In meningitis, which cerebrospinal fluid cell differential is typical for viral meningitis?

• A. Neutrophils
• B. Lymphocytes
• C. Eosinophils
• D. Basophils

Answer: (B)

Viral meningitis typically produces a lymphocytic pleocytosis in the CSF. This reflects the immune response to viruses in the CNS, where lymphocytes become the predominant white cells in the readout. In this pattern, the CSF usually shows an increased total cell count with a predominance of lymphocytes, and glucose is usually normal or near-normal with only a mild protein elevation. By contrast, bacterial meningitis tends to show neutrophil predominance, with low glucose and higher protein, while eosinophils point to parasitic infections or certain reactions, and basophils are not a typical feature. So the hallmark differential for viral meningitis is lymphocytes.