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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.
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