Biochemistry of CEREBROSPINAL FLUID

CSF COMPOSITION Normal CSF; clear, colorless, and odorless

Area Appearance Pressure Cells Protein Miscellaneous

Lumbar Clear/colorless

70-180 0-5(lymphocytes

)

<50 mg/dl Glucose50-75 mg/dl

Ventricular Clear/colorless

70-190 0-5(lymphocytes

)

5-15 mg/dl

Normal CSF values:

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

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

CEREBROSPINAL FLUID

CLINICAL CONSIDERATIONS

Various procedures have been developed to bypass the obstruction in noncommunicating hydrocephalus or to improve overall absorption in general

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.

CIRCULATION OF CSFLateral 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

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.

FUNCTIONS OF CSF

A shock absorberA mechanical bufferAct as cushion between the brain and craniumAct as a reservoir and regulates the contents of the craniumServes as a medium for nutritional exchange in CNSTransport hormones and hormone releasing factorsRemoves the metabolic waste products through absorption

CSF AND INFLAMMATIONIncreased 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.

CSF AND INFLAMMATIONIncreased 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.

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.

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.

CSF & LOW GLUCOSELow 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.

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.

Leukemia Cells in CSF

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.

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.

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

CONTRA-INDICATIONS FOR LP

Local skin infections over proposed puncture site (absolute contra-indication)Raised intracranial pressure (ICP); exception is pseudotumor cerebriSuspected spinal cord mass or intracranial mass lesion (based on lateralizing neurological findings or papilledema)Uncontrolled bleeding diathesisSpinal column deformities (may require fluoroscopic assistance)Lack of patient cooperation

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.

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

LUMBAR PUNCTURE

1. Material for sterile technique [gloves and mask are necessary]2. Spinal Needle, 20 and 22-gauge3. Manometer4. Three-way stopcock5. Sterile drapes6. 1% lidocaine without epinephrine in a 5-cc syringe with a 22 and 25-gauge needles7. Material for skin sterilization8. Adhesive dressing9. Sponges - 10 X 10 cm

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.

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.

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.

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.

LUMBAR PUNCTURE

CEREBROSPINAL FLUID

CEREBROSPINAL FLUID

CEREBROSPINAL FLUID

CEREBROSPINAL FLUID

CEREBROSPINAL FLUID

LUMBAR PUNCTURE

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

LUMBAR PUNCTUREFind 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

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