CSF modifications are common in children with TBM. In these cases, CSF shows a clear appearance, moderate pleocytosis with a predominance of lymphocytes, an increase in protein content and a very low glucose concentration. These findings are different from those usually reported for typical bacterial meningitis in which CSF is opaque, pleocytosis is very high, and neutrophils are predominant. Reduction in glucose content is usually less marked in comparison to purulent bacterial meningitis, where CSF glucose values below 5 mg/dL will often be found. Clear appearance, white blood cell count between 50 and 500 per mL with 50% or more lymphocytes, protein content greater than 1 g/L and a glucose content less than 2.2 mmol/L are considered to be indicative of TBM. However, atypical CSF findings have been repeatedly described in children with TBM.