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39 Cards in this Set

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  • Back
What is color of CSF?
Clear, colorless
What is CSF produced by?
Choroid Plexus
What is the total CSF in an adult?
90-150 ml (size of water bottle)
What is the rate of CSF formation?
500 ml / day
Where is the CSF located?
In the 4 ventricles of the brain

Subarachnoid space
CSF is primarily produced by the choroid plexus where?
In the four ventricles
What are the cells lining the ventricles of the brain?
Ependymal cells (cuboidal type glial cells)
What is the 2 step process of CSF formation?
1. Ultrafiltration of plasma across fenestrated capillary wall

2. Choroid epithelial cells secrete/transport components into ventricle
CSF has lower concentrations of what compared to the plasma?
1. Protein

2. Amino acids

3. K+
Why can't plasma/blood be used in the brain?
Far to unstable for the brain

CSF IS stable
What is the circulation pathway for CSF?
Ventricles --> Subarachnoid Space --> Arachnoid Granulations (where its reabsorbed)
Into which veins does the CSF drain?
Superior Sagittal Sinus and Spinal Veins
By what transport mechanism does CSF enter the veins?
Transcytosis
What are the 2 ways that CSF helps protect the physical aspects of the brain?
1. Bouyancy

2. Acting as a shock absorber
What are the 2 ways that CSF protects the metabolic functions of the brain?
1. Maintains stable extracellular environment

2. Provides excretory waste drainage
What are the 2 routes into the CNS?
1. Blood-CSF barrier

2. Blood-Brain Barrier
What are the 3 layers of physical barriers in the BBB?
1. Tight junctions btwn non-fenestrated capillary endothelial cells

2. Thick Basement Membrane

3. Astrocyte Endfoot
What is NOT permeable to the BBB?
1. Large Charged Molecules

2. Many drugs
What IS permeable to the BBB?
1. Water

2. Uncharged and lipid soluble molecules (O2, caffeine, ethanol, etc)
What are the few small areas of the brain that lack a definitive BBB?
Circumventricular Organs
The circumventricular organs are thought to be apart of what system?
Neuroendrocrine control system for monitoring plasma osmolarity and body temp

(also provides mech for post. pituitary to release hormones directly into blood)
What are the 4 most common indications to evaluate CSF?
1. CNS infection

2. Subarachnoid Hemorrhage

3. CNS Malignancy

4. Demyelinating Disease
Where is the spinal needle inserted in a spinal tap?
L3/L4 or L4/L5

Because below the SC
When should a lumbar puncture NOT be performed?
In the case of raised ICP

Puncture would cause cerebral herniation
What is the most common complication of a lumbar puncture?
Headache (occurs in 10-30% of patients)
What are the 4 appearances that pathologic CSF can have?
1. Cloudy - due to infection

2. Bloody - subarachnoid hemorrhage

3. Xanthochromia (discoloration)

4. Viscous - tumor
Does normal CSF have RBC or WBCs in it?
NO (or very minimal)
Increased CSF neutrophils can be an indication of what?
Bacterial meningitis
Increased CSF lympochytes can be an indication of what?
Viral menigitis
Decreased glucose as a result of infection is caused by what?
Responding leukocytes and transport mechs

NOT by the invading bacteria
Apart from gram stainging and culture, what is another test used to detect the presence of a pathogen?
Latex agglutination antigen assay

ex: Streptococcus and Cryptococcus
What is meningitis?
Inflammation of the meninges
Which is more prevalent, viral or bacterial meningitis?
Viral
Which is more deadly, viral or bacterial meningitis?
Bacterial
What are the 5 main symptoms of meningitis?
1. Fever

2. Stiff Neck

3. Headache

4. Altered mental status

5. Photophobia
What are the 3 major familis of viruses that cause menigitis?
1. Enteroviruses

2. Herpesviruses

3. Arboviruses (spread by insects)
What is encephalitis?
Infection involving parenchyma of brain

(Meningitis is limited to meninges)
What are the 3 mechanisms by which pathogens enter the CNS?
1. Bacterial surface proteins attach to endothelial cells and migrate across BBB (ex: strep pneumonia)

2. Trojan horse - cross inside circulating cell

3. Physically disrupt BBB (following trauma/neurosurgery)
Does everyone with bacterial sepsis develop a CNS infection?
NO, not all bacteria are able to cross an intact BBB