BODY FLUIDS Flashcards
What are serous membranes?
Connective tissue containing capillaries, and lymphatics, normally lined a single layer of mesothelial cells
What are synovial fluids?
The viscous fluid which acts as a lubricant between joints (such as shoulder + knee joints)
What does the pleural fluid cover & line?
Covers lungs and lines the thorax
What does the pericardial fluid cover?
Covers and surrounds the heart
What is thoracentesis?
Aspiration of pleural fluid
What is pericardiocentesis?
Aspiration of pericardial fluid
What is paracentesis?
Aspiration of peritoneal fluid
What is arthrocentesis?
joint aspiration of synovial fluid
What is fluid volume dependent on?
Formation, reabsorption and effusion
What is effusion?
An increase in fluid between serous membranes
What is a transudate, and what does it cause?
- Excess fluid due to systemic disease such as congestive heart failure
- It causes an increase in hydrostatic pressure and decreases in osmotic pressure due to low albumin
What is an exudate, and what does it cause?
- Excess fluid due to localized causes such as infection or inflammation
- Causes an increase in capillary permeability and a decrease in absorption
Aka known as pus
What is malignant mesothelioma?
A rare tumor associated with asbestos
What contributes to the deposition of crystals in joints? (5)
- Increasing age
- Familial predisposition
- Joint damage
- Alcoholism/High protein diet
- Metabolic disorders
What is gout and what does it involve?
- An autosomal dominant, inherited defect in purine metabolism
- Involves hyperuricemia and deposition of monosodium urate crystals (MSU)
What is pseudogout?
- Autosomal recessive inherited defect of inorganic metabolism
- Involves deposition of calcium pyrophosphate dehydrate (CPPD)
What are the characteristics of Monosodium Urate Crystals?
- Strongly birefringent
- Yellow when parallel
- Blue when perpendicular
- Needle or rod-shaped
What are the characteristics of Calcium Pyrophosphate Dihydrate (CPPD) Crystals?
- Weakly birefringent
- Blue when parallel
- Yellow when perpendicular
- Usually needle, rod-shapes, rhomboid or plates
Positive vs Negative Birefringence
Positive: appears blue
Negative appears yellow
What are the functions of CSF?
1) Mechanical protection: acts as a fluid shock absorber and protects from the pressure change
2) Chemical protection: buffers the brain providing a constant chemical environment necessary for proper neuronal signaling
3) Circulation: medium for the exchange of nutrients and waste products between the blood and nervous tissue
Where is CSF produced?
70% is formed by secretion from the choroid plexus
What is a choroid plexus?
Composed of capillary networks covered by ependymal cells that form CSF from blood plasma by filtration and secretion
What tubes for CSF are sent to which lab?
Tube 1: Chemistry, serology, immunology
Tube 2: For microbiology
Tube 3: For Hematology
What are the CSF microbiology media?
Blood and chocolate agar
Purpose of lactate test for CSF
Represent end products of glucose metabolism; high levels suggest bacterial infection and rule out viral
Purpose of Chloride test for CSF
Useful in diagnosis of tuberculosis
Purpose of Glutamine test for CSF
Product of ammonia + alpha-ketoglutarate. In severe liver disease, excess of ammonia can cause coma. Also increased in Reye’s syndrome.
Purpose of CK-BB test for CSF
Detects brain injury, optimum time of detection is 24-72hrs.
Purpose of D-Dimer for CSF
Increased in subarachnoid hemorrhage, normal in bloody tap
What results indicate a bacterial CSF?
- Elevated WBC count
- Neutrophils present
- Marked protein elevation
- Decreased glucose
- Elevated lactate
What results indicate a viral CSF?
- Elevated WBC count
- Lymphocytes present
- Moderate protein elevation
- Normal glucose & lactate
What results indicate a tubercular CSF?
- Elevated WBC count
- Lymphocytes and monocytes present
- Moderate to marked protein elevation
- Decreased glucose
- Elevated lactate
What results indicate a fungal CSF?
- Elevated WBC count
- Lymphocytes and monocytes present
- Moderate to marked protein elevation
- Normal to decreased glucose
- Elevated lactate
Which anticoagulants are suitable for the collection of Serous and Synovial fluids
EDTA is recommended (to prevent clotting)
What is the main consideration to be aware of when a CSF count is performed on an automated analyzer?
The background count must be performed to eliminate the possibility of contaminates being counted as nucleated cells.
What is considered a critical finding in serous fluids?
Malignant cells
What type of diluting fluid is used for Manual WBC count?
2% Acetic Acid hemolyzes the red
blood cells
What type of diluting fluid is used for Manual RBC count?
Saline
What type of diluting fluid is used for Manual PLT count?
1% Ammonium oxalate
What are the preferred microscopes when doing manual cell counts?
Neubauer or Brightline, Phase contrast microscope
When would you perform a manual WBC count?
PBF estimates are considerably lower than automated due to platelet clumps and obtaining a new sample is not feasible. If the analyzer is broken, and the manual is the backup method.
The cerebrospinal fluid that is yellow in color is sometimes referred to as
Xanthochromic
Which of the following would cause a low glucose level in a CSF?
Bacterial meningitis
Which cells can be seen in a “normal” adult CSF?
Lymphocytes and monocytes
What is indicated if the first tube collected for a CSF specimen is bloody but the remaining tubes are progressively clearer?
Traumatic tap
What does pleocytosis indicate in a CSF?
Increased number of WBC
Which fluid is often pre-treated with hyaluronidase?
Synovial Fluid
In a polarizing microscope, what order should the parts be to demonstrate crystals on a dark background?
Light Source, polarizer, crystal, analyzer
What does the presence of xanthochromia indicate in CSF?
RBC breakdown products
What are the primary cells seen in normal Synovial fluid?
Monocytes
What does birefringence indicate?
The ability to refract light in 2 dimensions @ 90 degrees to each other
What best describes a Serous Fluid function?
Fluid that provides lubrication against each membrane surface
When would NRBCs be seen in a CSF?
Bone Marrow Contamination
