Synovial Fluid Flashcards
Synovial fluid, often referred to as
Joint fluid
Viscous liquid found in the cavities of the movable joints (diarthroses) or synovial joints
Synovial fluid
The bones in the synovial joints are lined with _____ and separated by a _____ containing the _____
Smooth articular cartilage
Cavity
Synovial fluid
The joint is enclosed in a fibrous joint capsule lined by the _____
Synovial membrane
The synovial membrane contains specialized cells called
Synoviocytes
Function of smooth articular cartilage and synovial fluid
Lubricates joints
Reduce friction between the bones during joint movement
Provides nutrients to the articular cartilage/ vascular-deficient cartilage
Lessens shock of joint compression during walking and jogging
Synovial fluid is formed as nonselective ultrafiltrate of plasma across the synovial membrane except for the exclusion of high-molecular-weight proteins. True or False?
True
The synoviocytes secrete a _____ containing _____ and a small amount of _____ which contribute to the noticeable viscosity of synovial fluid
Mucopolysaccharide
Hyaluronic acid
Protein
Synovial fluid is formed as nonselective ultrafiltrate of plasma. True or False?
True
Most of the chemical constituents of synovial fluid have concentrations similar to plasma values. True or False?
True
Damage to the articular membranes produces pain and stiffness in the joints, collectively referred to as
Arthritis
Classification of joint disorder due to degenerative causes
Noninflammatory
Classification of joint disorder due to immunologic/crystal-induced causes
Inflammatory
Classification of joint disorder due to microbial causes
Septic
Classification of joint disorder due to anticoagulant overdose
Hemorrhagic
REVIEW LABORATORY FINDINGS IN JOINT DISORDERS
REVIEWHIN MO SA NOTES
Synovial fluid is collected by needle aspiration called
Arthrocentesis
Normal amount of fluid in the adult knee cavity
<3.5 mL
> 25 mL synovial fluid indicates
Inflammation
Normal synovial fluid does not clot. True or False?
True
Fluid from a diseased joint may contain _____ and will _____
Fibrinogen
Clot
Synovial fluid is often collected in a syringe that has been moistened with _____
Heparin
Powdered anticoagulants should not be used. True or False? If so, why?
True; because they may produce artifacts that interfere with crystal analysis
All testing should be done _____ to prevent _____ in crystals
As soon as possible
Cellular lysis and possible changes
Required tube type for Gram stain and culture
Sterile heparinized or sodium polyanethol sulfonate
Required tube type for Cell counts
Heparin or liquid ethylenediaminetetraacetic acid (EDTA)
Required tube type for Glucose analysis
Sodium fluoride
Required tube type for all other tests
Nonanticoagulated
Normal color and clarity of synovial fluid
Colorless to pale yellow
Turbid synovial fluid indicates
WBCs, Synovial cell debris, and Fibrin
Deeper yellow synovial fluid indicates
Noninflammatory and inflammatory effusions
Greenish synovial fluid indicates
Bacterial infection
Red synovial fluid indicates
Traumatic tap, Hemorrhagic arthritis
Milky synovial fluid indicates
Crystal induced
The word “synovial” comes from the Latin word for
Egg, ovum
Normal viscous synovial fluid resembles
Egg white
How to distinguish hemorrhagic arthritis from traumatic aspiration
Observe uneven distribution of blood or blood streak in the specimens
Arthritis affects both the production of hyaluronate and its ability to polymerize. True or False?
True
Viscosity test for synovial fluid
String test
Hyaluronate Polymerization Test
Positive result of String test
String measuring 4-6 cm
Positive result of Hyaluronate Polymerization Test
Solid clot surrounded by clear fluid
Describe the grading of synovial fluid viscosity
Good=Solid clot
Fair=Soft clot
Low=Friable clot
Poor=No clot
How to identify a questionable fluid as synovial fluid?
Formation of a mucin clot after adding acetic acid
Most frequently performed cell count on synovial fluid
Total leukocyte count
Normal RBC count in synovial fluid
<2000 cells/µL
Normal WBC count in synovial fluid
<200 cells/µL
WBC count in synovial fluid that indicates severe infections
100,000 WBC/µL or higher
Why is it that traditional WBC diluent cannot be used?
Because it contains acetic acid that causes the formation of mucin clots
Neutrophil containing characteristic ingested “round body”
LE cell
Vacuolated macrophage with ingested neutrophils
Reiter cell (Neutrophages)
Neutrophil with small, dark cytoplasmic granules consisting precipitated rheumatoid factor
RA cell (Ragocyte)
Refractile intracellular and extracellular globules
Fat droplets
Ground pepper appearance inclusion
Ochronotic shards
Primary crystal; found in cases of gout
Monosodium urate (uric acid) (MSU)
Primary crystal; seen with pseudogout
Calcium pyrophosphate dihydrate (CPPD)
Crystal associated with calcified cartilage degeneration, cholesterol crystals associated with chronic inflammation, corticosteroids after injections
Hydroxyapatite (basic calcium phosphate)
Crystal seen in renal dialysis patients
Calcium oxalate crystals
Crystal examination should be performed soon after fluid collection to ensure that crystals are not affected by changes in temperature and pH. True or False?
True
CPPD crystals are usually located within ______ while MSU crystals _____ and therefore do not appear in vacuoles
Vacuoles of the neutrophils
Lyse phagosome membranes
Positive identification of crystal is made by using
First order red-compensated polarized light
A control slide for the polarization properties of MSU can be prepared using
Betamethasone acetate corticosteroid
MSU crystal is more highly birefringent and appears brighter against the dark background than CPPD crystal. True or False?
True
Microscope that detects for the presence or absence of birefringence
Polarizing microscope
Microscope that confirms the type of birefringence (positive or negative)
Compensated polarizing microscope
_____ : run parallel to the long axis = _____ Birefringence = _____ color
MSU
Negative
Yellow
CPPD: run _____ to the long axis = _____ Birefringence = _____ color
Perpendicular
Positive
Blue
Cholesterol, oxalate, corticosteroid crystals, and contaminants exhibit birefringence. True or False?
True
Apatite crystals are birefringent. True or False?
False; not birefringent
Most frequently requested chemistry test for synovial fluid
Glucose test
Normal synovial fluid glucose value
<10 mg/dL lower than the blood value
To prevent falsely decreased values caused by glycolysis, specimens should be analyzed within _____ or preserved with _____
1 hour
Sodium fluoride
Lactic acid levels are usually increased in patients with _____ arthritis
Septic
Normal synovial fluid lactic acid value
<30mg/dL
> 30mg/dL lactic acid indicates
Septic arthritis
Normal synovial fluid total protein value
<3 g/dL
Increased levels of total protein are found in _____ and _____disorders
Inflammatory
Hemorrhagic
Measured as a first evaluation in suspected cases of gout
Uric acid
Used to monitor the severity and prognosis of rheumatoid arthritis (RA)
Lactate or acid phosphatase
Two of the most important tests performed on synovial fluid
Gram stains
Cultures
Routine bacterial cultures should include an enrichment medium, such as
Chocolate agar
Common organisms that infect synovial fluid
Staphylococcus and Streptococcus, fastidious Haemophilus species and Neisseria gonorrhoeae
Causative agent of Lyme disease
Borrelia burgdorferi