CSF Flashcards
3 Layers of the Meninges
Dura mater, arachnoid mater, pia mater
outer layer; lines the skull and vertebral
canal
Dura mater
filamentous (spider-like) inner
membrane.
Arachnoid mater
thin membrane lining the surfaces of the
brain and spinal cord.
Pia mater
Choroid Plexuses of the 2 lumbar ventricles & the 3rd and 4th ventricles
site of production of CSF.
approximate volume of CSF produce every hour.
20 mL
tight-fitting structure of the
endothelial cells in the choroid plexuses
Blood-Brain-Barrier
method used to routinely collect CSF.
Puncture between the 3rd, 4th Or 5th Lumbar Vertebra
left over after each section has performed its tests may also be used for additional chemical or serologic tests.
Supernatant Fluid
should not be discarded and should be frozen until there is no further use for it.
Excess Fluid
usually determine whether the blood is the result of hemorrhage or a traumatic tap.
Three visual examinations of the collected specimens
routinely performed on CSF specimens
White Blood Cell Count (WBC)
usually determined only when a traumatic tap has occurred
Red Blood Cell Count
should be performed immediately.
Any cell count
routinely used for performing CSF cell counts.
Improved Neubauer counting chamber
have not been used for performing CSF cell counts.
Electronic cell counters
made with normal saline
Dilutions for total cell counts
Counted in the four corner squares and the center
square on both sides of the hemocytometer.
TOTAL CELL COUNT
Lysis of RBCs must be obtained
WBC COUNT
Counted in the four corner squares, and the center square on both sides of the hemocytometer and the number is multiplied by the dilution factor to obtain the number of WBCs per microliter.
WBC COUNT
for spinal fluid RBC and WBC counts.
Liquid commercial controls
must be soaked in a bactericidal solution for at least 15 minutes and then thoroughly rinsed with water and cleaned with isopropyl alcohol.
Non-disposable counting chambers
should be checked biweekly for contamination by examining them in a counting chamber under 400× magnification.
All diluents
Performed on a stained smear.
DIFFERENTIAL COUNT ON A CSF SPECIMEN
Methods available for specimen concentration
Sedimentation, Filtration,Centrifugation! Cytocentrifugation
removed and saved for additional tests
supernatant fluid
slides made from the suspended sediment are allowed to air dry and are stained with
Wright’s stain.
should be counted, classified, and reported in terms of percentage.
100 cells
majority of cells found in normal CSF.
Lymphocytes & Monocytes
predominance of lymphocytes to monocytes.
Adults
predominance of monocytes to lymphocytes.
Children
presence of increased number of these
normal cells; considered abnormal
Pleocytosis
Immature leukocytes, eosinophils, plasma cells,
macrophages, increased tissue cells, and malignant cells
abnormal
high CSF WBC Count – majority of
the cells (+) Neutrophils
Bacterial Meningitis
moderately elevated CSF WBC count with a high percentage of lymphocytes and monocytes.
Viral, fungal, tubercular or parasitic meningitis
Increased eosinophils are seen in the CSF in association with:
Parasitic Infections! Fungal Infections (Primarily Coccidioides immitis), Introduction of Foreign Material
most frequently seen after diagnostic procedures, Often appear in clusters, (+) Uniform Appearance
Nonpathologically significant cells
from the epithelial lining of the choroid plexus.
Choroidal Cells
are from the lining of the ventricles and neural canal
Ependymal Cells
represent lining cells from the arachnoid
Spindle-Shaped Cells
Lymphoblasts, myeloblasts, and monoblasts in the CSF are frequently seen as a serious complication of acute leukemias
HEMATOLOGIC ORIGIN
Metastatic carcinoma cells of nonhematologic origin are primarily from lung, breast, renal, and gastrointestinal malignancies
NON-HEMATOLOGIC ORIGIN
Nucleoli are often more prominent than in blood smears.
HEMATOLOGIC ORIGIN
Cells from primary CNS tumors include astrocytomas, retinoblastomas, and medulloblastomas
NON-HEMATOLOGIC ORIGIN
Lymphoma cells are also seen in the CSF and indicate dissemination from the lymphoid tissue.
HEMATOLOGIC ORIGIN
They usually appear in clusters and must be distinguished from normal clusters of ependymal, choroid plexus, lymphoma, and leukemia cells.
NON-HEMATOLOGIC ORIGIN
They resemble large and small lymphocytes and usually appear in clusters of large, small, or mixed cells based on the classification of the lymphoma.
HEMATOLOGIC ORIGIN
Fusing of cell walls and nuclear irregularities hyperchromatic nucleoli are seen in clusters of malignant cells.
NON-HEMATOLOGIC ORIGIN
Nuclei may appear cleaved, and prominent nucleoli are present.
HEMATOLOGIC ORIGIN
not the same as the plasma values.
Reference values for CSF chemicals
result from alterations in the permeability of the blood–brain barrier or increased production or metabolism
Abnormal values
most frequently performed chemical test on CSF
Protein Determination
Reference values for total CSF protein
15 to 45 mg/dL
makes up the most of the CSF protein
ALBUMIN
2ND most prevalent fraction in CSF
Pre-Albumin
include primary haptoglobin &
ceruloplasmin
Alpha Globulins
major beta globulin present
Transferrin
separate carbohydrate-deficient transferrin fraction, seen in CSF; NOT in serum
TAU
primarily immunoglobulin G(IgG)
CSF gamma globulin
with only a small amount of immunoglobulin A(IgA)
CSF gamma globulin
not found in normal CSF.
Immunoglobulin M (IgM), fibrinogen, and beta
lipoprotein
calculated after determining the concentration of CSF albumin in milligrams per deciliter and the serum concentration in grams per deciliter
CSF/serum albumin index
represents an intact blood-brain- barrier
Index value less than 9
a comparison of the CSF/serum albumin index with the CSF/serum IgG index, compensates for any IgG entering the CSF via the blood–brain barrier. performed by dividing the CSF/serum IgG index by the CSF/serum albumin index
Calculation of an IgG index
indicate IgG production within the CNS
Values greater than 0.70
primary purpose for performing CSF protein electrophoresis
To detect oligoclonal bands (represents inflammation within the CNS)
indicates immunoglobulin production
Oligoclonal Bands
must be performed
simultaneously.
Serum electrophoresis
valuable tool in diagnosing multiple sclerosis when accompanied by an increased IgG index
Presence of two or more oligoclonal bands in the CSF
that are not present in the serum
method of choice when determining whether a fluid is actually CSF
CSF immunofixation electrophoresis (IFE) and isoelectric focusing (IEF) followed by silver staining
approximately 60-70% that of the plasma glucose
Reference Value of CSF GLUCOSE
must be run for comparison for an accurate evaluation of CSF glucose
Blood Glucose Test
should be drawn about 2 hours before the spinal tap to allow time for equilibration between the blood and fluid
Sample for blood glucose
Specimens should be tested immediately
CSF GLUCOSE
provides more reliable information when the initial diagnosis is difficult
CSF lactate levels greater than 25 mg/dL
levels greater than 35 mg/dL
Bacterial Meningitis
lower than 25 mg/dL.
Viral Meningitis
may be obtained on xanthochromic or hemolyzed fluid
Falsely elevated results
can result from any condition that decreases oxygen flow to the tissues
Elevated CSF Lactate: not limited to meningitis
frequently used to monitor severe head injuries
CSF lactate levels
Normal Concentration: 8 to 18 mg/dL
CSF GULATAMINE
result in increased blood and CSF ammonia.
Elevated levels are associated with liver disorders
provides an indirect test for
the presence of excess ammonia in the CSF
Determining CSF glutamine
almost always seen when glutamine levels are more than 35 mg/dL
Some Disturbance of Consciousness
have elevated CSF glutamine levels
75% of children with Reye syndrome
routinely performed on CSF from all suspected cases of meningitis, although its value lies in detecting bacterial and fungal organisms
Gram Stain
should be performed on concentrated specimens
All smears and cultures
should be centrifuged at 1500 g for 15 minutes
CSF
should be prepared from the sediment
slides and cultures
Blood cultures should be taken
CSF ANALYSIS: MICROBIOLOGY TEST
Organisms most frequently encountered
Streptococcus pneumoniae (gram-positive cocci), Haemophilus influenzae (pleomorphic gram-negative rods), Escherichia coli (gram- negative rods), and Neisseria meningitidis (gram-negative cocci)
not routinely performed
Acid-fast or fluorescent antibody stains
performed to detect the presence of thickly encapsulated Cryptococcus neoformans
India Ink Preparation
seen more often than a positive India ink
Gram stain for the classic starburst pattern (produced by Cryptococcus)
performed to detect the presence of neurosyphilis
Serologic testing of the CSF
procedure recommended by CDC to diagnose neurosyphilis
Venereal Disease Research Laboratories (VDRL)
not recommended because it is less sensitive than the VDRL
Rapid plasma reagin (RPR) test
care must be taken to prevent contamination with blood
the FTA-ABS is used
