Procalcitonin (PCT) has proving its efficacy to distinguish bacterial from aseptic meningitis in children. Nevertheless, its use in routine is limited by its cost and availability; especially in low and middle income countries. It is now acknowledging that
eosinopenia is a markers of infection and/or severity of the systemic inflammatory response.
The white blood cell were systematically gathering at the admission to evaluate the eosinophil count; But the characteristic data were all comparing in between 2 groups; But some of the documenting bacterial meningitis (DBP) and in the aseptic meningitis which are including the documenting of the viral meningitis (DVM) and also the non documenting meningitis (ND).
Bio markers for meningitis
But the impact of the eosinophil count on the diagnosis of meningitis; In between the groups of DBM, DVM, and ND meningitis; the mean of eosinophil count was statistically different (p =0.0001) and confirmed between bacterial and aseptic meningitis.
The usual markers performed for the diagnosis of bacterial meningitis; namely CRP, procalcitonin (PCT), proteinorachia,
glycorachia, and lactatorachia, are reporting; For a threshold of eosinopenia defined < 100/mm3, the area under; the curve (AUC) was of 0.79 when dealing with absolute values of eosinophils and 0.80 in case of percentage. For comparison, AUC of CRP was better at 0.91 whereas PCT reaching a value of 0.93.
Aseptic meningitis in pediatrics
But the deeper the eosinopenia is; the higher the specificity is to distinguish bacterial from aseptic meningitis in pediatrics. Indeed, an eosinophil count < 100/mm3 has a sensitivity of 87% and a specificity of 44% which can reach up to 73% if the eosinophil count is below 5/mm3.
Such marker is easily obtaining with a simple blood sample without the need to wait for complementary biochemical tests which making it helpful for a rapid orientation diagnosis of bacterial meningitis before the realization of a lumbar puncture. By believing that the presence of eosinopenia should guide the physician to determine whether the patient is deemed to
require a rapid initiation of antimicrobial therapy, in addition to usual signs of orientation in case of meningitis.