The Diagnostic Values Of Increased Platelet Count In Childhood Bacterial Meningitis

Objective:The objective was to explore the value of the complete blood count,including counts for platelets,white blood cells,and the concentration of C-reaction protein from patients in the diagnosis of bacterial meningitis at various time points.From this study,we can find predictors for early differential diagnosis of bacterial meningitis and viral encephalitis.Methods:The research cohort:115 children diagnosed with bacterial meningitis as observation group and 120 children diagnosed with viral encephalitis as controls at Shenzhen Children's Hospital were studied retrospectively,from January 2007 to December 2017.Clinical data of demographic characteristics,etiology,clinical manifestations and laboratory examinations at different times were collected.Results:1.Blood PLT count and CRP levels were significantly higher in the children with bacterial meningitis than those with viral encephalitis at each time of examination(P<0.05).The WBC level increased significantly both in the bacterial meningitis group and in the viral encephalitis group,but with no significant differences(P>0.05)on day 3 of disease course.Compared with the control group on day 7,14 of disease course,the WBC in the bacterial meningitis group increased significantly(P<0.05).2.On day 3 of disease course,the area under the ROC curve of PLT combined with CRP was 0.881,which had high accuracy.When the best cut-off value of platelet count was389.00×10~9/L,the specificity of diagnosis(86.60%)was lower than the specificity of CRP(91.60%,best cut-off value 21.80 mg/L).However,the area under the curve of WBC count was 0.524(P>0.05).There was no significant difference between the diagnosis of bacterial meningitis and viral encephalitis.The diagnostic sensitivity of platelet count increased from 34.9%alone to 78.3%in combination with CRP.3.On the seventh day of disease course,when the best cut-off value of platelet count was445.00×10~9/L,the specificity and positive predictive value of diagnosis were higher than those of CRP.The sensitivity of platelet count increased from 49.4%to 88.0%in combination with CRP.4.On the fourteenth day of disease course,the area under the ROC curve of the PLT,CRP level and WBC were 0.787(95%confidence interval[CI],0.720–0.855)and 0.774(95%CI,0.686–0.823),0.686(95%CI,0.605–0.767)respectively,which showed that the accuracy of PLT count in the diagnosis of bacterial meningitis was higher than that of WBC and CRP.The sensitivity and specificity of diagnosis were 65.20%,86.80%,respectively,when the best cut-off value of platelet count was 500.00×10~9/L.The area under the ROC curve of PLT combined with CRP was 0.858(95%CI,0.803–0.912),which has good accuracy.The sensitivity and specificity of PLT combined with CRP were 79.8%,79.1%,respectively.Therefore,the accuracy of platelet count combined with CRP in the diagnosis of bacterial meningitis is higher than that of PLT count and CRP alone.Conclusion:1.The sensitivity of blood platelet count in the diagnosis of bacterial meningitis is gradually increasing over with the prolongation of the disease course,and its combination with CRP can improve the sensitivity of diagnosis of bacterial meningitis.2.After anti-infective treatment,the blood WBC count and CRP of the children with bacterial meningitis become normal,but the PLT count increased gradually,and the optimal cut-off value increased gradually at different times of the disease course.Whereas the blood WBC count,CRP and PLT counts did not change much in children with viral encephalitis.Therefore,the increased of PLT count may be a quick,convenient marker of bacterial meningitis.