Cerebrospinal fluid analysis Flashcards
Dura mater
outer membrane of brain
arachnoid mater
middle membrane of brain
pia mater
inner membrane
choroid plexus cells
in the center of the brain area
produces cerebrospinal fluid
composition of cerebrospinal fluid
selective secretion from plasma NOT an ultrafiltrate
collection
3+ sterile tubes
1: chemical & immunological testing
2: microbiology
3: cell count & cytology
4: optional, micro
crystal clear color
normal cerebrospinal fluid
cloud or turbid color
wbcs, increased protein or lipid concentration
milky color
wbcs, increased protein or lipid concentration
xanthrochromic color
pink to orange color rbcs degradation increased serum bilirubin carotene markedly increased protein melanoma pigment
hemolyzed/bloody color
intracranial hemorrhage or traumatic tap
traumatic tap
greatest amount of blood in tube 1 & least in tube 3
after centrifugation , colorless supernatant
may see clots present in tubes bc of fibrinogen
hemorrhage
consistent amount of blood in all three tubes
after centrifuge, xanthochromic supernatant
macrophages with phagocytized RBcs
routine tests on CSF
cell count & differential
protein
glucose
temps for tube storages
1: can be frozen if needed
2: micro- room temp
3: refrigerated for cell counts
traumatic tap & wbcs
correct for contamination
D-dimer for hemorrhage & traumatic tap
hemorrhage: positive D-dimer
traumatic tap: negative D-dimer
range for RBCs in CSF
0 rbcs/ul for all ages
cytospin
pro: good cellular recovery & preservation; rapid & simple
con: production of some aberrant cells
cytocentrifugation
particle sedimentation speed increases w/ the rotational speed of the centrifuge; it is faster for large or dense particles & slower for small or light particles
2 categories of cytocentrifugation
- remove the suspension fluid during cell sedimentation
2. retain the suspension fluid during cell sedimentation
normal adult CSF differential
lymphs & monos = 70:30
few neutrophils
few lining cells & macrophages
normal children CSF differential
monos > lymphs
ependymal cells & macrophage
neutrophilia
bacterial meningitis
macrophages present
recent hemorrhage usually
appear 2-4 hours after RBC introduction
protein
usually determined to assess the integrity of the blood-brain barrier
also used to indicate CNS pathology
15-45 mg/dl
increased protein
decreased reabsorption into the venous blood
increased synthesis of immunoglobulin
contamination w/ blood during tap
decreased protein
increased reabsorption by the arachnoid villi due to increased intracranial pressure
fluid leaking !!
CSF/ serum albumin index
used to evaluate the integrity of blood-brain barrier
CSF IgG index
used to measure IgG synthesis w/in the CNS
multiple sclerosis >0.70
protein electrophoresis
4 bands: tranthyretin (TTR), albumin, two transferrin bands
tau transferrin migrates in beta 2 region & in synthesized almost exclusively in CNS
oligoclonal banding in the y region
presence in CSF & absence in serum is highly indicative of multiple sclerosis
glucose
60-70% of plasma concentration
decreased: bacterial meningitis or defective glucose transport
bacterial meningitis picture
up WBCs, up neutrophil
down glucose
lactate
increased levels - anaerobic metabolism
>35 mg/dl found in bacterial meningitis
25-30 mg/dl in viral
increased CSF lactate correlates with what?
low CSF glucose levels
better diagnostic indicator of bacterial meningitis than either parameter alone
Glutamine
produced in the CNS by brain cells from ammonia & alpha-ketoglutarate
indirect measurement of excess ammonia in CSF
elevated glutamine
seen w/ liver disorders that have increased blood & CSF ammonia
