Body Fluid Flashcards
(42 cards)
CSF
Liquid that surrounds the brain and spinal cord and flows in the subarachnoid space
Functions of CSF
1) Physical support and protection
2) Provision of controlled chemical environment to supply nutrients and removal of wastes
3) Intracerebral and extracerebral transport
Lumbar puncture is performed where?
L3/L4 and lower
CSF Tube order
Tube 1: Chemistry and serology
Tube 2: Microbiology
Tube 3: Hematology
Tube 4: extra or send out tests/cytology
Why do we collect a lumbar puncture and perform an investigation of CSF?
- for suspected CNS infection
- Demylinating disease
- Malignancy
- hemorrhage into CNS
Appearance of CSF
Color: colorless
Clarity: clear
NOTE
Cloudy: cellular particles and debris
Yellow: xanthochromia (blood is gone—older bleed)
Brown: old blood
Red: fresh blood
Traumatic tap gets clearer as tubes progress
What are the 4 main biochemical markers in CSF?
- Glucose
- Protein (total and specific)
- Lactate
- Glutamine
When should you collect a blood glucose when comparing glucose levels in CSF?
2-4 hours prior
T/F:
Increased CSF glucose levels are clinically significant
FALSE: it just confirms that there is hyperglycemia
What are the causes for decreased CSF glucose levels (hypoglycorrhachia)?
- Disorder in carrier-mediated transport of glucose into CSF
- Active metabolism of glucose by cells or organisms
- Increased metabolism by the CNS
___ in the CSF reflect selective ultrafiltration of the CSF BBB
Protein levels
T/F:
All proteins found in blood is found in CSF
TRUE, just in much lower levels
Total protein in CSF is ___-___% of plasma
0.5-1%
What are causes of decreased protein levels in CSF?
- Decreased dialysis of proteins from the plasma
- Increased protein loss (removal of excessive volumes of CSF)
- Leakage from a tear in the dura, CSF otorrhea (ear), or CSF rinorrhea (nose)
What are causes of increased levels of protein in CSF?
- Lysis of contaminant blood from traumatic tap
- Increased permeability of the epithelial membrane
- Increased production by CNS tissue
- Obstruction
- BBB becomes more permeable from bacterial or fungal infections
Albumin MUST cross the BBB because it is produced by the ___
Liver
What does a CSF serum albumin index of <9 indicate?
That the BBB is intact
What is the CSF serum albumin index equation?
(CSF albumin (mg/dL))/(Serum albumin (mg/dL))
T/F: IgG must cross the BBB to enter the CSF
FALSE: IgG can be produced by local synthesis from plasma cells within the CSF
What is the normal value of CSF IgG index?
<0.73
What does the IgG index aid in?
- Aids in the diagnosing demyelinating diseases - MS, SSPE
- MS is most common inflammatory demyelinating disease
What is the significance of seeing an oligoclonal band pattern in a CSF ELP
The presence of an oligoclonal band pattern supersede the report of normal protein levels and there is a cause for concern in the serum doesn’t show the same pattern.
Oligoclonal banding in the gamma region, involving a small number of IgG clones, are usually seen with MS or SSPE
What does testing for lactate tell us?
It is an indicator of anaerobic metabolism. Time critical and ideally collected in a NaFl tube
What does testing for Glutamine tell us?
Glutamine levels correlate to NH3 in the CNS and is elevated in patients with hepatic encephalopathy
