Pneumococcal meningitis in adults: spectrum of complications and prognostic factors in a series of 87 cases

Prognostic factors and determinants of fatal outcome due to bacterial meningitis in the Lazio region of Italy, 1996–2000

OBJECTIVES

To estimate case fatality rates (CFR) of bacterial meningitis and analyze factors associated with mortality due to bacterial meningitis in the Italian region of Lazio.

METHODS

Patients reported with bacterial meningitis during the period 1996-2000, who died within 30 days from hospitalization (cases), were compared with survivors (controls) for factors related to healthcare. Age, gender, residence, bacterial agent, co-morbidities, and signs of disease severity were also analyzed in the final model. Healthcare factors were analyzed using current surveillance databases.

RESULTS

Disease severity (OR=8.84; 95% CI=3.35-23.34) and age >44 years (OR=4.59; 95% CI=2.01-10.48) were the risk factors most strongly associated with death, while treatment in an infectious diseases ward was a protective factor, although modified by patient residence and by co-morbidities.

CONCLUSIONS

This protective effect was possibly due to differences in treatment protocols between the infectious diseases ward and other wards. The protective effect was found to be stronger for residents of Rome, suggesting delayed access to infectious diseases wards for non-residents. The difference in risk of dying from meningitis at younger ages than that found in other studies should be further evaluated, using information on bacteria serogroups and antibiotic susceptibility.

The burden of pneumococcal disease in the Canadian population before routine use of the seven-valent pneumococcal conjugate vaccine

BACKGROUND

In the United States, implementation of the seven-valent conjugate vaccine into childhood immunization schedules has had an effect on the burden of pneumococcal disease in all ages of the population. To evaluate the impact in Canada, it is essential to have an estimate of the burden of pneumococcal disease before routine use of the vaccine.

METHODS

The incidence and costs of pneumococcal disease in the Canadian population in 2001 were estimated from various sources, including published studies, provincial databases and expert opinion.

RESULTS

In 2001, there were 565,000 cases of pneumococcal disease in the Canadian population, with invasive infections representing 0.7%, pneumonia 7.5% and acute otitis media 91.8% of cases. There were a total of 3000 deaths, mainly as a result of pneumonia and largely attributable to the population aged 65 years or older. There were 54,330 life-years lost due to pneumococcal disease, and 37,430 quality-adjusted life-years lost due to acute disease, long-term sequelae and deaths. Societal costs were estimated to be $193 million (range $155 to $295 million), with 82% borne by the health system and 18% borne by families. Invasive pneumococcal infections represented 17% of the costs and noninvasive infections represented 83%, with approximately one-half of this proportion attributable to acute otitis media and myringotomy.

CONCLUSIONS

The burden of pneumococcal disease before routine use of the pneumococcal conjugate vaccine was substantial in all age groups of the Canadian population. This estimate provides a baseline for further analysis of the direct and indirect impacts of the vaccine.

[N-acetyl-L-cysteine as a therapeutic option in bacterial meningitis]

Despite antibiotic therapy, supportive intensive care, and adjunctive treatment with dexamethasone, the mortality and morbidity remain high in patients with bacterial meningitis. The intracranial complications that mainly contribute to the poor outcome are in part a result of the production of reactive oxygen and nitrogen species. Experimental studies have shown that the prognosis for bacterial meningitis can be improved by the administration of antioxidants. Especially adjunctive therapy with N-acetyl-L-cystein (NAC) was shown to have mainly positive effects. Since NAC is already in clinical use in high doses for treating other diseases (e.g., acetaminophen intoxication) and only minor side effects have been observed, there is justified hope that adjunctive therapy with NAC could improve the prognosis of patients with bacterial meningitis.

International integrated database for the evaluation of severe sepsis and drotrecogin alfa (activated) therapy: 28-day survival and safety

PURPOSE

To enhance the understanding of severe sepsis, a database of patients from multiple clinical trials spanning a 6-year period was constructed. Initial analyses evaluated the 28-day survival in the placebo group and further assessed the treatment effect of drotrecogin alfa (activated) (DrotAA).

METHODS

Five severe sepsis studies with similar entry criteria were combined, and baseline characteristics and 28-day mortality were evaluated (4459 severe sepsis patients; placebo, n = 1231; DrotAA, n = 3228). An integrated data analysis with propensity score adjustment was performed. Twenty-one variables selected by stepwise logistic regression were included in a propensity score of differences between the 2 groups of patients.

RESULTS

Over the 6-year period of these trials, there was no change in placebo mortality rates overall (P = .67), nor in subgroups of Acute Physiology and Chronic Health Evaluation score >/=25 (P = .73) or multiple organ dysfunction (P = .38). The adjusted relative hazard risk for DrotAA patients was 0.84 (95% confidence interval, 0.73-0.95; P = .007). Serious bleeding (0.8% in placebo vs 3.5% in DrotAA, P < .0001) was increased during the DrotAA infusion period.

CONCLUSIONS

Initial analyses indicate that placebo mortality remained unchanged over a recent 6-year period. These analyses also further substantiate that treatment with DrotAA is associated with improved survival.

Outcome of 8-hour dosing intervals with beta-lactam antibiotics in adult acute bacterial meningitis

The outcome of dosing with beta-lactam antibiotics at 8-h intervals for adult patients with community-acquired acute bacterial meningitis was retrospectively analysed at Sahlgrenska University Hospital, Gothenburg, Sweden. 80 medical records were identified for a 6-y period from 1999 to 2004. The most common pathogens noted were Streptococcus pneumoniae (47.5%), Neiseria meningitidis (12.5%), and Listeria monocytogenes (5.0%). Other bacteria were diagnosed in 16.3% of all episodes, but the bacteriological aetiology remained unknown in 18.8%. 79 episodes of bacterial meningitis were treated with beta-lactam antibiotics at 8-h dosing intervals. The mortality rate in these patients was 6.3%, with an incidence of permanent neurological deficiencies of 24.1%. Our study shows that a low mortality rate can be achieved using beta-lactam antibiotics at longer dosing intervals than usually recommended by international guidelines.

Oxidative stress in pneumococcal meningitis: A future target for adjunctive therapy?

Despite antibiotic therapy and supportive intensive care, the morbidity and mortality of pneumococcal meningitis remain unacceptably high. During the last years, reactive oxygen (ROS) and nitrogen species (RNS), and peroxynitrite, were found to be produced in large amounts during pneumococcal meningitis. Although most likely intended to fight the invasive pathogens, they seem to lead to substantial collateral damage instead. This is because ROS and RNS can exert a vast variety of toxic actions, e.g., through lipid peroxidation, DNA strand breakage followed by PARP activation and subsequent cellular energy depletion, production of inflammatory cytokines, and activation of matrix metalloproteinases. Animal models of pneumococcal meningitis have shown that these interactions contribute to massive meningeal inflammation, disruption of the blood-brain barrier, alterations of the cerebral autoregulation, neuronal cell death, and cochlear destruction. Thus, the production of ROS and RNS seems at least in part to be responsible for the poor outcome of patients with pneumococcal meningitis. In consequence, reactive oxygen and nitrogen species such as peroxynitrite have been investigated as potential targets for adjunctive therapy in pneumococcal meningitis. Among the multiple agents tested, one promising drug is N-acetyl-l-cysteine (NAC), which significantly reduced cerebral and cochlear complications in animal models of experimental pneumococcal meningitis.

Detrimental role of delayed antibiotic administration and penicillin-nonsusceptible strains in adult intensive care unit patients with pneumococcal meningitis: the PNEUMOREA prospective multicenter study

OBJECTIVE

To identify factors associated with mortality and morbidity among adults admitted to intensive care units (ICUs) for pneumococcal meningitis, particularly the impact of delayed antibiotic administration.

DESIGN

We conducted a prospective, multicenter, observational study of 156 consecutive adults hospitalized for pneumococcal meningitis. We analyzed parameters associated with 3-month survival.

SETTING

Fifty-six medical and medical-surgical ICUs in France.

INTERVENTION

None.

RESULTS

Of the 148 strains isolated, 56 (38%) were nonsusceptible to penicillin G. At 3 months after ICU admission, the mortality rate was 33% (51/156), and 34% of survivors (36/105) had neurologic sequelae. Multivariate analysis identified three variables as independently associated with 3-month mortality: Simplified Acute Physiology Score II (odds ration [OR], 1.12; 95% confidence interval [CI], 1.072-1.153; p = .002); isolation of a nonsusceptible strain (OR, 6.83; 95% CI, 2.94-20.8; p < 10(-4)), and an interval of >3 hrs between hospital admission and administration of antibiotics (OR, 14.12; 95% CI, 3.93-50.9; p < 10(-4)). In contrast, a cerebrospinal fluid leukocyte count >10(3) cells/microL had a protective effect (OR, 0.30; 95% CI, 0.10-0.944; p = 0.04).

CONCLUSIONS

Independent of severity at the time of ICU admission, isolation of penicillin-nonsusceptible strains and a delay in antibiotic treatment following admission were predictors of mortality among patients with pneumococcal meningitis.

Dexamethasone in adults with community-acquired bacterial meningitis

Bacterial meningitis in adults is a severe disease with high fatality and morbidity rates. Experimental studies have shown that the inflammatory response in the subarachnoid space is associated with an unfavourable outcome. In these experiments, corticosteroids, and in particular dexamethasone, were able to reduce the inflammatory cascades in the subarachnoid space. The use of corticosteroids as adjunctive therapy in adults with bacterial meningitis has been evaluated in six studies, performed over a time period of 40 years. Most studies on adjunctive dexamethasone therapy in adults with bacterial meningitis were limited by methodological flaws. In 2002, a study with sufficient statistical power to show significant differences was published. This European Dexamethasone Study showed that adjunctive dexamethasone therapy reduced the rate of unfavourable outcomes in adults with bacterial meningitis from 25% to 15%. In this study, adjunctive treatment with dexamethasone was given before or with the first dose of antibacterials, without serious adverse effects. A quantitative review showed a consistent beneficial effect of dexamethasone on mortality and a borderline statistical beneficial effect on neurological sequelae. On the basis of the available evidence, adjunctive dexamethasone therapy should be initiated before or with the first dose of antibacterials and continued for 4 days in all adults with suspected or proven bacterial meningitis, regardless of bacterial aetiology. In patients with both meningitis and septic shock, dexamethasone therapy cannot be unequivocally recommended, but the use of lower doses seems reasonable at present. Since prompt use of dexamethasone and appropriate antibacterials improves the prognosis of adults with bacterial meningitis, hospitals will require protocols to include dexamethasone with the initial antibacterial therapy.

Attenuated cerebrospinal fluid leukocyte count and sepsis in adults with pneumococcal meningitis: a prospective cohort study

Background

A low cerebrospinal fluid (CSF) white-blood cell count (WBC) has been identified as an independent risk factor for adverse outcome in adults with bacterial meningitis. Whereas a low CSF WBC indicates the presence of sepsis with early meningitis in patients with meningococcal infections, the relation between CSF WBC and outcome in patients with pneumococcal meningitis is not understood.

Methods

We examined the relation between CSF WBC, bacteraemia and sepsis in a prospective cohort study that included 352 episodes of pneumococcal meningitis, confirmed by CSF culture, occurring in patients aged >16 years.

Results

CSF WBC was recorded in 320 of 352 episodes (91%). Median CSF WBC was 2530 per mm³ (interquartile range 531–6983 per mm³) and 104 patients (33%) had a CSF WBC <1000/mm³. Patients with a CSF WBC <1000/mm³ were more likely to have an unfavourable outcome (defined as a Glasgow Outcome Scale score of 1–4) than those with a higher WBC (74 of 104 [71%] vs. 87 of 216 [43%]; P < 0.001). CSF WBC was significantly associated with blood WBC (Spearman's test 0.29), CSF protein level (0.20), thrombocyte count (0.21), erythrocyte sedimentation rate (-0.15), and C-reactive protein levels (-0.18). Patients with a CSF WBC <1000/mm³ more often had a positive blood culture (72 of 84 [86%] vs. 138 of 196 [70%]; P = 0.01) and more often developed systemic complications (cardiorespiratory failure, sepsis) than those with a higher WBC (53 of 104 [51%] vs. 69 of 216 [32%]; P = 0.001). In a multivariate analysis, advanced age (Odds ratio per 10-year increments 1.22, 95%CI 1.02–1.45), a positive blood culture (Odds ratio 2.46, 95%CI 1.17–5.14), and a low thrombocyte count on admission (Odds ratio per 100,000/mm³ increments 0.67, 95% CI 0.47–0.97) were associated with a CSF WBC <1000/mm³.

Conclusion

A low CSF WBC in adults with pneumococcal meningitis is related to the presence of signs of sepsis and systemic complications. Invasive pneumococcal infections should possibly be regarded as a continuum from meningitis to sepsis.

Community-acquired Listeria monocytogenes meningitis in adults

BACKGROUND

Listeria monocytogenes is the third most common cause of bacterial meningitis.

METHODS

We prospectively evaluated 30 episodes of community-acquired L. monocytogenes meningitis, confirmed by culture of cerebrospinal fluid specimens, in a nationwide study in The Netherlands. Outcome was graded using the Glasgow outcome score; an unfavorable outcome was defined as a score of 1-4.

RESULTS

We found 30 episodes of L. monocytogenes meningitis. All patients were immunocompromised or > 50 years old. In 19 (63%) of 30 patients, symptoms were present for > 24 h; in 8 patients (27%), symptoms were present for > or = 4 days. The classic triad of fever, neck stiffness, and change in mental status was present in 13 (43%) of 30 patients. An individual cerebrospinal fluid indicator of bacterial meningitis was present in 23 (77%) of 30 cases. Gram staining of cerebrospinal fluid samples revealed the causative organism in 7 (28%) of 25 cases. The initial antimicrobial therapy was amoxicillin based for 21 (70%) of 30 patients. The coverage of initial antimicrobial therapy was microbiologically inadequate for 9 (30%) of the patients. The mortality rate was 17% (5 of 30), and 8 (27%) of 30 patients experienced an unfavorable outcome. Inadequate initial antimicrobial therapy was not related to outcome.

CONCLUSIONS

In contrast with previous reports, we found that patients with meningitis due to L. monocytogenes do not present with atypical clinical features; however, typical cerebrospinal fluid findings predictive for bacterial meningitis might be absent. A high proportion of patients received initial antimicrobial therapy that did not cover L. monocytogenes.

Drug Insight: adjunctive therapies in adults with bacterial meningitis

Despite the availability of effective antibiotics, mortality and morbidity rates associated with bacterial meningitis are high. Studies in animals have shown that bacterial lysis, induced by treatment with antibiotics, leads to inflammation in the subarachnoid space, which might contribute to an unfavorable outcome. The management of adults with bacterial meningitis can be complex, and common complications include meningoencephalitis, systemic compromise, stroke and raised intracranial pressure. Various adjunctive therapies have been described to improve outcome in such patients, including anti-inflammatory agents, anticoagulant therapies, and strategies to reduce intracranial pressure. Although a recent randomized trial provided evidence in favor of dexamethasone treatment, few randomized clinical studies are available for other adjunctive therapies in adults with bacterial meningitis. This review briefly summarizes the pathogenesis and pathophysiology of bacterial meningitis, and focuses on the evidence for and against use of the available adjunctive therapies in clinical practice.

Doxycycline reduces mortality and injury to the brain and cochlea in experimental pneumococcal meningitis

Bacterial meningitis is characterized by an inflammatory reaction to the invading pathogens that can ultimately lead to sensorineural hearing loss, permanent brain injury, or death. The matrix metalloproteinases (MMPs) and tumor necrosis factor alpha-converting enzyme (TACE) are key mediators that promote inflammation, blood-brain barrier disruption, and brain injury in bacterial meningitis. Doxycycline is a clinically used antibiotic with anti-inflammatory effects that lead to reduced cytokine release and the inhibition of MMPs. Here, doxycycline inhibited TACE with a 50% inhibitory dose of 74 microM in vitro and reduced the amount of tumor necrosis factor alpha released into the cerebrospinal fluid by 90% in vivo. In an infant rat model of pneumococcal meningitis, a single dose of doxycycline (30 mg/kg) given as adjuvant therapy in addition to ceftriaxone 18 h after infection significantly reduced the mortality, the blood-brain barrier disruption, and the extent of cortical brain injury. Adjuvant doxycycline (30 mg/kg given subcutaneously once daily for 4 days) also attenuated hearing loss, as assessed by auditory brainstem response audiometry, and neuronal death in the cochlear spiral ganglion at 3 weeks after infection. Thus, doxycycline, probably as a result of its anti-inflammatory properties, had broad beneficial effects in the brain and the cochlea and improved survival in this model of pneumococcal meningitis in infant rats.

Highly purified lipoteichoic acid induced pro-inflammatory signalling in primary culture of rat microglia through Toll-like receptor 2: selective potentiation of nitric oxide production by muramyl dipeptide

In contrast to the role of lipopolysaccharide from Gram-negative bacteria, the role of Gram-positive bacterial components in inducing inflammation in the CNS remains controversial. We studied the potency of highly purified lipoteichoic acid and muramyl dipeptide isolated from Staphylococcus aureus to activate primary cultures of rat microglia. Exposure of pure microglial cultures to lipoteichoic acid triggered a significant time- and dose-dependent production of pro-inflammatory cytokines (tumour-necrosis factor-alpha, interleukin-1beta, interleukin-6) and nitric oxide. Muramyl dipeptide strongly and selectively potentiated lipoteichoic acid-induced inducible nitric oxide synthase expression and nitric oxide production. However, it did not have any significant influence on the production of pro-inflammatory cytokines. As bacterial components are recognised by the innate immunity through Toll-like receptors (TLRs) we showed that lipoteichoic acid was recognised in microglia by the TLR2 and lipopolysaccharide by the TLR4, as cells isolated from mice lacking TLR2 or TLR4 did not produce pro-inflammatory cytokines and nitric oxide upon lipoteichoic acid or lipopolysaccharide stimulation, respectively. Lipoteichoic acid-induced glia activation was mediated by p38 and ERK1/2 MAP kinases, as pretreatment with inhibitor of p38 or ERK1/2 decreased lipoteichoic acid-induced cytokine release, iNOS mRNA expression and nitric oxide production. The observed pro-inflammatory response induced by lipoteichoic acid-activated microglia could play a major role in the inflammatory response of CNS induced by Gram-positive bacteria.

ENHANCE: results of a global open-label trial of drotrecogin alfa (activated) in children with severe sepsis

OBJECTIVE

To gather additional 28-day all-cause mortality data and safety information for pediatric patients with severe sepsis who received drotrecogin alfa (activated) (DrotAA).

DESIGN AND SETTING

Single-arm, open-label, multicentered study conducted in 59 study sites in 15 countries.

PATIENTS

One-hundred eighty-eight children (term newborn to <18 yrs old) with severe sepsis were consecutively enrolled in the study.

INTERVENTION

Administration of DrotAA, 24 microg/kg/hr for 96 hrs.

MAIN OUTCOME MEASURES

Four-day and 28-day all-cause mortality, safety information, and protein C levels.

RESULTS

: One-hundred eighty-seven patients completed the study. The 4-day mortality rate was 7.0%, and the 28-day mortality rate was 13.4%. At baseline, 57.6% of patients were severely deficient in protein C (a level < or = 40% of normal). There was a statistically significant association between increased 28-day mortality and decreased end-of-infusion protein C levels (p < .001), greater number of baseline organ dysfunctions (p < .001), and greater baseline ventilator use (p = .03). Bleeding was the most significant complication observed. Serious bleeding events (including anemia without a bleeding source) were experienced by 27.7% of patients (n = 52). Six of the serious bleeding events (3.2%) were considered related to administration of DrotAA. During infusion, serious bleeding events with an identified source of bleeding were experienced by 5.9% of patients (n = 11). Central nervous system bleeding was experienced by 2.7% (n = 5). Two of the intracranial hemorrhages were fatal and occurred postinfusion.

CONCLUSIONS

Without a placebo control, no efficacy conclusions are possible. Subgroups at higher risk of death were identified, and the change in protein C level from baseline was predictive of survival. The most significant complication observed was bleeding. Risk factors for serious bleeding appear to be multiple organ failure, thrombocytopenia, and coagulopathy.

Pneumococcal meningitis in adults: new approaches to management and prevention

Since the virtual eradication of meningitis due to Haemophilus influenzae type B by vaccination in the developed world, pneumococcal meningitis has become the leading cause of bacterial meningitis beyond the neonatal period. Clinical and experimental research has increased our knowledge about the pathophysiology and pathogenesis of the disease over the past decades. Despite the availability of effective antibiotics, supportive care facilities, and recent advances in adjunctive strategies-ie, adjunctive dexamethasone-mortality and morbidity rates associated with pneumococcal meningitis remain unacceptably high. Although preliminary results after the introduction of the pneumococcal conjugate vaccine are promising, the incidence of multidrug-resistant pneumococcal strains is rising worldwide. Here we discuss clinical aspects of pneumococcal meningitis in adults, with focus on pathophysiology, and stress the urgent need for adequate preventive measures and new effective treatments.

Protein expression pattern in experimental pneumococcal meningitis

In this study, we investigated cytokine expression during experimental pneumococcal meningitis. Mice were intracisternally infected with Streptococcus pneumoniae and treated with ceftriaxone starting at 24 h after infection. At different time points before and after antibiotic therapy, the cytokine expression pattern was determined in mouse brains using protein arrays. Underlining the power of this method, the meningitis-relevant cytokines interleukin-1beta (IL-1beta), IL-6, KC, macrophage inflammatory protein-2 (MIP-2), and monocyte chemoattractant protein-1 (MCP-1/CCL2) were markedly elevated in infected animals. Newly identified proteins during the acute stage of the disease (until 30 h after infection) included lymphotactin (XCL-1), MIP-1gamma (CCL9) and MCP-5 (CCL12), cytokine responsive gene- 2 (CRG-2/CXCL10) and CXCL16, and insulin-like growth factor binding protein 3 (IGFBP3). During later stages, an induction of T-cell activation-3 (TCA-3/CCL1), platelet factor-4 (PF-4/CXCL4) and stromal derived factor-1alpha (SDF-1alpha/CXCL13), and IL-4 was observed. The validity of this method was supported by an additional ELISA analysis of the expression profile of CXCL16 and IGFBP3, which was identical to that observed by protein array. In conclusion, the use of protein array technology led to an extension of the current picture of protein expression in pneumococcal meningitis. Most important, new factors that might play a role in pneumococcal meningitis were identified.

Dexamethasone treatment in adults with pneumococcal meningitis: risk factors for death

In experimental meningitis, adjunctive treatment with steroids reduces cerebrospinal fluid inflammation and thereby improves neurological outcome. On the basis of these findings, several clinical trials have assessed treatment with adjunctive steroids in bacterial meningitis, with conflicting results. Recently, the results of the European Dexamethasone Study showed a beneficial effect of adjunctive dexamethasone in adults with bacterial meningitis. In that study, the effect of dexamethasone on outcome was most striking in patients with pneumococcal meningitis. The aim of the present study was to further evaluate the effect of dexamethasone in adults with pneumococcal meningitis by performing a post hoc analysis of the European Dexamethasone Study. In a multivariate analysis, tachycardia (p=0.02), advanced age (p=0.03), low score on the Glasgow Coma Scale (p=0.03), positive blood culture (p=0.04), and absence of dexamethasone therapy (p=0.05) were independent predictors for death. Patients who were treated with adjunctive dexamethasone were less likely to develop both systemic and neurological complications during hospitalisation, compared with patients who received placebo. In conclusion, independent risk factors for death in pneumococcal meningitis are tachycardia, advanced age, low level of consciousness, bacteraemia, and absence of dexamethasone therapy. Treatment with adjunctive dexamethasone in adults with pneumococcal meningitis reduces both systemic and neurological complications.

Clinical features, complications, and outcome in adults with pneumococcal meningitis: a prospective case series

BACKGROUND

Bacterial meningitis is a grave disease of high incidence, especially in less developed countries. Here, we describe its clinical presentation, spectrum of complications, prognostic factors, and outcome in adults with pneumococcal meningitis.

METHODS

From October, 1998, to April, 2002, we assessed 352 episodes of community-acquired pneumococcal meningitis, confirmed by culture of cerebrospinal fluid (CSF), which occurred in patients older than 16 years. Predictors for an unfavourable outcome (Glasgow outcome scale score 1-4) were identified by logistic regression with multiple imputation techniques.

FINDINGS

245 (70%) episodes of pneumococcal meningitis were associated with an underlying disorder. Cranial CT was done for 85% of episodes and revealed underlying disorders in 17% (50/299) and meningitis-associated intracranial complications in 39% (117/299). Independent predictors for an unfavourable outcome were a low score on the Glasgow coma scale, cranial nerve palsies, a raised erythrocyte sedimentation rate, a CSF leucocyte count less than 1000 cells per mm(3), and a high CSF protein concentration on admission. Overall in-hospital mortality was 30%. Prevalence of neurological and systemic complications did not differ between patients aged younger than 60 years and those aged 60 years and older; however, systemic complications were the cause of death in 59% (32/54) of fatal episodes in patients aged 60 years and older, whereas neurological complications were the cause of death in 65% (20/31) of fatal episodes in younger patients.

INTERPRETATION

Pneumococcal meningitis is associated with high mortality and morbidity rates in adults. Whereas neurological complications are the leading cause of death in younger patients, elderly patients die predominantly from systemic complications.

Brainstem infarcts as an early manifestation of Streptococcus anginosus meningitis

BACKGROUND AND PURPOSE

Vasculitis and infarcts are well-established sequelae of bacterial meningitis. However, early large-vessel involvement is rare, particularly within the brainstem. There has been one previous case report of a young male who presented with pontine infarct as an early manifestation of Streptococcus milleri meningitis. We present another case of brainstem infarction associated with meningitis caused by Streptococcus anginosus.

CASE DESCRIPTION

We report a 58-year-old man who developed constitutional symptoms and gait instability, followed by progressive stupor. On examination, he had a Glasgow Coma Scale of 8 with intact brainstem reflexes and no focal findings. Magnetic resonance imaging documented bilateral pontine infarcts. S. anginosus was isolated from cerebrospinal fluid. Despite proper antibiotic treatment, the patient remained comatose and care was withdrawn. Postmortem examination revealed the meningitis was predominantly localized at the base of the brain. In addition, ventriculitis, multiple abscesses, and multiple infarcts in the pons and midbrain were found.

CONCLUSION

S. anginosus, which is part of the normal human flora, causes invasive pyogenic infections and is an uncommon cause of bacterial meningitis. This type of infection is mostly situated at the base of the brain and has a propensity to encase the basilar artery and its perforators, thus causing brainstem stroke early in its course.

Incidence and outcome of pneumococcal meningitis in northern England

Since pneumococcal meningitis continues to have high mortality and morbidity, and may be under-reported to national surveillance systems, the present study was conducted to assess the incidence, features, and outcomes of microbiologically confirmed cases of pneumococcal meningitis in North Yorkshire, England, between 1997 and 2002. The review revealed 50 cases, which accounted for an incidence of 1.1. per 100,000 per year. The incidence was markedly seasonal, with 76% of cases occurring in the winter months. Mortality was 28%, and 28% of the survivors suffered long-term sequelae. A high Glasgow Coma Score on hospital admission was significantly associated with survival. There were 12 children in the study, aged 2 months to 2 years, and none of them would have been classified as candidates for conjugate pneumococcal vaccination according to UK recommendations.

Development of adjunctive therapies for bacterial meningitis and lessons from knockout mice

Bacterial meningitis is a medical emergency and is optimally managed in an intensive care environment. Despite the use of antibiotics, the prognosis of this disease is poor because of central nervous system complications such as brain edema formation, cerebrovascular alterations, intracranial hemorrhage, and hydrocephalus. Effective adjunctive therapies are still missing. Experimental studies with animal models have provided new insights into the pathophysiology during the acute phase of bacterial meningitis. In recent years, knockout mice have become a powerful tool to investigate the role of particular genes and have also been applied in bacterial meningitis research. The use of these mice offered new insights into the role of different cytokines, proteases, and oxidants involved in the inflammatory cascade. Translating this knowledge into new therapies will provide new treatment strategies for this serious disease in the future.

Clinical presentation and prognostic factors of Streptococcus pneumoniae meningitis according to the focus of infection

Background

We conducted a nationwide study in Denmark to identify clinical features and prognostic factors in patients with Streptococcus pneumoniae according to the focus of infection.

Methods

Based on a nationwide registration, clinical information's was prospectively collected from all reported cases of pneumococcal meningitis during a 2-year period (1999–2000). Clinical and laboratory findings at admission, clinical course and outcome of the disease including follow-up audiological examinations were collected retrospectively. The focus of infection was determined according to the clinical diagnosis made by the physicians and after review of the medical records.

Results

187 consecutive cases with S. pneumoniae meningitis were included in the study. The most common focus was ear (30%), followed by lung (18%), sinus (8%), and other (2%). In 42% of cases a primary infection focus could not be determined. On admission, fever and an altered mental status were the most frequent findings (in 93% and 94% of cases, respectively), whereas back rigidity, headache and convulsion were found in 57%, 41% and 11% of cases, respectively. 21% of patients died during hospitalisation (adults: 27% vs. children: 2%, Fisher Exact Test, P < 0.001), and the causes of death were due to neurological – and systemic complications or the combination of both in 8%, 5% and 6% of cases, respectively. Other causes (e.g. gastrointestinal bleeding, incurable cancer) accounted for 2% of cases. 41% of survivors had neurological sequelae (hearing loss: 24%, focal neurological deficits: 16%, and the combination of both: 1%). The mortality varied with the focus of the infection (otogenic: 7%, sinusitic: 33%, pneumonic: 26%, other kind of focus: 50%, no primary infection focus: 21%, Log rank test: P = 0.0005). Prognostic factors associated with fatal outcome in univariate logistic regression analysis were advanced age, presence of an underlying disease, history of headache, presence of a lung focus, absence of an otogenic focus, having a CT-scan prior to lumbar puncture, convulsions, requirement of assisted ventilation, and alterations in various CSF parameters (WBC <500 cells/μL, high protein levels, glucose levels<1 mmol/L, low CSF/blood glucose levels), P < 0.05. Independent prognostic factor associated with fatal outcome in multivariate logistic regression analysis was convulsions (OR: 4.53, 95%CI: (1.74–11.8), p = 0.002), whereas presence of an otogenic focus was independently associated with a better survival (OR: 6.09, 95%CI: (1.75–21.2), P = 0.005).

Conclusion

These results emphasize the prognostic importance of an early recognition of a predisposing focus to pneumococcal meningitis.

In bacterial meningitis cortical brain damage is associated with changes in parenchymal MMP-9/TIMP-1 ratio and increased collagen type IV degradation

Adverse outcome in bacterial meningitis is associated with the breakdown of the blood-brain barrier (BBB). Matrix-metalloproteinases (MMPs) facilitate this process by degradation of components of the BBB. This in turn results in acute complications of bacterial meningitis including edema formation, increased intracranial pressure and subsequent ischemia. We determined the parenchymal balance of MMP-9 and TIMP-1 (tissue inhibitor of MMP) and the structural integrity of the BBB in relation to cortical damage in an infant rat model of pneumococcal meningitis. The data demonstrate that the extent of cortical damage is significantly associated with parenchymal gelatinolytic activity and collagen type IV degradation. The increased gelatinolysis was found to be associated with a brain parenchymal imbalance of MMP-9/TIMP-1. These findings provide support to the concept that MMPs mediated disruption of the BBB contributes to the pathogenesis of bacterial meningitis and that protection of the vascular unit may have neuroprotective potential.

Meningoencephalitis caused by Streptococcus pneumoniae: a diagnostic and therapeutic challenge. Diagnosis with diffusion-weighted MRI leading to treatment with corticosteroids

Streptococcus pneumoniae is a common cause of bacterial meningitis but only rarely causes other infections such as brain abscess, encephalitis, encephalomyelitis or meningoencephalitis. We report on three adult patients with meningoencephalitis caused by S. pneumoniae. In all three, CT and MRI revealed widespread brain lesions, suggesting extensive parenchymal injury. Diffusion-weighted MRI showed lesions with restricted diffusion, reflecting local areas of ischaemia with cytotoxic oedema secondary to an immunologically mediated necrotising vasculitis and thrombosis. High levels of markers of neuronal, glial and myelin damage were found in the cerebrospinal fluid. According to the literature, brain parenchyma lesions in adults with pneumococcal meningoencephalitis are often associated with death or severe neurological deficit. Our patients were treated with pulse doses of glucocorticoids: this resulted in dramatic clinical improvement and an excellent final neurological recovery.

Inflammatory neurodegeneration induced by lipoteichoic acid from Staphylococcus aureus is mediated by glia activation, nitrosative and oxidative stress, and caspase activation

In this study we investigated the mechanisms of neuronal cell death induced by lipoteichoic acid (LTA) and muramyl dipeptide (MDP) from Gram-positive bacterial cell walls using primary cultures of rat cerebellum granule cells (CGCs) and rat cortical glial cells (astrocytes and microglia). LTA (+/- MDP) from Staphylococcus aureus induced a strong inflammatory response of both types of glial cells (release of interleukin-1beta, tumour necrosis factor-alpha and nitric oxide). The death of CGCs was caused by activated glia because in the absence of glia (treatment with 7.5 microm cytosine-d-arabinoside to inhibit non-neuronal cell proliferation) LTA + MDP did not cause significant cell death (less than 20%). In addition, staining with rhodamine-labelled LTA confirmed that LTA was bound only to microglia and astrocytes (not neurones). Neuronal cell death induced by LTA (+/- MDP)-activated glia was partially blocked by an inducible nitric oxide synthase inhibitor (1400 W; 100 microm), and completely blocked by a superoxide dismutase mimetic [manganese (III) tetrakis (4-benzoic acid)porphyrin chloride; 50 microm] and a peroxynitrite scavenger [5,10,15,20-tetrakis (4-sulfonatophenyl) porphyrinato iron (III); 100 microm] suggesting that nitric oxide and peroxynitrite contributed to LTA-induced cell death. Moreover, neuronal cell death was inhibited by selective inhibitors of caspase-3 (z-DEVD-fmk; 50 microm) and caspase-8 (z-Ile-Glu(O-Me)-Thr-Asp(O-Me) fluoromethyl ketone; 50 microm) indicating that they were involved in LTA-induced neuronal cell death.

Increased Expression of BDNF and Proliferation of Dentate Granule Cells After Bacterial Meningitis

Proliferation and differentiation of neural progenitor cells is increased after bacterial meningitis. To identify endogenous factors involved in neurogenesis, expression of brain-derived neurotrophic factor (BDNF), TrkB, nerve growth factor (NGF), and glial cell line-derived neurotrophic factor (GDNF) was investigated. C57BL/6 mice were infected by intracerebral injection of Streptococcus pneumoniae. Mice were killed 30 hours later or treated with ceftriaxone and killed 4 days after infection. Hippocampal BDNF mRNA levels were increased 2.4-fold 4 days after infection (p = 0.026). Similarly, BDNF protein levels in the hippocampal formation were higher in infected mice than in control animals (p = 0.0003). This was accompanied by an elevated proliferation of dentate granule cells (p = 0.0002). BDNF protein was located predominantly in the hippocampal CA3/4 area and the hilus of the dentate gyrus. The density of dentate granule cells expressing the BDNF receptor TrkB as well as mRNA levels of TrkB in the hippocampal formation were increased 4 days after infection (p = 0.027 and 0.0048, respectively). Conversely, NGF mRNA levels at 30 hours after infection were reduced by approximately 50% (p = 0.004). No significant changes in GDNF expression were observed. In conclusion, increased synthesis of BDNF and TrkB suggests a contribution of this neurotrophic factor to neurogenesis after bacterial meningitis.

Drotrecogin alfa (activated) in patients with severe sepsis presenting with purpura fulminans, meningitis, or meningococcal disease: a retrospective analysis of patients enrolled in recent clinical studies

INTRODUCTION

We report data from adult and pediatric patients with severe sepsis from studies evaluating drotrecogin alfa (activated) (DrotAA) and presenting with purpura fulminans (PF), meningitis (MEN), or meningococcal disease (MD) (PF/MEN/MD). Such conditions may be associated with an increased bleeding risk but occur in a relatively small proportion of patients presenting with severe sepsis; pooling data across clinical trials provides an opportunity for improving the characterization of outcomes.

METHODS

A retrospective analysis of placebo-controlled, open-label, and compassionate-use trials was conducted. Adult patients received infusions of either DrotAA or placebo. All pediatric patients (<18 years old) received DrotAA. 189 adult and 121 pediatric patients presented with PF/MEN/MD.

RESULTS

Fewer adult patients with PF/MEN/MD met cardiovascular (68.3% versus 78.8%) or respiratory (57.8% versus 80.5%) organ dysfunction entry criteria than those without. DrotAA-treated adult patients with PF/MEN/MD (n = 163) had an observed 28-day mortality rate of 19.0%, a 28-day serious bleeding event (SBE) rate of 6.1%, and an intracranial hemorrhage (ICH) rate of 4.3%. Six of the seven ICHs occurred in patients with MEN (three of whom were more than 65 years old with a history of hypertension). DrotAA-treated adult patients without PF/MEN/MD (n = 3,088) had an observed 28-day mortality rate of 25.5%, a 28-day SBE rate of 5.8%, and an ICH rate of 1.0%. In contrast, a greater number of pediatric patients with PF/MEN/MD met the cardiovascular organ dysfunction entry criterion (93.5% versus 82.5%) than those without. DrotAA-treated PF/MEN/MD pediatric patients (n = 119) had a 14-day mortality rate of 10.1%, an SBE rate of 5.9%, and an ICH rate of 2.5%. DrotAA-treated pediatric patients without PF/MEN/MD (n = 142) had a 14-day mortality rate of 14.1%, an SBE rate of 9.2%, and an ICH rate of 3.5%.

CONCLUSION

DrotAA-treated adult patients with severe sepsis presenting with PF/MEN/MD had a similar SBE rate, a lower observed 28-day mortality rate, and a higher observed rate of ICH than DrotAA-treated patients without PF/MEN/MD. DrotAA-treated pediatric patients with severe sepsis with PF/MEN/MD may differ from adults, because all three outcome rates (SBE, mortality, and ICH) were lower in pediatric patients with PF/MEN/MD.

Training room management of medical conditions: infectious diseases

Management of infectious diseases in athletes encompasses a wide range of pathogens, clinical presentations, and treatment options. Certain athletic activities and training regimens may predispose athletes to increased risk of contracting infectious diseases, some of which may limit athletic participation and pose the threat of significant morbidity. The sports medicine physician plays an important role as a first line of defense in preventing, recognizing, and appropriately treating infectious diseases in athletes.

Antibody neutralization of vascular endothelial growth factor (VEGF) fails to attenuate vascular permeability and brain edema in experimental pneumococcal meningitis

To determine the contribution of vascular endothelial growth factor (VEGF) to cerebral edema formation in bacterial meningitis, we used a VEGF neutralizing antibody to block VEGF in rabbits, following induction of meningitis by intracisternal inoculation with 10(9) heat-killed pneumococci. At 8 h, cerebrospinal fluid (CSF) VEGF was significantly elevated in infected untreated animals, and correlated with CSF white blood cell (WBC) count (r=0.56, P=0.004), and brain water content (r=0.42, P=0.04). Blocking of VEGF did not attenuate brain edema, blood-brain barrier disruption, or CSF pleocytosis. The functional role of VEGF in the pathophysiology of BM remains elusive.

Bacterial Meningitis in Children

Acute bacterial meningitis is still an important cause of morbidity and mortality in children worldwide. Recently, Haemophilus influenzae type b (Hib), once a common cause of meningitis, has virtually disappeared in developed nations, reflecting the overwhelming success of Hib vaccination. Unfortunately, Hib remains a significant pathogen in resource-poor countries. The introduction of the conjugated pneumococcal vaccine in 2000 may lead to similar future trends as witnessed with Hib. As the resistance of Streptococcus pneumoniae to penicillin and cephalosporins continues to evolve, vancomycin has become an important antibacterial in the treatment of bacterial meningitis. The unreliable penetration of this agent into cerebrospinal fluid is of concern, which is compounded by the controversial use of corticosteroids in paediatric meningitis. Some data suggest that in certain situations the addition of rifampicin (rifampin) to ceftriaxone may be a better choice. While dexamethasone is now considered the standard adjunctive therapy in the treatment of pneumococcal meningitis in adult patients, the benefit in children is not so clear and remains controversial; thus, there is no definitive paediatric recommendation. Several anti-inflammatory agents currently under investigation may be used in the future as adjunctive therapy for bacterial meningitis. It is clear that the current concepts in the treatment of childhood bacterial meningitis are evolving, and other antibacterial options and possible alternatives such as carbapenems and fluoroquinolones should be considered. Fluid restriction because of the Syndrome of Inappropriate Antidiuretic Hormone Secretion is widely advocated and used. Yet, this practice was recently challenged. It seems that most patients with meningitis do not need fluid restriction. The overwhelming success of the conjugated Hib vaccine and the encouraging results of the new conjugated pneumococcal and meningococcal vaccines suggest that the ideal management of bacterial meningitis is prevention and vaccines development against the most common bacterial agents are the best solution.

Clinical features and prognostic factors in adults with bacterial meningitis

BACKGROUND

We conducted a nationwide study in the Netherlands to determine clinical features and prognostic factors in adults with community-acquired acute bacterial meningitis.

METHODS

From October 1998 to April 2002, all Dutch patients with community-acquired acute bacterial meningitis, confirmed by cerebrospinal fluid cultures, were prospectively evaluated. All patients underwent a neurologic examination on admission and at discharge, and outcomes were classified as unfavorable (defined by a Glasgow Outcome Scale score of 1 to 4 points at discharge) or favorable (a score of 5). Predictors of an unfavorable outcome were identified through logistic-regression analysis.

RESULTS

We evaluated 696 episodes of community-acquired acute bacterial meningitis. The most common pathogens were Streptococcus pneumoniae (51 percent of episodes) and Neisseria meningitidis (37 percent). The classic triad of fever, neck stiffness, and a change in mental status was present in only 44 percent of episodes; however, 95 percent had at least two of the four symptoms of headache, fever, neck stiffness, and altered mental status. On admission, 14 percent of patients were comatose and 33 percent had focal neurologic abnormalities. The overall mortality rate was 21 percent. The mortality rate was higher among patients with pneumococcal meningitis than among those with meningococcal meningitis (30 percent vs. 7 percent, P<0.001). The outcome was unfavorable in 34 percent of episodes. Risk factors for an unfavorable outcome were advanced age, presence of otitis or sinusitis, absence of rash, a low score on the Glasgow Coma Scale on admission, tachycardia, a positive blood culture, an elevated erythrocyte sedimentation rate, thrombocytopenia, and a low cerebrospinal fluid white-cell count.

CONCLUSIONS

In adults presenting with community-acquired acute bacterial meningitis, the sensitivity of the classic triad of fever, neck stiffness, and altered mental status is low, but almost all present with at least two of the four symptoms of headache, fever, neck stiffness, and altered mental status. The mortality associated with bacterial meningitis remains high, and the strongest risk factors for an unfavorable outcome are those that are indicative of systemic compromise, a low level of consciousness, and infection with S. pneumoniae.

[Symptomatic headache. Essential differential diagnosis]

A patient is suspected of suffering from a potentially life threatening headache according to the following typical warning signs: sudden onset headache, worst headache, neurological findings, fever, neck stiffness, epileptic seizures and deterioration of vigilance. It is far more dangerous not to recognize potentially life threatening headaches like subarachnoid bleeding, meningitis, encephalitis, arterial dissection or epidural hematoma than to over diagnose it. Immediate and specific neurological and radiological investigations (CT, MRI, CSF) are necessary in each patient presenting with those findings. The morbidity and mortality of those patients mainly depend on the beginning of the therapy. This article focuses on the diagnosis of potentially life threatening headache disorders.

MyD88 is required for mounting a robust host immune response to Streptococcus pneumoniae in the CNS

Myeloid differentiation factor 88 (MyD88) is an essential intracellular signal transducer in Toll-like receptor (TLR) and interleukin (IL)-1 receptor family member-mediated cell activation. In order to characterize the role of MyD88 in pneumococcal meningitis we used gene-targeted mice lacking functional MyD88 expression. At 24 h after intracisternal infection, MyD88- deficient mice displayed a markedly diminished inflammatory host response in the CNS, as evidenced by reduced CSF pleocytosis and expression of cytokines, chemokines and complement factors. The reduced CNS inflammation was paralleled by a marked reduction in the prognostic relevant CNS complications, such as brain oedema formation. Nevertheless, MyD88 deficiency was associated with a worsening of disease which seemed to be attributable to severe bacteraemia. This notion was supported by the unexpected observation that infected MyD88-deficient mice displayed enhanced mRNA expression of inflammatory mediators [such as the proinflammatory cytokine tumour necrosis factor alpha (TNF-alpha) and the CXC chemokine macrophage inflammatory protein (MIP-2)] in the lung and consequently increased cell influx in the bronchoalveolar lavage fluid, compared with infected wild-type mice. Thus, the present study demonstrated for the first time an important role of MyD88 in immune activation to bacterial pathogens within the CNS. The role played by MyD88 in mounting an immune response to Streptococcus pneumoniae, however, seems to be dependent on the anatomical compartment involved.

Adjunctive dexamethasone treatment in acute bacterial meningitis

The initiation of antibiotic treatment on suspicion of bacterial meningitis is important, but it is not enough to improve the prognosis for patients, especially those with pneumococcal meningitis. The mortality and morbidity of pneumococcal meningitis are still devastating, and results of a recent randomised trial have shown evidence in favour of dexamethasone treatment given before or with the first antibiotic dose. Adjuvant dexamethasone is unequivocally recommended in children and adults with haemophilus meningitis or pneumococcal meningitis. The benefit of adjunctive dexamethasone is likely to be greatest in patients who are otherwise healthy and present early with acute bacterial meningitis. Dexamethasone is not currently recommended for the treatment of gram-negative bacillary meningitis and neonatal meningitis. Dexamethasone, before or with the first dose of antibiotic, is likely to be one of the most significant practice changes that will benefit many adults and children with common types of acute bacterial meningitis and has been of proven value in the developed world.

Bacterial meningitis: Diagnosis and treatment

Bacterial meningitis, once almost universally fatal, remains a cause of serious neurologic illness and subsequent disability. The initial diagnosis, although sometimes clear-cut, can be subtle and difficult. Appropriate intervention may have a favorable influence on outcome. The advent of corticosteroids and brain imaging has improved management but created controversy concerning the sequence at which various interventions should be introduced. Empiric treatment with antibiotics is important in the initial stages. Complications can arise, such as seizures, increased intracranial pressure, and ischemia. The prognosis remains unfavorable for some affected individuals in spite of advances in antibiotic management and supportive care.