CHAPTER 12: SYNOVIAL FLUID Flashcards
Synovial fluid or otherwise known as?
Joint fluid
The synovial membrane contains specialized cells called?
synoviocytes
These secrete hyaluronic acid & a small amount of protein into the fluid
synoviocytes
Damage to the articular membranes produces
pain and stiffness in the joints, collectively referred to as
Arthritis
Synovial fluid is collected by needle aspiration called
arthrocentesis
In collecting synovial fluid, the barrel of the syringe is?
moistened with heparin (fluid)
Why is using powdered anticoagulant not recommended for athrocentesis?
because powdered coagulant could interfere during microscopic examinations (false positive for presence of crystals)
What are the main functions of synovial fluid?
- Reduce friction between the bones during joint movement by providing lubrication
- Provides nutrients to articulating cartilages
- Lessen shock of joint compression during activities (walking/jogging)
It is the wear & tear of joints; common in elder patients
Ostearthritis
It is an arthritis which causes autoimmune disorder
Rheumatoid arthritis
What tube type is used for gram stain and culture
Sterile heparinized or sodium polyanethol sulfonate (SPS)
What tube type is used for all other tests?
Nonanticoagulated
What tube type is used for glucose analysis?
Sodium fluoride
What tube type is used for cell counts?
Heparin or liquid ethylenediaminetetraacetic acid (EDTA)
What is the normal volume of synovial fluid? But the fluid level can increase to ________ with inflammation
<3.5 mL; >25 mL
What is the normal leukocyte count of synovial fluid?
<200 cells/ uL
What is the normal color of synovial fluid?
Colorless to pale yellow
What is the normal glucose-plasma difference of synovial fluid?
<10 mg/dL, lower than the blood glucose level
What is the normal value of crystals of synovial fluid?
none present
What is the normal value of the total protein for synovial fluid?
<3 g/dL
What is the normal viscosity of synovial fluid?
Able to form a string 4 to 6 cm long
What is the normal value of neutrophils for synovial fluid?
<25% of the differential
What are the routing laboratory testing done with the synovial fluid?
- WBC Differential count
- Gram staining and culture
- Microscopic examination for presence of crystals
Its laboratory findings are: Clear, yellow fluid
Good viscosity
WBCs <1000 L
Neutrophils <30%
Similar to blood glucose.
Noninflammatory
Its laboratory findings are:
Cloudy or milky fluid
Low viscosity
WBCs up to 100,000 L
Neutrophils <70%
Decreased glucose level
Crystals present
Crystal-induced
origin (Inflammatory)
Its laboratory findings are:
Cloudy, red fluid
Low viscosity
WBCs equal to blood
Neutrophils equal to blood
Normal glucose level
Hemorrhagic
What are the possible laboratory findings if the joint disorder is immunologic origin (inflammatory)?
- Cloudy, yellow fluid
- Poor viscosity
- WBCs 2,000 to 75,000 L
- Neutrophils >50%
- Decreased glucose level
- Possible autoantibodies present
What are the possible laboratory findings if the joint disorder is septic?
- Cloudy, yellow-green fluid
- Variable viscosity
- WBCs 50,000 to 100,000L
- Neutrophils >75%
- Decreased glucose level
- Positive culture and Gram stain
What is the color of the synovial fluid if its hemorrhagic?
there’s presence of blood (Determine if from traumatic tap)
Its has a greenish tinge commonly due to Pseudomonas aeruginosa
Septic
If the synovial fluid is deeper yellow in color it is possibly:
Non-inflammatory
and inflammatory
What are the pathologic significance of a noninflammatory joint disorder?
Degenerative joint disorders,
osteoarthritis
What is the pathologic significance of a septic joint disorder?
Microbial infection
What are the pathologic significance of a hemorrhagic joint disorder?
- Traumatic injury
- tumors
- hemophilia
- other coagulation
disorders - Anticoagulant overdose
Its pathologic significance are:
Immunologic disorders, rheumatoid arthritis, systemic lupus
erythematosus, scleroderma, polymyositis, ankylosing
spondylitis, rheumatic fever, Lyme arthritis
Crystal-induced gout,
pseudogout
Inflammatory
Milky synovial fluid could indicate presence of?
Cyrstals
It comes from the polymerization of the hyaluronic acid and is essential for the proper lubrication of the joints
Viscosity
This is the test for observing the ability of the synovial fluid to form a string
String test
Measurement of the amount of hyaluronate polymerization
Ropes or mucin clot test
Why should counts be performed as soon as possible?
To prevent cellular disintegration
Clear fluids can usually be counted ________, but dilutions are necessary when fluids are _____ or ______
undiluted and turbid or bloody, respectively
Differential counts should be performed on ______ preparations or on thinly smeared slides
cytocentrifuged
Prior to slide preparation, Fluid should be incubated with?
hyaluronidase
If the synovial fluid is very viscous, it is pretreated by?
adding a pinch of hyaluronidase to 0.5 mL
of fluid or one drop of 0.05% hyaluronidase in
phosphate buffer per milliliter of fluid
What are the primary cells found in differential count of synovial fluid?
Mononuclear cells
(monocytes, macrophages) and synovial tissue
cells
It is a macrophage that has phagocytosed one or more neutrophil
Reiter cell (center)
Also known as RA cells. Has neutrophil-like characteristics w/ dark cytoplasmic granules which contains immune complexes
Ragocytes
It is associated with Rheumatoid Arthritis & immunologic inflammations
Ragocytes
What are the primary crystals seen in synovial fluid?
- monosodium urate (uric acid) (MSU) found in
cases of gout - calcium pyrophosphate (CPPD) seen with
pseudogout
This crystal is associated with calcified cartilage degeneration
Apatite (basic calcium phosphate)
This crystal is found in the synovial fluid following injections
corticosteroids
This crystal is found in renal dialysis patients
calcium oxalate crystals
This crystal is associated with chronic inflammation
cholesterol crystals
What are the possible artifacts that can be found in synovial fluid?
- talcum powder
- starch from gloves
- precipitated anticoagulants
- dust
- scratches on slides and coverslips
Why should crystal examination be performed right after fluid collection?
to ensure that crystals are not affected by changes in temperature and pH
Fluid must be examined prior to?
WBC disintegration
For Tube 1: The first 4 to 5 mL of the synovial fluid obtained should be placed into?
plain, nonanticoagulated red
tube and observed for clotting
For Tube 2: The next 4 to 5 mL is collected into a tube to
which 25 units (U) of?
sodium heparin per mL which is then added to an EDTA tube
For Tube 3: The last 4 to 5 mL is placed into?
a sterile tube to which 25 U per mL heparin is added or to a sodium polyanethol sulfonate (SPS) tube
The supernatant of this tube is used for chemical or immunologic analysis.
Tube 1
Which tube is used for cell count, differential count, and crystal identification
Tube 2
Which tube is used for microbiological studies?
Tube 3
Why used you not use fluids that contain acetic acid to dilute synovial fluids?
because the acetic acid can cause mucin clot formation and cell
clumping
