Here are the normal parameters :
Pressure = 50-180 mmH2O
Color = clear
RBC count = 0-4 x 10^6/L
WBC count = 0-4 x 10^6/L
Glucose = >60% of the serum level
Protein = < 0.45 g/L
Microbiology = sterile//no growth
Subarachnoid haemorrhage :
Pressure increased, bloody, RBC count increased, WBC = normal/increased, glucose = normal, protein = increased, sterile
Acute bacterial meningitis :
Pressure normal/increased, cloudy/turbid, RBC count = normal, WBC = 1000-5000 polymorphs, glucose = decreased, protein = increased, organism present on gram stain/culture
Viral meningitis
Pressure normal, clear, RBC count = normal, WBC = 10-2000 lymphocytes, glucose = normal, protein = normal/increased, sterile/viral DNA or RNA present
Tuberculous meningitis
Pressure normal/increased, clear/cloudy, RBC count = normal, WBC = 50-5000 lymphocytes, glucose = decreased, protein = increased, ZN stain/Auramine stain
Remember this —–>
Elevated CSF protein is seen in infections, intracranial hemorrhages, multiple sclerosis, Guillain Barré syndrome, Syphilis, and malignancies (for our purposes). Low CSF protein is not significant.
High CSF glucose is only caused by high serum glucose (nothing else).
Low CSF glucose can be caused by bacterial and viral infections (although it can also be normal in infections), subarachnoid hemorrhages, and some inflammatory processes.