What CSF pattern is typical of viral meningitis?

• A. Lymphocytic predominance, normal glucose, normal to mildly elevated protein.
• B. Neutrophilic predominance, low glucose, high protein.
• C. Lymphocytic predominance, low glucose, high protein.
• D. Eosinophilic predominance with elevated glucose.

Answer: (A)

In viral meningitis, the CSF typically shows a lymphocytic predominance with normal glucose and normal to mildly elevated protein. This reflects the type of immune response to a viral infection, where lymphocytes are the main infiltrating cells and the inflammation is less intense than in bacterial meningitis, so glucose remains largely available and protein elevation is usually modest.

Why this fits best: viruses don’t consume glucose in CSF as aggressively as bacteria do, so the glucose level stays normal. The inflammatory process is lymphocyte-driven rather than neutrophil-dominated, which is why you see a higher percentage of lymphocytes and only a mild or no drastic rise in protein.

Why the other patterns aren’t typical: a neutrophilic predominance with low glucose and high protein points to bacterial meningitis, where bacteria and associated inflammation rapidly deplete glucose and drive a strong neutrophil response. A lymphocytic pattern with low glucose and high protein can be seen in tuberculous or fungal meningitis, where the inflammation is more protracted and glucose can drop; this is not the usual viral presentation. Eosinophilic predominance with elevated glucose is not a classic pattern for viral meningitis and is associated with other conditions such as parasitic infections or certain drug reactions.