Lesson 6: Cerebrospinal Fluid Flashcards
It provides a physiological system to supply nutrients to the nervous tissue, removing metabolic wastes, maintain intracranial pressure, and produce a mechanical barrier to cushion the brain and spinal cord against trauma
Cerebrospinal Fluid (CSF)
Outer layer of the meninges that lines the skull and vertebral canal
Dura mater
To maintain a stable volume, the circulating CSF is reabsorbed back into the blood capillaries in the ___________ at a rate equal to its production
arachnoid granulations/villae
A space between the arachnoid and pia mater where CSF flows
Subarachnoid space
A thin membrane lining the surfaces of the brain and spinal cord that is part of the meninges
Pia mater
Filamentous (spiderweb-like) inner membrane of the meninges
Arachnoid
The brain and spinal cord are lined by the?
Meninges
Three layers of the meninges
Dura mater (hard mother)
Arachnoid (spiderweb-like)
Pia mater (gentle mother)
CSF is produced in the?
Choroid plexus of the two lumbar ventricles and the third and fourth ventricles
How much CSF is produced in adult every hour?
20 mL
Volume of CSF in adults and neonates
Adults: 90 to 150 mL
Neonates: 10 to 60 mL
These act as one-way valves that respond to pressure within the CNS and prevent reflux of the fluid
Cells of the arachnoid granulations
2 diseases that cause disruption of the blood-brain barrier which allows WBCs, proteins, and additional chemicals to enter the CSF
Meningitis
Multiple sclerosis
This is the tight-fitting structure of the endothelial cells in the choroid plexus that prevent the passage of many molecules
Blood-brain barrier
Where is CSF collected by lumbar puncture?
Between the 3rd and 4th or
Between the 4th and 5th lumbar vertebrae
How many specimens are collected for CSF?
3 tubes
Designated sections for the 3 tubes collected for CSF
Tube 1: Chemistry and Serology
Tube 2: Microbiology
Tube 3: Hematology
This tube is used for chemical and serological tests because these tests are least affected by blood or bacteria introduced as a result of the tap procedure.
Tube 1
This tube is used for the cell count because it is the least likely to contain cells introduced by the spinal tap procedure.
Tube 3
True or False
A fourth tube may be drawn for the microbiology laboratory to better exclude skin contamination or for additional serological tests
True
If the tests are not possible to perform, specimens are maintained in the following manner:
Hematology:
Microbiology:
Chemistry and Serology:
Hematology: refrigerated up to 4 hours
Microbiology: remain at room temperature
Chemistry and Serology: Frozen
Technical Tip: Cells must be counted within 1 hour of collection when the specimen is maintained at room temperature
Yehey!
This tube is usually is designated for testing in the microbiology laboratory
Tube 2
True or False
Tests for CSF are performed on a STAT basis
True
After testing, what should be done if there is excess fluid?
It should not be discarded and should be frozen until there is no further use for it
A cloudy, turbid, or milky specimen can be the result of an increased concentration of?
Protein
Aside from increased concentration of proteins, a cloudy CSF specimen could be indicative of infection, with it being caused by the presence of?
White blood cells
The major terminology used to describe CSF appearance are:
Crystal-clear
Cloudy or Turbid
Milky
Xanthochromic
Hemolyzed/Bloody
Technical Tip: If only one tube can be collected, it must be tested first by microbiology
Kudos to Bacteria!!
What is the distribution of blood from a cerebral HEMORRHAGE throughout the three CSF specimen tubes?
There is equal distribution of blood on the 3 CSF specimen tubes
Xanthochromia vary on the amount of blood and length of time it has been present:
Pink:
Orange:
Yellow:
Pink: very slight amount of oxyhemoglobin
Orange: heavy hemolysis
Yellow: conversion of oxyhemoglobin to unconjugated bilirubin
The most common factor that cause Xanthochromia
Presence of RBC degradation products
Technical Tip: It is not unusual for cell counts requested to be performed on both Tubes 1 and 4 to check for cellular contamination by the puncture
WOW! THAT’S GREAT!
It is a term used to describe CSF supernatant that is pink, orange, or yellow
Xanthochromia
Traumatic collection is also known as?
Tap
Grossly bloody CSF can be an indication of what type of hemorrhage?
Intracranial hemorrhage
Fluid collected from a traumatic tap may form clots due to the introduction of what in the specimen?
plasma fibrinogen
What is the distribution of blood from a traumatic tap throughout the three CSF specimen tubes?
Tube 1: Heaviest concentration
Tube 2 and 3: amount will gradually diminish
Why does bloody CSF caused by intracranial hemorrhage do not clot?
It does not contain enough fibrinogen
A classic “web-like pellicle” is associated with ___________ and can be seen after overnight refrigeration of the fluid
tubercular meningitis
To examine a bloody fluid for the presence of xanthochromia, the fluid should be centrifuged in a ____________ and the supernatant examined against a ___________
centrifuged in a microhematocrit tube
examined against a white background
RBCs must remain in the CSF for approximately how many hours before noticeable hemolysis begins?
2 hours