Determination Of Excitatory Amino Acids In Cerebrospinal Fluid And Clinical Significance In Children With Bacterial Meningitis

Objectives To study the change of excitatory amino acids (EAA) glutamate (Glu) and aspartic (Asp) in cerebrospinal fluid (CSF)of children with bacterial meningitis and their function in pathophysiological mechanisms and clinical significance.Methods Aaccording to the clinical diagnosis criterion 40 patients of bacterial meningitis were chosen and classified into two groups, 28 cases of mild state, 12 cases of severe state , the clinical severity of the disease was assessed on admission. CSF control samples were obtained from 16 children without neurogenic diseases. The CSF samples were obtained by lumber puncture on admission before the beginning of antibiotic treatment and on the 21st day after the beginning of antibiotic treatment. The third group CSF samples were gotten from those who had poor clinical outcome three months since they were discharged from hospital. In addition to standard CSF investigations, including cell count ,cyctologic findings, protein analysis , glucose levels, theconcentration of glutamate and aspartate in the CSF was measured. All CSF samples were marked conscientiously and frozen immediately and stored for use at -30 in a refrigerator. The concentration of excitatory amino glutamate and aspartate was measured by high-performance liquid chromatography.Results 1. The CSF levels of excitatory amino glutamate and aspartate of children with bacterial meningitis were significantly higher than those of the controls (P<0.001 and 0.05). 2.The CSF levels of excitatory amino acid of patients with severe state were increased than those of mild state (P<0.001) 3. After 21 days antibiotic treatment , the concentration of excitatory amino acids were decreased significantly in 24 patients. However, in 8 patients the levels remained higher and their clinical outcomes were significantly worse than those of lower levels in the second CSF analysis(x2=6.095, P<0.05). The concentration of glutamate and aspartate of those who had poor clinical outcome three months since they were discharged from hospital did not decreased the normal levels. 4.The CSF levels of excitatory amino acid were negatively correlated with the concentrations of CSF glucose and positively correlated with the concentrations of protein in CSF.Conclusions 1. The changing of EAA in CSF in children with bacterial meningitis indicates that they may participate in pathophysiological mechanisms of BM. 2.Testing the levels of EAA will contribute to the judgment of the severity of cerebral injury of BM.3. A prolonged increase of EAA levels in the CSF may predict poor clinical outcome in patients with BM.Our findings showed that the concentrations of EAA in CSF are sensitive and reliable biochemical markers for evaluating the extent of brain damage of patients with bacterial meningitis and testing EAA concentration provided helpful clinical study data to us for the clinical use of the inhibitor of EAA receptor.