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In what 2 sites is CSF formed?
1. 70% in choroid plexus in lateral/3rd/4th ventricles.
2. 30% in ependymal lining of ventricles/subarachnoid space.
What 'actions' allow CSF to be formed?
1. Filtration by capillaries
2. Active secretion by epithelial cells.
Describe CSF composition:
-K+ Ca2+ Bicarb, Glucose/Protein
-CSF acidity
-K+, Ca++, Bicarb, Glu and Protein are lower than blood.
-Sodium/osmolarity are same.
-More acidic than plasma.
What can get into the Brain past the BBB without help?
Only water! Relatively permeable to it in fact.
What diffuses through the BBB?
Lipid-soluble substances.
What is transported actively into the brain?
Glucose, Sodium, Chloride, Mg.
What are the 3 ways to enter the CSF?
1. Diffuse if lipid-soluble
2. Facilitated/Active transport
3. Ion channels
What causes CSF circulation?
Pressure changes caused by:
What are the 3functions of CSF?
1. Nourish brain
2. Take away wastes
3. Cushion from trauma/float.
What are 4 ways to collect CSF?
1. Lumbar puncture
2. Cisternal puncture
3. Lateral cervical puncture
4. Ventricular cannular shunt
5 diagnostic indications for LP:
-MS/Guillan barre
4 therapeutic indications of LP:
-Radiographic contrast media
-Amphotericin - for fungal meningitis.
Normal CSF pressure:
If there are only 1 or 2 tubes of CSF drawn, where do they go first?
1. Micro
2. Heme
3. Chemistry
How Soon must CSF be run?
Within ONE HOUR.
What cells are normal on a CSF diff? in Whom?
Adults: 65 lymph:35 mono
Newbrn: 70 mono: 30 lymph
-Rare PMN
-Rare choroid plexus, ependymal, neuroectodermal
-Rare mesothelial
What are abnormal cells on a CSF diff?
-PMNS many
-Lymphs many
-reactive lymphs
-Plasma cells
What is a siderophage?
A macrophage that has hemosiderin in it.. and has been confirmed with PPB.
Which cancers readily metastesize to the CNS?
What do nRBCs indicate in the CSF?
BM contamination.
When are nRBCs normal in the CSF?
When they are in the circulating blood of neonates.
What might Eosinophils indicate when in the CSF?
-Allergic rxtns
-Parasitic infections
-C. immitis
-Shunts, meds
What chemistries are most indicative of CSF abnormality?
What others might be run?
What is normal CSF Protein?
15-45 mg/dL
Why would CSF protein be low?
Leaking CSF
What are 4 methods for protein on CSF?
-Protein fractionation
What should the CSF:serum albumin index be?
Less than nine.
What should the gammaglobulin component of total protien be?
Less than 12%
If the gammaglobulin fraction is increased, what is suspect?
-Cerebral disease
What especially indicates multiple sclerosis?
Oligoclonal bands on protein fractionation EVEN when symptoms go away.
What 3 pieces of data help diagnose MS?
-Increased IgG index
-Oligoclonal banding
-Myelin Basic PRotein increase
What is normal CSF glucose?
What does Increase mean?
What does Decrease mean?
50-60% of the blood glucose
-Increase = increased blood glu
-Decrease = diseased state
What is decreased CSF Glucose normally caused by?
-Impaired transport across BBB
-Increased brain use
-LEukocyte use
What is CSF glucose decrease usually seen in?
-Bacterial meningitis
-Tubercular meningitis
What is normal LD?
10-25 mg/dl
When are Lactate and LD increased?
-Oxygen deprivation to brain
-Bacterial, fungal, TB meningitis
When are Lactate and LD normal?
viral meningitis
what is glutamine masurement useful for?
indicating CSF amonia levels
-elevated puts patients at risk of coma.
What are 6 tests used for microbiological and immunolog analysis of CSF?
1. Gram stain
2. India ink
3. CIE
4. Latex agglutination
5. Ziehl-Neelsen
6. Limulus lysate
what is the limulus lysate test for?
to detect gram negative rods.
How does the limulus lysate test work?
-Blood from horseshoe crabs has copper
-Coagulates in presence of GNB
abrev. meaning for CSF
cerebrospinal fluid

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