Biochemistry of Cerebrospinal fluid (CNF)

CLINICAL CONSIDERATIONSNoncommunicating (obstructive) hydrocephalus occurs more frequentlyCSF of ventricles unable to reach subarachnoid spaceProduction of CSF continuesGyri are flattened against inside of skullIf skull is still pliable head may enlarge

1. Biochemistry of CEREBROSPINAL
FLUID
CSF COMPOSITION
Normal CSF; clear, colorless, and odorless
Area Appearance Pressure Cells Protein Miscellaneou
s
Lumbar Clear/colorless 70-180 0-5
(lymphocytes)
<50 mg/dl Glucose
50-75 mg/dl
Ventricular Clear/colorless 70-190 0-5
(lymphocytes)
5-15 mg/dl
Normal CSF values:

3. CEREBROSPINAL FLUID
CLINICAL CONSIDERATIONS
Noncommunicating
(obstructive) hydrocephalus
occurs more frequently
CSF of ventricles unable to
reach subarachnoid space
Production of CSF continues
Gyri are flattened against
inside of skull
If skull is still pliable head may
enlarge

4. CEREBROSPINAL FLUID
CLINICAL CONSIDERATIONS
Communicating
hydrocephalus; obstruction is
in subarchnoid space due to
thickening of the arachnoid
with resultant block of return-
flow channels
Can be the result of prior
bleeding or meningitis
If ICP is increased due to
excess CSF, central canal of
spinal cord may dilate

5. CEREBROSPINAL FLUID
CLINICAL
CONSIDERATIONS
Various procedures have
been developed to bypass
the obstruction in
noncommunicating
hydrocephalus or to
improve overall absorption
in general

6. CIRCULATION OF CSF
Circulation: CSF is mainly formed in choroid pleaxus of the
lateral ventricle.
CSF passes from the lateral ventricle to the third ventricle
through the interventricular foramen (foramen of Monro).
From third ventricle it passes to the fourth ventricle through
the cerebrol aqueduct. The circulation is aided by the arterial
pulsations of the choroid plexuses.
From the fourth ventricle (CSF) passes to the subarachnoid
space around the brain and spinal cord through the foramen
of magendie and foramina of luschka.

7. CIRCULATION OF CSF
Lateral ventricle
Foramen of Monro [Interventricular foramen]
Third ventricle:
Subarachnoid space of Brain and Spinal cord
Fourth ventricle:
Cerebral aqueduct
Foramen of megendie and formen of luschka

8. CIRCULATION OF CSF
Circulation: CSF slowly moves cerebromedullary
cistern and pontine cisterns and flows superiorly
through the interval in the tentorium cerebelli to
reach the inferior surface of the cerebrum. It moves
superiority over the lateral aspect of each cerebrol
hemisphere.

9. FUNCTIONS OF CSF
A shock absorber
A mechanical buffer
Act as cushion between the brain and cranium
Act as a reservoir and regulates the contents of the cranium
Serves as a medium for nutritional exchange in CNS
Transport hormones and hormone releasing factors
Removes the metabolic waste products through absorption

10. CSF AND INFLAMMATION
Increased inflammatory cells [pleocytosis] may
be caused by infectious and noninfectious processes.
Polymorphonuclear pleocytosis indicates acute
suppurative meningitis.
Mononuclear cells are seen in viral infections
(meningoencephalitis, aseptic meningitis), syphilis,
neuroborreliosis, tuberculous meningitis, multiple
sclerosis, brain abscess and brain tumors.

11. CSF AND INFLAMMATION
Increased inflammatory cells [pleocytosis] may
be caused by infectious and noninfectious processes.
Polymorphonuclear pleocytosis indicates acute
suppurative meningitis.
Mononuclear cells are seen in viral infections
(meningoencephalitis, aseptic meningitis), syphilis,
neuroborreliosis, tuberculous meningitis, multiple
sclerosis, brain abscess and brain tumors.

12. CSF AND PROTEINS
Increased protein: CSF protein may rise to 500 mg/dl in
bacterial meningitis.
A more moderate increase (150-200 mg/dl) occurs in
inflammatory diseases of meninges (meningitis,
encephalitis), intracranial tumors, subarachnoid
hemorrhage, and cerebral infarction.
A more severe increase occurs in the Guillain-Barré
syndrome and acoustic and spinal schwannoma.

13. CSF AND PROTEINS
Multiple sclerosis: CSF protein is normal or mildly
increased.
Increased IgG in CSF, but not in serum [IgG/albumin index
normally 10:1].
90% of MS patients have oligoclonal IgG bands in the CSF.

Oligoclonal bands occur in the CSF only not in the serum.
The CSF in MS often contains myelin fragments and myelin
basic protein (MBP).
MBP can be detected by radioimmunoassay. MBP is not
specific for MS. It can appear in any condition causing
brain necrosis, including infarcts.

14. CSF & LOW GLUCOSE
Low glucose in CSF:
This condition is seen in suppurative tuberculosis
Fungal infections
Sarcoidosis
Meningeal dissemination of tumors.
Glucose is consumed by leukocytes and tumor cells.

15. BLOOD IN CSF
Blood: Blood may be spilled into the CSF by accidental
puncture of a leptomeningeal vein during entry of the LP
needle.
Such blood stains the fluid that is drawn initially and
clears gradually. If it does not clear, blood indicates
subarachnoid hemorrhage.
Erythrocytes from subarachnoid hemorrhage are cleared
in 3 to 7 days. A few neutrophils and mononuclear cells
may also be present as a result of meningeal irritation.

16. Leukemia Cells in CSF

17. CSF AND XZNTHOCHROMIA
Xanthochromia [blonde color] of the CSF
following subarachnoid hemorrhage is due to
oxyhemoglobin which appears in 4 to 6 hours and
bilirubin which appears in two days.

Xanthochromia may also be seen with hemorrhagic
infarcts, brain tumors, and jaundice.

18. CSF AND TUMOUR CELLS
Tumor cells indicate dissemination of metastatic or
primary brain tumors in the subarachnoid space.
The most common among the latter is medulloblastoma.
They can be best detected by cytological examination.
A mononuclear inflammatory reaction is often seen in
addition to the tumor cells.

19. Indications
In medicine, a lumbar puncture is a diagnostic
in order to collect a sample of cerebrospinal fluid
(CSF) and therapeutic procedure:
Diagnostic for: biochemical, microbiological,
and cytological analysis
Therapeutic for: relieving increased
intracranial pressure, and injecting medication
intarthecally for spinal anesthesia and
chemotherapy.
INDICATIONS OF CSF EXAMINATION

20. CONTRA-INDICATIONS FOR LP
Local skin infections over proposed puncture site
(absolute contra-indication)
Raised intracranial pressure (ICP); exception is
pseudotumor cerebri
Suspected spinal cord mass or intracranial mass
lesion (based on lateralizing neurological findings or
papilledema)
Uncontrolled bleeding diathesis
Spinal column deformities (may require fluoroscopic
assistance)
Lack of patient cooperation

21. LUMBAR PUNCTURE
A lumbar puncture also called a spinal tap is a
procedure where a sample of cerebrospinal fluid is
taken for examination.
CSF is mainly used to diagnose meningitis [an
infection of the meninges].
It is also used to diagnose some other conditions
of the brain and spinal cord.

22. PRECAUTIONS FOR LUMBAR PUNCTURE
 Asked to sign a consent form

 Ask about taking any medicines
 Are allergic to any medicines
 Have / had any bleeding problems
 Ask about medications such as aspirin or warfarin

 Ask the female patient might be pregnant
 Empty the bladder before the procedure

23. LUMBAR PUNCTURE
1. Material for sterile technique [gloves and mask
are necessary]
2. Spinal Needle, 20 and 22-gauge
3. Manometer
4. Three-way stopcock
5. Sterile drapes
6. 1% lidocaine without epinephrine in a 5-cc
syringe with a 22 and 25-gauge needles
7. Material for skin sterilization
8. Adhesive dressing
9. Sponges - 10 X 10 cm

24. LUMBAR PUNCTURE [Complications]
Post lumbar puncture headache occurs in 10% to 30% of
patients within 1 to 3 days and lasts 2 to 7 days.
The pain is relieved by lying flat.
Treatment consists of bed rest and fluid with simple
analgesics.

25. LUMBAR PUNCTURE [Complications]
Headache following a lumbar puncture is a common and
often debilitating syndrome.
Continued leakage of cerebrospinal fluid from a puncture
site decreases intracranial pressure, which leads to
traction on pain-sensitive intracranial structures.
The headache is characteristically postural, often
associated with nausea and optic, vestibular, or otic
symptoms. Although usually self-limited after a few days,
severe postural pain can incapacitate the patient.
Management is mainly symptomatic, but definitive
treatment with the epidural blood patching technique is
safe and effective when done by an expert operator.

26. LUMBAR PUNCTURE
Patient usually lie on a bed on side with knees pulled
up against the chest.
It may also done with sitting up and leaning forward on
some pillows. Sterilize the area.
push a needle through the skin and tissues between
two vertebra into the space around the spinal cord
which is filled with CSF.
CSF leaks back through the needle and is collected in a
sterile container.
As soon as the required amount of fluid is collected the
needle is taken out and a plaster is put over the site of
needle entry.

27. LUMBAR PUNCTURE
Sent the sample to lab to be examined under
the microscope to look for bacteria.
It is also 'cultured' for any bacterial growth
The fluid can also be tested for protein, sugar
and other chemicals if necessary.
Sometimes also measure the pressure of the
fluid. This is done by attaching a special tube to
the needle which can measure the pressure of
the fluid coming out.

28. LUMBAR PUNCTURE

29. CEREBROSPINAL FLUID

30. CEREBROSPINAL FLUID

31. CEREBROSPINAL FLUID

32. CEREBROSPINAL FLUID

33. CEREBROSPINAL FLUID

34. LUMBAR PUNCTURE

35. LUMBAR PUNCTURE
Place the patient in the lateral decubitus position lying on
the edge of the bed and facing away from operator.
Place the patient in a knee-chest position with the neck
flexed.
The patient's head should rest on a pillow, so that the
entire cranio-spinal axis is parallel to the bed.
Sitting position is the second choice because there may
be a greater risk of herniation and CSF pressure cannot
be measured

36. LUMBAR PUNCTURE
Find the posterior iliac crest and palpate the L4 spinous
process, and mark the spot with a fingernail.
Prepare the skin by starting at the puncture site.

Anesthetize the skin using the 1% lidocaine in the 5 mL
syringe with the 25-gauge needle. Change to 22-gauge
needle before anesthetizing between the spinous process.
Insert in the midline with the needle parallel to the floor
and the point directed toward the patient's umbilicus

37. LUMBAR PUNCTURE
Advance slowly about 2 cm or until a "pop'' (piercing a
membrane of the dura) is heard.
Then withdraw the stylet in every 2- to 3-mm advance of
the needle to check for CSF return.
If the needle meets the bone or if blood returns (hitting
the venous plexus anterior to the spinal canal), withdraw
to the skin and redirect the needle.
If CSF return cannot be obtained, try one disk space
down