Assessment of five laboratory tests for differential diagnosis in bacterial and viral meningoencephalitides.

The usefulness of five different laboratory tests for differential diagnosis in bacterial and viral meningoencephalitides was assessed. The clinical manifestations and cytochemical alterations of cerebrospinal fluid (CSF) were used as criteria for diagnostic selection. The causal agent was identified by means of CSF cultures in 47.8 per cent of bacterial meningoencephalitis cases; Gram stain was postive in CSF smear in 34.8 per cent and protein electrophoresis in CSF did not show significant differences when compared to cases of bacterial or viral etiology and the control group. PH and CSF lactate determinations allowed diagnosis of all cases of bacterial meningoencephalitis and was not modified in those cases where this disease was of a viral origin. We suggest to add these determinations to the initial cytochemical study of CSF in all cases where meningoencephalitis is suspected.