Which CSF pattern characterizes bacterial meningitis compared with viral meningitis?

Which CSF pattern characterizes bacterial meningitis compared with viral meningitis?

• A. Bacterial meningitis shows high opening pressure, neutrophilic WBCs, low glucose, and high protein; viral meningitis shows lymphocytic predominance, normal glucose, normal to mildly elevated protein.
• B. Bacterial meningitis shows low opening pressure; viral meningitis shows neutrophilic WBCs.
• C. Bacterial and viral meningitis have identical CSF findings.
• D. Bacterial meningitis shows low protein and high glucose.

Answer: (A)

Distinguishing CSF profiles is the key idea here: bacterial meningitis typically causes an inflammatory exudate with high opening pressure, neutrophil-predominant pleocytosis, low CSF glucose, and high protein. This reflects rapid bacterial growth and disruption of the blood-brain barrier, with glucose being consumed by bacteria and leukocytes and protein increasing due to inflammation. Viral meningitis, in contrast, usually shows lymphocytic predominance, with normal glucose and normal to mildly elevated protein, and opening pressure is often normal. Therefore, the pattern of high opening pressure, neutrophils, low glucose, and high protein aligns with bacterial meningitis, while viral meningitis would present with lymphocytes and normal glucose and only modest protein changes. The other patterns—low opening pressure with neutrophils, identical CSF findings, or low protein with high glucose—do not fit the typical bacterial versus viral distinction.

Distinguishing CSF profiles is the key idea here: bacterial meningitis typically causes an inflammatory exudate with high opening pressure, neutrophil-predominant pleocytosis, low CSF glucose, and high protein. This reflects rapid bacterial growth and disruption of the blood-brain barrier, with glucose being consumed by bacteria and leukocytes and protein increasing due to inflammation. Viral meningitis, in contrast, usually shows lymphocytic predominance, with normal glucose and normal to mildly elevated protein, and opening pressure is often normal. Therefore, the pattern of high opening pressure, neutrophils, low glucose, and high protein aligns with bacterial meningitis, while viral meningitis would present with lymphocytes and normal glucose and only modest protein changes. The other patterns—low opening pressure with neutrophils, identical CSF findings, or low protein with high glucose—do not fit the typical bacterial versus viral distinction.