BODY FLUIDS Flashcards
is an ultrafiltrate of plasma containing glucose, electrolytes, amino acids, and other small molecules found in plasma, but it has very little protein and few cells.
ANS:
Cerebrospinal fluid (CSF)
CSF is withdrawn from the
subarachnoid space
performed by inserting the needle between the fourth and fifth lumbar vertebrae (L4-L5).
Lumbar puncture (spinal tap)
This location is used because the spinal cord stops near L2, and a needle introduced below this level will miss the cord.
L4-L5
Precautions in getting CSF
= only a small amount of CSF for analysis
= only if the benefits are thought to outweigh the risks.
a) In bleeding disorders, lumbar puncture can cause hemorrhage that can compress the spinal cord.
b) increased spinal column pressure, (brain tumor and other conditions), removal of CSF can cause the brain to herniate, compressing the brain stem and other vital structures and leading to irreversible brain damage or death.
c) Meningitis may be caused by bacteria introduced during the puncture.
d) avoid contamination with skin flora.
e) CSF should be refrigerated if analysis is delayed.
AFTER CARE OF GETTING CSF
- puncture site covered with a sterile bandage.
- patient should remain lying for four to six hours after the lumbar puncture.
- Vital signs should be monitored every 15 minutes for four hours, then every 30 minutes for another four hours.
- The puncture site should be observed for signs of weeping or swelling for 24 hours.
- The neurological status of the patient should also be evaluated for such symptoms as numbness and/or tingling in the lower extremities.
Risk of Lumbar Tap
a) headache
b) stiff neck and nausea
c) puncture site leak
d) puncture site appears red and swollen
e) puncture site infection
NORMAL RESULTS of CSF •gross appearance: •specific gravity: •glucose: •total protein: •LD: •lactate: •leukocytes (white blood cells): - (adults and children); - in infants; - (newborns) •differential: - lymphocytes; - monocytes and macrophages; - other cells •culture: •RBC count:
• gross appearance: clear and colorless
• specific gravity: 1.006–1.009
• glucose: 40–80 mg/dL
• total protein: 15–45 mg/dL
• LD: 1/10 of serum level
• lactate: less than 35 mg/dL
• leukocytes (white blood cells):
- 0–6/microL (adults and children);
- up to 19/microL in infants; up to 30/microL (newborns)
• differential: 60–80 percent lymphocytes;
up to 30 percent monocytes and macrophages;
other cells 2 percent or less.
Monocytes and macrophages are somewhat higher in neonates, and make up as much as 80 percent or more, with only 20 percent or less being lymphocytes.
•culture: sterile
• RBC count: normally, none unless the needle passes though a blood vessel on route to the CSF
Assignments of Test Tubes for CSF
1st tube: chemical or serologic tests
2nd tube: microbiological tests including molecular diagnostics
3rd tube: microscopic examination, Differential Count
4th tube: cytological examination
This tube assignment reduces
- the chances of a falsely elevated white cell count caused by a traumatic tap (bleeding into the subarachnoid space at the puncture site),
- and contamination of the bacterial culture by skin germs or flora.
GROSS EXAMINATION OF CSF:
Straw, pink, yellow, or amber pigments (xanthochromia)
presence of bilirubin, hemoglobin, red blood cells, or increased protein
GROSS EXAMINATION OF CSF:
Turbidity
increased number of cells
Differente a subarachnoid hemorrhage from a traumatic tap.
The latter is often associated with sequential clearing of
CSF as it is collected; streaks of blood in an otherwise clear
fluid; or a sample that clots.
CSF GLUCOSE
<40mg/dl
bacterial and fungal meningitis and in malignancy
CSF PROTEIN
Normal:
15-40mg/dl
CSF LACTATE
- increased lactate
- no increase
- bacterial and fungal meningitis =increased lactate
- viral meningitis = no increase
This enzyme is elevated in bacterial and fungal meningitis, malignancy, and subarachnoid hemorrhage.
LACTATE DEHYDROGENASE
The number of white blood cells in CSF is very low, predominated by
Lymphocytes