Table 3.
CSF FINDINGS IN BACTERIAL, VIRAL, TUBERCULOUS, AND FUNGAL MENINGITIS
| Bacterial meningitis | Viral meningitis | Tuberculous meningitis | Fungal meningitis | |
|---|---|---|---|---|
| Protein | Elevated | Mildly elevated | Elevated | Elevated |
| Glucose | <50% blood glucose | Normala | <50% blood glucose | <50% blood glucose |
| Cells | Polys | Lymphs or lymphs+polysb | Lymphs+polys | Lymphs |
| Other | Gram stain, culturec | PCR (viral culture) | AFB stain culture (20 ml CSF) | India ink prep cryptococcal Ag culture (20 ml CSF) |
| PCR | PCR |
a
CSF glucose may occasionally be depressed in meningitis due to mumps, lymphocytic choriomeningitis virus, or herpes zoster.
b
CSF during the first 24 hr of viral meningitis may contain a mixture of lymphocytes and polymorphonuclear leukocytes. In these cases, in contrast to bacterial meningitis, CSF glucose is usually normal and follow-up lumbar puncture 24 hr later will often but not always show lymphocytes only.
c
Positive Gram's stain requires approximately 105 colony-forming untis (CFU)/ml of CSF. Approximately 25% of Gram's stains will be positive if CSF contains 103 CFU/m. Prior antibiotic treatment will reduce this amount by 20%.