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PubMed2005

Thrombopoietin in the cerebrospinal fluid of patients with aseptic and bacterial meningitis.

Despite the recent evidence of the localization of thrombopoietin (TPO) and its receptor in the central nervous system (CNS), TPO protein concentrations in the cerebrospinal fluid (CSF) remained to be clarified. We previously reported that serum TPO is increased in children with meningitis. To determine changes in TPO concentrations in the CSF by meningitis and to explore the relationship between serum and CSF TPO concentrations, we measured TPO concentrations in 110 CSF samples and 33 serum/CSF pairs from 11 bacterial meningitis, 49 aseptic meningitis, and 50 nonmeningitis children. In only 12% (13 of 110) of CSF samples (0 bacterial meningitis, 8 aseptic meningitis, and 5 controls), TPO concentrations could be determined (24.1 +/- 29.0 pg/ml). CSF TPO concentrations did not significantly differ among the three groups and did not correlate with age. TPO concentrations in all serum samples were detectable, and mean concentrations in bacterial meningitis (510.6 +/- 237.0 pg/ml) were significantly higher than those in aseptic meningitis (136.6 +/- 71.6, p < 0.01) and controls (181.3 +/- 88.3, p < 0.01). These findings suggest that TPO is not produced in the CNS of patients with meningitis and that TPO did not cross the blood-brain barrier even during meningeal infection.

Adolescent↗
PubMed2002

The impact of new diagnostic methodologies in the management of meningitis in adults at a teaching hospital.

BACKGROUND: Suspected meningitis is a frequent reason for admission to hospital in the UK. While bacterial meningitis requires prompt antibiotic therapy to reduce mortality and morbidity, enteroviral meningitis, the most frequent viral cause, is almost invariably a benign disease. AIM: To determine the clinical presentation, laboratory findings and outcome of meningitis by microbiological aetiology and patient age, and to assess the clinical management of adults presenting with meningitis, with reference to national guidelines. DESIGN: Retrospective case-note review. METHODS: Adult (>14 years) admissions to Addenbrooke's Hospital with meningitis or meningococcal septicaemia March 1996-September 2001 were audited retrospectively. The case definition was: symptoms compatible with meningitis, and either abnormal CSF (leukocytes >5x10(9)/ml) or meningococcal disease. The only exclusion criterion was the presence of a ventricular shunt. RESULTS: Only 30% of patients seen by a General Practitioner were given pre-admission antibiotics. In a substantial number of cases, including those with bacterial meningitis, antibiotic administration was delayed either because patients were sent for CT head scans (delaying a lumbar puncture) or because the diagnosis was not considered, especially in elderly patients with reduced conscious levels. There were no confirmed cases of H. influenzae meningitis. Overall outcomes in terms of mortality and disability were similar to UK national data. A surprising number of patients (40%) were afebrile on admission. DISCUSSION: The proportion of patients with meningitis given pre-hospital antibiotics by GPs is still worryingly low, although early hospital management has improved. Improved diagnostic facilities, particularly viral PCR assays, reduce antibiotic usage and hospital stay, with considerable financial savings.

Adolescent↗
PubMed2000

Value of cerebrospinal fluid leukocyte aggregation in distinguishing the causes of meningitis in children.

BACKGROUND: Current laboratory tests often cannot distinguish between bacterial and aseptic meningitis rapidly and accurately. The ability to make a prompt diagnosis has important implications for the management and outcome of children with meningitis. The observation that leukocytes aggregate in the cerebrospinal fluid (CSF) has been previously reported, and it has been advocated as a reliable method to distinguish the causes of meningitis in children. OBJECTIVE: To investigate the utility of CSF leukocyte aggregation as a screening test to distinguish between bacterial and aseptic meningitis. METHODS: We compared the clinical and laboratory indices of 109 prospectively enrolled patients with meningitis (67 bacterial, 23 viral, 19 undefined etiology) and evaluated the validity of the CSF leukocyte aggregation test. The predefined leukocyte aggregation scores (LAS) were compared among the types of meningitis, and correlations with other markers of inflammation were calculated. RESULTS: The median LAS was significantly higher (P < 0.001) in the bacterial (32.1%; range, 0 to 84.1%) than in the viral (0%; range, 0 to 16.6%) or undefined (0%; range, 0 to 20.7%) groups. The optimal sensitivity of the leukocyte aggregation test, 98.5 to 92.5%, was demonstrated with LAS values of 0 to 3%. The corresponding specificity was 64.3 to 88.1%. The peripheral white blood cell (WBC) count, serum C-reactive protein, CSF WBC count, blood culture, CSF Gram stain and CSF culture were inferior to the LAS as screening tests when compared individually. The LAS was as effective as CSF protein, TNF-alpha, IL-1-beta, IL-6 and IL-8 to predict bacterial meningitis. In a logistic regression model that included routine laboratory tests, the best predictor of bacterial meningitis was the LAS (odds ratio, 1.6 to 3.7). Significant correlations were demonstrated between the LAS and CSF protein, CSF WBC count, IL-1-beta, IL-6 and IL-8. Duration of symptoms before diagnosis, pretreatment with antibiotics, HIV-1 infection status and CSF red blood cell count did not significantly alter the LAS. CONCLUSIONS: There is no single test to diagnose the etiology of meningitis in children promptly and accurately. The finding of leukocyte aggregation in CSF might be of value as a sensitive adjunctive screening tool for the timely diagnosis of bacterial meningitis, recognizing that it has low specificity and potential practical limitations.

Adolescent↗
PubMed1997

The production of macrophage inflammatory protein-1alpha in the cerebrospinal fluid at the initial stage of meningitis in children.

Neutrophils in the cerebrospinal fluid (CSF) increase during the initial stage of meningitis. Some cytokines induce the accumulation of such neutrophils, and we and other investigators have revealed transient increases in the levels of granulocyte-colony stimulating factor (G-csf) and IL-8 in the CSF of patients with meningitis. To explore the coordination of other cytokines with G-csf and IL-8 in the neutrophil accumulation in the CSF, we herein investigated macrophage inflammatory protein-1alpha (MIP-1alpha), which can induce the infiltration of neutrophils. The modulation of MIP-1alpha levels in the CSF in children with bacterial (n = 10) and aseptic (n = 22) meningitis was examined using an ELISA. MIP-1alpha levels in the CSF were detectable at the stage with symptoms of meningitis: 289.9 +/- 270.7 ng/L in the bacterial meningitis group and 16.1 +/- 12.5 ng/L in the aseptic meningitis group. These levels decreased with the improvement of symptoms. MIP-1alpha was not detectable (<6 ng/L) in all of the control patients without meningitis (n = 19). The MIP-1alpha levels in the CSF showed a significant correlation with the CSF neutrophil counts (r = 0.750, p < 0.0001; n = 80) of meningitis, and the values of MIP-1alpha (log ng/L)/neutrophil counts (log/L) ratio were calculated (1.003 +/- 0.576). The MIP-1alpha levels in the serum were significantly lower than those in the CSF (p = 0.0464). We found MIP-1alpha mRNA in the CSF cells by the reverse transcriptase-PCR method, and high levels of MIP-1alpha protein in the culture media from mononuclear cells in the CSF in vitro. In summary, The MIP-1alpha level increases in the CSF at the symptomatic stage of meningitis in children, and its cellular source is, in part, mononuclear cells which have infiltrated the CSF. We propose that MIP-1alpha, in addition to G-csf and IL-8, plays an important role in the accumulation of neutrophils in the CSF of patients with meningitis.

Adolescent↗
PubMed1999

[Levels of interleukin-6 in cerebrospinal fluid of patients with meningitis].

UNLABELLED: Interleukin-6 (IL-6) is a multifunctional cytokine that regulates the immune response, differentiation of B cells, activation of T lymphocytes and acute phase reactions. AIM OF THE STUDY: Quantitation of interleukin-6 in cerebrospinal fluid from patients with purulent bacterial meningitis (PBM) and viral meningitis (VM) on the first day of hospitalization. PATIENTS AND METHODS: IL-6 activity was measured in cerebrospinal fluid (CSF) of 15 children with VM (predominantly 13/15 caused by mumps virus) in age ranging from 2.5 to 15 years and 13 patients with PBM (age ranging from 18 to 52 years). The control group consisted of 10 patients with meningeal syndrome and normal laboratory estimation of CSF (white cells count, concentration of glucose and protein). The IL-6 assays were performed using immunoenzymatic method, ELISA (Amersham) technique. RESULTS: Increased levels of IL-6 were detected in the CSF of patients with bacterial meningitis and with viral meningitis. CSF IL-6 levels were 6 times greater in patients with purulent bacterial versus viral meningitis. The highest level of IL-6 was observed in a 18 years old patient with pneumococcal meningitis who died. CONCLUSION: We suggest that cytokine levels may be valuable in distinguishing patients with purulent bacterial meningitis from viral meningitis and may help in prognosis of patients with purulent meningitis.

Adolescent↗
PubMed2006

Evaluation of enzymes in pyogenic and tuberculous meningitis.

OBJECTIVES: Lactic dehydrogenase (LDH), creatine kinase (CK) and gamma glutamyl transpeptidase (GGTP) were measured serially in cerebrospinal fluid (CSF) and serum in twenty five cases of meningitis and an equal number of age and sex matched healthy control subjects with an aim to find out their diagnostic and prognostic significance in cases of meningitis. METHODS: The enzymatic activity was measured serially (day 0, 4th and 7th) in cerebrospinal fluid (CSF) and serum in twenty-five cases of meningitis consisting of fifteen cases of pyogenic meningitis (PM) and ten of tuberculous meningitis (TBM) and an equal number of age and sex matched healthy control. The clinical details including the level of consciousness and neurological deficit were correlated with the enzymatic activity and prognosis. RESULTS: The levels of these enzymes were significantly elevated in all the cases of meningitis in serum as well as CSF as compared to control subjects. The activity was significantly higher in pyogenic than tuberculous meningitis (p<0.001) and it was higher in CSF than in serum (p<0.001). The maximum elevation in activity of GGTP and LDH were seen on the first day whereas CK was highest on 4th day and thereafter, the activity of all the enzymes declined in the majority of cases who had shown clinical improvement. However, in three cases of pyogenic and five cases of tuberculous meningitis, the enzymatic activity on subsequent estimation, increased serially. All these eight cases died. Further, the basal enzymatic activity in all these eight cases that died was higher as compared to those who survived. Of all the enzymes, CSF GGTP levels correlated best with the clinical picture. CONCLUSIONS: It is concluded that GGTP, CK and LDH were significantly elevated in cases of meningitis. It was not possible to differentiate the type of meningitis on the basis of enzymatic activity in any of them. However, it was possible to predict prognosis because higher basal activity and serial rise were associated with poor prognosis.

Adult↗
PubMed1984

Adenosine deaminase levels in cerebrospinal fluid in the diagnosis of tuberculous meningitis.

The prognosis of tuberculous meningitis is closely linked to the stage at which treatment is started. At the same time the diagnosis will often have to be made on purely circumstantial evidence. Adenosine deaminase activity in the cerebrospinal fluid was evaluated as a diagnostic aid in 30 cases of tuberculous meningitis. Cerebrospinal fluid adenosine deaminase levels differentiated tuberculous meningitis cases from those with aseptic meningitis being higher than 4 U/l in all and higher than 6 U/l in 90% of cases of tuberculous meningitis, but lower than 6 U/l in aseptic meningitis and less than 4 U/l in normal controls. It could not distinguish bacterial meningitis from tuberculous or aseptic meningitis. In cases of low-cell-count bacterial meningitis, the mean cerebrospinal fluid adenosine deaminase level was significantly lower than in cases of tuberculous meningitis with a similar cell count, but considerable overlap of results in the two groups was still to be found.

Adenosine Deaminase↗
PubMed1994

Prospective study of bacterial meningitis in North East Thames region, 1991-3, during introduction of Haemophilus influenzae vaccine.

OBJECTIVE: To describe the epidemiology of primary bacterial meningitis in the North East Thames region over a three year period before and during the introduction of the vaccine for Haemophilus influenzae type b. DESIGN: Analysis of information on cases of primary bacterial meningitis identified by microbiology laboratories in the region, with collection of case data by questionnaire. MAIN OUTCOME MEASURES: Annual incidence rates for types of meningitis according to age and ethnic group. RESULTS: The annual incidence rates for the three major causes of bacterial meningitis in the general population were 1.9/100,000 for Neisseria meningitidis, 1.6/100,000 for Haemophilus influenzae before vaccination, and 1.0/100,000 for Streptococcus pneumoniae. Higher rates of H influenzae meningitis were found in Asians compared with white people (3.6/100,000 v 1.5/100,000, P = 0.01). As a result of the vaccine programme introduced in October 1992 the number of cases of H influenzae meningitis in children under 5 years has fallen by 87%. CONCLUSIONS: Bacterial meningitis is a serious problem especially in preschool children. There are differences in the incidence of some causes of bacterial meningitis in different ethnic groups; with H influenzae type b being significantly more common among black and Asian people than among white people. The immunisation programme for H influenzae type b in the North East Thames region has been successful in reducing the incidence of this type of meningitis in Asian and white populations. The numbers were too small to evaluate in the black population.

Adolescent↗
PubMed1993

Meningeal arterial patterns in great apes: implications for hominid vascular evolution.

Arterial meningeal patterns were observed for 100 hemispheres from great ape endocasts (Pan paniscus, Pan troglodytes, Gorilla gorilla, and Pongo pygmaeus). Eight patterns emerged based on the relative contributions to the walls and dura mater of the middle part of the braincase of meningeal arteries that stem from two sources. These arteries enter the braincase through either the orbit (delivering blood from the internal carotid artery) or through the base of the middle cranial fossa (via the middle meningeal artery whose blood comes from the external carotid artery). The three genera of apes manifest different frequencies of the eight patterns, with orangutans highly dependent on orbital meningeal arteries at one extreme, and chimpanzees showing the greatest reliance on the middle meningeal artery at the other. As was the case in an earlier study of rhesus monkeys, there is a trend across the two genera of African apes for increased mean cranial capacity to be associated with increased reliance on the internal carotid artery for supplying the middle portion of the braincase. However, unlike the case for macaques, this trend does not reach statistical significance in African apes. Because it is rare for humans to manifest significant arterial contributions from the orbit to the middle cranial fossa, the comparative data on monkeys, apes, and humans suggest that, during the course of vascular evolution in Homo, the middle meningeal artery eventually took over supply of the entire middle cranial fossa. This hypothesis should be tested in the hominid fossil record. Earlier work on meningeal arterial patterns in apes has traditionally relied on Adachi's system that was determined from humans and focuses on the origin of the middle branch of the middle meningeal artery. As a result, the extensive orbital contributions to the middle portion of the braincase that characterize apes were not recognized and the eight patterns described in this paper were often erroneously assigned to the three patterns that adequately describe only humans. Adachi's system should therefore be abandoned for nonhuman primates and early hominids. A correct understanding of meningeal arterial evolution cannot be achieved until the orbital contributions to the meningeal arteries are recognized and incorporated into an evolutionary study that spans from apes to fossil hominids to living people.

Animals↗
PubMed1997

Blood-brain barrier permeability during the development of experimental bacterial meningitis in the rat.

In an attempt to examine whether routes of bacterial entry into the central nervous system have any bearing on subsequent changes in blood-brain barrier permeability, we examined cerebrospinal fluid (CSF) penetration of circulating 125I-albumin in two different models of experimental meningitis due to K1 Escherichia coli, type III group B streptococcus, or Haemophilus influenzae type b in infant rats: hematogenous meningitis subsequent to subcutaneous inoculation of bacteria vs meningitis induced by direct inoculation of bacteria into the CSF via the cisterna magna. In the model of hematogenous meningitis, the mean CSF penetration was significantly greater in animals with H. influenzae type b meningitis than in those with meningitis due to K1 E. coli or type III group B streptococcus. In contrast, the mean CSF penetration was significantly enhanced in all animals with meningitis induced by intracisternal inoculation regardless of infecting pathogens. Tumor necrosis factor activity in CSF appeared to correlate with the functional penetration of circulating albumin across the blood-brain barrier in both models of experimental meningitis. These findings suggest that the alterations of blood-brain barrier permeability during development of experimental meningitis may vary for different models of inducing meningitis and that the mechanisms responsible for these different permeability changes may be multifactorial.

Animals↗
PubMedDate not supplied

Dexamethasone in bacterial meningitis: to use or not to use?

Permanent neurologic disabilities are seen in up to a quarter of survivors of bacterial meningitis despite major improvements in therapy. Experimental studies have demonstrated that most of the pathology in meningitis is mediated by inflammatory cytokines such as tumor necrosis factor (TNF) and interleukin-1 (IL-1), which are produced by host cells in response to bacterial invasion of the meninges. Dexamethasone has been used in a number of clinical trials to moderate the host response and to improve neurologic outcome of meningitis. Results of six randomized, placebo controlled trials are summarized in this review. Dexamethasone treatment did not lower mortality. Only a moderate, but not a significant reduction in the neurologic and audiologic sequelae was seen in dexamethasone recipients when Haemophilus influenzae type b (Hib) was the causative agent of meningitis. Following routine use of Hib vaccine, meningitis caused by this agent has virtually disappeared in the USA. Hence, findings from these trials may no longer be applicable in countries with high rates of immunization against Hib. Presently, there is little or no evidence showing a benefit of dexamethasone therapy in meningitis caused by S. pneumoniae or N. meningitidis. Global emergence of penicillin and cephalosporin resistant S. pneumoniae has raised new concerns about the use of dexamethasone in pneumococcal meningitis. Since dexamethasone significantly decreases the penetration and concentration of vancomycin and ceftriaxone in the CSF and delays CSF sterilization, adjunctive dexamethasone therapy may increase the risk of treatment failure in meningitis caused by antibiotic resistant pneumococci. An antibiotic combination should be used in the treatment of meningitis caused by antibiotic resistant pneumococci, particularly if dexamethasone is also being administered concurrently.

Animals↗
PubMed2002

Clinical study of 44 cases of Staphylococcus aureus meningitis.

In order to describe the clinical features and outcome of Staphylococcus aureus meningitis, the charts of 44 cases seen at one teaching hospital during a 20-year period were retrospectively reviewed. Staphylococcus aureus was the fifth most common cause of bacterial meningitis (10.2% of cases). There were 28 (63%) cases of postoperative meningitis and 16 (37%) of spontaneous meningitis. Patients with postoperative meningitis were younger than patients with spontaneous meningitis (mean age, 40.3 vs. 59.3 years; P=0.04) and had a lower frequency of community-acquired infection (32.1% vs. 93.8%; P<0.01), severe underlying diseases (28% vs. 87%; P<0.01) and associated staphylococcal infection (35% vs. 75%; P=0.01). The clinical presentation was similar in both groups, but patients with postoperative meningitis had a lower frequency of altered mental status (39% vs. 75%; P=0.02), meningeal signs (28% vs. 62%; P=0.02), petechial rash (0% vs. 18%; P=0.04), bacteremia (7% vs. 75%; P<0.01), and septic shock (0% vs. 44%; P<0.01). Most patients were treated with cloxacillin or vancomycin, with or without rifampicin, for a mean period of 22.5 days (range, 1-100 days). Overall mortality was 27%, and the mortality rate was higher for cases of spontaneous than postoperative meningitis (50% vs. 14%; P=0.01). Mortality correlated significantly with advanced age, spontaneous meningitis, altered mental status, and the presence of severe underlying diseases, bacteremia, and septic shock.

Anti-Bacterial Agents↗
PubMed1985

Role of cephalosporins in the treatment of bacterial meningitis in adults. Overview with special emphasis on ceftazidime.

Experience with the use of first-generation cephalosporins in bacterial meningitis has been disappointing; low concentrations were obtained in the cerebrospinal fluid, and therapeutic failures were encountered. Of the second-generation cephalosporins cefamandole, cefuroxime, and cefoxitin, only cefuroxime has proved efficacy in meningitis caused by meningococci, pneumococci, or Hemophilus influenzae. The third-generation cephalosporins offer new advantages in the treatment of meningitis because they are active at the cerebrospinal fluid concentrations obtainable. Cefotaxime has produced high cure rates in patients with meningitis caused by meningococci, pneumococci, or H. influenzae. Several controlled comparative studies indicate that ceftriaxone is as effective as conventional treatment in therapy for neonatal or childhood meningitis caused by Streptococcus agalactiae, Escherichia coli, or H. influenzae. Moxalactam has been found in uncontrolled studies to be effective when the cause was enteric gram-negative bacilli. Ceftazidime is a new cephalosporin with a high degree of beta-lactamase stability and a broad antibacterial spectrum, which includes Pseudomonas aeruginosa that enters the cerebrospinal fluid. Data from 29 patients who received ceftazidime as monotherapy for bacterial meningitis showed an overall cure or improvement rate of 75.9 percent. Therapy failed in three patients with meningitis caused by gram-positive organisms (Staphylococcus aureus, S. epidermidis, S. agalactiae), and in three with gram-negative organisms. Of 14 patients with Pseudomonas meningitis, 11 showed a cure, as did six of six patients with meningitis caused by Enterobacter, Serratia, or Acinetobacter. More, preferably controlled, studies of the efficacy of ceftazidime in the treatment of meningitis should be undertaken.

Adult↗
PubMed1995

Cocultures of meningeal and astrocytic cells--a model for the formation of the glial-limiting membrane.

The glial-limiting membrane at the border of the central nervous system (CNS) consists of glial endfeet covered by a basal lamina. The formation of the glia limitans seems to be controlled by adjacent meninges but only little is known about this interaction. In the present study astrocytes and meningeal cells were investigated in vitro to see if cocultures of these cells can serve as a suitable model for the differentiation of the glial-limiting membrane and can be used to define the conditions under which the glial-limiting membrane develops. The following observations were made in cocultures of meningeal and astrocytic cells of two-day-old rats: (i) epithelioid astrocytes were transformed into stellate cells; (ii) single colonies of proliferating epithelioid astrocytes were generated; (iii) the area around these colonies becomes devoid of meningeal cells, which seem to form a circular border around the astroglial islands; (iv) from the glial colonies long thin glial processes grow towards the surrounding meningeal cells, terminating at the site of contact; (v) in the contact zone between meningeal cells and astrocytes irregular shaped deposits of electron dense material resembling a basal lamina were seen. These observations indicate that indeed a structure resembling a glial-limiting membrane develops in cocultures of meningeal and astrocytic cells. Its formation depends on the balance of growth promoting effects of meningeal cells on astrocytes and growth inhibiting effects of astrocytes on meningeal cells. Both activities can be enriched from conditioned media of pure astrocytic or meningeal cell culture. The proposed model of meningo-astrocytic cocultures may be a helpful instrument for further investigations on the formation of the glia limitans.

Animals↗
PubMed2006

A novel immune-to-CNS communication pathway: cells of the meninges surrounding the spinal cord CSF space produce proinflammatory cytokines in response to an inflammatory stimulus.

Pain is enhanced in response to elevations of proinflammatory cytokines in spinal cerebrospinal fluid (CSF), following either intrathecal injection of these cytokines or intrathecal immune challenge with HIV-1 gp120 that induces cytokine release. Spinal cord glia have been assumed to be the source of endogenous proinflammatory cytokines that enhance pain. However, assuming that spinal cord glia are the sole source of CSF cytokines may be an underestimate, as the cellular composition of the meninges surrounding the spinal cord CSF space includes several cell types known to produce proinflammatory cytokines. The present experiments provide the first investigation of the immunocompetent nature of the spinal cord meninges. Here, we explore whether rat meninges are responsive to intrathecal gp120. These studies demonstrate that: (a) intrathecal gp120 upregulates meningeal gene expression of proinflammatory signals, including tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), interleukin 6 (IL-6), and inducible nitric oxide synthase (iNOS), and (b) intrathecal gp120 induces meningeal release of TNF-alpha, IL-1beta, and IL-6. In addition, stimulation of isolated meninges in vitro with gp120 induced the release of TNF-alpha and IL-1beta, indicating that the resident cells of the meninges are able to respond without immune cell recruitment. Taken together, these data document that the meninges are responsive to immunogenic stimuli in the CSF and that the meninges may be a source of immune products detected in CSF. The ability of the meninges to release to proinflammatory signals suggests a potential role in the modulation of pain.

Animals↗
PubMed1998

Effect of induced hyperglycemia on brain cell membrane function and energy metabolism during the early phase of experimental meningitis in newborn piglets.

This study was done to elucidate the mechanism of hypoglycorrhachia and elevated lactate concentrations leading to neuronal dysfunction in neonatal meningitis, and to determine the effects of induced hyperglycemia on these disturbances. Thirty-eight newborn piglets were divided into three groups: 12 in the control group (CG), 12 in the normoglycemic meningitis group (NG), and 14 in the hyperglycemic meningitis group (HG). Meningitis was induced by intracisternal injection of 108 cfu of Escherichia coli. Hyperglycemia (blood glucose 300-400 mg dl-1) was induced and maintained for 60 min before induction of meningitis and throughout the experiment using modified glucose clamp technique. CSF-to-blood glucose ratio decreased significantly in NG. In HG, baseline CSF-to-blood glucose ratio was lower than two other groups, but increased at 1 h after induction of meningitis. CSF lactate concentration was increased progressively in both meningitis groups, and positively correlated with CSF leukocyte numbers (r=0.41, p<0.001) and TNF-alpha level (r=0.43, p<0.001). Brain glucose concentration was significantly increased in HG and showed inverse correlation with CSF leukocyte numbers (r=-0.59, p<0.01). Brain lactate concentration was not significantly different among three groups and positively correlated with the CSF TNF-alpha level (r=0.51, p<0.05). Lipid peroxidation products were increased in NG. Na+,K+-ATPase activity, ATP/PCr concentrations were not different among three groups. Increased intracranial pressure, CSF pleocytosis (214+/-59 vs. 437+/-214/mm3, p<0.02) and increased lipid peroxidation products observed in NG were reduced in HG. These results suggest that hypoglycorrhachia and elevated lactate concentration in the CSF during meningitis originates primarily from the increased anaerobic glycolysis in the subarachnoid space, induced by TNF-alpha and leukocytes. Induced hyperglycemia attenuates the inflammatory responses of meningitis and might be beneficial by providing an increased glucose delivery to meet its increased demand in meningitis.

Animals↗
PubMed2002

Diagnosis of adult tuberculous meningitis by use of clinical and laboratory features.

BACKGROUND: The diagnosis of tuberculous meningitis is difficult. Discrimination of cases from those of bacterial meningitis by clinical features alone is often impossible, and current laboratory methods remain inadequate or inaccessible in developing countries. We aimed to create a simple diagnostic aid for tuberculous meningitis in adults on the basis of clinical and basic laboratory features. METHODS: We compared the clinical and laboratory features on admission of 251 adults at an infectious disease hospital in Vietnam who satisfied diagnostic criteria for tuberculous (n=143) or bacterial (n=108) meningitis. Features independently predictive of tuberculous meningitis were modelled by multivariate logistic regression to create a diagnostic rule, and by a classification-tree method. The performance of both diagnostic aids was assessed by resubstitution and prospective test data methods. FINDINGS: Five features were predictive of a diagnosis of tuberculous meningitis: age, length of history, white-blood-cell count, total cerebrospinal fluid white-cell count, and cerebrospinal fluid neutrophil proportion. A diagnostic rule developed from these features was 97% sensitive and 91% specific by resubstitution, and 86% sensitive and 79% specific when applied prospectively to a further 42 adults with tuberculous meningitis, and 33 with bacterial meningitis. The corresponding values for the classification tree were 99% and 93% by resubstitution, and 88% and 70% with prospective test data. INTERPRETATION: This study suggests that simple clinical and laboratory data can help in the diagnosis of adults with tuberculous meningitis. Although the usefulness of the diagnostic rule will vary depending on the prevalence of tuberculosis and HIV-1 infection, we suggest it be applied to adults with meningitis and a low cerebrospinal fluid glucose, particularly in settings with limited microbiological resources.

Adolescent↗
PubMed2002

The meninges contribute to the conditioned taste avoidance induced by neural cooling in male rats.

After consumption of a novel sucrose solution, temporary cooling of neural areas that mediate conditioned taste avoidance can itself induce conditioned avoidance to the sucrose. It has been suggested that this effect is either a result of inactivation of neurons in these areas or of cooling the meninges. In a series of studies, we demonstrated that cooling the outer layer of the meninges, the dura mater, does not contribute to the conditioned taste avoidance induced by cooling any of these areas. The present experiments were designed to determine whether the inner layers of the meninges are involved. If they are involved, then one would expect that cooling locations in the brain that do not mediate conditioned taste avoidance, such as the caudate putamen (CP), would induce conditioned taste avoidance as long as the meninges were cooled as well. One also would expect that cooling neural tissue without cooling the meninges would reduce the strength of the conditioned taste avoidance. Experiment 1 established that the temperature of the neural tissue and meninges around the cold probes implanted in the CP were cooled to temperatures that have been shown to block synaptic transmission. Experiment 2 demonstrated that cooling the caudate putamen and overlying cortex and meninges induced conditioned taste avoidance. In experiment 3, a circle of meninges was cut away so that the caudate putamen and overlying cortex could be cooled without cooling the meninges. The strength of the conditioned taste avoidance was substantially reduced, but it was not entirely eliminated. These data support the hypothesis that cooling the meninges contributes to the conditioned taste avoidance induced by neural cooling. They also allow the possibility that neural inactivation produces physiological changes that can induce conditioned taste avoidance.

Animals↗