Prediction of cerebrospinal fluid parameters for tuberculous meningitis.

Background: Tuberculous meningitis is the most lethal form of tuberculosis, but current diagnostic methods are inadequate. The measurement of cerebrospinal fluid parameters can provide early information for diagnosis. The present study focus on the validity of the cut-off value of cerebrospinal fluid parameters according to the Lancet consensus of scoring system for diagnosis of tuberculous meningitis.

Method: A total of 100 confirmed patients were enrolled in this study. We evaluated significance of protein level (>1 g/l), chloride level (<120 mmol/l), glucose level (<2.2 mmol/l), cell counts (10-500 cells/μl, lymphocytic pleocytosis (>50%), and neutrophil predominance (>50%) in early diagnosis of tuberculous meningitis.

Result: The cerebrospinal fluid parameters were significantly different between the tuberculous meningitis group and the control group. The independent factors for diagnosis of tuberculous meningitis were protein level (>1 g/l), glucose level (<2.2 mmol/l), cell counts (10-500 cells/μl and neutrophil predominance >50%). Neutrophil predominance (>50%) performed the best with the area under the curve of 89.7%. The sensitivity of protein level (>1 g/l), glucose level (<2.2 mmol/l), cell counts (10-500 cells/μl) and neutrophil predominance (>50%) for diagnosis of tuberculous meningitis were 66%, 58%, 86%, and 54%, and the specificity were 84%, 98%, 32%, and 98%. There are 84% patients in tuberculous meningitis group at least having two positive parameters among the four independent parameters, while only 10% in control group.

Conclusion: The cerebrospinal fluid parameters can help the clinicians to make a prompt diagnosis in the early stage of the disease.