CSF Interpretation Flashcards
Where is CSF produced?
Subarachnoid space and choroid plexuses
How many choroid plexuses are there?
4
What drains CSF?
Arachnoid villi
How does CSF get to the subarachnoid space?
Via lateral apertures of 4th ventricle
What does CSF surroung?
All aspects of central nervous tissue
What are CSF functions?
Physical support, pressure regulation, nutrients, transmitters
In general, CSF contains _____ K, Ca, glucose, and protein than serum
Less
In general, CSF contains _____ Cl, Na, and Mg than serum
More
Where can you obtain CSF?
Cisterna magna or lumbar
Which direction does CSF predominantly flow?
Caudally (collect CSF caudal to lesion)
What are contraindications to CSF collection?
ICP, coagulopathy, malformations
What is the sensitivity and specificity of a CSF tap?
Usually very sensitive but non-specific
How soon after collection should CSF be analyzed?
Within an hour; purple top tube + serum + hetastarch or refrigerate thereafter
How will using a purple top tube affect CSF analysis?
Falsely elevates protein
What color is caused by old hemorrhage and accumulation of blood pigments?
Xanthochromic (straw yellow)
How much glucose is in CSF?
80% of what is in serum
How much protein is in CSF?
Significantly less (reported as mg/dL in CSF and g/dL in serum)
What is normal protein for a cisterna CSF tap?
<25mg/dL
What is normal protein for a lumbar CSF tap?
<35mg/dL
What is a normal WBC count for CSF?
<5/microliter
Should RBC be in a CSF analysis?
Not unless there is disease or poor collection technique
What is the most helpful aspect of CSF evaluation due to its high specificity?
Cytology
How does Listeria monocytogens affects CSF?
Mononuclear pleocytosis
How does thromboembolic meningoencephalitis (Histophilus somnus) affect CSF?
Neutrophilic pleocytosis, xanthrochromic/cloudy
Indicates prior hemorrhage
Xanthrochromic (yellow discoloration)
