Which CSF pattern is typical of bacterial meningitis compared with viral meningitis?

• A. Bacterial meningitis shows normal CSF glucose and low protein.
• B. Bacterial meningitis shows high CSF glucose and lymphocytic pleocytosis.
• C. Bacterial meningitis shows neutrophilic pleocytosis, low CSF glucose, and high protein; viral meningitis shows normal/slightly reduced glucose and lymphocytic pleocytosis.
• D. Viral meningitis shows neutrophilic pleocytosis.

Answer: (C)

CSF findings differentiate bacterial from viral meningitis. In bacterial meningitis, the CSF typically shows neutrophilic pleocytosis with a low glucose level and elevated protein, reflecting a robust neutrophil-driven inflammatory response and consumption of glucose in the infected fluid. In viral meningitis, the CSF more often has lymphocytic pleocytosis with normal or only mildly reduced glucose and only modestly elevated protein, due to a different inflammatory pattern and preserved glucose.

Thus the description of neutrophilic pleocytosis with low CSF glucose and high protein best fits bacterial meningitis, while viral meningitis tends to have lymphocytic pleocytosis with normal or lightly reduced glucose.