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It is produced principally in choroid plexus of each lateral ventricle , exists the brain via the foramine luschka & magendi and flows over cortex to be absorbed into the venous system along the sagittal sinus.

Approx 150ml is produced.

Protein

• Elevated protein are seen in bacterial, crytpotococcal, tuberculous meningits & neuroborreliosis.In viral meningitis protein is raised to a lesser degree.

• Non infectious causes includes SAH, CNS Vasculitis, Neoplasm.

• Proteins are elevated in 80% of patients with leptomeningeal mets.

• Albuminocytologic dissosciation is a hallmark in AIDP &CIDP.

• NPH, Spinal stenosis, polyneuropathy and high BMI is assosciated with increased CSF serum albumin quotient.

Oligoclonal Bands

• The detection of intrathecal oligoclonal IgG in CSF is useful for diagnosis for MS. It is also used in assisting paraneoplastic disorder, ADEM and CNS infection.

Cytological Examination

• It should be performed within 2h after puncture, preferably within 30min because of lysis of RBC and WBC.

CSF Glucose concentration & CSF/serum glucose ration & Ratio

• A CSF/S. Glucose ratio less than 0.4 – 0.5 is considered to be pathological.

• Increased lactate levels indicates bacterial and fungal infection.

Reference

• Harrison

• Routine CSF Analysis ; European Handbook of Neurological Management