Cerebrospinal fluid leukocyte aggregation in meningitis

OBJECTIVE: To evaluate whether the difference in aggregation of cerebrospinal fluid cells from patients with bacterial, viral, aseptic and partially treated meningitis can be used for diagnostic purposes. METHODS: Cerebrospinal fluid samples of 100 patients with meningitis (15 bacterial, 13 partially treated, 10 viral and 62 aseptic) were compared on the basis of the predefined leukocyte aggregation score (LAS). RESULTS: Mean LAS was 56% in the bacterial meningitis group (range, 15 to 90%), 5.8% in the partially treated meningitis group (range, 0 to 27%), 2% in the proven viral meningitis group (range, 0 to 5%) and 2% in the aseptic meningitis group (range, 0 to 15%). All patients with bacterial meningitis had a LAS of > 15%, whereas all those with viral or aseptic meningitis had a score of < 15%. Although most patients with partially treated meningitis had a low LAS, several had higher scores, which may indicate bacterial infection. There was no statistical correlation between number of cells, type of cells (mononuclear or polymorphonuclear) or cerebrospinal fluid protein and glucose concentration and degree of leukocyte aggregation for the different groups. CONCLUSION: Measurement of the LAS may contribute to the immediate differential diagnosis of bacterial or viral meningitis, especially in patients with very high pleocytosis, as sometimes seen in enteroviral meningitis. It may also serve as a guide for the likelihood of bacterial infection in cases of partially treated meningitis. Additional studies are needed to confirm these observations.