FACULTY OF MEDICAL AND
HEALTH TECHNOLOGY
Medical Laboratory Technology
department
Lecture - 3 - CSF
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CSF
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The cerebrospinal Fluid [CSF] is a clear, colorless
transparent, tissue fluid . present in the cerebral
ventricles, spinal canal, and subarachnoid spaces.
Source:
CSF is formed in the ventricular choroid plexuses in
the brain by both active secretion and ultrafiltration
from plasma(70%)
30% of CSF is formed as interstitial fluid within the
intercellular spaces of the brain and spinal cord
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Function of cerebrospinal fluid
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• mechanic protection of brain and spinal
cord . protection against microorganisms
• transport of biomolecules to the brain
• clearance of catabolites (CO2, lactate)
• maintenance of constant intracranial
pressure
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Sample collection
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Spinal fluid is normally obtained from the
lumbar region
Procedure of sampling:
The skin of the lumbar region cover the space
between third and fourth or fourth and fifth lumbar
vertebrae should be thoroughly cleaned and a small
bleb is made in the skin with 2% procaine then a
spinal needle is introduced into the spinal canal
through the bleb
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Sample collection
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Then, 3-4 ml are allowed to drip into plain
tubes.:
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The first tube should be for chemical and serological
tests ( specimen may be contaminated with cell
debris or skin bacteria)
The second tube for microbiological tests (should be
sterile)
The third tube for microscopic and cytological tests
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Physical examination
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Color
Specific gravity
Reaction
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Cells
Pressure
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Clear
1.004-1.007
Alkaline and does not
coagulate
0-3/ cmm
90~180 mm of H2O in adults
10-100 mm of H2O in children
or
80-180 mmHg
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Physical examination
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1. normal CSF is clear with appearance and
viscosity comparable to water.
Cloudy or turbid CSF may be dt leukocytes,
erythrocytes, microorganisms, radiographic contrast
media
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2. Colour: gross blood may be dt traumatic or
bleeding subarachnoid or intra cerebral
hemorrhage.
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Elevated pressure
Congestive heart failure
Infection (cryptococcal meningitis), tumor
Cerebral edema
Mass lesion
 Decreased pressure
Spinal-subarachnoid block
Dehydration
Circulatory collapse
CSF leakage
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Proteins
Glucose
Cholesterol
Na+
Ca+
Urea
Creatinine
Lactic acid
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20-40 mg/dl
50-80 mg/dl
0.2 mg/dl
147 meq/Kg
2.3 meq/kg
12.0 mg/dl
1.5 mg/dl
10-22 mg/dl ml
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Chemical examination
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1. CSF protein:
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It is an ultrafilterate of plasma through walls of
capillaries in meningies and choroid plexuses
Spinal fluid protein ranges from 20-45 mg/dl in
adults with higher levels in neonates dt immaturity
of blood-CSF barrier
CSF proteins include low molecular wt plasma
proteins e.g prealbumin, albumin and transferrin
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CSF proteins increase
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Increased permeability of blood-CSF barrier
(traumatic injury, intrcerebral hemorrhage,
meningitis)
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Increased synthesis of immunoglobulins in csf
(e.g. multiple sclerosis)
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Chemical examination
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2. CSF glucose:
Normally is 50-65% of blood glucose
In viral infection glucose normal
Decreased CSF glucose may be dt bactrerial
meningitis, hypoglycemia, subarachnoid
hemorrhage, tumors, TB, fungal ….
Increased levels is dt Diabetes mellitus, DM
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Chemical examination
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3. CSF lactate
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Independent of blood lactate level
Dt anaerobic metabolism
Adult levels is about 10-22mg/dl
Is used to Defrantited bacterial , tuberculous from
viral meningitis as it is elevated in bacterial,
tuberculous and fungal meningitis only
Elevated also in severe head injuries
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Chemical examination
4. CSF chloride:
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Reflects only blood chloride level
Decreased in tuberculous meningitis
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5. CSF lactate dehydrogenase (LDH)
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Normally very much lower than serum activity.
LD 5 isoenzyme is increases in brain metastatic
tumors while total LDH activity increase in primary
brain tumors
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Relationship number of elements –
total protein
• Protein-cytologic dissociation –
increased total protein, normal number of elements, present in
tumours and blockade of CSF circulation –compressive
syndrome, late phase of chronic neuroinfections
• Cyto-protein dissociation
– in early – acute phase of meningities
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• Protein-cytologic association –
elevation of both proteins and elements
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