Detection of content of cerebrospinal fluid lactic acid in identifying the infection of central nervous system

Objective:To identify viral meningitis,purulent meningitis and tuberculous meningitis by detecting the content of cerebrospinal fluid lactic acid(CSF LA) in patients with infections of central nervous system.Methods:The value of lactic acid was detected by using copper sulphate.Results:The content of CSF LA was 16.0±3.6 mg% in normal control group,17.2±4.2 mg% in viral meningitis group,60.8±12.6 mg% in purulent meningitis group,51.5±12.9 mg% in tuberculous meningitis group and 17.7±5.4 mg% in cysticercosis group.The contents of CSF LA in purulent meningitis and tuberculous meningitis groups were significantly higher than those in the other three groups( P 0.01).But there was no significant difference between the two groups( P 0.05).By dynamic detection of CSF LA,we could see that in purulent meningitis group it took 8.0±2.7 days of CSF LA to lower to normal level (30 mg%),whereas in tuberculous meningitis group it took 21±6.3 days,which was remarkably longer than that in purulent meningitis group( P 0.01).Conclusions:The contents of CSF LA in purulent meningitis and tuberculous meningitis groups were significantly higher than that in normal control group,viral meningitis group and cysticercosis group.[