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39 Cards in this Set
- Front
- Back
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What is color of CSF?
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Clear, colorless
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What is CSF produced by?
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Choroid Plexus
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What is the total CSF in an adult?
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90-150 ml (size of water bottle)
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What is the rate of CSF formation?
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500 ml / day
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Where is the CSF located?
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In the 4 ventricles of the brain
Subarachnoid space |
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CSF is primarily produced by the choroid plexus where?
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In the four ventricles
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What are the cells lining the ventricles of the brain?
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Ependymal cells (cuboidal type glial cells)
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What is the 2 step process of CSF formation?
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1. Ultrafiltration of plasma across fenestrated capillary wall
2. Choroid epithelial cells secrete/transport components into ventricle |
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CSF has lower concentrations of what compared to the plasma?
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1. Protein
2. Amino acids 3. K+ |
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Why can't plasma/blood be used in the brain?
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Far to unstable for the brain
CSF IS stable |
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What is the circulation pathway for CSF?
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Ventricles --> Subarachnoid Space --> Arachnoid Granulations (where its reabsorbed)
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Into which veins does the CSF drain?
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Superior Sagittal Sinus and Spinal Veins
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By what transport mechanism does CSF enter the veins?
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Transcytosis
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What are the 2 ways that CSF helps protect the physical aspects of the brain?
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1. Bouyancy
2. Acting as a shock absorber |
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What are the 2 ways that CSF protects the metabolic functions of the brain?
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1. Maintains stable extracellular environment
2. Provides excretory waste drainage |
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What are the 2 routes into the CNS?
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1. Blood-CSF barrier
2. Blood-Brain Barrier |
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What are the 3 layers of physical barriers in the BBB?
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1. Tight junctions btwn non-fenestrated capillary endothelial cells
2. Thick Basement Membrane 3. Astrocyte Endfoot |
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What is NOT permeable to the BBB?
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1. Large Charged Molecules
2. Many drugs |
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What IS permeable to the BBB?
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1. Water
2. Uncharged and lipid soluble molecules (O2, caffeine, ethanol, etc) |
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What are the few small areas of the brain that lack a definitive BBB?
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Circumventricular Organs
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The circumventricular organs are thought to be apart of what system?
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Neuroendrocrine control system for monitoring plasma osmolarity and body temp
(also provides mech for post. pituitary to release hormones directly into blood) |
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What are the 4 most common indications to evaluate CSF?
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1. CNS infection
2. Subarachnoid Hemorrhage 3. CNS Malignancy 4. Demyelinating Disease |
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Where is the spinal needle inserted in a spinal tap?
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L3/L4 or L4/L5
Because below the SC |
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When should a lumbar puncture NOT be performed?
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In the case of raised ICP
Puncture would cause cerebral herniation |
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What is the most common complication of a lumbar puncture?
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Headache (occurs in 10-30% of patients)
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What are the 4 appearances that pathologic CSF can have?
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1. Cloudy - due to infection
2. Bloody - subarachnoid hemorrhage 3. Xanthochromia (discoloration) 4. Viscous - tumor |
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Does normal CSF have RBC or WBCs in it?
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NO (or very minimal)
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Increased CSF neutrophils can be an indication of what?
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Bacterial meningitis
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Increased CSF lympochytes can be an indication of what?
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Viral menigitis
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Decreased glucose as a result of infection is caused by what?
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Responding leukocytes and transport mechs
NOT by the invading bacteria |
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Apart from gram stainging and culture, what is another test used to detect the presence of a pathogen?
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Latex agglutination antigen assay
ex: Streptococcus and Cryptococcus |
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What is meningitis?
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Inflammation of the meninges
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Which is more prevalent, viral or bacterial meningitis?
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Viral
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Which is more deadly, viral or bacterial meningitis?
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Bacterial
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What are the 5 main symptoms of meningitis?
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1. Fever
2. Stiff Neck 3. Headache 4. Altered mental status 5. Photophobia |
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What are the 3 major familis of viruses that cause menigitis?
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1. Enteroviruses
2. Herpesviruses 3. Arboviruses (spread by insects) |
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What is encephalitis?
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Infection involving parenchyma of brain
(Meningitis is limited to meninges) |
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What are the 3 mechanisms by which pathogens enter the CNS?
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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) |
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Does everyone with bacterial sepsis develop a CNS infection?
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NO, not all bacteria are able to cross an intact BBB
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