Synovial Fluid Flashcards
Formation of synovial fluid
Plasma ultrafiltrate through loose synovial membranes and secretions of synoviocytes
Composition of synovial fluid compared to plasma
Close to plasma: electrolytes, uric acid, glucose
1/3 of plasma: protein, immunoglobulins
What is the lubricant that makes synovial fluid viscous?
Hyaluronate
Normal synovial fluid values
Volume: <3.5
Viscosity: high
Clarity: clear
Color colorless/straw
WBC: <150
Polys%: <25
Gram stain: -
Noninflammatory joint disorder (category I) values
these are degenerative
Volume: >3.5
Viscosity: high
Clarity: clear
Color: straw/yellow
WBC: <1000
Polys%: <25
Gram stain: -
Inflammatory (category 2) joint condition values
these are crystal induced or have immunologic origin
Volume: >3.5
Viscosity: low
Clarity: cloudy
Color: yellow
WBC: 5k-75k
Polys%: 50-70
Gram stain: -
Septic (category 3) joint disorder values
Volume: >3.5
Viscosity: mixed
Clarity: opaque
Color: mixed
WBC: >50,000
Polys%: >70
Gram stain: often +
Collection process is called
Arthrocentesis
Hemorrhagic (category 4) joint disorder values
caused by trauma or coag defic.
Volume: >3.5
Viscosity: low
Clarity: mixed
Color: red
WBC: similar to blood
Polys%: ^
Gram stain: -
Purpose and method of mucin clot test
Synovial fluid easily contaminated by others
- Mucin clot test makes a dilution with acetic acid
- If it clots, then it is confirmed synovial
Things that make synovial fluid cloudy
WBCs, red cells, synoviocytes, crystals, fat, fibrin, debris, ortho shards
2 general things that cause decreased viscosity
- Decreased synthesis of hyaluronate
- Breakdown of hyaluronate (inflammation
Clotting of synovial fluid
Always abnormal, fibrinogen present
- Membrane damage or traumatic tap
Increased protein causes and significance
Causes: increased membrane perm., increased synthesis
Significance: RA, septic arthritis, crystal damage
Glucose changes in values
Decreased values abnormal
- Difference between blood and synovial >20 mg/dl: possible sepsis
- If the difference is <20 mg/dl: infection not likely
Uric acid and lactate in chemical analysis
Increased uric acid in gout in both fluid and serum
Increased lactate in septic arthritis, anaerobic glycolysis during inflammatory process
Normal cell diff
60% monos/macros
30% lymphs
6% neutrs
4% synovial lining cells
Increased PMNs causes
bacterial infection
gout, late RA
Increased monos causes
Crystal induced arthritis, serum sickness
Increased lymphocytes causes
Acute RA stages
Crystal formation and analysis
Formation: affected by temp, pH, time
Polaraized miccroscopy shpws the colors with compensator plate
Monosodium urate crystals
Gouty arthritis
Needle is pointy, negatively bifringent
Parallel: yellow
Perpendicular: blue
Calcium pyrophosphate dihydrate crystals
Pseudogout from breakdown of cartilage, degenerative arthritis or caused by thyroid problems/diabetes
Small, blunt ends
Weal positive birefringence
Parallel: blue
Perpendicular: yellow
Other crystals found in synovial fluid
- Cholesterol: chronic inflamm conditions
- Apatite: arthritic conditions
- Hydroxyapatite: acute inflamm reaction
- Corticosteroid: post intra articular injection
Lyme arthritis pathogen and process
Untreated Lyme disease develops arthritis sometimes, large joints
- Borrelia burgdorferi
Gout vs. Pseudogout
Gout: metabolic disorder w increased serum/joint uric acid, MSU crystals
Pseudogout: degenerative disorder, increased serum calcium, CPPD crystals
