From the Guidelines
In bacterial meningitis, cerebrospinal fluid (CSF) typically shows decreased glucose levels and elevated protein levels, with CSF glucose usually less than 40 mg/dL or less than 50% of the simultaneous serum glucose concentration, and protein levels typically elevated above 100 mg/dL 1.
Key Findings
- The changes in CSF glucose and protein levels occur due to bacterial consumption of glucose and inflammation that disrupts the blood-brain barrier, allowing proteins to leak into the CSF 1.
- The inflammatory response also impairs glucose transport across the blood-brain barrier, further contributing to low CSF glucose levels 1.
- These findings contrast with viral meningitis, where glucose is typically normal and protein may be only mildly elevated 1.
Diagnostic Approach
- When evaluating a patient with suspected meningitis, these CSF parameters should be interpreted alongside cell count (typically showing neutrophil predominance in bacterial infection), Gram stain, and culture results for accurate diagnosis 1.
- The combination of low glucose and high protein has high sensitivity for bacterial meningitis, though not perfect, and should prompt empiric antibiotic treatment while awaiting culture results 1.
Clinical Considerations
- It is essential to determine CSF leukocyte count, protein, and glucose concentration, and to perform CSF culture and Gram stain in patients with suspected bacterial meningitis 1.
- Blood cultures should also be performed before the first dose of antibiotics is administered 1.
- The diagnosis of bacterial meningitis can be challenging, especially in neonates, where CSF abnormalities may be absent or minimal 1.
From the Research
Glucose and Protein CSF Levels in Bacterial Infections
- The provided studies do not directly address glucose and protein CSF levels in bacterial infections [ 2, 3, 4, 5, 6 ].
- However, it is known that bacterial infections of the central nervous system can cause changes in cerebrospinal fluid (CSF) composition, including glucose and protein levels.
- Typically, bacterial meningitis is characterized by low CSF glucose levels and elevated protein levels [ 2, 3, 5 ].
- The studies focus on the diagnosis and management of bacterial central nervous system infections, including acute bacterial meningitis, subdural empyema, intracerebral abscess, and ventriculitis [ 2, 3, 5 ].
- They discuss the importance of prompt and adequate antibiotic therapy, as well as neurosurgical interventions in some cases [ 2, 3, 5 ].
- The use of real-time PCR, Gram stain, and culture for diagnosing bacterial meningitis is also discussed, with real-time PCR and Gram stain showing high accuracy and being less affected by antibiotic presence [ 4, 6 ].