B IOCHEMISTRY P RACTICAL By: Dr. Beenish Zaki

CSF A NALYSIS

C EREBROSPINAL FLUID The surface of the central nervous system is covered by the meninges: Duramater Arachnoid Piamater. The space between arachnoid and piamater is called sub-arachnoid space. CSF is secreted by the choroid plexuses. In normal healthy adults rate of CSF formation is ml/24hrs.

CSF FORMATION AND CIRCULATION

SITE OF WITHDRAWL CSF is withdrawn by a procedure called lumbar puncture. Spinal cord ends near the first lumbar vertebra. CSF is obtained by passing Lumbar Puncture (L.P) needle between L4-L5. Second preferred site is L3-L4 into the sub- arachnoid space.

SITE OF LUMBAR PUNCTURE

NORMAL COMPOSITION: Colour : Clear colorless; no coagulum or deposit PH : 7.3 Pressure: mm of Hg Specific gravity: Cells : 0-4 mononuclear cells/mm 3 Protein content: 10-45mg/dl Globulins: absent Glucose: mg/dl Chlorides: meq/l

M EASURING OPENING PRESSURE

ABNORMALITIES In appearance Blood stained a)Due to traumatic tap RBC under microscope have normal shape b) In pathological conditions like sub-arachnoid haemorrhage in this blood is homogeneously mixed with CSF under microscope RBC have a crenated appearence.

ABNORMALITIES C ONT ’ In appearance Xanthochromia:-Yellow colorization of CSF due to either: bilirubin Carotenoids Turbidity :- is due to presence polymorphs/mm 3 Coagulum:- In tuberculosis meningitis cob-web like coagulum is seen if the fluid is allowed to stand overnight from the web tubercle bacilli can be examined easily under microscope.

ABNORMALITIES C ONT ’ In Glucose CSF glucose is increased in :- Diabetes Encephalitis Cerebral abscess CSF glucose is decreased in :- Meningitis due to bacteria. The glucose reduces from the fluid because the organisms are glycolytic and thus use up the glucose.

A CASE A 19 year old student presents with fever, headache, nausea, vomiting. On examination there is neck stiffness.

INDICATION FOR CSF COLLECTION CSF infection Hemorrhage Malignancy Demyelinating Diseases

CSF PROTEINS ESTIMATION

M ETHOD AND P RINCIPLE Method: Turbidity Method Principle: Proteins are precipitated with Trichloro acetic acid which gives a turbidity.

P ROCEDURE ProcedureBlank(ml)Test(ml) Sample-1.00 Reagent TCA Mix well and take reading immediately using green filter

O BSERVATION AND C ALCULATION O.D of Test= O.D of Standard=0.16 Concentration of sample = O.D Test X concentration of standard (mg/dl) O.D Standard O.D Test x O.D-Optical Density

R EFERENCE RANGE A ND C LINICAL C ONDITIONS Adult: mg/dl CSF Protein Increased in: Meningitis Meningoma Acoustic Neuroma Multiple Sclerosis CSF Protein Decreased in: Malnutrition

CSF C HLORIDE ESTIMATION

M ETHOD AND P RINCIPLE Method: Titration Method Principle: Chlorides present in CSF reacts with Silver nitrate to form silver chloride this reacts with the indicator to form a colored complex

P ROCEDURE Pipette 1ml of CSF and 2ml of distilled water into a conical flask. Add 3 drops of potassium chromate as the indicator. Titrate against silver nitrate in the burette to a faint brick red color which is the end point.

O BSERVATION AND C ALCULATION Initial Reading= Final Reading= Concentration of sample: mEq. Chloride per liter of CSF= ml of silver nitrate solution required x 30 mEq/L= Milliequivalent/L

R EFERENCE RANGE A ND C LINICAL C ONDITIONS Adult: mEq/L CSF Chloride Increased in: Hypertension Renal disease CSF Chloride Decreased in: Meningitis

T HANK YOU !