Body Fluids Flashcards

1
Q

CSF
Flows where?
Functions?

A
  • Flows in subarachnoid space
  • Functions to give physical support/protection, controlled chem environment to supply nutrients/remove wastes, and transport
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2
Q

Lumbar puncture area and tube order

A
  • L3/L4
    1. Chemistry/Serology
    2. Microbiology
    3. Hematology
    4. Extra/cytology
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3
Q

Why investigate CSF?

A
  • Infection
  • Demyelinating disease
  • Malignancy
  • Hemorrhage into CNS
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4
Q

What color is xanthrochromic CSF and why is it that color?

A

Yellow due to bilirubin from RBC breakdown in old hemorrhage

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5
Q

T/F: CSF from fresh hemorrhage tends to clot

A

False
CSF from traumatic tap (decreasing amounts of redness in each successive tube) tends to clot

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6
Q

4 main markers in CSF

A
  • Glucose
  • Protein (total/specific)
  • Lactate
  • Glutamine
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7
Q

How to prep CSF specimen for analysis

A

Always centrifuge even if clear/colorless!

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8
Q

Glucose in CSF
CSF transport
When to collect
Conc in CSF

A
  • Enters CSF through facilitative protein transport
  • Collect blood glucose 2-4 hrs prior
  • CSF glucose conc 60-70% of plasma glucose (but no longer applies once >600 mg/dL)
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9
Q

Hypoglycorrhachia

A

Decreased CSF glucose levels

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10
Q

Causes of hypoglycorrhachia + examples

A
  • Disorder in carrier-mediated transport of glucose into CSF
  • Active metabolism of glucose by cells/organisms
  • Increased metabolism by CNS
  • Examples: meningitis, meningeal neoplasia, brain tumor
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11
Q

Consumption of glucose usually has increased _____ level due to ______ glycolysis by organisms or tissue

A

Lactate
anaerobic

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12
Q

What do CSF protein levels reflect?

A

Selective ultrafiltration of CSF blood-brain barrier

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13
Q

Total protein conc in CSF

A

0.5%-1.0% of plasma
Not proportional due to specificity of ultrafiltration process

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14
Q

Which analysis should accompany CSF protein analysis?

A

Serum

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15
Q

Causes of decreased protein CSF

A
  • Decreased dialysis of proteins from plasma
  • Increased protein loss (removal of excessive volumes of CSF)
  • Leakage from a tear in the dura, CSF otorrhea (ear), or CSF rhinorrhea (nose)
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16
Q

How to detect CSF leakage

A

Analysis of beta-transferrin bc it’s unique to CSF

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17
Q

Causes of increased protein in CSF

A
  • Lysis of contaminant blood from traumatic tap
  • Increased permeability of epithelial membrane
  • Increased production by CNS tissue obstruction
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18
Q

How do bacterial/fungal infections affect the BBB?

A

Increase permeability

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19
Q

T/F: Protein in CSF is NOT diagnostic of infectious meningitis - helpful though

A

True

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20
Q

Normal CSF and serum prealbumin conc. Why is it measured in both?

A
  • CSF > serum conc
  • Used to normalize IgG values to determine source
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21
Q

Describe proteins of highest interest in CSF

A
  • Albumin: must cross BBB
  • IgG: Can be produced by local synthesis from plasma cells within the CSF
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22
Q

Index value of protein which indicates intact BBB

A

protein index < 9

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23
Q

IgG index
How to calculate
What does it help diagnose
Normal value

A
  • Use CSF serum index
  • Helps diagnose demyelinating diseases (MS, SSPE)
  • Normal IgG < 0.73
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24
Q

How does serum albumin affect CSF levels?

A

Increases CSF levels due to membrane permeability

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25
Q

What does increased CSF IgG without concomitant CSF albumin suggest?

A

Local production (MS/SSPE)

26
Q

How does bacterial meningitis affect membrane permeability and protein production?

A

Increases both

27
Q

When to perform CSF protein electrophoresis?

A
  • When CSF protein is elevated without clear etiology
  • Normal CSF protein in pts with inflammatory disease symptoms
28
Q

Oligoclonal bands

A
  • Multiple banding in gamma region, involves small number of IgG clones
  • Presence of oligoclonal bands supersedes the report of normal protein levels
  • Usually seen with MS or SSPE
29
Q

Lactate CSF marker
Useful indicator of what?
Collect in which tube?

A
  • Indicator of anaerobic metabolism
  • Sodium fluoride tube bc time critical
30
Q

Glutamine
Formation
Correlate to…
Elevated in pts with ___

A
  • Ammonia + glutamate -> glutamine
  • Ammonia not stable for testing but glutamine levels correlate to ammonia in CNS
  • Hepatic encephalopathy
31
Q

Serous fluids
Parietal membrane
Visceral membrane
Definition

A
  • Parietal membrane = lines cavity wall
  • Visceral membrane = line organs
  • Def: ultrafiltrate of plasma
32
Q

Pleural
Pericardial
Peritoneal

A
  • Lung
  • Heart
  • Abdominal
33
Q

Effusion

A

Accumulation of serous fluid

34
Q

Transudate

A
  • Occurs during various system disorders that disrupt fluid filtration, fluid reabsorption, or both
  • Congestive heart failure, hepatic cirrhosis, nephrotic syndrome
35
Q

Exudate

A
  • Occurs during inflammatory processes that result in damage to blood vessel walls, body cavity membrane damage, or decreased reabsorption by the lymphatic system
  • Infections, inflammation, hemorrhages, malignancies
36
Q

Tests used to differentiate btwn transudate and exudate

A
  • Fluid appearance
  • Specific gravity
  • Amylase
  • Glucose
  • Lactate dehydrogenase
  • Proteins
  • Ammonia
  • Lipids
  • pH
37
Q

Pleural fluid
Location
How formed?
Volume
Exits how

A
  • Outer layer of pleural space (systemic circulation) and inner (visceral) layer for bronchial circulation
  • Ultrafiltrate of plasma
  • 3-20 ml
  • Drains into lymphatics of visceral pleura and visceral circulation
38
Q

Thoracentesis

A

Removal of pleural fluid (from thorax)

39
Q

Pleural fluid transudates

A
  • Secondary to non-pleural pathology
  • Biochem/cellular abnormalities consistent with non-inflammatory changes in fluid dynamics
  • E.g., hypoproteinemia due to malnutrition -> reduced osmotic pressure, reduced fluid resorption in capillaries
40
Q

Pleural fluid exudates

A
  • Primary involvement of the pleura and lung (infection)
  • Immediate attention required
  • E.g., infection-mediated damage to membranes allowing increased fluid entry into pleural space
41
Q

How did transudates/exudates used to be determined? What do we use now?

A
  • Used to be based on protein concentration
  • Now use Light’s criteria
42
Q

Pleural fluid
Cholesterol
Fluid to serum cholesterol ratio
Fluid to serum bilirubin ratio
Further characterization

A
  • Exudate chol > 60 mg/dL
  • Exudates ratio >= 0.3
  • Exudates ratio >= 0.6
  • Glucose, lactate, amylase, triglyceride, pH, uric acid
43
Q

Pleural fluid lab findings
Inflammation
Pancreatitis
Triglyceride
pH
Uric acid

A
  • Inflammation: reduced glucose or increased lactate
  • Pancreatitis: increased amylase
  • Triglyceride: 2-10X serum levels, thoracic duct leakage
  • pH <= 7.2 means infection
    pH close to 6.0 means esophageal rupture
  • Uric acid: significantly lower in exudates than transudates
44
Q

Pericardial fluid
Causes of pericardial effusions
Transudate/exudate categorization
Volume
Pericardiocentesis done when?

A
  • Causes: damage to mesothelium
  • Almost always exudates
  • Normally fluid < 50 ml
  • Dangerous procedure, rarely performed. Do only if cultures needed for infection or cytology for sus malignancy
45
Q

Peritoneal fluid
Indicator of disease?
Excess fluid terminology
Fluid visualized by ____

A
  • Fluid > 50 ml indicates disease
  • Ascites
  • Ultrasound
46
Q

Peritoneal fluid
Cause of exudate
Cause of transudate
WBC

A
  • Primary pathology (metastatic ovarian, prostate, or colon cancer, infective peritonitis)
  • Secondary pathology (portal hyper tension most common)
  • PMNs < 250 cells/um: peritonitis
47
Q

How to differentiate causes of peritoneal fluid issues

A
  • Serum-ascites albumin gradient (SAAG)
  • (Serum albumin ) - (fluid albumin) = SAAG
  • Difference >= 1.1 g/dL means transudative
  • Difference < 1.1 g/dL means exudative
48
Q

Amniotic fluid
Function
Sources
Continuous contact with ___

A
  • Functions to cushion fetus, regulate temp, allow fetal movement, matrix for influx of glucose/sodium/potassium, fetal urination/swallowing balance
  • Sources: mother, mainly by transudation across fetal skin; last half of pregnancy fetal urination major volume source bc skin less permeable
  • Fetal GI tract, buccal cavity, lungs
49
Q

Amniocentesis

A
  • Amniotic sac puncture
  • Done less bc can get baby DNA from mom’s blood
  • Ultrasound guided
  • Analyze for: congenital diseases, neural tube defects, HDN, fetal pulmonary dev
  • Mainly done to assess fetal lung maturity
50
Q

Hemolytic disease of the newborn (HDN)
Definition
Sample handling

A
  • Definition: syndrome of fetus resulting from incompatibility between maternal and fetal blood (Rh- mom, Rh+ baby). Maternal Ab to fetal RBCs cause Hgb breakdown and bilirubin may appear in amniotic fluid
  • Sample centrifuged fast and protected from light
51
Q

Neural tube defects
Screen initially done for __
Calculate using ___

A
  • Screen maternal serum for alpha-fetoprotein (AFP)
  • Calculate using multiple of median (MoM)
52
Q

Fetal lung maturity
Definition
Lipid content as lungs mature
Quant tests

A
  • Definition: Determine if sufficient specific phospholipids are present to prevent alveolar collapse if fetus was delivered
  • As lungs mature, see phospholipid increase (PG and lecithin)
  • Quant tests: L/S ratio (2.0 breakpoint), PG, and lamellar body counts
53
Q

What is given to the mother to enhance fetal surfactant production?

A

Steroids

54
Q

PG test in AF

A
  • PG must be performed along with L/S ratio
  • PG increases proportionally with lecithin
  • Diabetic moms: dev of PG delayed
55
Q

Lamellar body counts in AF

A
  • Phospholipids secreted by type II alveolar cells
  • Lamellated packets of surfactant conc can predict fetal lung maturity
56
Q

Sweat
Clinical use
Conc considered positive for disease
How is it measured?
Affected by ___

A
  • Cystic fibrosis (autosomal recessive, electrolyte/mucus secretion abnormalities)
  • Chloride > 60 mmol/L
  • Measure chloride levels in sweat mixed with DI water
  • Affected by hydration levels
57
Q

Synovial fluid
Formation
Synovial membrane secretes ____
Function
Volume
Sample prep

A
  • Formed as ultrafiltration of plasma across synovial membrane
  • Mucoprotein-rich hyaluronic acid gives viscosity
  • Functions as join lubricant and transport medium for delivery of nutrients and removal of cell wastes
  • Vol <= 3 ml
  • Add hyaluronidase to break down mucoprotein matrix
58
Q

Synovial fluid
Chemical analysis
Normal range
Synovial: serum glucose ratio

A
  • Total protein (TP), glucose, uric acid, LD
  • TP 1-3 g/dL
  • 0.9:1.0 normal best way to eval glucose levels
    Decreased ratio: inflammation and sepsis
59
Q

Uric acid normal range

A

6-8 mg/dL

60
Q

Lactic acid normal range and septic arthritis amounts

A
  • Normal < 25 mg/dL
  • Septic arthritis up to 1000 mg/dL