Which bacterial meningitis clinical features in CSF include a high white blood cell count with predominance of PMNs?

In cases of bacterial meningitis, the cerebrospinal fluid (CSF) typically reveals a high white blood cell count (pleocytosis) with a predominance of polymorphonuclear leukocytes (PMNs), which are often referred to as neutrophils. This hallmark finding occurs due to the acute inflammatory response elicited by the presence of bacteria in the CSF. The elevated PMNs in the CSF reflect the body's immune response to the bacterial infection, as neutrophils are among the first responders to bacterial invaders.

In contrast, viral meningitis is characterized by a predominance of lymphocytes, while fungal and parasitic meningitis can also show lymphocytic dominance but may have other distinguishing features and lower overall white blood cell counts compared to bacterial meningitis. These differences in the CSF profile are critical for clinicians in diagnosing the type of meningitis and determining the appropriate treatment strategy. Hence, the distinct presence of PMNs in a high white blood cell count in the CSF specifically points towards bacterial meningitis.