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Terms in this set (123)
-mainly composed of secretion from the choroid
plexus the 4 ventricles of the brain
-is a selective secretion of plasma
cerebrospinal fluid (CSF)
-has higher Na, Cl and Mg than plasma does
-has lower K, Ca and protein than plasma
-adults have 85-150 mL
3 layered membrane that surrounds the brain and
spinal cord
-pia mater: inside layer touching neural tissue
-arachnoid mater: middle later that resembles spider
meninges
web
-dura mater: outer layer that is next to bone
-CSF enters the space between arachnoid and pia
mater to bathe and protect neural tissue
CSF forms, circulates into the the areas surrounding
the neural tissues (brain and spinal cord) and is
CSF circulation
reabsorbed into blood
-20 mL are processed per hour
when reabsorption of CSF is blocked and CSF
hydrocephalus
builds up
the interface between blood and CSF
blood brain barrier -accounts for differences in electrolytes, proteins
and other solutes between blood and CSF
, -collected by aseptic lumbar puncture between 3rd
and 4th lumbar interspace using local anesthesia
-initial/ opening pressure taken with manometer on
the spinal needle (taken while patient laying down,
should be 50-180 mm Hg)
CSF collection -closing pressure (taken after sample collection) is
10-30 mm Hg lower
-pressure values and volume of CSF collected (up
to 20 mL) are recorded
-if pressure is too low or high only 1-2 mL should be
taken
-1: chemistry (may contain skin contaminant)
-2: microbiology (likely contains no more skin
CSF collection tubes
contaminant)
-3: cell counts
-should be clear and colorless and similar thickness
to water
-turbidity is related to number of cells in the sample
CSF physical examination
-cloudy appearance is associated with increased
WBCs, RBCs or may be caused by increased protein
or microorganisms
, increased number of cells in CSF
-increased neutrophils: bacterial meningitis, or viral,
fungal, Tb or parasitic infection
-lymphocytes: increased in viral, Tb, or fungal
infections or late stages of syphilitic meningitis
-plasma cells: make Ab's, typically only seen in
multiple sclerosis, and acute viral infection or
chronic inflammatory conditions
-monocytes: increased in Tb, fungal meningitis,
chronic bacterial meningitis, or rupture of cerebral
pleocytosis
abscess (typically present in infections that go on
for a long time)
-eosinophils: indicates parasitic, fungal or allergic
reactions (reaction to intracranial shunt)
-macrophage: found after hemorrhage to clean up
-other cells: check if malignant
-malignant cells: primary tumor in the CNS OR
metastasis from leukemia or lymphoma and
chemotherapeutics will need to be injected directly
into spinal fluid (can't bass blood brain barrier)
-traumatic tap: greatest blood volume in tube 1,
least blood in tube 3, after centrifugation
supernatant liquid is colorless
-hemorrhage: consistent amount of blood present
blood in CSF in all sample tubes, after centrifugation supernatant
fluid is still xanthochromic (appears yellow/ orange
due to bilirubin)
-need to determine if hemorrhage is subarachnoid
or intracerebral
-normal cell count is 0-5 WBC/ul
-increased WBC count indicates disease of the CNS
CSF microscopic or other condition like leukemia
examination -RBCs normally present
-cell counts need to be performed immediately to
prevent lysing WBCs