Term
| Go through the path of CSF from lat ventricles to reabsorption? |
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Definition
1st & 2nd>interventricular foramen (of Monro)>3rd>Cerebral aqueduct (Sylvius)>4th>Foremen of Luschka(lat) or Magendie(med)>arachnoid granulations>superior sagittal sinus
-Note; the choroid plexus secretes CSF into all ventricles |
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Term
| How much CSF does a normal adult have? How much do they make a day and what makes it? |
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Definition
-A normal adult has between 90 and 150 mL
-400-500mL is secreted a day
-70% of that is secreted by the choroid plexus |
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Term
| What is the normal tonicity and pH of CSF? |
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Definition
-It isotonic with serum (a bit under 300mOsm/L)
-It has a normal pH of 7.33 (a bit more acidic than blood which is 7.4 for arterial) |
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Term
| Compared to serum, what are the Na+, K+, Ca2+, Mg2+, Cl-, HCO3- and glucose levels in CSF? |
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Definition
-Na+ is equal
-Cl- and Mg2+ are higher in CSF
-K+, Ca2+, HCO3-, and glucose are lower
-Also, there is a much lower protein content |
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Term
| Are there white cells in the CSF? |
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Definition
-A few monocytes and leukocytes is normal, but not many
-But if we see many or polymorphonuclear leukocytes (i.e. B.E.*N. granulocytes), that is abnormal, and often indicative of bacterial meningitis |
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Term
| What do increased protein levels in CSF indicate? |
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Definition
| -May indicate a CNS tumor |
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Term
| What are the two ways we get communicating hydrocephalus? What could cause each? |
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Definition
-Too much production or not enough reabsorption
-Too much production can result from a choroid plexus papilloma
-Not enough reabsorption can result from meningitis |
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Term
| What is normal pressure hydrocephalus? What are the symptoms? |
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Definition
-It is a common type of communicating hydrocephalus that presents with CSF pressure that is a bit high, but still normal, because the ventricles expand to accommodate more volume
-This presses the cortex against the skull and causes the classic combo of; dementia, gait apraxia, and urinary incontinence
-Most common in elderly (esp. since there is less tissue) |
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Term
| What is gait apraxia anyway? |
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Definition
-It is the inability to initiate walking even though leg strength and coordination is normal when seated
-It is indicative of cerebral pathology (frontal lobe tumors, hydrocephalus, etc.)
-Patients will have a shuffle where they don't lift their feet
-Also known as a "magnetic gait" |
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Term
| Give two example of what causes noncommunicating hydrocephalus? |
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Definition
-Arnold Chiari malformation
-Dandy Walker malformation |
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Term
| What is the Dandy Walker malformation? |
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Definition
-The foramina of Magendie and Luschka don't open
-Causes dilation of the 4th ventricle
-Also presents with agenesis of the cerebellar vermis and splenium (back part) of the corpus callosum |
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Term
| What is holoprosencephaly? |
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Definition
-Remember, prosencephalon just means forebrain
-Therefore, this is when there is incomplete separation of the cerebral hemispheres
-Mainly this is seen in trisomy 13 (Patau) |
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Term
| What forms the blood-brain and blood-CSF barriers? What helps maintain the blood-brain barrier? |
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Definition
-Capilares of brain and choroid plexus, respectively
-Not, it is not the arachnoid granulations that form what we call the blood-CSF barrier
-Water diffuses across each readily, but glucose needs a transporter
-Astrocytes help maintain the blood-brain barrier |
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Term
| What is hydrocephalus ex vacuo? |
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Definition
| -When there is CSF where brain tissue has been lost (from atrophy, surgery, stroke, etc.) |
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