[Cerebrospinal fluid lysozyme in meningitis in children. Value in establishing the etiologic diagnosis].

Cerebrospinal fluid lysozyme (CSF-LZM) concentrations were determined in 62 controls, 28 viral meningitis and 22 bacterial meningitis, as compared to CSF lactic acid routinely used. CSF-LZM measurement was performed by a rapid turbidimetric assay which required 50 microliters CSF only. The mean CSF-LZM concentration of the control group was 0.23 mg/l, the highest value being 0.65 mg/l. The mean LZM levels in viral meningitis were 1.10 mg/l, never exceeding 3 mg/l. The range of pretreatment LZM levels in bacterial meningitis was 7.2 to 65 mg/l and above 3 mg/l in all cases 48 h after treatment. On the 6th day after admission, 12 of 16 samples showed abnormal values. The CSF-LZM assay seems to be of more value than that of lactic acid. Thus, before treatment, LZM concentrations were 10 to 100 fold higher than that of the normal values, with persistent high levels on the 2nd and even on the 6th day of treatment (whereas lactic acid values were all normal on day 6).