Which of the following are the common CSF findings suggestive of bacterial meningitis?

BTSC Staff Nurse 30July-2025

Medical & Surgical Nursing

Easy

Appeared in: BTSC Staff Nurse 30July-2025

Explanation

Bacterial meningitis is characterized by a classic triad of CSF findings: low glucose, high protein, and a high white blood cell count dominated by neutrophils.
Bacteria consume glucose for energy, leading to decreased CSF glucose levels (hypoglycorrhachia).
The infection causes inflammation, which increases the permeability of the blood-brain barrier, allowing protein to leak into the CSF, thus elevating protein levels.
Polymorphonuclear leukocytes (neutrophils) are the primary immune cells that respond to acute bacterial infections, so their numbers are significantly increased in the CSF.

Option A: This profile is incorrect for bacterial meningitis. Elevated glucose is the opposite of what is expected, and a predominance of lymphocytes is characteristic of viral, not bacterial, meningitis.
Option C: This combination of findings is characteristic of viral meningitis, not bacterial. In viral meningitis, glucose levels are typically normal because viruses do not consume glucose, and the inflammatory response is dominated by lymphocytes.
Option D: This option is incorrect because both the glucose and protein levels are wrong. Glucose is decreased (not elevated) and protein is elevated (not normal) in bacterial meningitis.

Clinical Relevance

Nursing practice connection: Knowing Interpretation of Cerebrospinal Fluid (CSF) analysis for the diagnosis of bacterial meningitis helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Bacterial meningitis is a medical emergency requiring immediate diagnosis and treatment to prevent severe neurological complications or death.
Nurses play a critical role in recognizing the signs of meningitis, preparing the patient for an urgent lumbar puncture (LP), ensuring CSF samples are handled correctly and sent to the lab promptly, and administering empiric antibiotics as soon as they are prescribed.
Patient safety is paramount. The nurse must monitor for signs of increased intracranial pressure (e.g., deteriorating consciousness, pupillary changes, Cushing's triad) before, during, and after the LP.

How to Approach the Question

First, identify the core concept: the question asks for the specific CSF profile of bacterial meningitis.
Recall the pathophysiology. Bacteria are living organisms that need energy; they consume glucose from their environment (the CSF). This immediately points to 'decreased glucose'.
Remember that a bacterial infection triggers an acute, intense inflammatory response. This response involves neutrophils (polymorphonuclear leukocytes) and makes the blood-brain barrier leaky, allowing large molecules like protein to enter the CSF. This points to 'elevated protein' and 'predominantly polymorphonuclear leukocytes'.
Evaluate each option against this pathophysiological model.
Option A is wrong (elevated glucose, lymphocytes).
Option B matches all three criteria (decreased glucose, elevated protein, polymorphs).

Concept Tested & Keywords

Concept Tested: Interpretation of Cerebrospinal Fluid (CSF) analysis for the diagnosis of bacterial meningitis.
Stem keywords: CSF findings, bacterial meningitis
Lead-in keywords: common, suggestive of
Negative lead-in flag: false

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E6 Medicine Harrison 22e Part 1 p. 1161-1163

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