Application Value Of Cerebrospinal Fluid Lactate And Serum Procalcitonin In Differential Diagnosis Of Intracranial Infectious Diseases In Children

Objective:To explore the application value of cerebrospinal fluid lactate and serum procalcitonin in differential diagnosis of intracranial infectious diseases in children.Methods:To collect the clinical data of40children of intracranial infectious diseases admitted into Neurology department of Children’s Hospital of Chongqing Medical University from November2011to February2012. All of patients had blood routine test,38cases had serum lactate test,34children had serum CRP examination,17cases made blood culture, and28cases had serum procalcitonin(PCT) examination. All the cases did lumbar puncture within24-72hours after admitting. After cerebrospinal fluid(CSF) were collected, CSF lactate(CSF-LA) and the traditional markers of CSF (leucocyte count, percentage of polymorpho-nuclear leukocytes, protein, glucose, chlorides, CSF/plasma glucose quotient and culture) had been measured.28cases made CSF smear. After antibiotic treatment for10days, CSF-LA of2patients in bacterial meningitis group had remeasured. And according to symptoms, physical examination and laboratory tests,14cases were diagnosed to have bacterial meningitis, and26cases viral encephalitis. And then analyze the changes of CSF-LA, PCT and the traditional markers of CSF in the two groups.Results:(1) Blood routine test and serum CRP:There were61.5%of cases with leucocyte count more than10X109/L in bacterial meningitis group, and46.2%in viral encephalitis. The difference was not statistically significant between the two groups(P>0.05). As for serum CRP,58.3%of patients had CRP more than8mg/L in bacterial meningitis group, and31.8%in viral encephalitis group. There was no statistically significance (P>0.05).(2) CSF routine and biochemistry examinations:The differences of leucocyte count, protein and glucose between bacterial meningitis and viral encephalitis were marked statistically significant(P<0.01). There was also statistically significance in the percentage of polymorphonuclear leukocytes between two groups. But for such patients whose CSF did not show typic manifestation of bacterial meningitis, there was no statistically significance in leucocyte count compared with viral encephalitis. Though the differences of protein and glucose between patients without typic CSF manifestation of bacterial meningitis and viral encephalitis group were marked statistically significant(P<0.01), the data of them overlapped partially. As for CSF/plasma glucose quotient,35.7%of patients had this quotient less than40%in bacterial meningitis group, and none in viral encephalitis group. There was marked statistically significance(P<0.01). But there was no statistically significance in CSF/plasma glucose quotient between patients with atypic CSF manifestation of bacterial meningitis and viral encephalitis group(P>0.05).(3) Microscopic examination: In40cases studied,28cases were made CSF smear, but there were no positive. For culture, only1case of bacterial meningitis was positive in CSF culture, and2cases positive in blood culture. All the cases of viral encephalitis group were negative both in CSF culture and blood culture.(4) CSF lactate acid: CSF-LA was (2.68±1.50)mmol/L in bacterial meningitis group, and (1.25±0.24)mmol/L in viral encephalitis group. The difference was markedly statistically significant between two groups (P＜0.01). When the cut-off value for CSF-LA was1.6mmol/L in this study, the ability to discriminate bacterial from viral infection showed a sensitivity of71.4%and specificity of96.2%, and there was markedly statistically significance between patients with atypic CSF manifestation of bacterial meningitis and viral encephalitis group(P<0.01). CSF-LA was correlated with CSF leucocyte count and glucose. But it was independent of serum lactate concentration.(5) Serum PCT:45.0%of cases had PCT more than0.5ng/mL in bacterial meningitis group, and5.9%in viral encephalitis group. There was statistically significance between bacterial meningitis and viral encephalitis group(P<0.05).Conclusions:(1) Blood routine test and serum CRP had low specificity in differentiating different intracranial infectious diseases.(2) CSF routine and biochemistry examinations could help doctors distinguish bacterial meningitis from viral encephalitis. But because of the overlapped CSF markers between bacterial meningitis and viral encephalitis, it is hard to differentiate each other through the atypic CSF manifestation.(3) The positive rate of bacteria culture was low.(4) Cases in bacterial meningitis had higher CSF-LA than in viral encephalitis. Even for patients without typic CSF manifestation of bacterial meningitis, CSF-LA was considered a good biomarker for differentiating bacterial from viral intracranial infection at a cut-off of1.6mmol/L. So CSF-LA was a powerful test to discriminate different intracranial infectious diseases.(5) PCT was higher in bacterial meningitis than viral encephalitis. Few cases in viral encephalitis group had elevated PCT, so PCT could be proposed as one of an important differential marker between bacterial meningitis and viral encephalitis. (6) Because of the treatment before lumbar puncture, doctors should diagnose bacterial meningitis according to the symptoms, the markers of CSF and some serum markers of inflammation.