04/08/23 1E. S. MOKGWANE; 4TH YR MED

CHARECTERISTICS OF NORMAL CSFTotal Volume: 150mlColour: colourless, like waterTransparency: clear, like waterOsmolality at 37o C: 281mOsm/LSpecific Gravity: 1.006 to 1.008Presure: 80-100 mm H2O

04/08/23 2E. S. MOKGWANE; 4TH YR MED

ACID-BASE BALANCEpH 7.31pCO2 47g mmHgHCO3 22g mEq/LSodium 138 – 150 mEq/LPotassium 2.7 to 3g mEq/LChloride 116 to 127 mEq/LCalcium 2.0 to 2.5 mEq/LMagnesium 2.0 to 2.5 mEq/LLactic Acid 1.1 to 2.8 mmol/L

04/08/23 3E. S. MOKGWANE; 4TH YR MED

APPEARANCE1. BRIGHT RED

•Recent haemorrhage involving the subarachnoid

•Damage to a blood vessel during puncture

04/08/23 4E. S. MOKGWANE; 4TH YR MED

APPERANCE

2. XANTHOCROMIA•Suggests subarachnoid haemorrhage in

recent past (days).

Rarely Xanthochromia may be due to:• Severe Jaundice• Carotenaemia• Rifampicin

04/08/23 5E. S. MOKGWANE; 4TH YR MED

APPERANCE

3. TURBID

white cells presentsuggest bacterial infection.

04/08/23 6E. S. MOKGWANE; 4TH YR MED

APPERANCE

4. PIGMENTS• Oxyhaemoglobin – Released with lysis of red

cells detected in the supernatant fluid within 2h after SAH.

• Bilirubin – maximum at 48hrs after SAH.

04/08/23 7E. S. MOKGWANE; 4TH YR MED

TOTAL PROTEIN

0.5% or 1/200 that of plasmaTypical reference values for a lumbar tap:Age g/L<1 month <1.91-3 months <0.953-12 months <0.51-10 years <0.4>10 years <0.7

04/08/23 8E. S. MOKGWANE; 4TH YR MED

TOTAL PROTEIN IS RAISED IN:

1. Infection (white cells, pus) e.g. bacterial meningitis

2. Blood Contamination3. Chronic inflammatory diseases of the CNS.4. Froin’s syndrome5.Lysis of contaminated blood from traumatic tap6.Increased permeability of the epithelial

membrane7.Increased production by CNS tissue

04/08/23 9E. S. MOKGWANE; 4TH YR MED

DECREASED CSF GLUCOSE

• Disorder in carrier –mediated transport of glucose into CSF

• Active metabolism of glucose by cells or organisms

• Increased metabolism by CNS eg Brain tumor, diffuse, meningeal neoplasia.

04/08/23 10E. S. MOKGWANE; 4TH YR MED

SUMMARY OF A TYPICAL CSF FINDINGS

NORMAL BACTERIA VIRAL TB

Cells 0-5 >1000 <1000 <500

Polymorphs 0 Predominate

Early +/- Increased

Lymphocytes

5 Late Predominate

Increased

Glucose 60-80 Decreased Normal Decreased

CSF Plasma: Glucose ratio

66% <40% Normal <30%

Protein 5-40 Increased +/- Increased

Increased

Culture Negative Positive Negative +TB04/08/23 11E. S. MOKGWANE; 4TH YR MED

END

04/08/23 12E. S. MOKGWANE; 4TH YR MED