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
The microscopic finding of macrophages containing ingested RBCs (erythrophagocytosis) or hemosiderin granules indicates?
Intracranial hemorrhage
Detection of fibrin degradation product _______ by later agglutination immunoassay indicates fibrin formation at a hemorrhage site
D-dimer
What cell count is performed routinely on CSF specimens?
Leukocyte (WBC) count
Normal adult CSF contains __ to __ WBCs/uL
0 to 5 WBCs/ uL
For QC of CSF and other body fluid cell counts, all diluents should be checked _______ for contamination by examining them in a counting chamber under 400x magnification
biweekly
Dilution for total cell counts are made with _________, mixed by inversion, and loaded into the hemocytometer with a Pasteur pipette
normal saline
Any cell count should be performed immediately because WBCs (particularly granulocytes) and RBCs begin to lyse within _______, and 40% of WBCs disintegrate after ______
RBCs lyse within 1 hour
40% of WBCs disintegrate after 2 hours
Specimens that contain ___ WBCs or ___ RBCs/uL may appear clear, so it is necessary to examine all specimens microscopically
200 WBCs/uL
400 RBCs/uL
Specimens that cannot be analyzed immediately should be refrigerated up to how many hours?
4 hours
The speed of the cytocentrifuge should be checked ______ with a tachometer
monthly
Which has higher WBCs present in their CSF? Adult or children?
Children have higher WBCs present , and as many as 30 mononuclear cell/uL can be considered normal in newborns
Technical Tip: The number of squares counted for CSF varies between laboratories. If a different number of squares is counted, use the standard Neubauer formula to obtain the number of cells per microliter
THANK YOU SO MUCH!
For WBC count, specimens requiring dilution can be diluted in the manner described, by substituting __________ to lyse the RBCs
3% glacial acetic acid
Adding this stain to the diluting fluid stains the WBCs, providing better differentiation between neutrophils and mononuclear cells
Methylene blue
In a CSF WBC count, how many drops of mixed specimen are dropped in a clean tube?
4 drops
In a CSF WBC count, how many minutes would you allow the pipette to sit before discarding the first drop and loading the hemocytometer?
1 minute
If nondisposable counting chambers are used, they must be soaked in bactericidal solution for at least how many minutes?
15 minutes
Lymphocyte to monocyte ratio in Adults and Children
Lymphocyte to Monocyte Ratio
Adult: 70:30
Children: 30:70
The cells found in normal CSF are primarily ________ and ________
lymphocytes and monocytes
In addition to bacterial meningitis, increased neutrophils are seen in ______ stages (1 to 2 days) of viral, fungal, tubercular, and parasitic meningitis
early stages
The presence of increased number of normal cells is considered abnormal, this is termed as?
Pleocytosis
Cytocentrifuge Recovery Chart: Identify the number of cells on cytocentrifuge slide
Number of WBCs Counted in Chamber:
0
1-5
6-10
11-20
21
0 = 0-40
1-5 = 20-100
6-10 = 60 -150
11-20 = 150-250
21 = 251
High CSF WBC count of the majority is lymphocytes and monocytes that is slightly elevated suggests meningitis of _____, _____, _____, or ______ origin
viral, tubercular, fungal, or parasitic origin
High CSF WBC count of the majority is neutrophils is indicative of?
Bacterial meningitis
Although of little clinical significance, what WBC type may be increased after hemorrhage in the CNS, repeated lumbar punctures, and injection of medications or radiographic dye?
Neutrophils
Neutrophils with ______ nuclei indicate degenerating cells
pyknotic
These are seen as a result of contamination from bone marrow during the spinal tap and this is found in approximately 1% of specimens
NRBCs (Nucleated RBCs)
True or False
After cytocentrifugation, neutrophils may contain cytoplasmic vacuoles
True
Capillary structures and endothelial cells may be seen after a?
Traumatic tap
A mixture of lymphocytes and monocytes is common in cases of what type of meningitis? (3)
Viral
Tubercular
Fungal
Increased eosinophils are seen in the CSF in association with parasitic infection and what fungal infection?
Coccidiodes immitis
Macrophages appear within __ to __ hours after RBCs enter the CSF and frequently are seen after repeated taps
2 to 4 hours
Further degradation of the phagocytized RBCs result in the appearance of dark blue or black iron-containing __________
Hemosiderin granules
These represent further degeneration and are iron-free, consisting of hemoglobin and unconjugated bilirubin
Yellow hematoidin crystals
Lymphoblasts, myeloblasts, and monoblasts in the CSF are seen frequently as a serious complication of?
Acute leukemia
These are cells from the epithelial lining of the choroid plexus. They are seen singularly and in clumps. Usually nucleoli are absent, and nuclei have a uniform appearance.
Choroidal cells
These are cells from the lining of the ventricles and neural canal. They have less defined cell membranes and frequently are seen in clusters. Often nucleoli are present.
Ependymal cells
These cells represent lining cells from the “arachnoid”. Usually they are seen in clusters and may be seen with systemic malignancies.
Spindle-shaped cells
These are cells seen in the CSF and also indicate dissemination from the lymphoid tissue. They resemble large and small lymphocytes and usually appear in clusters of large, small, or mixed cells.
Nuclei may appear “cleaved”
Lymphoma cells
These are cells primarily from malignancies in the lung, breast, renal system, and gastrointestinal system
Metastatic carcinoma cells of nonhematologic origin
Cells from “PRIMARY CNS TUMORS” include?
Astrocytomas
Retinoblastomas
Medulloblastomas
Reference value for total CSF protein
15 to 45 mg/dL
Chemical Test performed most frequently on CSF
Protein determination
It is the major beta-globulin present
Transferrin
Alpha globulins include primarily ________ and _______
haptoglobin and ceruloplasmin
True or False
CSF contains protein fractions similar to those found in serum; however, the ratio of CSF proteins to serum proteins varies among the fractions
True
What makes up most of the CSF protein?
Albumin
Second most prevalent fraction in the CSF?
Transthyretin (previously called prealbumin)
It is a separate carbohydrate-deficient transferrin fraction seen in CSF but not in serum
tau protein
What is the primary CSF gamma globulin?
IgG
What immunoglobulin has only a small amount in the CSF?
IgA
True or False
IgM, fibrinogen, and beta lipoprotein are normally found in normal CSF
False, they are NOT found in normal CSF
Abnormally low values of protein occurs when?
Fluid is leaking from the CNS
These are the most common causes of elevated CSF protein
Meningitis
Hemorrhagic conditions that damage the blood-brain barrier
CSF/Serum albumin index formula:
CSF albumin (mg/dL) / Serum albumin (g/dL)
An index value less than 9 in CSF/Serum albumin index represents an?
Intact blood brain barrier
In Normal IgG index, this value indicates IgG production within the CNS
greater than 0.70 (> 0.70)
The primary purpose for performing CSF protein electrophoresis is to detect what?
Oligoclonal bands (represents inflammation within the CNS)
Oligoclonal bands are located in what region of the protein electrophoresis?
Gamma region
It is a major component of the myelin nerve sheath surrounding axons of nerves in the nervous system
Myelin basic protein (MBP)
The presence of MBP indicates recent destruction of the?
Myelin sheath (demyelination)
