CERBROSPINAL FLUID
CERBROSPINAL FLUID
Dr. Vijay Marakala, MBBS, MD.BIOCHEMISTRYIMS, MSU.
CERBROSPINAL FLUID
CERBROSPINAL FLUID
CSF is formed by active secretion from the cells of the choroid
plexuses of ventricles of the brain.
CERBROSPINAL FLUID
CERBROSPINAL FLUID
CERBROSPINAL FLUIDBlood Brain Barrier
6There is a secure barrier between the blood and the csf fluids
that surround the brain called the Blood Brain Barrier This barrier
is due to the tight fitting endothelial cells that prevent
filtration of larger moleculesDue to the blood brain barrier, CSF
composition is very different from that of plasma.
And therefore CSF is NOT considered an ultrafiltrate of
plasma.
Tjherefor
Controls / restricts / filters blood componentsRestricts entry
of large molecules, cells, etc.Therefore CSF composition is unlike
bloods**
CERBROSPINAL FLUID ANALYSISTo confirm diagnosis of
meningitisEvaluate for intracranial hemorrhageDiagnose
malignancies, leukemia Investigate central nervous system
disorders
7Four categories of disease lead to 4 Indications for
analysis
CSF us analyzed To confirm diagnosis of meningitis , Evaluate
for intracranial hemorrhage, to Diagnose malignancies, and leukemia
and to Investigate central nervous system disorders
CERBROSPINAL FLUID ANALYSIS
You will be studying in year 2Pathology and Microbiology
CERBROSPINAL FLUID - COLLECTIONCSF can be collected by passing a
lumbar puncture needle between the 3rd and 4th or 4th and 5th
lumbar vertebrae into subarachnoid space.
CERBROSPINAL FLUID - COLLECTION
11
As the spinal fluid is removed it is collected into a series of
tubes. The tubes are numbered to indicate how the fluid was
removed. In other words, The first fluid that is removed will go
into tube 1, the next amout of fluid will be in tube 2 and so
forth.
Usually 3 tubes are collected, but sometimes you will see four
tubes.
Tube 1 chemistries and serologyTube 2 microbiology culturesTube
3 hematology
If there was a 4 th tube, usually the first tube is set aside
tube number 2 then becomes tube 1, tube 3 becomes number 2. Sounds
confusing, but every thing just slides down a number.Keep in mind
that the goal is to have the hematology tube be the last sample
removed, so any cells present can be definitely said to have come
from the spinal cannal and not a result of a traumic stick.
All csf Testing considered STAT and always keep in mind that csf
samples are potentially infectious
CERBROSPINAL FLUID NORMAL CSFColour and appearance Clear,
colourless, no coagulum or depositSpecific gravity 1.006 to
1.007Cells 0 to 4 mononuclear cells per cubic mmpH7.3 7.4Protein10
to 45mg per 100mlGlucose 40 to 80mg per 100 mlChloride120 to 130
mmol per litreUrea10-40mg per 100mlCalcium 5.5 to 6mg per 100ml
The biochemical composition of CSF is slightly different from
that of plasma
CERBROSPINAL FLUID - APPEARANCENormally, CSF is perfectly clear,
colourless, and transparent.
CERBROSPINAL FLUIDFINDING IN CSFTRAUMATIC TAPSUBARACHNOID
HEMORRHAGEXanthochromiaAbsent (unless CSF protein >150 mg/dl or
severe jaundice)Typically present if duration over 2-12
hoursClottingMay occur (incubate at 37C)Absent Gross BloodTypically
varies from tube to tube (greatest in Tube #1)Usually uniform in
all tubesCSF PressureUsually normalElevatedRepeat puncture in
higher interspaceOften clearSimilar to initial tap
DIFFERENCES BETWEEN TRAUMATIC TAP AND SUBARACHNOID
HEMORRHAGE
CERBROSPINAL FLUID - Protein
Predominant is Albumin fraction. Decreased levels not
significant Increases levelsDamaged Blood Brain barrier (as in
meningitis or hemorrhage)Production of immunoglobulins within CNS
(MS) Degeneration of neural tissueNormal 15 45 mg/dL . Albumin:
56-76%1-Globulin: 2-7%2-Globulin: 3.5-12%-and IgG-globulin:
8-18%IgG: 7-12%
15Cerebrospinal Fluid (CSF) protein
The first of the CSF chemistriys to discuss is the protein
CSF proteins normal value is very low, as compared to serum or
plasma. The csf protein normal range is 15 45 mg/dL . In normal
situations, albumin is the only protein fraction found.
The presence of the IgG gobulin fraction brings about the
concern of whether it came from a damage in the blood- brain
barrier or whether it was produced within the central nervous
system it self.
Protein electrophoresis is one method used to identify the
presence of an oligoclonal meaning few or small clone or /
malignant bands.Decreased levels of csf protein are not
significant, the pathology lies finding an abnormally increased
protein level.
CSF protein is best measured by a Dye-binding methods where the
protein will couple with a dye or other molecule that can be easily
measured in a spectrphotometer.
The Alkaline biuret procedure has been used, but Coomassie
brilliant blue procedure is preferred. In this procedure - a blue
color produced is proportional to the amount of protein present (
and follows Beers Law)
CERBROSPINAL FLUID - GLUCOSESelectively transported across
blood-brain barrierNormal values: 60-70% of blood glucoseGlycolysis
reduces level quickly.Procedure performed as for blood specimen
-GLUCOSE OXIDASE PEROXIDASE METHODDecreased levels seen in
bacterial & fungal meningitisHypoglycemiaBrain
tumorsLeukemiaDamage to CNS
Normal 45 80 mg/dL .
16The next csf chemistry test is glucose
Glucose is Selectively transported across blood-brain
barrierNormal csf glucose level is @ 60-70% of the patients current
blood glucose.It is very important that the csf glucose be analyzed
quickly . As any organisms or cells present in the csf will quickly
reduce the glucose level. When testing, the patients blood glucose
should also be tested in parallel to provide a reference or
expected value.
The csf glucose Procedure is performed in the same manner as for
blood specimenDecreased levels of CSF glucose are part of the
hallmark findings seen in bacterial & fungal meningitis
A patient who is hypoglycemic ( has low blood sugar) will have
low CSF glucose. Other reasons for decreased CSF glucose include
Brain tumors, Leukemias and as a result of Central nervous system
damage.
Bacterial MeningitisViral MeningitisTuberculous MeningitisBrain
TumorProteinIncreasedNormalIncreasedIncreasedGlucoseDecreasedNormalorslightly
affectedDecreasedDecreased
CERBROSPINAL FLUID
CERBROSPINAL FLUID - CHLORIDEBacterial infection 600-700 mg%
Viral infection moderately decreased3) Fungal infection Normal or
slightly decreased 4) Acute purulent meningitis 600-700 mg%5)
Tubeculous meningitis 500-600 mg%
6) Brain tumour Normal or slightly decreased7) Brain tumour
Normal 8) Acute syphilitic meningitis Normal (globulin normal)9)
Encephalitis lethargic Normal 10) Cerebral hemorrhage Normal
Normal 120 to 130mmol/l or 600 to 700mg/dl .
