Which CSF pattern is typical of bacterial meningitis?

• A. High opening pressure, neutrophilic WBCs, low glucose, high protein.
• B. Normal opening pressure, lymphocytic predominance, normal glucose.
• C. Low opening pressure, eosinophilic predominance.
• D. Normal pressure with elevated glucose and protein.

Answer: (A)

Bacterial meningitis typically produces an inflammatory exudate in the subarachnoid space that changes several CSF parameters. The opening pressure is usually elevated because of the inflammatory process and resulting brain swelling. The white blood cell count in the CSF shows neutrophilic predominance, reflecting an acute bacterial infection. Glucose in the CSF drops because bacteria consume glucose and inflammation disrupts transport of glucose from the blood into the CSF. Protein levels rise due to increased permeability of the blood-brain barrier and leakage of plasma proteins into the CSF. When you see a pattern described as high opening pressure, neutrophils dominating the WBCs, low glucose, and high protein, it best matches bacterial meningitis. In contrast, viral meningitis more commonly shows lymphocytic predominance with normal glucose, and other patterns (like eosinophils or very low glucose) point to different etiologies.