E. Normal CSF result – Explanation
| There results are consistent with normal CSF – an alternative diagnosis should be considered |
Meningitis: CSF analysis
The table below summarises the characteristic cerebrospinal fluid (CSF) findings in meningitis:
| Bacterial | Viral | Tuberculous | |
| Appearance | Cloudy | Clear/cloudy | Fibrin web |
| Glucose | Low (< 1/2 plasma) | Normal* | Low (< 1/2 plasma) |
| Protein | High (> 1 g/l) | Normal/raised | High (> 1 g/l) |
| White cells | 10 – 5,000 polymorphs/mm3 | 15 – 1,000 lymphocytes/mm3 | 10 – 1,000 lymphocytes/mm3 |
The Ziehl-Neelsen stain is only 20% sensitive in the detection of tuberculous meningitis and
therefore PCR is sometimes used (sensitivity = 75%)
*mumps is unusual in being associated with a low glucose level in a proportion of cases. A low
glucose may also be seen in herpes encephalitis
| Serum glucose 4.9 mmol/l |
Lumbar puncture reveals:
| Opening pressure | 14 cmCSF |
| Appearance | Cloudy |
| Glucose | 1.7 mmol/l |
| Protein | 1.9 g/l |
| White cells | 900 / mm3 (90% polymorphs) |
