Body Fluids Flashcards
What are the major functions of cerebrospinal fluid?
- physiological system to supply nutrients to central nervous system
- remove metabolic waste
- mechanical barrier to cushion brain and spinal cord from trauma
What is the normal volume of cerebrospinal fluid?
140 -170 mL
Where does the cerebrospinal fluid flow?
in the subarachnoid space between the pia mater and arachnoid
What is the purpose of the blood-brain barrier?
protects and restricts entry of macromolecular from blood to cerebrospinal fluid to brain
How is cerebrospinal fluid collected?
by lumbar puncture beneath third, fourth, or fifth vertebrae
What cerebrospinal fluid tubes belong to which department?
1: Chemistry/Serology
2: Microbiology
3: Hematology Cell Count
4: Cytology/Extra
How should you handle a cerebrospinal fluid collection if it cannot done be done STAT?
Hematology: Refrigerated
Chemistry: Frozen
Microbiology: Room Temperature
What does a clear cerebrospinal fluid indicate?
normal
What does a cloudy/turbid/milky cerebrospinal fluid indicate?
- protein or lipid
- WBC/Bacteria from Meningitis
- RBC from Hemorrhage/Traumatic Tap
What does a xanthochromia cerebrospinal fluid indicate?
- supernatant with pink/orange/yellow color
- RBC Degradation
- others: increased bilirubin or protein concentration, presence of carotene or melanoma pigment
How would a subarachnoid hemorrhage affect the cerebrospinal fluid?
- xanthochromia present in all tubes
- blood cerebrospinal fluid caused by intracranial hemorrhage does not contain enough fibrinogen to clot
- presence of macrophages containing ingested RBCs or hemosiderin granules
- positive D-Dimer indicates formation of fibrin at hemorrhage site
How would a traumatic tap affect the cerebrospinal fluid?
- uneven distribution of blood between four tubes
- clot formation from plasma fibrinogen leaking into cerebrospinal fluid
- supernatant usually clear
What are the normal cell counts for cerebrospinal fluid?
- 0-5 WBC/uL in adults
- 0-30 mononuclear cells/uL in neonates
Why do you need to perform cerebrospinal fluid immediately?
WBC/RBC begin to lyse in less than an hour, 40% of granulocytes disintegrate after two hours
What is the hemocytometer calculation equation?
(cells counted x dilution)/(# of squares x 0.1 uL)
What are the normal findings in cerebrospinal fluid?
no RBC, 0-5 lymphocytes and/or monocytes, ependymal cells
What are the abnormal findings in cerebrospinal fluid?
any RBCs, RBCs ingested in macrophages, WBC>5, neutrophils, blasts, malignant cells, plasma cells, reactive lymphocytes, eosinophils, bacteria, fungi, hemosiderin
What disease states are associated with increased lymphocytes?
HIV & AIDS, multiple sclerosis, viral infections
What disease states are associated with increased eosinophils?
parasitic infections, fungal infections
What disease states are associated with increased neutrophils?
meningitis, repeated lumbar punctures, injection of medications/dyes
What disease states are associated with increased macrophages?
appear 2-4 hours after RBCs enter cerebrospinal fluid, previous hemorrhage
What is a normal protein level in cerebrospinal fluid?
15-45 mg/dL in adults; higher in infant/elderly
What is the most abundant protein found in cerebrospinal fluid?
albumin
What does decreased protein in cerebrospinal fluid?
fluid leaking from central nervous system
What does increased protein in cerebrospinal fluid?
- damage to blood-brain barrier (meningitis, hemorrhage)
- immunoglobulin production in central nervous system
- decreased clearance of normal protein
- degradation of neural tissue
What is considered a normal value for plasma glucose?
60-70% of plasma glucose (plasma glucose of 1000 mg/dL would have a normal cerebrospinal fluid glucose of 65 mg/dL)
What does an elevated serum glucose indicate?
elevated cerebrospinal fluid glucose
What does a decreased cerebrospinal fluid glucose help determine?
causative agent of meningitis
What does a decreased glucose, increased leukocytes with neutrophils in cerebrospinal fluid indicate?
bacterial
What does a decreased glucose, increased leukocytes with lymphocytes in cerebrospinal fluid indicate?
tubercular
What does a normal glucose with increased leukocyte with lymphocytes in cerebrospinal fluid indicate?
viral
What significant values show up in bacterial meningitis?
increase in neutrophils, low cerebrospinal fluid glucose, high cerebrospinal fluid lactate, high cerebrospinal fluid protein
What significant values show up in viral meningitis?
increase in lymphocytes and monocytes, normal cerebrospinal fluid glucose, normal cerebrospinal fluid lactate
What are serous fluids?
closed cavities of body lined with two serous membranes; serous fluid beneath membranes provide lubrication as surfaces move
What is parietal fluid?
fluid that lines cavity wall
What is visceral fluid?
fluid that covers organs within cavity
How is serous fluid formed?
ultrafiltrates of plasma; production and reabsorption subject to hydrostatic and oncotic pressure from capillaries serving the cavity