The beneficial effects of early dexamethasone administration in infants and children with bacterial meningitis

Corticosteroids for viral central nervous system infections

PURPOSE OF REVIEW

Viruses are frequent causes of central nervous system (CNS) infection. Lacking specific antiviral treatment or inadequate clinical response may lead to treatment with corticosteroids. This review describes the rationale for and clinical experience with the use of adjunctive corticosteroids for viral CNS infections.

RECENT FINDINGS

Corticosteroids display anti-inflammatory, immunosuppressive, antiproliferative, and vasoconstrictive effects by genomic and nongenomic regulation of human cells. Recent population-based studies consistently show that empiric dexamethasone during diagnostic work-up for meningitis has neither been associated with improved outcome nor adverse effects in viral meningitis. Myelitis is most often due to noninfectious causes and standard empiric treatment includes high-dose methylprednisolone. There are no convincing data on viral myelitis to support a change of this approach. Corticosteroids have occasionally been employed in different types of viral encephalitis. Observational data and a few randomized clinical trials have not documented any substantial beneficial effects of adjunctive corticosteroids in viral encephalitis. Risks of harm with current treatment regimens remained low in published studies.

SUMMARY

Except for myelitis, there are no data to support routine use of corticosteroids for viral CNS infections. Large, multidisciplinary syndromic platform trials of all-cause encephalitis may be a viable way to inform treatment guidelines.

Interactions of the Pneumococcus with the Central Nervous System: Postnatal Meningitis Versus Fetal Neurodevelopment

In young children, pneumococcal meningitis epitomizes the paradigm of a destructive innate inflammatory response in the central nervous system: a five-alarm fire. In contrast, cell-free bacterial components reaching the fetal brain from an infected mother signal a quiet, noninflammatory immune response that drives abnormal neurodevelopment, changing brain architecture through neuroproliferation. This review addresses the difference between prenatal and postnatal bacterial-host signaling within the brain.

Inflammation unites diverse acute and chronic diseases

BACKGROUND

Inflammation and immunity contribute pivotally to diverse acute and chronic diseases. Inflammatory pathways have become increasingly targets for therapy. Yet, despite substantial similarity in mechanisms and pathways, the scientific, medical, pharma and biotechnology sectors have generally focused programs finely on a single disease entity or organ system. This insularity may impede progress in innovation and the harnessing of powerful new insights into inflammation biology ripe for clinical translation.

METHODS

A multidisciplinary thinktank reviewed highlights how inflammation contributes to diverse diseases, disturbed homeostasis, ageing and impaired healthspan. We explored how common inflammatory and immune mechanisms that operate in key conditions in their respective domains. This consensus review highlights the high degree of commonality of inflammatory mechanisms in a diverse array of conditions that together contribute a major part of the global burden of morbidity and mortality and present an enormous challenge to public health and drain on resources.

RESULTS

We demonstrate how that shared inflammatory mechanisms unite many seemingly disparate diseases, both acute and chronic. The examples of infection, cardiovascular conditions, pulmonary diseases, rheumatological disorders, dementia, cancer and ageing illustrate the overlapping pathogenesis. We outline opportunities to synergize, reduce duplication and consolidate efforts of the clinical, research and pharmaceutical communities. Enhanced recognition of these commonalties should promote cross-fertilization and hasten progress in this rapidly moving domain.

CONCLUSIONS

Greater appreciation of the shared mechanisms should simplify understanding seemingly disparate diseases for clinicians and help them to recognize inflammation as a therapeutic target which the development of novel therapies is rendering actionable.

Adjunctive treatments for pneumococcal meningitis: a systematic review of experimental animal models

New treatments are needed to improve the prognosis of pneumococcal meningitis. We performed a systematic review on adjunctive treatments in animal models of pneumococcal meningitis in order to identify treatments with the most potential to progress to clinical trials. Studies testing therapy adjunctive to antibiotics in animal models of pneumococcal meningitis were included. A literature search was performed using Medline, Embase and Scopus for studies published from 1990 up to 17 February 2023. Two investigators screened studies for inclusion and independently extracted data. Treatment effect was assessed on the clinical parameters disease severity, hearing loss and cognitive impairment and the biological parameters inflammation, brain injury and bacterial load. Adjunctive treatments were evaluated by their effect on these outcomes and the quality, number and size of studies that investigated the treatments. Risk of bias was assessed with the SYRCLE risk of bias tool. A total of 58 of 2462 identified studies were included, which used 2703 experimental animals. Disease modelling was performed in rats (29 studies), rabbits (13 studies), mice (12 studies), gerbils (3 studies) or both rats and mice (1 study). Meningitis was induced by injection of Streptococcus pneumoniae into the subarachnoid space. Randomization of experimental groups was performed in 37 of 58 studies (64%) and 12 studies (12%) were investigator-blinded. Overall, 54 treatment regimens using 46 adjunctive drugs were evaluated: most commonly dexamethasone (16 studies), daptomycin (5 studies), complement component 5 (C5; 3 studies) antibody and Mn(III)tetrakis(4-benzoicacid)porphyrin chloride (MnTBAP; 3 studies). The most frequently evaluated outcome parameters were inflammation [32 studies (55%)] and brain injury [32 studies (55%)], followed by disease severity [30 studies (52%)], hearing loss [24 studies (41%)], bacterial load [18 studies (31%)] and cognitive impairment [9 studies (16%)]. Adjunctive therapy that improved clinical outcomes in multiple studies was dexamethasone (6 studies), C5 antibodies (3 studies) and daptomycin (3 studies). HMGB1 inhibitors, matrix metalloproteinase inhibitors, neurotrophins, antioxidants and paquinimod also improved clinical parameters but only in single or small studies. Evaluating the treatment effect of adjunctive therapy was complicated by study heterogeneity regarding the animal models used and outcomes reported. In conclusion, 24 of 54 treatment regimens (44%) tested improved clinically relevant outcomes in experimental pneumococcal meningitis but few were tested in multiple well-designed studies. The most promising new adjunctive treatments are with C5 antibodies or daptomycin, suggesting that these drugs could be tested in clinical trials.

Association of Corticosteroid Treatment With Outcomes in Pediatric Patients With Bacterial Meningitis: A Systematic Review and Meta-analysis of Randomized Controlled Trials

PURPOSE

Controversy has arisen among the overall benefit and potential risks in the use of corticosteroids for the treatment of pediatric bacterial meningitis. This systematic review and meta-analysis aims to provide evidence of the use of corticosteroids in the treatment of bacterial meningitis in children.

METHODS

Electronic databases (PubMed, Embase, Cochrane Central Register of Controlled Trials, and other databases) were searched from inception until March 9, 2021. Randomized clinical trials focused on corticosteroids as adjuvant therapy in pediatric bacterial meningitis were considered eligible. The primary outcomes were hearing loss and neurologic sequelae. Secondary outcomes were mean days before resolution of fever, mortality, secondary fever, and reactive arthritis. Fixed- or random-effects models were used to evaluate the association between corticosteroids therapy and outcomes by calculating risk ratios (RRs) and mean differences (MDs) with corresponding 95% CIs. Two independent reviewers completed citation screening, data extraction, and risk assessment.

FINDINGS

Twenty-nine studies with 3433 patients were included. An obvious benefit was found in the treatment of corticosteroids in hearing loss (RR = 0.62; 95% CI, 0.47-0.81; I² = 17%; P = 0.0006). No benefit was found in the rate of neurologic sequelae. However, obvious benefit was found in the low-dosage subgroup (0.6 mg/kg per day) (RR = 0.60; 95% CI, 0.47-0.77; I² = 0%; P < 0.0001) but not in the high-dosage subgroup (0.8 mg/kg per day). An increasing rate of secondary fever was found when using corticosteroids (RR = 1.29; 95% CI, 1.10-1.51; I² = 13%; P = 0.001). Corticosteroids could significantly decrease the mean days before resolution of fever (MD = -1.48; 95% CI, -1.79 to -1.17; I² = 84%, P < 0.00001). No difference was found in the rate of mortality and reactive arthritis.

IMPLICATIONS

The findings of this study suggest that the administration of corticosteroids is associated with reduced hearing loss and neurologic sequelae especially in children using a low dose of corticosteroids. Benefits also included a reduction in the mean number of days before resolution of fever.

Adjuvant corticosteroids for prevention of kidney scarring in children with acute pyelonephritis: a systematic review and meta-analysis

BACKGROUND

Acute pyelonephritis in children may result in permanent kidney scarring that is primarily caused by inflammation during acute infection. Antibiotic therapy alone is not enough to significantly reduce kidney scarring, and adjuvant corticosteroid therapy has shown a significant reduction in inflammatory cytokines in urine prompting its evaluation in randomised controlled trials. A few clinical trials showed a trend towards a reduction in renal scarring but did not have an adequate sample size to show a significant effect. Therefore, we planned to synthesise the available evidence on the role of corticosteroids as adjuvant therapy in reducing kidney scarring.

OBJECTIVE

To assess the efficacy and safety of adjuvant corticosteroid therapy for the prevention of kidney scarring in children with acute pyelonephritis.

DESIGN

Systematic review and meta-analysis.

SETTING

Community-acquired febrile urinary tract infections.

PATIENTS

Children (less than 18 years) with acute pyelonephritis.

INTERVENTION

Adjuvant corticosteroid therapy (along with antibiotic treatment).

MAIN OUTCOME MEASURES

Primary: efficacy in preventing kidney scarring; secondary: serious adverse events associated with corticosteroid therapy.

RESULTS

Three randomised trials (529 children) were included. Corticosteroids are effective in lowering the risk of kidney scarring as compared with placebo (risk ratio (RR): 0.57; 95% CI 0.36 to 0.90). No significant increase risk of bacteraemia (RR: 1.38; 95% CI 0.23 to 8.23) and hospitalisation (RR: 0.87; 95% CI 0.3 to 2.55) was observed in corticosteroid group.

CONCLUSION

Moderate quality evidence suggests that short duration 'adjuvant corticosteroid therapy' along with routine antibiotic therapy in acute febrile urinary tract infection significantly reduces the risk of kidney scarring without any significant adverse effects.

Immune activation during Paenibacillus brain infection in African infants with frequent cytomegalovirus co-infection

Inflammation during neonatal brain infections leads to significant secondary sequelae such as hydrocephalus, which often follows neonatal sepsis in the developing world. In 100 African hydrocephalic infants we identified the biological pathways that account for this response. The dominant bacterial pathogen was a Paenibacillus species, with frequent cytomegalovirus co-infection. A proteogenomic strategy was employed to confirm host immune response to Paenibacillus and to define the interplay within the host immune response network. Immune activation emphasized neuroinflammation, oxidative stress reaction, and extracellular matrix organization. The innate immune system response included neutrophil activity, signaling via IL-4, IL-12, IL-13, interferon, and Jak/STAT pathways. Platelet-activating factors and factors involved with microbe recognition such as Class I MHC antigen-presenting complex were also increased. Evidence suggests that dysregulated neuroinflammation propagates inflammatory hydrocephalus, and these pathways are potential targets for adjunctive treatments to reduce the hazards of neuroinflammation and risk of hydrocephalus following neonatal sepsis.

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There is a characteristic immune response to Paenibacillus brain infection

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There is a characteristic immune response to CMV brain infection

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The matching immune response validates pathogen genomic presence

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The combined results support molecular infection causality

Transcranial Doppler Ultrasonographic Evaluation of Cerebrovascular Abnormalities in Children With Acute Bacterial Meningitis

Introduction: Bacterial meningitis (BM) is a global public health concern that results in significant morbidity and mortality. Cerebral arterial narrowing contributes to stroke in BM and may be amenable to intervention. However, it is difficult to diagnose in resource-limited settings where the disease is common. Methods: This was a prospective observational study from September 2015 to December 2019 in sub-Saharan Africa. Children 1 month-18 years of age with neutrophilic pleocytosis or a bacterial pathogen identified in the cerebrospinal fluid were enrolled. Transcranial Doppler ultrasound (TCD) of the middle cerebral arteries was performed daily with the aim to identify flow abnormalities consistent with vascular narrowing. Results: Forty-seven patients were analyzed. The majority had Streptococcus pneumoniae (36%) or Neisseria meningitides (36%) meningitis. Admission TCD was normal in 10 (21%). High flow with a normal pulsatility index (PI) was seen in 20 (43%) and high flow with a low PI was identified in 7 (15%). Ten (21%) had low flow. All children with a normal TCD had a good outcome. Patients with a high-risk TCD flow pattern (high flow/low PI or low flow) were more likely to have a poor outcome (82 vs. 38%, p = 0.001). Conclusions: Abnormal TCD flow patterns were common in children with BM and identified those at high risk of poor neurological outcome.

Mini-Review: Bioactivities of Bacterial Cell Envelopes in the Central Nervous System

During acute bacterial meningitis, recognition of the bacterial envelope by immune cells of the central nervous system (CNS) generates a robust response that is essential to clear bacteria. This response is further amplified during treatment when lytic antibiotics, required for cure, also generate a burst of highly inflammatory cell envelope debris. Different peptidoglycan (PG) subcomponents interact with neurons, glia, and the blood brain barrier resulting in the entire symptom complex of meningitis. Recently, this CNS-cell envelope signaling axis has been extended to non-inflammatory recognition of cell wall components circulating from endogenous bacteria to the brain resulting in both benefit and chronic damage. This review will describe the molecular details of a broad array of cell envelope-induced responses in the CNS and what current strategies can be implemented to improve clinical outcome.

Comparative efficacy of antibiotic(s) alone or in combination of corticosteroids in adults with acute bacterial meningitis: A systematic review and network meta-analysis

OBJECTIVE

To compare relative efficacy of different antibiotic therapies either with or without the addition of corticosteroids among adult patients with acute bacterial meningitis on all-cause mortality, neurological complications and any hearing loss.

METHODS

We searched nine databases from inception to 8 February 2018 for randomized controlled trials evaluating pharmacological interventions and clinical outcomes in adult bacterial meningitis. An updated search from 9 February to 9 March 2020 was performed, and no new studies met the inclusion criteria. Study quality was assessed using the revised Cochrane Risk of Bias Tool. The Grading of Recommendations Assessment, Development and Evaluation system was used for quality of evidences evaluation. Meta-analyses were conducted to estimate the risk ratio with 95% confidence interval for both direct and indirect comparisons on the primary outcomes of all-cause mortality, neurologic sequelae and any hearing loss. The study was registered in PROSPERO (CRD42018108062).

RESULTS

Nine RCTs were included in systematic review, involving 1,002 participants with a mean age ranging between 25.3 to 50.56 years. Six RCTs were finally included in the network-meta analysis. No significant difference between treatment was noted in meta-analysis. Network meta-analysis suggests that corticosteroids in combination with antibiotic therapy was more effective in reducing the risk of any hearing loss compared to mono antibiotic therapy (RR 0.64; 95%CI, 0.45 to 0.91, 4 RCTs, moderate certainty of evidence). Numerical lower risk of mortality and neurological complications was also shown for adjunctive corticosteroids in combination with antibiotic therapy versus mono antibiotic therapy (RR 0.65; 95%CI, 0.42 to 1.02, 6 RCTs, moderate certainty of evidence; RR 0.75; 95%CI, 0.47 to 1.18, 6 RCTs, moderate certainty of evidence). No differences were noted in the adverse events between different therapies. The overall certainty of evidence was moderate to very low for all primary outcomes examined.

CONCLUSIONS

Results of this study suggest that corticosteroids therapy in combination with antibiotic is more effective than mono antibiotic therapy in reducing the risk of any hearing loss in adult patients with acute bacterial meningitis. More well-design RCTs to investigate relative effective treatments in acute bacterial meningitis particularly in adult population should be mandated to aid clinicians in treatment recommendations.

CT-guided drainage of a brainstem abscess in a cat as an emergency treatment procedure

Case summary

A 3-year-old male neutered domestic shorthair cat was presented with a 1-week progressive and rapidly deteriorating history of lethargy and abnormal behaviour. Neurolocalisation indicated multifocal intracranial lesions (right oculomotor nerve, brainstem [obtundation, non-ambulatory tetraparesis, vestibular dysfunction and intermittent decerebrate rigidity] and possibly the thalamus [left-sided pleurothotonus]), or more likely a single brainstem lesion with mass effect. MRI of the brain demonstrated a brainstem abscess causing severe dorsal displacement particularly affecting the pons and the medulla oblongata causing cerebellar vermis herniation through the foramen magnum. CT-guided free-hand technique drainage of the brain abscess was performed and broad spectrum antibiotics were started based on sensitivity results. The cat recovered uneventfully from anaesthesia displaying marked improvement immediately after the procedure. Antibiotics were continued for 8 months; repeat imaging prior to withdrawal found complete resolution of the brainstem abscess.

Relevance and novel information

Free-hand CT-guided drainage of a brainstem abscess is not without risk; however, in this case it led to significant clinical improvement and stabilisation likely owing to reduced intracranial pressure. It also provided a diagnostic sample that allowed successful medical treatment planning and outcome. To our knowledge, this is the first report describing the successful management of a brainstem abscess by CT-guided drainage in the veterinary literature. It suggests that stereotactic drainage followed by medical therapy can be considered a successful therapeutic alternative to brain surgery or medical treatment alone, providing an emergency treatment in cases of acute brainstem dysfunction.

Acute Bacterial Meningitis: Challenges to Better Antibiotic Therapy

Bacterial meningitis is a medical emergency requiring highly bactericidal antibiotics to achieve cure. Many challenges exist to achieving optimal patient outcome. First, antibiotics must pass the blood brain barrier. Once in the subarachnoid space, achieving bactericidal therapy involves circumventing antibiotic resistance and, more commonly, antibiotic tolerance arising from the slow growth of bacteria in the nutrient poor cerebrospinal fluid. Finally, bactericidal therapy is most often bacteriolytic, and debris from lysis is highly inflammatory. Controlling damage from lytic products may require adjunctive therapy to prevent neuronal death. These challenges are an extreme example of the different requirements for treating infections in different body sites.

Neuroinvasive Listeria monocytogenes Infection Triggers IFN-Activation of Microglia and Upregulates Microglial miR-155

MicroRNA (miR) miR-155 modulates microglial activation and polarization, but its role in activation of microglia during bacterial brain infection is unclear. We studied miR-155 expression in brains of C57BL/6 (B6.WT) mice infected i.p. with the neuro-invasive bacterial pathogen Listeria monocytogenes (L. monocytogenes). Infected mice were treated with ampicillin starting 2 days (d) post-infection (p.i.) and analyzed 3d, 7d, and 14d p.i. Virulent L. monocytogenes strains EGD and 10403s upregulated miR-155 in whole brain 7 d p.i. whereas infection with avirulent, non-neurotropic Δhly or ΔactA L. monocytogenes mutants did not. Similarly, infection with virulent but not mutated bacteria upregulated IFN-γ mRNA in the brain at 7 d p.i. Upregulation of miR-155 in microglia was confirmed by qPCR of flow cytometry-sorted CD45^intCD11b^pos brain cells. Subsequently, brain leukocyte influxes and gene expression in sorted microglia were compared in L. monocytogenes-infected B6.WT and B6.Cg-Mir155tm1.1Rsky/J (B6.miR-155^−/−) mice. Brain influxes of Ly-6C^high monocytes and upregulation of IFN-related genes in microglia were similar to B6.WT mice at 3 d p.i. In contrast, by d 7 p.i. expressions of microglial IFN-related genes, including markers of M1 polarization, were significantly lower in B6.miR-155^−/− mice and by 14 d p.i., influxes of activated T-lymphocytes were markedly reduced. Notably, CD45^highCD11b^pos brain cells from B6.miR-155^−/− mice isolated at 7 d p.i. expressed 2-fold fewer IFN-γ transcripts than did cells from B6.WT mice suggesting reduced IFN-γ stimulation contributed to dampened gene expression in B6.miR-155^−/− microglia. Lastly, in vitro stimulation of 7 d p.i. brain cells with heat-killed L. monocytogenes induced greater production of TNF in B6.miR-155^−/− microglia than in B6.WT microglia. Thus, miR-155 affects brain inflammation by multiple mechanisms during neuroinvasive L. monocytogenes infection. Peripheral miR-155 promotes brain inflammation through its required role in optimal development of IFN-γ-secreting lymphocytes that enter the brain and activate microglia. Microglial miR-155 promotes M1 polarization, and also inhibits inflammatory responses to stimulation by heat-killed L. monocytogenes, perhaps by targeting Tab2.

Clinical Outcomes and Risk Factors of Meningitis among Children in Referral Hospital, Ethiopia, 2016: A Retrospective Chart Review

BACKGROUND

Meningitis remains a major cause of mortality and morbidity in patients in many countries of the world including Ethiopia. Information on clinical outcomes of meningitis, susceptibility of the causative microorganism to rationalize treatment and associated risk factors is scare. The objective of this study was to assess the risk factors and clinical outcomes of meningitis among children in Felege Hiwot Referral Hospital, Bahir Dar, Northwest Ethiopia.

METHOD

A retrospective cross sectional study was conducted in Felege Hiwot Referral Hospital from January 2016 to May 2016. Data were checked for completeness, inconsistencies and entered into SPSS for windows version 20.0. Lottery method was used to select charts. One hundred seventy-nine pediatric patient files were used in the study.

RESULT

About 15% children with meningitis developed poor outcomes: developed complication, referred to higher facility, died and left against medical advice. In this study, season of admission [AOR= 5 (1.191, 20.991)], immunization status [AOR= 20.912 (3.325, 131.502)], clinical presentations [AOR= 8.779 (1.599, 48.192)] and corticosteroid administration [AOR= 8.215 (1.220, 55.328)] were the determinant factors for clinical outcome of meningitis.

CONCLUSION

In this study, about 15% of children with meningitis developed poor outcomes. The determinant factors for poor outcome of meningitis were: season of admission, immunization status, clinical presentations and corticoid administration. Creating community awareness about risk factors of meningitis, early diagnosis and treatment of cases, improving vaccination coverage and use of corticosteroids are recommended to improve the clinical outcome of children affected with meningitis.

Meta-analysis of adjunctive dexamethasone to improve clinical outcome of bacterial meningitis in children

BACKGROUND

The current recommended therapies for bacterial meningitis are effective antimicrobial agents and the implementation of childhood vaccination programs. However, the role of adjunctive dexamethasone therapy in bacterial meningitis remains controversial.

METHODS

Using meta-analysis, this study aims to investigate the efficacy of adjunctive dexamethasone therapy in bacterial meningitis by comparing it with antibiotic therapy. Documents of randomized controlled trials (RCT) related to the treatment of bacterial meningitis in children with dexamethasone published since the establishment of the databases to December in 2016 were retrieved from the databases of Cochrane Library, Pubmed, MEDLINE, EMBASE, Chinese BioMedical Literature Database, and China National Knowledge Infrastructure. The references in RCT were retrieved by hands at the same time. Full texts of screened documents were searched and given qualitative review, and then, all RCT included were analyzed statistically by using Review Manger 5.3 software.

RESULTS

The search yielded 15 studies (2409 children cases), among which 4 fall in grade A and 11 were grade B. The results of meta-analysis have shown that patients who received dexamethasone have significantly lower risks in incidence of hearing loss (OR = 0.68, 95%CI 0.53-0.89, P = 0.004) and severe neurological sequelae (OR = 0.59, 95%CI 0.37-0.95, P = 0.03), but the follow-up mortality is hardly effected (OR = 0.86, 95%CI 0.67-1.10, P = 0.23).

CONCLUSIONS

Evidence has proven that the adjunctive administration of dexamethasone is conducive to treating children with bacterial meningitis to a certain extent, to decreasing the possibility of hearing loss and severe neurological sequelae, but has no significant effect on the follow-up mortality.

Changing Epidemiology of Haemophilus influenzae in Children

Haemophilus influenzae remains a common cause of illness in children throughout the world. Before the introduction of vaccination, H influenzae type b (Hib) disease was the leading cause of bacterial meningitis in young children and a frequent cause of pneumonia, epiglottitis, and septic arthritis. Clinicians should remain diligent in counseling parents on the dangers of Hib and provide vaccination starting at 2 months of age. The epidemiology of invasive H influenzae disease is shifting. It is imperative that clinicians recognize the changing epidemiology and antibiotic resistance patterns for H influenzae to optimize care in hospital and ambulatory settings.

Inhibition of DAMP signaling as an effective adjunctive treatment strategy in pneumococcal meningitis

BACKGROUND

Pneumococcal meningitis remains a potentially lethal and debilitating disease, mainly due to brain damage from sustained inflammation. The release of danger-associated molecular patterns (DAMPs), like myeloid-related protein 14 (MRP14) and high mobility group box 1 protein (HMGB1), plays a major role in persistence of inflammation. In this study, we evaluated if paquinimod, an MRP14-inhibitor, and an anti-HMGB1 antibody can improve clinical outcome as adjunctive therapeutics in pneumococcal meningitis.

METHODS

We tested the adjuvant administration of paquinimod and the anti-HMGB1 antibody in our pneumococcal meningitis mouse model assessing clinical (clinical score, open-field-test, temperature) and pathophysiological parameters (intracranial pressure, white blood cell count in CSF, bleeding area) as well as bacterial titers in blood and brain 24 h after administration and 48 h after infection. Furthermore, we explored the interactions of these two agents with dexamethasone, the standard adjuvant treatment in pneumococcal meningitis (PM), and daptomycin, a non-bacteriolytic antibiotic preventing pathogen-associated molecular pattern (PAMP) release.

RESULTS

Adjunctive inhibition of MRP14 or HMGB1 reduced mortality in mice with PM. This effect was lost when the two anti-DAMP agents were given simultaneously, possibly due to excessive immunosuppression. Combining anti-PAMP (daptomycin) and anti-DAMP treatments did not produce synergistic results; instead, the anti-DAMP treatment alone was sufficient and superior. The combination of anti-HMGB1 with dexamethasone did not diminish the effect of the former.

CONCLUSIONS

DAMP inhibition possesses good potential as an adjuvant treatment approach in PM, as it improves clinical outcome and can be given together with the standard adjuvant dexamethasone without drug effect loss in experimental PM.

Combination therapy with ampicillin and azithromycin improved outcomes in a mouse model of group B streptococcal sepsis

BACKGROUND

Evidence suggests that β-lactam monotherapy of streptococcal infections may incite stronger inflammation and is inferior to combination therapy with macrolides. We hypothesized that use of macrolides alone or in combination with a β-lactam for group B streptococcal (GBS) sepsis would improve outcomes by reducing inflammation.

METHODS

TNF-α was measured from supernatants of RAW 264.7 cells stimulated with GBS isolates, in presence of four treatment regimens: ampicillin alone, azithromycin alone, or combination of azithromycin plus ampicillin. Mouse model of GBS sepsis was developed and treated with same four regimens. Clinical sepsis scores were monitored; serum cytokines (TNF-α, IL-6, IL-10) and chemokines (MIP-1α) were measured at the end.

RESULTS

GBS isolates exposed to azithromycin or combination (compared to ampicillin alone) stimulated less TNF production in vitro. In the murine sepsis model, mortality was lower along with decreased sepsis scores in mice treated with combination therapy. Mean serum IL-6 was lower in mice treated with azithromycin alone (66±52 pg/ml) or combination of ampicillin plus azithromycin (52±22 pg/ml) compared to ampicillin alone (260±160 pg/ml) (p<0.005).

CONCLUSIONS

Combination therapy of ampicillin+azithromycin improved outcomes in a murine GBS sepsis model; this therapeutic approach deserves additional study.

Dexamethasone for Parapneumonic Pleural Effusion: A Randomized, Double-Blind, Clinical Trial

OBJECTIVE

To assess whether dexamethasone (DXM) decreases the time to recovery in patients with parapneumonic pleural effusion.

STUDY DESIGN

This was a multicenter, randomized, double blind, parallel-group, placebo-controlled clinical trial of 60 children, ranging in age from 1 month to 14 years, with community-acquired pneumonia (CAP) and pleural effusion. Patients received either intravenous DXM (0.25?mg/kg/dose) or placebo every 6 hours over a period of 48 hours, along with antibiotics. The primary endpoint was the time to recovery in hours, defined objectively. We also evaluated complications and adverse events.

RESULTS

Among the 60 randomized patients (mean age, 4.7 years; 58% female), 57 (95%) completed the study. Compared with placebo recipients, the patients receiving DXM had a shorter time to recovery, after adjustment by severity group and stratification by center (hazard ratio, 1.95; 95% CI, 1.10-3.45; P?=?.021). The median time to recovery for patients receiving DXM was 68 hours (2.8 days) shorter than patients receiving placebo (109 hours vs 177 hours; P?=?.037). In exploratory subgroup analysis, the median time to recovery for patients with simple effusion receiving DXM was 76 hours (3.1 days) shorter than for patients with simple effusion receiving placebo (P?=?.017). The median time to recovery for patients with complicated effusion receiving DXM was 14 hours (0.5 days) shorter than for patients with complicated effusion receiving placebo (P?=?.66). The difference in the effect of DXM in the 2 severity groups was not statistically significant (P?=?.138 for interaction). There were no significant differences in complications or adverse events attributable to the study drugs, except for hyperglycemia.

CONCLUSION

In this trial, DXM seemed to be a safe and effective adjunctive therapy for parapneumonic pleural effusion.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01261546.

Central Nervous System Infections in the Critically Ill

Central nervous system (CNS) infections are frequently encountered in the intensive care unit setting and are a significant source of morbidity and mortality. The constantly changing trends in microbial resistance, as well as the pharmacokinetic difficulties in providing effective concentrations of antimicrobials at the site of infection represent a unique challenge to clinicians. Achievement of a successful outcome in patientswith CNS infections is reliant on eradication of the offending pathogen and management of any neurologic complications. This requires an anatomic and physiologic understanding of the different types of CNS infection, diagnostic strategies, associated complications, causative organisms, and the principles that govern drug distribution into the CNS. This article serves as a review of the epidemiology, pathophysiology, diagnosis, and treatment options for a variety of CNS infections, with a focus on those commonly encountered in an intensive care setting.

The Effects of Superoxide Dismutase in Gerbils with Bacterial Meningitis

BACKGROUND: Inflammatory products, such as oxygen radicals generated during the course of bacterial meningitis, can damage nerve endings, hair cells, and/or supporting cells in the cochlea. Superoxide dismutase (SOD), an O2-scavenger, has been shown to play an important role in the protection against radical toxicity in various animal experiments.

OBJECTIVE: To study the antioxidant effects of SOD on the inflammatory response of gerbils with bacterial meningitis.

STUDY DESIGN: Meningitis was induced in three groups of 10 gerbils by intrathecal (IT) injection of Streptococcus pneumoniae into the cisterna magna. Group 1 received IT SOD, group 2 received intramuscular (IM) SOD, and group 3, the control group, received IM normal saline. Histologic data and auditory brainstem responses (ABR) were obtained from each gerbil.

RESULTS: Fibrosis and/or neo-ossification were near absent in the IT SOD group and significantly less fibrosis occurred in the IM group (IT vs. IM: P = 0.010; IT vs. control group: P = 0.001). The amount of surviving spiral ganglion cells correlated inversely with the extent of fibrosis (r = −0.753, P < 0.00001).

CONCLUSIONS: IT injection of SOD significantly reduced cochlear fibrosis and neo-ossification, reduced the spiral ganglion cell loss, and decreased damage of the cochlear components following bacterial meningitis.

Meta-analysis of studies comparing adjuvant dexamethasone to glycerol to improve clinical outcome of bacterial meningitis

Background:

Neurological complications are a problematic factor in acute bacterial meningitis; hence, its prevention is the key to ensure the success of meningitis treatment. Glycerol and dexamethasone are both applied in this regard. Oral glycerol is an appropriate alternative instead of intravenous dexamethasone because it does not have problems related to intravenous injection, the high cost, and drug complications. The main objective of this study was to compare the efficacy of adjuvant dexamethasone versus glycerol in order to improve the clinical outcome of bacterial meningitis.

Materials and Methods:

We conducted a search on the available resources including PubMed, Ovid, Elsevier, Cochrane, and another search engines such as Google till 2014. All clinical trials that were performed in the field of comparing the effectiveness of the two drugs and met the inclusion criteria were gathered and after extraction the relative risk (RR) values, the pooled RR was calculated. The main outcome was neurological complications. Meta-analysis of the data was performed in Stata version 11.2 using both fixed and random effect models, weighting each study by inverse of variance.

Results:

In 5 comparative studies (1,340 patients), the rate of neurological complications of glycerol compared to that of dexamethasone was 1.02 [95% confidence interval (CI), 0.98 compared to 1.12]. The rate of neurological complications of dexamethasone compared to dexamethasone + glycerol was 1 (95% CI, 0.97 compared to 1.03), dexamethasone compared to placebo was 0.99 (95% CI, 0.97 compared to 1.03), glycerol compared to glycerol + dexamethasone was 0.98 (95% CI, 0.94 compared to 1.02), and glycerol compared to placebo was 0.97 (95% CI, 0.94 compared to 1.01). In these studies, no difference was reported between dexamethasone and glycerol in terms of reducing neurological complications.

Conclusion:

Although there were some weak evidences for the nonstatistical significant effect of glycerol in the prevention of neurologic complication after meningitis, there was no difference between glycerol and dexamethasone.

Adjuvant corticosteroids for reducing death in neonatal bacterial meningitis

BACKGROUND

Bacterial meningitis remains a significant cause of neonatal and childhood morbidity and mortality in many countries of the world, particularly in developing countries. In some instances, children recover but remain impaired as a result of neurological sequelae such as hearing loss, developmental delay and cognitive impairment.

OBJECTIVES

To assess the effectiveness and safety of adjunctive corticosteroids in reducing death and neurological sequelae in neonates with bacterial meningitis.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 7), MEDLINE via PubMed (1966 to July 2015), African Index Medicus (up to January 2015), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (up to July 2015), EMBASE (up to July 2015) and the metaRegister of Controlled Trials (mRCT) for ongoing trials.

SELECTION CRITERIA

All randomised controlled trials (RCTs) or quasi-RCTs of adjunctive corticosteroids for treatment of neonates with bacterial meningitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed and extracted data on methods, participants, interventions and outcomes (all-cause death until hospital discharge, presence of sensorineural deafness at one year and presence of neurological deficits or developmental delay at two years, adverse events). Risk ratio (RR), risk difference (RD) and number needed to treat for an additional beneficial outcome (NNTB) or number needed to treat for an additional harmful outcome (NNTH) were calculated when appropriate. We assessed quality using the Cochrane risk of bias assessment tool and the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) system.

MAIN RESULTS

We found two trials with 132 participants that met our inclusion criteria. One of the included trials was a quasi-randomised trial.Adjunctive corticosteroids reduced the risk of death (typical RR 0.46, 95% confidence interval (CI) 0.24 to 0.88; typical RD -0.19, 95% CI -0.33 to -0.04; NNTB = 6; two studies, 132 participants, very low-quality evidence) but did not have a significant effect on the number of infants with sensorineural deafness at two years (RR 1.80, 95% CI 0.18 to 18.21; RD 0.04, 95% CI -0.12 to 0.21; one study, 38 participants, low-quality evidence). In one trial, dexamethasone reduced the likelihood of hearing loss at four to 10 weeks post discharge (RR 0.41, 95% CI 0.17 to 0.98; RD -0.25, 95% CI -0.48 to -0.01; one study, 59 participants, low-quality evidence). Data reported on the other outcomes of interest were insufficient.

AUTHORS' CONCLUSIONS

Very low-quality data from two randomised controlled trials suggest that some reduction in death and hearing loss may result from use of adjunctive steroids alongside standard antibiotic therapy for treatment of patients with neonatal meningitis. Benefit is not yet seen with regards to reduction in neurological sequelae. Researchers who wish to clarify these findings must conduct more robustly designed trials with greater numbers of participants, evaluating more relevant outcomes and providing adequate follow-up.

Corticosteroids for acute bacterial meningitis

BACKGROUND

In experimental studies, the outcome of bacterial meningitis has been related to the severity of inflammation in the subarachnoid space. Corticosteroids reduce this inflammatory response.

OBJECTIVES

To examine the effect of adjuvant corticosteroid therapy versus placebo on mortality, hearing loss and neurological sequelae in people of all ages with acute bacterial meningitis.

SEARCH METHODS

We searched CENTRAL (2015, Issue 1), MEDLINE (1966 to January week 4, 2015), EMBASE (1974 to February 2015), Web of Science (2010 to February 2015), CINAHL (2010 to February 2015) and LILACS (2010 to February 2015).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of corticosteroids for acute bacterial meningitis.

DATA COLLECTION AND ANALYSIS

We scored RCTs for methodological quality. We collected outcomes and adverse effects. We performed subgroup analyses for children and adults, causative organisms, low-income versus high-income countries, time of steroid administration and study quality.

MAIN RESULTS

We included 25 studies involving 4121 participants (2511 children and 1517 adults; 93 mixed population). Four studies were of high quality with no risk of bias, 14 of medium quality and seven of low quality, indicating a moderate risk of bias for the total analysis. Nine studies were performed in low-income countries and 16 in high-income countries.Corticosteroids were associated with a non-significant reduction in mortality (17.8% versus 19.9%; risk ratio (RR) 0.90, 95% confidence interval (CI) 0.80 to 1.01, P value = 0.07). A similar non-significant reduction in mortality was observed in adults receiving corticosteroids (RR 0.74, 95% CI 0.53 to 1.05, P value = 0.09). Corticosteroids were associated with lower rates of severe hearing loss (RR 0.67, 95% CI 0.51 to 0.88), any hearing loss (RR 0.74, 95% CI 0.63 to 0.87) and neurological sequelae (RR 0.83, 95% CI 0.69 to 1.00).Subgroup analyses for causative organisms showed that corticosteroids reduced mortality in Streptococcus pneumoniae (S. pneumoniae) meningitis (RR 0.84, 95% CI 0.72 to 0.98), but not in Haemophilus influenzae (H. influenzae) orNeisseria meningitidis (N. meningitidis) meningitis. Corticosteroids reduced severe hearing loss in children with H. influenzae meningitis (RR 0.34, 95% CI 0.20 to 0.59) but not in children with meningitis due to non-Haemophilus species.In high-income countries, corticosteroids reduced severe hearing loss (RR 0.51, 95% CI 0.35 to 0.73), any hearing loss (RR 0.58, 95% CI 0.45 to 0.73) and short-term neurological sequelae (RR 0.64, 95% CI 0.48 to 0.85). There was no beneficial effect of corticosteroid therapy in low-income countries.Subgroup analysis for study quality showed no effect of corticosteroids on severe hearing loss in high-quality studies.Corticosteroid treatment was associated with an increase in recurrent fever (RR 1.27, 95% CI 1.09 to 1.47), but not with other adverse events.

AUTHORS' CONCLUSIONS

Corticosteroids significantly reduced hearing loss and neurological sequelae, but did not reduce overall mortality. Data support the use of corticosteroids in patients with bacterial meningitis in high-income countries. We found no beneficial effect in low-income countries.

Perioperative measures to improve outcome after subarachnoid hemorrhage-revisiting the concept of secondary brain injury

Progress in the management of aneurysmal subarachnoid hemorrhage (SAH) is reflected most clearly in a continuously decreasing case fatality rate over the last decades. The purpose of the present review is to identify the relevant factors responsible for this progress and to outline future possibilities of improvement. Although data on intracerebral hemorrhage and ischemic stroke are less homogeneous, the respective data suggest that reduction of case fatalities could also be achieved with these types of stroke. Therefore, advances of general neurocritical care may be the common denominator responsible for the decreasing case fatality rates. Additionally, a change in practice with regard to treatment of elderly patients that is more active may also be a factor. Regarding SAH, the majority of unfavorable outcomes is still related to early or delayed cerebral injury. Therefore, efforts to pharmacologically prevent secondary neuronal damage are likely to play a certain role in achieving improvement in overall outcome. However, the data from previous randomized clinical trials conducted during the last three decades does not strongly support this. A clear benefit has only been proven for oral nimodipine, whereas other calcium antagonists and the rho-kinase inhibitors were not conclusively shown to have a significant effect on functional outcome, and all other tested substances disappointed in clinical trials. Regarding ischemic stroke and traumatic brain injury, intensive clinical research has also been conducted during the last 30 years to improve outcome and to minimize secondary neuronal injury. For ischemic stroke, treatment focusing on reversal of the primary pathomechanism, such as thrombolysis, proved effective, but none of the pharmacological neuroprotective concepts resulted in any benefit. To date, decompressive hemicraniectomy has been the only effective effort focused at reducing secondary damage that resulted in a clear reduction of mortality. In the case of traumatic brain injury, none of the pharmacological or other efforts to limit secondary damage met our hopes. In summary, although limited, pharmacotherapy to limit delayed neuronal injury is more effective for SAH than for ischemic stroke and traumatic brain injury. The disappointing results of most trials addressing secondary damage force one to question the general concept of mechanisms of secondary damage that do not also have a positive side in the natural course of the disease. For example, in the case of SAH, the data from the Cooperative Study from the 1960s showed that vasospasm to some degree protects against rerupture of unsecured aneurysms. Thus, one could argue from an evolutionary standpoint that the purpose of vasospasm was not exclusively a detrimental or suicide pathomechanism, but an attempt to protect against life-threating aneurysm rerupture. Because of the above-discussed arguments, SAH may indeed differ from ischemic stroke and traumatic brain injury with regard to the usefulness of blocking secondary mechanisms pharmacologically. Further efforts to limit vasospasm should therefore be made, and the most promising drugs, calcium antagonists, deserve further development. Because, with various drugs, systemic side effects counteracted the local beneficial effect, future efforts should focus on topical administration of drugs instead of systemic administration. Furthermore, efforts for a better understanding of the variations of the calcium channels and the interplay between the different types of calcium channels should be made.

Bacterial meningitis: new therapeutic approaches

Bacterial meningitis remains a disease with high mortality and long-term morbidity. Outcome critically depends on the rapid initiation of effective antibiotic therapy. Since a further increase of the incidence of pathogens resistant to antibacterials can be expected both in community-acquired and nosocomial bacterial meningitis, the choice of an optimum initial empirical antibiotic regimen will gain significance. In this context, the use of antibiotics which are bactericidal but do not lyse bacteria, may emerge as a therapeutic option. Conversely, the role of corticosteroids, which decrease the entry of hydrophilic antibacterials into the cerebrospinal fluid, as adjunctive therapy will probably decline as a consequence of the increasing antibiotic resistance of bacteria causing meningitis. Consequent vaccination of all children at present is the most efficient manner to reduce disease burden.

Invasive pneumococcal disease complicated by cerebral vasculitis, transient diabetes insipidus and spondylodiscitis

Invasive pneumococcal disease (IPD) is a potential life-threatening situation that requires immediate recognition and treatment. Cerebrovascular complications are uncommon and have been reported less frequently in adults than in children. We report a case of 59-year-old man with IPD complicated by cerebral vasculitis, transient central diabetes insipidus and spondylodiscitis. Each of these complications is rare and needs specific approach. Their association is even rarer and to the best of our knowledge this is the first case reported.

The pneumococcus: epidemiology, microbiology, and pathogenesis

The pneumococcus is the classic Gram-positive extracellular pathogen. The medical burden of diseases it causes is amongst the greatest in the world. Intense study for more than 100 years has yielded an understanding of fundamental aspects of its physiology, pathogenesis, and immunity. Efforts to control infection have led to the deployment of polysaccharide vaccines and an understanding of antibiotic resistance. The inflammatory response to pneumococci, one of the most potent in medicine, has revealed the double-edged sword of clearance of infection but at a cost of damage to host cells. In virtually every aspect of the infectious process, the pneumococcus has set the rules of the Gram-positive pathogenesis game.

Corticosteroids for acute bacterial meningitis

BACKGROUND

In experimental studies, the outcome of bacterial meningitis has been related to the severity of inflammation in the subarachnoid space. Corticosteroids reduce this inflammatory response.

OBJECTIVES

To examine the effect of adjuvant corticosteroid therapy versus placebo on mortality, hearing loss and neurological sequelae in people of all ages with acute bacterial meningitis.

SEARCH METHODS

We searched CENTRAL 2012, Issue 12, MEDLINE (1966 to January week 2, 2013), EMBASE (1974 to January 2013), Web of Science (2010 to January 2013), CINAHL (2010 to January 2013) and LILACS (2010 to January 2013).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of corticosteroids for acute bacterial meningitis.

DATA COLLECTION AND ANALYSIS

We scored RCTs for methodological quality. We collected outcomes and adverse effects. We performed subgroup analyses for children and adults, causative organisms, low-income versus high-income countries, time of steroid administration and study quality.

MAIN RESULTS

Twenty-five studies involving 4121 participants were included. Corticosteroids were associated with a non-significant reduction in mortality (17.8% versus 19.9%; risk ratio (RR) 0.90, 95% confidence interval (CI) 0.80 to 1.01, P = 0.07). A similar non-significant reduction in mortality was observed in adults receiving corticosteroids (RR 0.74, 95% CI 0.53 to 1.05, P = 0.09). Corticosteroids were associated with lower rates of severe hearing loss (RR 0.67, 95% CI 0.51 to 0.88), any hearing loss (RR 0.74, 95% CI 0.63 to 0.87) and neurological sequelae (RR 0.83, 95% CI 0.69 to 1.00).Subgroup analyses for causative organisms showed that corticosteroids reduced mortality in Streptococcus pneumoniae (S. pneumoniae) meningitis (RR 0.84, 95% CI 0.72 to 0.98), but not in Haemophilus influenzae (H. influenzae) orNeisseria meningitidis (N. meningitidis) meningitis. Corticosteroids reduced severe hearing loss in children with H. influenzae meningitis (RR 0.34, 95% CI 0.20 to 0.59) but not in children with meningitis due to non-Haemophilus species.In high-income countries, corticosteroids reduced severe hearing loss (RR 0.51, 95% CI 0.35 to 0.73), any hearing loss (RR 0.58, 95% CI 0.45 to 0.73) and short-term neurological sequelae (RR 0.64, 95% CI 0.48 to 0.85). There was no beneficial effect of corticosteroid therapy in low-income countries.Subgroup analysis for study quality showed no effect of corticosteroids on severe hearing loss in high-quality studies.Corticosteroid treatment was associated with an increase in recurrent fever (RR 1.27, 95% CI 1.09 to 1.47), but not with other adverse events.

AUTHORS' CONCLUSIONS

Corticosteroids significantly reduced hearing loss and neurological sequelae, but did not reduce overall mortality. Data support the use of corticosteroids in patients with bacterial meningitis in high-income countries. We found no beneficial effect in low-income countries.

Bacterial meningitis post-PCV7: declining incidence and treatment

The epidemiology of bacterial meningitis in the United States has changed tremendously in the past 20 years. Since the introduction of the Haemophilus influenzae type b vaccine in 1988, the incidence of H. influenzae type b meningitis has declined by at least 97%, and Streptococcus pneumoniae has emerged as the most common etiologic agent. The PCV7 (7-valent pneumococcal conjugate vaccine [Prevnar]; Wyeth Pharmaceuticals) vaccine, which targets 7 pneumococcal serotypes, was introduced in 2000 and has had an enormous impact on both the incidence and epidemiology of bacterial meningitis. This article reviews the impact of the PCV7 vaccine and the most up-to-date evidence on diagnosis and empiric therapy of suspected bacterial meningitis in the current day.

Role of dexamethasone in neonatal meningitis: a randomized controlled trial

OBJECTIVES

To evaluate the role of dexamethasone therapy in neonatal meningitis in a randomized placebo controlled trial.

METHODS

The participants were eighty neonates with meningitis randomized to receive dexamethasone or saline placebo. Dexamethasone was started prior to the first dose of antibiotics in the dose of 0.15 mg/kg intravenous 6 hourly for 2 d. Primary outcome measure was mortality. Secondary outcome measures included progression of systemic inflammatory response syndrome (SIRS) up to 48 h, differences in cerebrospinal fluid (CSF) cytokines between baseline levels and 24 h after enrolment and brain stem auditory evoked response (BAER) after 4 to 6 wk of discharge.

RESULTS

Baseline variables were comparable in both the groups. Mortality was significantly decreased in dexamethasone group (p = 0.005) and the absolute risk difference was 27.5 % (95 % CI 9.5-45.8 %). There was a significant reduction in cells per mm(3) (62.5 vs. 100) and proteins (162 vs. 217.5 mg/dl) after 24 h of treatment in the dexamethasone group. IL-1β was significantly reduced after 24 h in dexamethasone group (290 vs 665 pg/ml). TNF- α was significantly lower (157.5 vs 427.5 pg/ml) and sugar significantly higher (50 vs 38 mg/dl) in the dexamethasone group after 24 h. Significant difference was noted between dexamethasone and saline groups in the progression of SIRS.

CONCLUSIONS

Dexamethasone significantly reduced fatality, progression of SIRS and CSF inflammatory indices.

Treatment of bacterial meningitis: an update

INTRODUCTION

The introduction of protein conjugate vaccines for Haemophilus influenzae type b (Hib), Streptococcus pneumoniae (S. pneumoniae) and Neisseria meningitidis (N. menigitidis) has changed the epidemiology of bacterial meningitis. Bacterial meningitis continues to be an important cause of mortality and morbidity, and our incomplete knowledge of its pathogenesis and emergence of antimicrobial resistant bacteria contribute to such mortality and morbidity. An early empiric antibiotic treatment is critical for the management of patients with bacterial meningitis.

AREAS COVERED

This article gives an overview on optimal treatment strategies of bacterial meningitis, along with considerations of new insights on epidemiology, clinical and laboratory findings supportive of bacterial meningitis, chemoprophylaxis, selection of initial antimicrobial agents for suspected bacterial meningitis, antimicrobial resistance and utility of new antibiotics, status on anti-inflammatory agents and adjunctive therapy, and pathogenesis of bacterial meningitis.

EXPERT OPINION

Prompt treatment of bacterial meningitis with an appropriate antibiotic is essential. Optimal antimicrobial treatment of bacterial meningitis requires bactericidal agents able to penetrate the blood-brain barrier (BBB), with efficacy in cerebrospinal fluid (CSF). Several new antibiotics have been introduced for the treatment of meningitis caused by resistant bacteria, but their use in human studies has been limited. More complete understanding of the microbial and host interactions that are involved in the pathogenesis of bacterial meningitis and associated neurologic sequelae is likely to help in developing new strategies for the prevention and therapy of bacterial meningitis.

Should corticosteroids be used in bacterial meningitis in children?

Bacterial meningitis is one of the most serious infections in infants and children, with considerable morbidity and mortality. Despite the spreading of conjugated vaccines against Haemophilus influenzae type b (Hib), the most important pneumococcal serotypes and serogroup C meningococcus has reduced the incidence of this infection in developed countries, it still remains a global public health problem and an important cause of mortality and disability. Whether corticosteroids should be used as a complementary therapy to antibacterials is still not clear because of the disparate findings from clinical trials and clinical evidence. The aim of this review is to analyze the available evidence on the impact of corticosteroid therapy in infants and children with bacterial meningitis in developed countries in order to define whether they should be added routinely in the empiric therapy of such disease. Our analysis concluded that in high-income countries dexamethasone has shown good results to prevent hearing loss in Hib meningitis if administered before or at the same time as the first dose of antibiotics. Dexamethasone should be evaluated in pneumococcal meningitis: it may be less beneficial in children with delayed presentation to medical attention and may be unfavourable in case of cephalosporin-resistant pneumococci. On the contrary, there is no evidence to recommend the use of corticosteroids in meningococcal meningitis. Further studies that take into account the epidemiologic changes of recent years, consider enrolment based on the onset of symptoms and evaluate outcomes such as hearing loss and neurologic sequelae with advanced techniques are urgently needed.

Revisão sistemática do uso da dexametasona como terapia adjuvante na meningite bacteriana em crianças

OBJETIVO: Analisar a melhor evidência disponível nos últimos 15 anos com relação aos benefícios da terapia adjuvante com dexametasona na meningite bacteriana em população pediátrica. FONTES DE DADOS: Das bases de dados Medline, Lilacs e SciELO, foram analisados ensaios clínicos randomizados de 1996 a 2011, os quais comparavam a dexametasona ao placebo e/ou a outra terapia adjuvante em pacientes com meningite bacteriana diagnosticada laboratorialmente por critérios quimiocitológicos e/ou bacteriológicos, na faixa etária de 29 dias aos 18 anos. Os desfechos avaliados foram mortalidade e ocorrência de sequelas neurológicas e/ou auditivas. Foram excluídos estudos relacionados à meningite tuberculosa. SÍNTESE DOS DADOS: Com os critérios utilizados, foram identificadas cinco publicações correspondentes a quatro protocolos de estudo. Nenhum dos estudos mostrou diferenças entre a dexametasona e o placebo para os desfechos avaliados. Os estudos analisados tiveram alta qualidade (escore de Jadad et al=5). CONCLUSÕES: As evidências encontradas na literatura são insuficientes para indicar de forma rotineira o uso da dexametasona como terapia adjuvante para redução de mortalidade, perda auditiva e sequelas neurológicas em pacientes pediátricos com meningite bacteriana não tuberculosa.

The role of dexamethasone in the treatment of bacterial meningitis - a systematic review

Corticosteroids are used as an adjunct to antibiotics in the treatment of bacterial meningitis in an attempt to attenuate the intrathecal inflammatory response and thereby reduce mortality and morbidity. The purpose of the present paper is to provide a review of clinical studies of corticosteroids in the treatment of bacterial meningitis. Relevant literature was found in PubMed, the Cochrane databases, and references in studies. Forty-four publications of relevance were identified, comprising 29 publications of randomised studies, 10 publications reporting either non- or quasi-randomised studies, and five reporting retrospective studies, and nine meta-analyses. Taken together, dexamethasone treatment may be associated with a lower mortality in adults and fewer neurological and auditory sequelae in adults and children from high-income countries, in particular in adults suffering from pneumococcal meningitis. In contrast, studies conducted in developing countries have yielded less favourable results.

Dexamethasone therapy for bacterial meningitis: Better never than late?

A multicentre randomized controlled trial was conducted in children with bacterial meningitis using dexamethasone or placebo for four days within 24 h of starting antibiotics. Primary outcomes were hearing loss and neurological abnormalities at 12 months after meningitis. The dexamethasone (n=50) and placebo (n=51) groups were similar in age, severity of illness and etiological agent. Hearing loss occurred in 10% and 11% of the dexamethasone and placebo groups and neurological deficits occurred in 20% and 18% of patients, respectively. Duodenal perforation occurred in one dexamethasone-treated child. In conclusion, there was no significant benefit in those receiving dexamethasone. The lack of benefit may have been due to the delay in administration of dexamethasone (median delay of 11 h after antibiotics). Therefore, if dexamethasone is used for meningitis it should be given immediately with the antibiotic.

Adjunctive daptomycin attenuates brain damage and hearing loss more efficiently than rifampin in infant rat pneumococcal meningitis

Exacerbation of cerebrospinal fluid (CSF) inflammation in response to bacteriolysis by beta-lactam antibiotics contributes to brain damage and neurological sequelae in bacterial meningitis. Daptomycin, a nonlytic antibiotic acting on Gram-positive bacteria, lessens inflammation and brain injury compared to ceftriaxone. With a view to a clinical application for pediatric bacterial meningitis, we investigated the effect of combining daptomycin or rifampin with ceftriaxone in an infant rat pneumococcal meningitis model. Eleven-day-old Wistar rats with pneumococcal meningitis were randomized to treatment starting at 18 h after infection with (i) ceftriaxone (100 mg/kg of body weight, subcutaneously [s.c.], twice a day [b.i.d.]), (ii) daptomycin (10 mg/kg, s.c., daily) followed 15 min later by ceftriaxone, or (iii) rifampin (20 mg/kg, intraperitoneally [i.p.], b.i.d.) followed 15 min later by ceftriaxone. CSF was sampled at 6 and 22 h after the initiation of therapy and was assessed for concentrations of defined chemokines and cytokines. Brain damage was quantified by histomorphometry at 40 h after infection and hearing loss was assessed at 3 weeks after infection. Daptomycin plus ceftriaxone versus ceftriaxone significantly (P < 0.04) lowered CSF concentrations of monocyte chemoattractant protein 1 (MCP-1), MIP-1α, and interleukin 6 (IL-6) at 6 h and MIP-1α, IL-6, and IL-10 at 22 h after initiation of therapy, led to significantly (P < 0.01) less apoptosis, and significantly (P < 0.01) improved hearing capacity. While rifampin plus ceftriaxone versus ceftriaxone also led to lower CSF inflammation (P < 0.02 for IL-6 at 6 h), it had no significant effect on apoptosis and hearing capacity. Adjuvant daptomycin could therefore offer added benefits for the treatment of pediatric pneumococcal meningitis.

Dexamethasone for adult community-acquired bacterial meningitis: 20 years of experience in daily practice

The aim of the study was to assess adjunctive intravenous dexamethasone in adult community-acquired bacterial meningitis (BM) in daily practice. Analysis of consecutive patients (1990-2009) with acute community-acquired bacterial meningitis in a single centre in Zagreb, Croatia, N = 304. Adjusted relative risks [RR, dexamethasone vs. no dexamethasone (control)] of Glasgow Outcome Scale (GOS) = 1 (death) and GOS = 5 (full recovery) at discharge/end of specific treatment were estimated considering demographics; co-morbidity; BM pathogenesis and on-admission characteristics, and cerebrospinal fluid (CSF) inflammation markers; causative agent and antibiotic use. Two hundred forty (79%) patients had proven BM (43.1% Streptococcus pneumoniae, any other agent ≤ 8.2%). No independent effects of dexamethasone on GOS = 1 or GOS = 5 were observed in the entire cohort (dexamethasone n = 119, control n = 185; RR = 1.06, 95% CI 0.77-1.45 and RR = 0.99, CI 0.83-1.20, respectively), microbiologically proven disease (dexamethasone n = 104, control n = 136; RR = 0.97, CI 0.69-1.38 and RR = 1.03, CI 0.82-1.28), pneumococcal disease (dexamethasone n = 71, control n = 60; RR = 0.95, CI 0.53-1.70 and RR = 0.82, CI 0.57-1.18), and also in other BM, subgroups based on consciousness disturbance, CSF markers, prior use of antibiotics and timing of appropriate antibiotic treatment. CSF markers did not predict the outcomes.

CONCLUSIONS

Our experience does not substantiate the reported benefits of adjunctive dexamethasone in adult BM. Socio-economic and methodological factors do not seem to explain this discrepancy. Empirical use of dexamethasone in this setting appears controversial.

Mortality from bacterial meningitis in children in Kosovo

Bacterial meningitis is a severe infection responsible for high mortality. This prospective study of 277 pediatric bacterial meningitis cases was done to identify factors predicting death in children <16 years of age living and treated in a limited-resources country (Kosovo). Of the 277 children enrolled, 60 patients (22%) developed neurologic complications, and 15 children died (5%). The following variables were strongly correlated with mortality: altered mental status on admission (relative risk [RR] = 29.9), presentation of the initial cerebrospinal fluid as thick pus (RR = 29.9), prehospital seizures (RR = 23.5) and their recurrence >24 hours after admission (RR = 11.5), age <1 month (RR = 19.3), the use of inotropic agents (RR = 11.5), and admission after 5 days' duration of illness (P < .001). The mortality rate in children in Kosovo is similar to those reported from developing countries, and this is most likely due to the unfavorable living conditions.

The use of dexamethasone in bacterial meningitis in children and adults: a retrospective analysis

Bacterial meningitis is a life-threatening illness that results from bacterial infection of the meninges and is associated with high mortality and morbidity rate, especially when the Streptococcus pneumoniae is the causative agent. Dexamethasone as adjunctive therapy to antibiotics does not influence the outcome or the complications in children as well as in adults suffering bacterial meningitis. However, we identified some prognostic parameters in the outcome of bacterial meningitis, and when dexamethasone was given in presence of at least one of 3 poor prognostic CSF parameters (WBC < 1000/mm³, glucose < 20 mg/dl, lactate > 10 mg/dl) it substantially improved the outcome.