ABOUT CSF Cerebrospinal fluid (CSF) was first examined in the 19th century using primitive techniques (eg, sharpened bird quills).

Indications of CSF examination 1.Bacterial, viral or fungal meningitis. 2.Encephalitis. 3.To investigate for Malignant infiltrates eg acute leukemia, lymphoma.

Indication of CSF examination 4. Disorders with local immunoglobulin production in the CNS (multiple sclerosis). 5. Subarachnoid hemorrhage. 6. Spinal canal blockage

Methods of CSF collection  Lumber Puncture  CSF also can be obtained from the cisterna magna by a tap below the external occipital protuberance.

Lumber Puncture: uses Diagnostic and therapeutic uses 1.CSF examination [ diagnostic]  Therapeutic application of LP A.For spinal anesthesia, B.For introduction of radio opaque contrast media (eg, myelography), C.For injection of corticosteroids, antibiotics, and chemotherapeutic agents.

LP : Instruments and procedures

Which space you enter spinal canal ?  LP is performed in the interspaces between the lumbar vertebrae, usually at the L4-L5, or L3-L4 level.

Normal CSF values Cell count: <5 cells / cumm. mononuclears; Glucose: 60-70% of plasma levels (usually) mmol/L Lactate: mmol/L Protein: Full term neonate: g/L adult: g/L IgG/albumin ratio: <0.2

CSF Pressure  Normal range is mm H 2 0  May Increase in Brain Abscess and encephalitis.

Interpretation: acute bacterial meningitis (pyogenic). CSF appearances Cloudy Cell count Increased >1000 cell/cumm Cell Type Neutrophils ProteinNormal-high Sugar Very much Reduced Gram Stain Often Positive Culture Often positive

Viral meningitis CSF appearances Clear Clear Cell count Moderate Increase Cell type Lymphocyte ProteinIncreased SugarReduced CultureNegative

Fungal meningitis: Cryptococcus neoformans Meningitis [ AIDS] CSF appearances Clear or cloudy Cell count increased ( ) increased ( ) Cell type Lymphocytes, macrophage ProteinIncreased Wright Giemsa/India ink Positive of fungus CulturePositive

Other facts  In traumatic Tap = RBCs may be seen.

1. Physical ( macroscopic examination) 2. Chemical Analysis 3. Cytological Analysis

Value of macroscopic Examination  Pseudomonal meningitis may be associated with bright green CSF.  Red Colour if contain RBC ( hemorrhage)  Cob web coagulum = Tuberculosis

Xanthochromia : Intracranial Bleeding  The best way to distinguish RBCs related to intracranial bleeding is examination of the centrifuged supernatant CSF for xanthochromia (yellow color). N

Xanthochromia  Xanthochromia can persist up to several weeks following a subarachnoid hemorrhage

Differential diagnosis : Xanthochromia  Xanthochromia can be produced by spillover from a very high serum bilirubin level (ie, >15 mg/dL).

Chemical Analysis

High Protein  Demyelinating Polyneuropathies  Postinfectious states

Low glucose  Bacterial infection  Tumor infiltration, and may be one of the hallmarks of meningeal carcinomatosis.

Cytological Analysis

Cytological examination  Detection of malignant cells: Carcinoma, lymphoma or leukemia.

Oligoclonal bands; Increased IgG/albumin ratio 1. Demyelinating disorders, esp- Multiple Sclerosis. 2. Guillain-Barré syndrome,

Risk of LP Risk of LP  Post–spinal tap headache  Nerve root trauma (eg, previous surgery in the area, scar tissue)  CNS infection (eg, immunocompromised patients)  Intraspinal hematoma (eg, patients on anticoagulation therapy  Tonsillar Herniation

LP and CSF  In summary, LP and CSF examination, while their indications have been reduced, remain indispensable tools in the armamentarium of neurologic diagnosis.