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Transcript of Csf
Cerebrospinal Fluid
Presented by: Farhad Jahanfar
Contents
Chemical examination
Physical examination
Routine examination of csf
Specimen collection
Introduction
Cytoligical examination
Microbiological examination
First recognized by Cotugno in 1764
Both the brain and spinal cord are covered by three protective membranes referred to as the meninges
Between the arachnoid layer and the pia mater is a space called the subarachnoid space. It contains a clear, colorless fluid referred to as Cerebrospinal Fluid (CSF).
Supply nutrients to the nervous tissue,remove metabolic wastes and produce a mechanical barrier
CSF
CSF
CSF is produced in the choroid plexuses of the twolumbar ventricles and the third and fourth venticles.
choriod plexuses are capillary networks that formthe CSF from plasma by mechanisms of selective filtration under hydrostatic pressure and active transport secretion.
CSF
In adults, approximately 20 mL of fluid is produced every hours.( 500 ml per Day)
the total volume of CSF circulating throughout the adult Central Nervous System approximately 90 - 150 ml.
blood-brain barrier
Blood-csf barrier
CSF
CSF
Cerebrospinal fluid (CSF) analysis may be used to help diagnose a wide variety of diseases affecting the central
nervous system.
Infectious diseases such as meningitis and encephalitis
Bleeding (hemorrhaging)
Tumors
inflammation , autoimmune disorders, Guillain-Barré syndromeOr sarcoidose and multiple sclerosis
How is it used?
Specimen Collection and Handling(LP(
CSF is routinely collected by lumbar puncture between the third, fourth, or fifth lumbar vertebrae
Tube 1 for chemical and serologic tests because these tests are least affected by blood or bacteria
introduced as a result of the tap procedure;
Tube 2 is usually designated for the microbiology laboratory
Tube 3 is used for the cell count, because it is the least likely to contain cells introduced by the spinal tap
• Hematology tubes are refrigerated.
• Microbiology tubes remain at room temperature.
• Chemistry and serology tubes are frozen.
tests are performed on a STAT basis
CSF physical characteristics
.
Pressure
Increased CSF pressure: tumors, infection, abnormal accumulation of
CSF within the brain (hydrocephalus) , or bleeding.
Viscosity same consistency as water
thicker" may be seen in people with certain types of cancers or meningitis.
Appearance clear, cloudy or turbid, milky,xanthochromic, and hemolyzed/bloody.
90~180mmH2O Adults, 10~100mmH2O in children
WBC>200RBC>400
RBC>600
Xanthochromia is a term used to describe CSF supernatantthat is pink, orange, or yellow
pink (very slight amount of oxyhemoglobin( orange (heavy hemolysis(
yellow (conversion of oxyhemoglobin to unconjugated bilirubin(
Other causes of xanthochromia include elevated serumbilirubin, presence of the pigment carotene, markedlyincreased protein concentrations.
Traumatic Collection (Tap(
Grossly bloody CSF can be an indication of intracranial hemorrhage,but it may also be due to the puncture of a blood vessel during the spinal tap procedure.
1.Uneven Distribution of Blood
2.Clot Formation3.Xanthochromic Supernatant
Three visual examinations:
CSF glutamine
CSF LDH
Serological test
CSF glucose
CSF protein CSF lactic acid
CSF chemical tests
CSF Glucose
normal is about 2/3 the concentration of blood glucose (60% to 70%)
For an accurate evaluation of CSF Glucose,a blood glucose test must be run for comparison(2 hours prior (
Specimens should be tested immediately because glycolysis occurs rapidly in the CSF
CSF Glucose
CSF Glucose , WBC(neutrophils) :bacterial meningitis
CSF Glucose ,WBC(lymphocytes) : tubercular meningitis
CSF Glucose(Normal) ,WBC(lymphocytes) :viral meningitis
CSF Protein only a small amount is normally present in CSF
Normal values for total CSF protein are usually listed as
15 to 45 mg/dL higher values are found in infant
CSF IgG increased multiple sclerosis, herpes encephalitis, connective tissue diseases
and older persons.
the CSF contains protein fractions similar tothose found in serum
CSF
damage to the integrity of the BBB
Intrathecal synthesisprotein
CSF Protein
CSF/serum albumin index=CSF albumin (mg/dL(Serum albumin (g/dL(
IgG index =CSF IgG (mg/dL)/serum IgG (g/dL(
CSF albumin (mg/dL)/serum albumin (g/dL(
An index value less than 9 represents an intact BBB
values greater than 0.70 are indicative of IgG production within the CNS
Bacterial
Myelin basic protein(MBP(
Myelin protein:myelin basic protein, myelin oligodendrocyte glycoprotein, and proteolipid protein.
seen when the covering of nerves (myelin) breaks down, such as with multiple sclerosis.
Measurement of the amount of MBP in the CSF can be used to monitor the course of MS.
CNS trauma, tumor, and viral encephalitis,peripheral neoropathy,vasculitis. Guillain-Barré syndrome
CSF protein electrophoresis
oligoclonal bands
The bands are located in the gamma region of the protein electrophoresis, indicating immunoglobulin production.
presence of two or more oligoclonal bands in the CSF that are not present in the serum can be a valuable tool in the diagnosis MS.
Transthyretin(Pre-Albumin(
β2 Transferrin(tau)
α2 Macroglubolin(AMG(
CSF normally contain very low levels of AMG
there are several components to the blood-CSF barrier, with a few large pinocytic vesiclcs transporting proteins up to 1500A into the CSF.
Polyneuropathies:Increase of AMG
The level of AMG alone, or its relationship to levels of albumin and IgG, may therefore be helpful in differential diagnosis of
Neurological disorders.
In patients with bacterial meningitis, CSF AMG levels are on average 15 times higher than is the case with nonbacterial meningitis
CSF levels of AMG normally increase with age
AMG
Dye-binding methods such as Coomassie brilliant blue or Ponceau S are used.
Methodology
Turbidimetry
(Trichloroacetic acid&sulfosalicylic acid precipitation)
urinary protein reagent strips
CSF Lactate
In bacterial,tubercular, and fungal meningitis, the elevation of CSF lactate to levels greater than 25 mg/dL occurs.
Levels greater than 35 mg/dL are frequently seen with bacterial meningitis, whereas in viral meningitis, lactate levels remain lower than 25 mg/dL
falsely elevated results may be obtained on xanthochromic or hemolyzed fluid
CSF Glutamine
Glutamine is produced from ammonia and -ketoglutarate by
.the brain cells
The normal concentration of glutamine in the CSF is 8 to 18 mg/dL.
may be increased with liver disease, hepatic encephalopathy or Reye syndrome
Some disturbance of consciousness is almost
always seen when glutamine levels are more than 35 mg/dL(coma(
used to differentiate between bacterial and viral meningitis; the level is usually increased with bacterial meningitis and not with viral meningitis; may also be elevated with leukemia or stroke.
CSF LDH
Isoenzymes LD1 and LD2 are found in brain tissue.
Isoenzymes LD2 and LD3 are found in lymphocytes.
Isoenzymes LD4 and LD5 are found in neutrophils
CSF LDH
LD5 All
Bacterial meningitis Viral meningitis Metastatic tumors Primary neoplasm
LD4,LD5 LD1,LD2,LD3
CPK: Raised CPK is found in: Brain infract Brain tumors polineoropathy MS
CK-BB < 5 Slight injury
Mild injury 5<CK-BB <20
21>CK-BB< 50 Death
CRP: It is markedly increased with bacterial meningitis.
it is often used to distinguish between bacterial and viral meningitis
Tubercular meningitis L/15< : ADA
Tumor markers — Carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), and hCG may be increased in metastatic tumors.
PCR has been especially useful in the diagnosis
of viral meningitis
Serologic test: VDRL,FTA-ABS
Microscopic Examination
The cell count that is routinely performed on CSF specimens is the leukocyte (WBC) count.
Any cell count should be performed immediately(1 Hours)
Normal adult CSF contains :0 -5 WBCs/uL 0-30 WBC/ul : newborns
Children: 0-20 WBC/ul
0 :RBC
Calculation of CSF Cell Counts
Number of cells counted × dilution
Number of squares counted(9) × volume of 1 square(0.1(
cells/uL=
WBC Count
Dilutions for total cellcounts are made with normal saline
Lysis of RBCs must be obtained prior to performing the WBC count on either diluted or undiluted specimens
3% glacial acetic acid(Marcano(
Number of cells counted × dilution
Number of squares counted(4) × volume of 1 square(0.1(
WBC/ul=
Corrections for ContaminationCorrections for Contamination
WBC (added(=WBC(blood) ×RBC (CSF(
RBC (blood(
The specimen is centrifuged for 5 to 10 minutes
Differential Count
the suspended sediment are allowed to air dry and are stained with Wright’s stain
When the differential count is performed, 100 cells should be counted, classified, and reported in terms of percentage
:The WBC count seen in normal adult CSF isapproximately 70 %lymphocytesand 30 %monocytes
Increase Lymphocytes: Viral & Fungal meningitisMultiple sclerosis
Increased neutrophils: Bacterial Meningitis
cerebral abscess CNS hemorrhage
CNS infarct
77% of patients with bacterial meningitis will have a WBC count higher than 1,000 /mm,3
99% will have more than 100 per mm3. Having less than 100 WBCs/ mm3 is viral meningitis.
CSF gram stain
direct observation of microorganisms under a microscope
hemophilus influenza Neisseria meningitidis
Microbiological examination
A CSF culture is used to detect infectious organisms in the CSF(blood agar,chocolate agar)
Acid-fast staining should be done if tuberculosis is clinically suspected
Wright-gimsa staining: for Differential Count
Pathogens• Strep. pneumoniae
• Strep. agalactiae (Group B(• Listeria monocytogenes
• Aerobic Gram negative bacilli• Staphylococcus species
Haemophilus influenzae Neisseria meningitidis Streptococcus pneumoniae
5% Sheep blood agar
Chocolate agar