CSF findings differentiating bacterial from viral meningitis: which option best describes bacterial meningitis?

• A. Lymphocytic predominance, normal glucose, normal protein
• B. Lymphocytic predominance, normal or mildly reduced glucose, normal or elevated protein
• C. Neutrophilic predominance, low glucose, high protein
• D. Neutrophilic predominance, normal glucose, low protein

Answer: (C)

In bacterial meningitis, the CSF typically shows an acute neutrophilic response with changes in chemistry due to the infection. The presence of neutrophils indicates an acute bacterial process, the glucose level is usually low because bacteria consume glucose and inflammation impairs glucose transport into the CSF, and the protein level is high from increased blood–brain barrier permeability and inflammatory exudate. This combination—neutrophilic predominance, low glucose, and high protein—best fits the bacterial pattern.

In contrast, viral meningitis more often shows a lymphocytic predominance, with normal or only mildly reduced glucose and normal to mildly elevated protein. So the pattern described here aligns most closely with bacterial meningitis, rather than viral.