in combination with common anti-TB treatment or BCG vaccination, on disease outcome in an experimental murine model of active TB. Survival rate, bacillary load (BL) in lungs, and lung pathology were measured. The possible mechanism of action of LDA on the host's immune response was also evaluated by measuring levels of CD5L/AIM, selected cytokines/chemokines and other inflammatory markers in serum and lung tissue. LDA increased survival, had anti-inflammatory effects, reduced lung pathology, and decreased bacillary load in late-stage TB disease. Moreover, in combination with common anti-TB treatment, LDA enhanced survival and reduced lung pathology. Results from the immunological studies suggest the anti-inflammatory action of LDA at both a local and a systemic level. Our results showed a systemic decrease in neutrophilic recruitment, decreased levels of acute-phase reaction cytokines (IL-6, IL-1β, and TNF-α) at late stage and a delay in the decrease in T cell response (in terms of IFN-γ, IL-2, and IL-10 serum levels) that occurs during the course of Mycobacterium tuberculosis infection. An anti-inflammatory milieu was detected in the lung, with less neutrophil recruitment and lower levels of tissue factor. In conclusion, LDA may be beneficial as an adjunct to standard anti-TB treatment in the later stage of active TB by reducing excess, non-productive inflammation, while enhancing Th1-cell responses for elimination of the bacilli.

Non-Steroidal Anti-inflammatory Drugs As Host-Directed Therapy for Tuberculosis: A Systematic Review

Lengthy, antimicrobial therapy targeting the pathogen is the mainstay of conventional tuberculosis treatment, complicated by emerging drug resistances. Host-directed therapies, including non-steroidal anti-inflammatory drugs (NSAIDs), in contrast, target host factors to mitigate disease severity. In the present Systematic Review, we investigate whether NSAIDs display any effects as therapy of TB and discuss possible mechanisms of action of NSAIDs as adjunctive therapy of TB. Ten studies, seven preclinical studies in mice and three clinical trials, were included and systematically reviewed. Our results point toward a beneficial effect of NSAIDs as adjunct to current TB therapy regimens, mediated by decreased lung pathology balancing host-immune reaction. The determination of the best timing for their administration in order to obtain the potential beneficial effects needs further investigation. Even if the preclinical evidence requires clinical evaluation, NSAIDs might represent a potential safe, simple, and cheap improvement in therapy of TB.

Clinical and echocardiographic diagnosis, follow up and management of right-sided cardiac thrombi

BACKGROUND

Right-sided cardiac masses are infrequent and have varied clinical presentation. The present study describes the clinical features, echocardiographic findings and management of 19 patients presenting with right-sided cardiac thrombi in a tertiary care center in north India.

METHODS

This is a retrospective, single center observational study of consecutive patients over the period January 2003-2008 admitted in our emergency intensive care unit (EICU). We identified 38 patients with right-sided cardiac masses admitted to EICU diagnosed by transthoracic echocardiography of which 19 patients had right-sided thrombus. The echocardiographic findings were reviewed by two cardiologists in all patients. Treatment was not standardized and choice of therapy was based on judgment of attending physician.

RESULTS

The mean age of patients with cardiac thrombus was 36.6 ± 11.8 years. Right atrial (n = 17) and right ventricle (n = 2) thrombi were associated with deep vein thrombosis (DVT) in 7 (36.8%) and pulmonary embolism in 3 (15%) patients. 13 (68.4%) patients appeared to have in situ mural thrombus. 12 patients were managed with oral anticoagulants, 3 patients underwent surgery and 4 patients were thrombolysed. All the survivors had a mean follow-up of 40 ± 6 months (range--18-50 months).

CONCLUSIONS

Prompt echocardiographic examination in an appropriate clinical setting facilitates faster diagnosis and management of patients with right-sided cardiac thrombi. High incidence of in situ mural thrombus and varied comorbidities predisposing to right-sided cardiac thrombi besides DVT and pulmonary embolism need to be recognized. Oral anticoagulation and thrombolysis appear to be the mainstay of treatment with surgery limited for selected patients.

Seizures in an immunocompromised adolescent: a case report

Introduction

Tuberculosis is a progressive and disabling infection predominantly seen in low-income and middle-income countries. Immunocompromised patients are at a higher risk of contracting tuberculosis than the healthy population. The presentation may also be atypical, leading to delay in diagnosis. We report the first case of tuberculous cerebral vasculitis presenting with epilepsia partialis continua.

Case presentation

A 17-year-old adolescent boy of Sri Lankan Moor heritage was taking long-term immunosuppressants for nephrotic syndrome. He presented to hospital with focal fits affecting his left arm. He later developed choreiform movements of the same arm, progressing to epilepsia partialis continua and weakness. The gradually evolving focal neurological signs and underlying immunosuppression raised the possibility of localized cerebral infection or inflammation. Analysis of his cerebrospinal fluid showed lymphocytosis with normal cellular morphology. Magnetic resonance imaging was suggestive of progressive vasculitic infarctions of the cerebral cortex and basal ganglia. There was no evidence of active autoimmune or viral disease on hematological investigations, but molecular amplification detected Mycobacterium tuberculosis in his cerebrospinal fluid. Although our patient had been established on isoniazid preventive treatment for eight months before the episode, tuberculosis was nonetheless considered to be the most likely cause of the cerebral vasculitis. He was treated with a trial of anti-tuberculosis treatment, including streptomycin and adjunctive steroids, and made an uneventful recovery.

Conclusion

Clinicians should have a high index of suspicion for tuberculosis infection in patients with compromised immunity and other risk factors. The pathophysiological mechanisms underpinning cerebral vasculitis and epilepsia partialis continua are not completely understood. The efficacy of isoniazid prophylaxis in patients with immune suppression warrants further study. We present a regimen that successfully treated tuberculous cerebral vasculitis.

Infektionen

In diesem Kapitel werden zunächst die für die Neurointensivmedizin wesentlichen bakteriellen Infektionen (Meningitis, spinale und Hirnabszesse, Spondylodiszitis, septisch-embolische Herdenzephalitis) abgehandelt, die trotz gezielt eingesetzter Antibiotika und neurochirurgischer Therapieoptionen noch mit einer erheblichen Morbidität und Mortalität behaftet sind. Besonderheiten wie neurovaskuläre Komplikationen, die Tuberkulose des Nervensystems, Neuroborreliose, Neurosyphilis und opportunistische Infektionen bei Immunsuppressionszuständen finden hierbei besondere Berücksichtigung. Der zweite Teil dieses Kapitels behandelt akute und chronische Virusinfektionen des ZNS sowie in einem gesonderten Abschnitt die HIVInfektion und HIV-assoziierte Krankheitsbilder sowie Parasitosen und Pilzinfektionen, die in Industrieländern seit Einführung der HAART bei HIV zwar eher seltener, aber mit zunehmender Globalisierung auch in unseren Breiten immer noch anzutreffen sind.

Infectious causes of stroke

Most infectious pathogens have anecdotal evidence to support a link with stroke, but certain pathogens have more robust associations, in which causation is probable. Few dedicated prospective studies of stroke in the setting of infection have been done. The use of head imaging, a clinical standard of diagnostic care, to confirm stroke and stroke type is not universal. Data for stroke are scarce in locations where infections are probably most common, making it difficult to reach conclusions on how populations differ in terms of risk of infectious stroke. The treatment of infections and stroke, when concomitant, is based on almost no evidence and requires dedicated efforts to understand variations that might exist. We highlight the present knowledge and emphasise the need for stronger evidence to assist in the diagnosis, treatment, and secondary prevention of stroke in patients in whom an infectious cause for stroke is probable.

Tuberculous meningitis: more questions, still too few answers

Tuberculous meningitis is especially common in young children and people with untreated HIV infection, and it kills or disables roughly half of everyone affected. Childhood disease can be prevented by vaccination and by giving prophylactic isoniazid to children exposed to infectious adults, although improvements in worldwide tuberculosis control would lead to more effective prevention. Diagnosis is difficult because clinical features are non-specific and laboratory tests are insensitive, and treatment delay is the strongest risk factor for death. Large doses of rifampicin and fluoroquinolones might improve outcome, and the beneficial effect of adjunctive corticosteroids on survival might be augmented by aspirin and could be predicted by screening for a polymorphism in LTA4H, which encodes an enzyme involved in eicosanoid synthesis. However, these advances are insufficient in the face of drug-resistant tuberculosis and HIV co-infection. Many questions remain about the best approaches to prevent, diagnose, and treat tuberculous meningitis, and there are still too few answers.

Computational modeling of tuberculous meningitis reveals an important role for tumor necrosis factor-α

Tuberculosis is a global health issue with annually about 1.5 million deaths and 2 billion infected people worldwide. Extra-pulmonary tuberculosis comprises 13% of all cases of which tuberculous meningitis is the most severe. It has a high mortality and is often diagnosed once irreversible neurological damage has already occurred. Development of diagnostic and treatment strategies requires a thorough understanding of the pathogenesis of tuberculous meningitis. This disease is characterized by the formation of a cerebral granuloma, which is a collection of immune cells that attempt to immunologically restrain, and physically contain bacteria. The cytokine tumor necrosis factor-α is known for its important role in granuloma formation. Because traditional experimental animal studies exploring tuberculous meningitis are difficult and expensive, another approach is needed to begin to address this important and significant disease outcome. Here, we present an in silico model capturing the unique immunological environment of the brain that allows us to study the key mechanisms driving granuloma formation in time. Uncertainty and sensitivity analysis reveals a dose-dependent effect of tumor necrosis factor-α on bacterial load and immune cell numbers thereby influencing the onset of tuberculous meningitis. Insufficient levels result in bacterial overgrowth, whereas high levels lead to uncontrolled inflammation being detrimental to the host. These findings have important implications for the development of immuno-modulating treatment strategies for tuberculous meningitis.

Tuberculous meningitis

Tuberculous (TB) meningitis is common in resource-poor communities but also occurs in developed countries where the diagnosis is frequently delayed because of unfamiliarity with the disease. TB meningitis develops whenever a small intracranial tuberculoma (Rich focus) ruptures causing predominantly basal meningitis. This results in hydrocephalus, cranial nerve palsies, and ischemic brain injury secondary to tuberculous vasculitis. The primary source of TB is usually the lung. Early diagnosis is difficult because patients tend to present subacutely with nonspecific symptoms such as fever, cough, vomiting, listlessness, and failure to thrive. Lumbar puncture typically shows clear and colorless CSF with a low, predominantly lymphocytic, leukocytosis and raised protein and low glucose levels. Decision to treat is mostly clinical because of difficulty in demonstrating TB bacilli on routine smear and time needed for culture. A positive TB contact, Mantoux skin test, chest radiograph, CT/MRI brain scan, PCR for tuberculosis on CSF, and demonstration of TB bacilli from extraneural sources are invaluable in supporting a diagnosis of TB meningitis. Current World Health Organization guidelines recommend treatment with a four-drug regimen for 2 months, followed by a two-drug regimen for 10 months, the total duration of treatment being 12 months. Corticosteroids reduce mortality without changing neurological morbidity. Outcome relates closely to age and stage of disease.

Tuberculous meningitis in adults: a review of a decade of developments focusing on prognostic factors for outcome

Tuberculous meningitis (TBM) is the most severe form of TB. Despite treatment, mortality and long-term disability remain unacceptably high. Prevention, early recognition, diagnosis and treatment are fundamental to improving outcomes. However, an effective vaccine remains elusive, initial symptoms are nonspecific, and sensitive diagnostic tests are not available. There has been progress in our understanding of the immunopathology of TBM, and several factors have been found to be associated with susceptibility to infection, disease progression and clinical outcome. However, these have not yet impacted on treatment. Early treatment initiation and uninterrupted continuation, severity on presentation, seizures, stroke, cranial nerve involvement, cerebrospinal fluid cell count and lactate levels, hyponatreamia and coinfection with HIV are all found to be important prognostic factors for outcome. Pathogen lineage (Beijing genotype) and host genetics (polymorphisms in TLR2, TIRAP and LTA4H genes) can influence susceptibility to TBM. However, these findings have not yet impacted on treatment. Progress in vaccine development, opportunities for better diagnostic tests, novel insights into pathogenesis and an increasing evidence base for improving treatment should impact the current high mortality and morbidity, if translated to global and local guidelines.

Infektionen

Trotz Weiterentwicklung moderner Antibiotika in den letzten Jahren sind die Letalitätszahlen der bakteriellen (eitrigen) Meningitis weiterhin hoch; Überlebende haben häufig neurologische Residuen. Die ungünstigen klinischen Verläufe der bakteriellen Meningitis sind meist Folge intrakranieller Komplikationen, wie z. B. eines generalisierten Hirnödems, einer zerebrovaskulären arteriellen oder venösen Beteiligung oder eines Hydrozephalus.

The role of aspirin in childhood tuberculous meningitis

Arterial stroke is the main cause of poor outcome in childhood tuberculous meningitis. Aspirin has an antithrombotic action at low dose and anti-ischemic and anti-inflammatory properties, which are dose-related. The aim of the study was to explore the possible benefits of aspirin in children with tuberculous meningitis. A total of 146 consecutive children with a diagnosis of probable tuberculous meningitis were studied. Patients were randomized into 3 groups: (1) placebo group, (2) low-dose aspirin group, and (3) high-dose aspirin group. Twenty-nine additional patients who received aspirin before admission were excluded from the randomized study, but continued on low-dose aspirin. Aspirin, irrespective of dose, did not show any significant benefit regarding morbidity (hemiparesis and developmental outcome) and mortality. Aspirin was well tolerated, but 1 death was probably related to aspirin. The fact that the outcome of the high-dose aspirin group compared favorably with the other treatment groups despite younger age and more severe neurological involvement at baseline needs further investigation.

Thromboembolism and venous thrombosis of the deep veins in surgical children--an increasing challenge?

Children share many known predisposing risk factors for venous thromboembolism and deep venous thrombosis but appears less common and is probably underestimated. Fatal pulmonary embolism is rare but may also be missed because of low level of clinical awareness. The aim of this study was to investigate children with thromboembolism of deep veins to evaluate risk factors and highlight their danger.

METHODS

This was a retrospective review of all children (<13 years old) diagnosed with a venous thromboembolism (1993-2009). Clinical and radiologic features and any risk factors were documented. Venous thromboembolism was diagnosed on clinical suspicion together with compressive Doppler studies, spiral computed tomography, or magnetic resonance scan.

RESULTS

Eighteen children with a consistent clinical picture were identified (painful unilateral limb swelling). Their mean age was 9.3 years with a male/female ratio of 3.5:1. Predisposing factors were identified in 17 (95%). These included infective conditions (n = 11), previous femoral line (n = 3), trauma (n = 2), and complicated appendicitis (n = 2). Chronic infective and inflammatory conditions included tuberculosis (n = 4), HIV (n = 3), staphylococcal septicemia (n = 2), and Takayasu arteritis (n = 1). Pulmonary embolism occurred in 5 (28%), and 1 presented later with a post-phlebitic leg. Elevated factor VIII was seen in 3.

CONCLUSION

This study identified an association with known risk factors in most children with venous thromboembolism and suggests that those with femoral venous access or ongoing chronic infective states (eg, TB/HIV) are particularly at risk.

Prevention of secondary ischemic events by superficial temporal artery-middle cerebral artery bypass surgery after tuberculosis-induced vasculopathy in a 5-year-old child

Tuberculosis-related vasculopathy and resulting ischemic events are a common finding after tuberculous meningitis (TBM) in children. The authors report on a case of recurring ischemic episodes that were refractory to repetitive endovascular procedures (transluminal angioplasty, stent insertion, in-stent vessel dilation). After failure of endovascular treatment, extracranial-intracranial (EC-IC) bypass surgery was performed to prevent further ischemia. This 5-year-old girl presented with a series of ischemic events in the left middle cerebral artery (MCA) territory 12 months after her presentation with TBM. Angiography studies showed a 50% lumen reduction of the left MCA. After failure of antithrombocyte aggregation and repeated endovascular procedures to prevent new ischemia, EC-IC bypass surgery was performed. The left superficial temporal artery-MCA bypass was found to be capable of preventing new ischemic events in the 21-month follow-up period, despite a near-total MCA occlusion on follow-up conventional and MR angiography studies. Bypass surgery seems to be a reliable tool to augment cerebral blood flow in tuberculosis-related stenoocclusive changes of cerebral vasculature after the failure of endovascular procedures.