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Query: UMLS:C0085437 (bacterial meningitis)
 4,038 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study was carried out to elucidate the pathophysiologic mechanism of cerebral hyperemia observed during the early phase of bacterial meningitis. We tested the hypothesis that microbial invasion through the blood-brain barrier is responsible for cerebral vasodilation and hyperemia in meningitis. Escherichia coli was given either intravenously (i.v.) or intracisternally (i.c.) to closely mimic the primary or secondary bacterial invasion occurring in meningitis and newborn piglets were grouped according to their invasion results (+ or -); 12 in the i.v. (+) group, 14 in the i.v. (-) group, 13 in the i.c. (+) group, 15 in the i.c. (-) group. The results were compared with eight animals in the control group. Near infrared spectroscopy (NIRS) was employed to monitor changes in total hemoglobin (HbT), oxygenated hemoglobin (HbO), deoxygenated hemoglobin (Hb), deduced hemoglobin (HbD), and oxidized cytochrome aa3 (Cyt aa3). HbT, as an index of cerebral blood volume, increased progressively in both i.v. (+) and i.v. (-) groups and became significantly different from control and baseline values at 2 h. Hb significantly increased only in i.v. (+) group. HbD, as an index of cerebral blood flow, decreased significantly in i.v. (+), i.v.(-) and i.c. (-) groups and this change was mitigated in i.c. (+) group, HbO was reduced in i.c. (-) group and this decrease was attenuated in i.c. (+) group. Increased Cyt aa3 was observed in all experimental groups after bacterial inoculation. Changes in ICP, blood pressure, cerebral perfusion pressure, blood or CSF glucose or lactate, CSF TNF-alpha level, or CSF leukocytes number were not associated with changes in NIRS findings. These findings suggest that primary or secondary bacterial invasion across the blood-brain barrier is primarily responsible for cerebral vasodilation and hyperemia observed during the early phase of bacterial meningitis.
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PMID:Effects of microbial invasion on cerebral hemodynamics and oxygenation monitored by near infrared spectroscopy in experimental Escherichia coli meningitis in the newborn piglet. 1040 12

The E. coli endotoxin 0111 B4, a lipopolysaccharide (LPS), in a dose of 200 ng/kg body weight/50 microl artificial cerebrospinal fluid (CSF) was given intracisternally to 14-day-old rats. Four hours later CSF, blood and urine were sampled, and consecutive brain sections from the hypothalamic area of the brain were prepared for in situ hybridization. The LPS treatment resulted in a significant (p<0.001) pleocytosis and an elevation of the protein content of the CSF. There were no changes observed in the chemical parameters of the CSF, plasma, blood or urine, i.e. vasopressin (VP) levels, osmolality, Na+ and K+ concentrations, glucose level, pH, bicarbonate or PaCO2, PaO2 values. LPS injection, however, resulted in a significantly (p<0.01) increased VP mRNA level (121% of the control value) in the supraoptic nuclei (SON), but not in the paraventricular nuclei (PVN), as compared to controls. Our findings suggest an early effect of LPS on VP gene expression selectively in the SON of 14-days-old rats. This animal model might be suitable for studying the regulation of VP gene expression and the role of this peptide in the pathogenesis of bacterial meningitis in pediatric patients.
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PMID:Differential regulation of vasopressin gene expression in the hypothalamus of endotoxin-treated 14-day-old rat. 1042 32

The value of cerebrospinal fluid (CSF) lactate level and CSF/blood glucose ratio for the identification of bacterial meningitis following neurosurgery was assessed in a retrospective study. During a 3-year period, 73 patients fulfilled the inclusion criteria and could be grouped by preset criteria in one of three categories: proven bacterial meningitis (n = 12), presumed bacterial meningitis (n = 14), and nonbacterial meningeal syndrome (n = 47). Of 73 patients analyzed, 45% were treated with antibiotics and 33% with steroids at the time of first lumbar puncture. CSF lactate values (cutoff, 4 mmol/L), in comparison with CSF/blood glucose ratios (cutoff, 0.4), were associated with higher sensitivity (0.88 vs. 0.77), specificity (0.98 vs. 0.87), and positive (0.96 vs. 0.77) and negative (0.94 vs. 0.87) predictive values. In conclusion, determination of the CSF lactate value is a quick, sensitive, and specific test to identify patients with bacterial meningitis after neurosurgery.
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PMID:Predictive value of cerebrospinal fluid (CSF) lactate level versus CSF/blood glucose ratio for the diagnosis of bacterial meningitis following neurosurgery. 1081 58

The role of nitric oxide (NO) in childhood bacterial meningitis was investigated by determining the levels of nitrate/nitrite, stable end products of NO metabolism, in cerebrospinal fluid (CSF). Eighteen children with bacterial meningitis and 18 as a control group were included in the study. Mean (+/- SD) CSF nitrate/nitrite levels were 27.6 +/- 26 micromol/l in the bacterial meningitis group and 3.2 +/- 1.8 micromol/l in the control group (p = 0.0005). We found no correlation between CSF nitrate/nitrite levels and CSF white blood cell count (r = 0.22), protein (r = 0.26) or tumour necrosis factor alpha (TNF-alpha) levels (r = 0.046), but a moderate negative correlation between CSF nitrate/nitrite and glucose levels (r = -0.46).
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PMID:Cerebrospinal fluid nitric oxide levels in childhood bacterial meningitis. 1057 39

We evaluated the efficacy of alpha-phenyl-N-tertbutylnitrone as an adjunctive therapy in experimental bacterial meningitis in the newborn piglet. Meningitis was induced by intracisternal injection of 10(8) colony-forming units of Escherichia coli in 100 microl of saline. Alpha-Phenyl-N-tert-butylnitrone 100 mg/kg was given as a bolus intravenous injection 30 min before induction of meningitis. Although it completely abolished the elevated CSF tumor necrosis factor-a level observed in the meningitis group, alpha-phenyl-N-tert-butylnitrone did not down-modulate parameters of inflammatory responses such as increased intracranial pressure, hypoglycorrhachia, elevated CSF lactate level, and CSF leukocytosis observed in this group. However, alpha-phenyl-N-tert-butylnitrone treatment mitigated alterations in brain cell membrane structure and function during meningitis, evidenced by amelioration of increased brain cell membrane lipid peroxidation products (conjugated dienes) and decreased Na+, K+-ATPase activity. Reduced mean arterial blood pressure, cerebral perfusion pressure, brain glucose concentration, and cerebral energy stores and marginally increased brain lactate level observed in the meningitis group were also ameliorated. These results suggest that although it failed to attenuate the inflammatory responses, alpha-phenyl-N-tert-butylnitrone was effective in ameliorating brain injury in neonatal bacterial meningitis.
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PMID:Effect of alpha-phenyl-N-tert-butylnitrone on brain cell membrane function and energy metabolism in experimental Escherichia coli meningitis in the newborn piglet. 1064 28

This study was done to evaluate the anti-inflammatory effect and the ensuing neuroprotective effect of pentoxifylline in neonatal experimental bacterial meningitis. Newborn piglets were divided into three groups: 10 in the control group (CG), 13 in the meningitis group (MG), and 13 in the meningitis with pentoxifylline group (PG). Meningitis was induced by intracisternal injection of 10(8) colony-forming units of Escherichia coli in 100 microl of saline. In PG, 20 mg/kg of pentoxifylline was given as a bolus intravenous injection 30 min before induction of meningitis and 6 mg/kg/h was given continuously throughout the experiment. In PG, the increase of CSF TNF-alpha level observed in MG was abolished. Reduced brain glucose and ATP concentrations observed in MG were significantly increased in PG. However, other parameters of inflammatory responses such as increased intracranial pressure, reduced glucose and increased lactate concentrations in the CSF observed in MG were not significantly down-modulated. The extent of CSF leukocytosis was even higher in PG than in MG. Increased cerebral cortical cell membrane lipid peroxidation products and decreased Na(+),K(+)-ATPase activity observed in MG, indicative of meningitis-induced brain cell membrane dysfunction, tended to improve without statistical significance in PG. In summary, although some anti-inflammatory effects have been observed, the overall anti-inflammatory effects of pentoxifylline was very weak, and it failed to significantly reduce the brain damage in experimental neonatal bacterial meningitis.
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PMID:The efficacy of pentoxifylline as an anti-inflammatory agent in experimental Escherichia coli meningitis in the newborn piglet. 1082 75

The aim of this study was to validate, in a population of infants and children under 3.5 years of age, a diagnosis model that provides a figure for the probability of bacterial meningitis (pABM), based on four parameters collected at the time of the first lumbar tap: the cerebrospinal fluid (CSF) protein level, CSF polymorphonuclear cell count, blood glucose level, and leucocyte count. The best cut-off value for distinguishing between bacterial and viral meningitis was previously found to be 0.1, since 99% of meningitides associated with pABM<0.1 were viral. The charts of 103 consecutive children aged 0.1-3.5 years who had been hospitalised for acute meningitis were reviewed. Each case was sorted into the following three categories for aetiology: bacterial (positive CSF culture, n=48); viral (negative CSF culture and no other aetiology, and no antibiotic treatment after diagnosis, n=36); and undetermined (fitting neither of the first two definitions, n=19). After computation of pABM values in each case, the predictive values of the model were calculated for different pABM cut-off values. The results confirmed that the best cut-off pABM value was 0.1, for which the positive and negative predictive values in this model were 96% and 97%, respectively. Only one case of bacterial meningitis (lumbar tap performed early in an infant with meningococcal purpura fulminans with negative CSF culture) was associated with a pABM value of <0.1. This model is quite reliable for differentiating between bacterial and viral meningitis in children under 3.5 years of age, and it may enable physicians to withhold antibiotics in cases of meningitis of uncertain aetiology.
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PMID:Validation of a diagnosis model for differentiating bacterial from viral meningitis in infants and children under 3.5 years of age. 1094 15

The aim of this study was to validate a diagnosis model that provides pABM, the probability of bacterial versus viral meningitis, based on four parameters collected at the time of first lumbar tap: cerebrospinal fluid protein level, cerebrospinal fluid polymorphonuclear cell count, blood glucose level, and leucocyte count. The model was evaluated prospectively as an aid to therapeutic decision-making in 109 consecutive patients with acute meningitis and negative cerebrospinal fluid Gram stain. In each case pABM was computed before a therapeutic decision and three diagnoses were established successively: (i) clinical evaluation, i.e. before pABM computation (bacterial meningitis, viral meningitis, or meningitis of undetermined origin); (ii) computation of pABM (viral meningitis if pABM< 0.1, bacterial meningitis otherwise); and (iii) determination of definitive diagnosis (bacterial meningitis: positive cerebrospinal fluid culture; viral meningitis: negative cerebrospinal fluid culture, no other aetiology and no treatment; meningitis of undetermined origin: cases fitting neither of the first two diagnoses). The computed diagnosis was viral meningitis in 78 of the 80 cases diagnosed definitively as viral meningitis, and bacterial meningitis in four of the five cases diagnosed definitively as bacterial meningitis. Negative and positive predictive values and accuracy of the model were 98.7%, 66.7%, and 96.5%, respectively. The clinical diagnosis was undetermined in 22 cases, 15 of which were diagnosed definitively as viral cases; in all of these 15 cases, the computed diagnosis was viral meningitis, leading the physician to refrain from starting antibiotics in all of them. The results confirm that the model evaluated is reliable and aids in the identification of patients in whom antibiotics can be safely avoided.
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PMID:Prospective validation of a diagnosis model as an aid to therapeutic decision-making in acute meningitis. 1094 16

Brain injury due to bacterial meningitis results in a high mortality rate and significant neurologic sequelae in survivors. The objective of this study was to determine if the application of moderate hypothermia shortly after the administration of antibiotics would attenuate the inflammatory response and increase in intracranial pressure that occurs in meningitis. For this study we used a rabbit model of severe Group B streptococcal meningitis. The first component of this study evaluated the effects of hypothermia on blood-brain barrier function and markers of inflammation in meningitic animals. The second part of the study evaluated the effects of hypothermia on intracranial pressure, cerebral perfusion pressure and brain edema. This study demonstrates that the use of hypothermia preserves CSF/serum glucose ratio, decreases CSF protein and nitric oxide and attenuates myeloperoxidase activity in brain tissue. In the second part of this study we show a decrease in intracranial pressure, an improvement in cerebral perfusion pressure and a decrease in cerebral edema in hypothermic meningitic animals. We conclude that in the treatment of severe bacterial meningitis, the application of moderate hypothermia initiated shortly after antibiotic therapy improves short-term physiologic measures associated with brain injury.
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PMID:Hypothermia as an adjunctive treatment for severe bacterial meningitis. 1103 98

One hundred three episodes of acute bacterial meningitis in adults hospitalized in Edmonton's 2 largest hospitals from 1985 to 1996 were reviewed. Cases complicating neurosurgery were excluded. Most cases were community-acquired (87%). Twenty-three cases remained culture-negative, and there was no statistical relation between culture negativity and antibiotic pretreatment. Streptococcus pneumoniae was the predominant pathogen (52.5%), but Listeria monocytogenes was the second most common isolate, accounting for 12.5% of culture-positive cases. Compared to non-listerial meningitis, those with listeriosis were more likely to have negative cerebrospinal fluid (CSF) Gram stains (p = 0.07), CSF leukocyte counts < 1,000 cells/mm3 (p < 0.003), and normal CSF glucose (p = 0.006). Bacterial antigen detection was found to be of low sensitivity: 33% in all patients, but only 9% in cases with negative CSF Gram stains. The overall mortality was 18%, with 15 deaths directly attributable to acute meningitis; the case-fatality rates for S. pneumoniae and L. monocytogenes were 24% and 40%, respectively. Mortality was significantly higher among those with seizures (34% versus 7%, respectively; p < 0.001; OR = 17.6). Despite the urgency of acute bacterial meningitis, there were considerable delays in the institution of empiric antibiotics; mortality rates were slightly higher in those who experienced such a delay (16% versus 7% respectively; p = 0.18).
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PMID:Acute bacterial meningitis in adults. A 12-year review. 1114 34


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