Cerebrospinal fluid is a clear fluid circulation in and around the brain, spine and meninges. It helps supply nutrients and remove waste materials like amino acids etc. The composition of CSF is maintained by many mechanisms. Many diseases, especially infections can alter the constitution of CSF. Normal constitution of CSF is given below:
Parameter |
Normal Range |
Opening pressure |
7-18 |
Appearance |
Clear, colorless |
Protein (mg/Dl) |
23-38 |
Glucose (mmol/L) |
2/3rds serum glucose |
Gram stain |
Negative |
White cell count |
<5 cells |
When a person is affected by brain infection, it can change the values of parameters of CSF. CSF is withdrawn by lumbar puncture to check for the type of infection. Treatment depends on the results of this CSF analysis.
Parameter |
Normal Range |
Viral CNS Infection |
Bacterial CNS infection |
Opening pressure |
7-18 |
Normal or mildly increased |
>30 |
Appearance |
Clear, colorless |
Clear |
Turbid |
Protein (mg/Dl) |
23-38 |
Normal to decreased |
Increased |
Glucose (mmol/L) |
2/3rds serum glucose |
Normal |
Decreased |
Gram stain |
Negative |
Negative |
Positive in 61% cases |
White cell count |
<5 cells |
Lymphocytes raised |
Neutrophils raised |
If red blood cells ae seen in CSF, it is suggestive of bleeding (e.g subarachnoid hemorhage) or HSV encephalitis. Further microbiological tests will confirm the type of infection e. g PCR can confirm the type of infection.
Written by Dr Vaishalee Punj