Cerebrospinal fluid(1)

8/7/2019 Cerebrospinal fluid(1)

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Cerebrospinal fluidCerebrospinal fluidFormation and PhysiologyFormation and Physiology

~First recognized by Cotugno in 1764, CSF is the third major

fluid of the body.

PHYSIOLOGIC SYSTEM1. To supply nutrients to the nervous system

2. To remove metabolic wastes

3. To produce a mechanical barrier to cushion the brain and

spinal cord against trauma.

MENINGES LAYERS

1. Dura mater - outer layer

2. Arachnoid mater - middle layer

3. Pia mater - inner layer


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CSF flows through the subarachnoid spacebetween the arachnoid and pia mater

20 ml of fluid produced every hr in choroids

plexus and reabsorbed by arachnoid villi


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Specimen Collection and handling

CSF is collected by lumbar puncture between third,fourth, fifth lumbar vertebrae. It requires certain precautions

and careful technique to prevent the introduction of

infection or the damaging of neural tissue.

CSF usually collected in three sterile tubesLabel 1 / Tube 1 used for chemical and serologic test

( tubes are frozen)

Label 2 / Tube 2 used for microbiology lab

( room temp.)Label 3 / Tube 3 used for hematology (cell count)

( refrigerated)


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APPEARANCEAPPEARANCE

Major terminology used to describe CSF appearance:Major terminology used to describe CSF appearance:

Crystal clearCrystal clear Cloudy or turbidCloudy or turbid result of an increased protein or lipidresult of an increased protein or lipid

conc/presence of WBCconc/presence of WBC

milkymilky

hemolyzed / bloodyhemolyzed / bloody

xanthochromicxanthochromic supernatant is pink, orange, or yellowsupernatant is pink, orange, or yellow

1.1. pinkpink very slight amount of oxyhemoglobinvery slight amount of oxyhemoglobin

2.2. orangeorange heavy hemolysisheavy hemolysis

3.3. yellowyellow conversion of oxyhemoglobin to unconjugatedconversion of oxyhemoglobin to unconjugated

bilirubinbilirubin* other causes:* other causes:

Elevated serum bilirubinElevated serum bilirubin

Presence of the pigment carotenePresence of the pigment carotene

Markedly increase protein concMarkedly increase protein conc

Melanoma pigmentMelanoma pigment


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TRAUMATICCOLLECTIONTRAUMATICCOLLECTION

Grossly bloody CSF can be an indication of intracranialGrossly bloody CSF can be an indication of intracranial

hemorrhage or due to the puncture of a blood vessel duringhemorrhage or due to the puncture of a blood vessel duringspinal tap procedure (traumatic tap)spinal tap procedure (traumatic tap)

UNEVEN DISTRIBUTIONOF BLOODUNEVEN DISTRIBUTIONOF BLOOD

From the three test tubes whereas the heaviestFrom the three test tubes whereas the heaviestconcentration of blood was in the first tube then graduallyconcentration of blood was in the first tube then gradually

diminishing amounts in tube 2 and 3.diminishing amounts in tube 2 and 3.

CLOT FORMATIONCLOT FORMATION

Meningitis, Froins syndrome, and blockage ofCSFMeningitis, Froins syndrome, and blockage ofCSFcirculation through subarachnoid spacecirculation through subarachnoid space

XANTHOCHROMICSUPERNATANTXANTHOCHROMICSUPERNATANT Additional testing for differentiation includesAdditional testing for differentiation includes microscopicmicroscopic

examination and the Dexamination and the D--dimer testdimer test


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CELLCOUNTCELLCOUNT

RBC and WBC countRBC and WBC count

METHODOLOGYMETHODOLOGY

Normal adultNormal adult 00 5 WBCs/L5 WBCs/L ChildrenChildren 30 mononuclear cells/L ( 200WBC/ 400RBCs)30 mononuclear cells/L ( 200WBC/ 400RBCs)

TOTALCELLCOUNTTOTALCELLCOUNT

WBCCOUNTWBCCOUNT

CORRECTIONS FORCON

TAM

INA

TIONCORREC

TIONS FORCON

TAM

INA

TIONQUALITYCONTROLOF CSF AND OTHERBODY FLUIDQUALITYCONTROLOF CSF AND OTHERBODY FLUID

CELLCOUNTSCELLCOUNTS

DIFFERENTIALCOUNTONACSF SPECIMENDIFFERENTIALCOUNTONACSF SPECIMEN

Identifying the types of cells in the CSF is a valuable diagnosticIdentifying the types of cells in the CSF is a valuable diagnosticaid.the differential count should be performed on a stained smearaid.the differential count should be performed on a stained smearand not from the cells in the counting chamber. Poorand not from the cells in the counting chamber. Poorvisualization of the cells as they appear in the counting chambervisualization of the cells as they appear in the counting chamberled to the laboratory practice of reporting only the percentage ofled to the laboratory practice of reporting only the percentage ofmononuclear and polynuclear cells present.mononuclear and polynuclear cells present.


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CSF CONSTITUENTSCSF CONSTITUENTS

Cells found in normal CSF are lymphocytes andCells found in normal CSF are lymphocytes andmonocytesmonocytes

Pleocytosis is considered abnormal cells.Pleocytosis is considered abnormal cells. WBC count majority of the cells are neutrophilsWBC count majority of the cells are neutrophils

considered bacterial meningitis.And if moderatelyconsidered bacterial meningitis.And if moderatelyhigh percentage o flymphocytes and monocytes,high percentage o flymphocytes and monocytes,meningitis of viral, tubercular, fungal, or parasiticmeningitis of viral, tubercular, fungal, or parasiticorigin.origin.


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CSF SERUM RATIO

mg/dl mg/dl

Prealbumin 1.7 23.8 14

Albumin 15.5 3600 236

Ceruloplasmin 0.1 36.6 366

Transferrin 1.4 204 142

ImmunoglobulinG

1.2 987 802

Immunoglobulin

A

0.13 175 1346

CSF PROTEIN


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CLINICALSIGNIFICANCE OF ELEVATED PROTEINVALUESCLINICALSIGNIFICANCE OF ELEVATED PROTEINVALUES

Elevated total protein values are most frequently seen inElevated total protein values are most frequently seen in

pathologic conditions.Abnormally low values will be presentpathologic conditions.Abnormally low values will be presentwhen fluid is leaking from the CNS. Cause of elevated CSFwhen fluid is leaking from the CNS. Cause of elevated CSFprotein include the damage to the blood brain barrierprotein include the damage to the blood brain barrier

Protein fractionsProtein fractions

ElectrophoreseisElectrophoreseis

Myelin basic proteinMyelin basic protein

CSF GLUCOSECSF GLUCOSE

Glucose enters the CSF by selective transport across the bloodGlucose enters the CSF by selective transport across the blood--brainbrainbarrier, which result in a normal value that is approximately 60barrier, which result in a normal value that is approximately 60 7070percent that of the plasma glucose. The diagnostic significance ofCSFpercent that of the plasma glucose. The diagnostic significance ofCSF

glucose is confined to the finding of values that decreased in relation toglucose is confined to the finding of values that decreased in relation toplasma values.low CSF glucose can be considerable diagnostic value inplasma values.low CSF glucose can be considerable diagnostic value indetermining the causative agents in meningitis.determining the causative agents in meningitis.


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CSF LACTATECSF LACTATE The determination ofCSF lactate levels aid in the diagnosis andThe determination ofCSF lactate levels aid in the diagnosis and

management of meningitis cases. In bacterial, tubercular and fungalmanagement of meningitis cases. In bacterial, tubercular and fungalmeningitis.elevations ofCSF lactate greater than 25mg/dl. Destruction ofmeningitis.elevations ofCSF lactate greater than 25mg/dl. Destruction oftissue within the CNS owing to oxygen deprivation (hypoxia) causes thetissue within the CNS owing to oxygen deprivation (hypoxia) causes theproduction of increaded CSF lactic acid levels.production of increaded CSF lactic acid levels.

CSF GLUTAMINECSF GLUTAMINE

Glutamine is produced in the CNS by the brain cells from ammoniaGlutamine is produced in the CNS by the brain cells from ammonia

and alphaand alpha--ketoglutarate. This process serves to remove the toxicketoglutarate. This process serves to remove the toxicmetabolic waste product ammonia from the CNS. Normal concentrationmetabolic waste product ammonia from the CNS. Normal concentrationof ammonia is 8of ammonia is 8--18 mg/dl. Elevated levelsassociated with liver18 mg/dl. Elevated levelsassociated with liverdisorders.disorders.

CSF ENZYMESCSF ENZYMES LDHLDH LD1, LD2, LD3, LD4, LD%LD1, LD2, LD3, LD4, LD% CKCK BBBB


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MICROBIOLOGYTESTMICROBIOLOGYTESTFor positive identification, the microorganism must be recoveredFor positive identification, the microorganism must be recovered

from the fluid by growing it on the appropriate culture medium. Can takefrom the fluid by growing it on the appropriate culture medium. Can take24 hrs I cases of bacterial meningitis to 6 weeks for tubercular meningitis.24 hrs I cases of bacterial meningitis to 6 weeks for tubercular meningitis.In many instances, CSF culture is actually a confirmatory testIn many instances, CSF culture is actually a confirmatory test

GRAM STAINGRAM STAINIs routinely performed on CSF from all suspected cases of meningitisIs routinely performed on CSF from all suspected cases of meningitis

although its value lies on the detection of bacterial and fungal organisms.although its value lies on the detection of bacterial and fungal organisms.

Organisms most frequently encountered:Organisms most frequently encountered:

S. pneumoniae (gram positive cocci)S. pneumoniae (gram positive cocci)

H. influenzae ( pleomorphic gram negative rods)H. influenzae ( pleomorphic gram negative rods)

E. coli (gram negative rods)E. coli (gram negative rods)


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AcidAcid--fast is not routinely performed onfast is not routinely performed on

specimens unless tubercular menoingitis isspecimens unless tubercular menoingitis issuspected.suspected.

Latex Agglutination and ELISA provides aLatex Agglutination and ELISA provides arapid means for detecting microorganisms inrapid means for detecting microorganisms in

CSF.CSF.


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SEROLOGICTESTINGSEROLOGICTESTING

Serologic testing of the CSF is performed to detect theSerologic testing of the CSF is performed to detect the

presence of neurosyphilis. However, detection of thepresence of neurosyphilis. However, detection of theantibodies associated with syphilis in the CSF still remains aantibodies associated with syphilis in the CSF still remains anecessary diagnostic procedure.necessary diagnostic procedure.

Serologic tests:Serologic tests: VDRLVDRL FTAFTA ABSABS

TEACHINGCSF ANALYSISTEACHINGCSF ANALYSISMany of the problems that occur in the analysis ofCSFMany of the problems that occur in the analysis ofCSF

are result of inadequate training of the personnel performingare result of inadequate training of the personnel performingthe tests. This is considered that not only is CSF is difficultthe tests. This is considered that not only is CSF is difficultto collect.to collect.

Cerebrospinal fluid(1)

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