3. Introduction
CSF is the fluid surrounding the brain and
spinal cord.
This fluid is clear, watery liquid that protects
the CNS from injury and cushions it from the
surrounding bone structure.
It contains variety of Substances such as
Glucose, Protein, and WBCs from immune
system.
4. History
CSF was 1st examined in 19th century using
primitive techniques e.g. sharpened bird
quills.
CSF Analysis reached at its peak in 1950-60s
when no workup of a significant CNS problem
was performed without a lumbar Puncture.
Advent of sophisticated imaging techniques
particularly CT Scan and MRI, LP is no longer
an important test of most intra-caranial mass
lesion.
LP remains a critical procedure in the
diagnosis of CNS infections and Inflammatory
disease.
5. Purpose
The purpose of CSF analysis is to diagnose
medical Disorders that affect the CNS.
Viral and Bacterial Infections.
Tumors of Nervous System.
Syphilis, a Sexually transmitted disease.
Bleeding around the brain and spinal cord.
Multiple sclerosis,a disease that affects the myelin
coating of the nerve fibers.
Guilain-Barre syndrome,an inflammation of the
nerves.
6. Sample Collection
The Process to remove the CSF is called as
Lumber Puncture or spinal tap.
In rare cases such as spinal fluid blockage in
the middle of the back, doctor may perform a
Spinal Tap in the neck.
The Sample is drawn from the vertebrae
known as the L4-5 is preferable because the
spinal cord stops near L2 and the needle
introduce below this level will miss the Spinal
cord & encounters only nerve roots.
7. Sample Collection (Contd..)
A lumber Puncture takes about 30
minutes.
If the Patient has spinal arthritis or
obese ,it may be necessary to introduce
the spinal needle using x-ray guidance.
In Order to get an accurate sample of
CSF it is critical that a patient is in the
proper position.
8. Sample Collection (Contd..)
During a LP the doctor drapes the back with a
sterile covering.
The doctor inserts a hollow thin needle in the
space b/w two vertebrae of the lower back
and slowly advances it towards the Spine.
A steady flow of CSF normally the color of
water will begin to fill the needle as soon as it
enters the spine canal.
The doctor measures the CSF pressure with
a special instrument called a Manometer an
withdraw several vials of fluid for lab analysis.
9. Sample Collection (Contd..)
Patients can perform their normal
activities before a lumber puncture.
After the procedure the doctor covers
the site of the puncture with a sterile
bandage.
11. Risks
For most people the most common side effect
after the removal of CSF is headache.
10-30% of adult patients.
Up to 40 % of children.
It is caused by decreased CSF pressure.
A Stiff neck and nausea may accompany the
headache.
LP headache typically begins within 2 days
after the procedure and persist for few days
to several weeks.
Control of Pain by Several medication
containing Caffeine.
12. Precautions
A LP to withdraw a Small Amount of
CSF for analysis may lead to serious
complications.
LP should be performed with extreme
cautions.
People who have blood clotting or
bleeding disorders LP can cause
bleeding that compress the spinal cord.
13. CSF Lab Examination
Examination of the CSF can provide
important diagnostic information when there
is reason to suspect there has been trauma
or a non traumatic insult to the CNS.
Disorders that can be evaluated by
examination of the CNS are intracranial
hemorrhage infections, sclerosis, GuillainBarre syndrome and neurosyphilis.
14. Analysis
Like other body fluids, the CSF provides
a sample for analysis that often reveals
biochemical and cellular changes
reflective of disease processes.
Analysis of the cerebrospinal often
provides the evidence needed by the
physician
to
initiate
appropriate
treatment.
15. Color and appearance
Normal CSF should be clear and colorless.
Any coloration or cloudiness of the CSF is
considered abnormal.
Colors observed include white or pearlescent,
red, pink, orange and yellow.
Red of pink indicates the presence of blood.
16. Cell count
Both leukocyte and RBC counts are
performed on the CSF.
Normal spinal fluid usually contain fewer than
five to eight leukocytes per cubic mm (these
ranges vary from lab to lab).
Increase numbers of leukocytles indicate an
infectious process.
Increased numbers of RBC may indicate a
hemorrhage or a traumatic condition.
17. Leukocyte-differential
This procedure is referred to as the
leukocyte or white cell differential.
Most labs perform the differential while
performing the cell count on the
hemacytometer, differentiating on the
polynuclear and mononuclear cells.
Most patients with bacterial infections
will demonstrate increased numbers of
neutrophils while those with fungal,
tubercular and viral infection will have
increase numbers of lymphocytes.
18. Leukocyte-differential (Contd..)
The differential may also reveal other
cell types that may be of interest in
diagnosing certain conditions.
Appearance of CSF may indicate the
presence of a tumor.
Plasma cells may be observed in
several different disorders, including
multiple sclerosis and tuberculous
meningitis.
20. Gram stain and culture
A Gram’s stain is performed on almost all
cerebrospinal fluid samples.
Cultures are also set up in order to retrieve
and identify organisms present in the CSF.
If
the
physician
suspects
a
viral,
mycobacterial, or rickettsia organism, it is
important that special culture techniques be
followed for isolation of these organisms.
21. Chemical analysis
Chemical analysis are important in
helping to establish a diagnosis.
The spinal fluid protein is typically about
1/100th the concentration of protein in
blood.
Increased CSF protein may be due to
damage to the, CSF brain barrier
resulting in an increased permeability,
decreased removal of protein from the
CSF.
22. Chemical analysis
(Contd..)
Decreased protein levels are less commonly
encountered.
Common reasons are removal of large amounts of
CSF and leakage of CSF caused by trauma.
Glucose concentrations can be determined using the
same methodologies as used for blood.
The most common finding is a low glucose
concentration associated with most types of CNS
infections.
If patient is hyperglycemic, then the CSF glucose
concentrations will like wise be elevated and an
infection may be masked.
If the patient is hypoglycemic the physician may be
misled by a low CSF glucose.
23. Chemical analysis (Contd..)
Lactate determination is considered to be of
some use by physicians in differentiating
bacterial, tuberculous and fungal meningitis
from viral meningitis.
The lactate concentration in viral meningitis is
generally normal or low in comparison to that
in bacterial, tuberculous, or fungal meningitis.
Other chemical anaylses include Glutamine
(an indicator of excess ammonia in the CNS),
LDH, chloride, and bilirubin.
24. Serologic examination
Serologic examination of CSF is
typically involved with diagnosis of
neurosyphilis.
A fluorescent treponemalantibody
absorption (FTA-ABS) test for CSF has
also been developed.
The VENERAL DISEASE RESEARCH
LAB. (VDRL) Test is also used.
25. Other techniques
It is important to recognize other techniques
that have been used and may still be used for
CSF.
Immunoelectrophorsis (CIE), latex
agglutination tests for bacterial antigens,
enzyme linked immunosorbent assay (ELISA)
and limulus of gram-negative bacterial).
The nucleic acid probes using PCR are the
newest of the techniques being investigated
for indentification of specific infectious
agents.
