Strasinger AUBF - Synovial Fluid Ultimate Reviewer

Synovial fluid

Referred to as "joint fluid"

Synovial fluid

Viscous liquid found in the cavities of the movable joints (diarthroses) or synovial joints

Articular

Synovial fluid provides nutrients to the ___ cartilage

Joint compression

Synovial fluid lessens the shock of ___

Synovial fluid

Formed as an ultrafiltrate of plasma across the synovial membrane

Smooth articular cartilage

Lines the bones in the synovial joints

Synovial cavity

Contains synovial fluid, separates bones from the synovial joints

Joint

Enclosed in a fibrous joint capsule lined by the synovial membrane

Synoviocytes

Specialized cells from the synovial membrane

Synoviocytes

Secretes mucopolysaccharide containing hyaluronic acid and a small amount of protein into the fluid

Smooth articular cartilage

Friction from joint movement is reduced by the ___ and synovial fluid

Arthritis

Pain and stiffness in the joints due to damage of the articular membranes

Synovial fluid analysis

Helps in determining the pathologic origin of arthritis

Most performed tests in synovial fluid

WBC count, differential count, gram stain, culture, and crystal examination

<3.5 mL

Volume of normal synovial fluid

Colorless to pale yellow

Color of normal synovial fluid

Clear

Clarity of normal synovial fluid

Able to form a string 4 to 6 cm long

Viscosity of normal synovial fluid

<200 cells/uL

Leukocyte count of normal synovial fluid

<25% of the differential

Neutrophils found in normal synovial fluid

None present

Crystals found in normal synovial fluid

<10 mg/dL lower than the blood glucose level

Glucose plasma difference of normal synovial fluid

<3 g/dL

Total protein found in normal synovial fluid

Noninflammatory

Degenerative joint disorders, osteoarthritis

Inflammatory

Immunologic disorders, rheumatoid arthritis, systemic lupus erythematosus, scleroderma, polymyositis, ankylosing spondylitis, rheumatic fever, Lyme arthritis, Crystal-induced gout, pseudogout

Septic

Microbial infections

Hemorrhagic

Traumatic injury, tumors, hemophilia, other coagulation disorders, anticoagulant overdose

Noninflammatory

Lab findings: Clear, yellow fluid, Good viscosity, WBCs <1000 uL, Neutrophils <30%, Similar to blood glucose

Immunologic origin

Lab findings: Cloudy, yellow fluid, Poor viscosity, WBCs 2,000 to 75,000 uL, Neutrophils >50%, Decreased glucose level, Possible autoantibodies present

Crystal-induced origin

Lab findings: Cloudy or milky fluid, Low viscosity, WBCs up to 100,000 uL, Neutrophils <70%, Decreased glucose level, Crystal present

Septic

Lab findings: Cloudy, yellow-green fluid, Variable viscosity, WBCs 50,000 to 100,000 uL, Neutrophils >75%, Decreased glucose level, Positive culture and gram stain

Hemorrhagic

Lab findings: Cloudy, red fluid, Low viscosity, WBCs equal to blood, Neutrophils equal to blood, Normal glucose level

Arthrocentesis

Process of collecting synovial fluid by needle aspiration

Size, fluid buildup

Amount of fluid varies with the ___ of the joint and the extent of ___ in the joint

Volume

___collected should be recorded

Clot

Normal synovial fluid does not ___

Syringe moistened with heparin

Synovial fluid collected from diseased joint uses ____ with ____

Powdered anticoagulants

Should not be used because it may produce artifacts that interfere with crystal analysis

Non-anticoagulated tubes

Must be centrifuged and separated to prevent cellular elements from interfering with chemical and serologic analyses

Cellular lysis, changes

All testing should be done immediately if possible to prevent ____ and possible ___ in crystals

Sterile heparinized or sodium polyanethol sulfonate

Tube for gram stain and culture

Heparin or liquid ethylenediaminetetraacetic acid (EDTA)

Tubes for cell counts

Sodium fluoride

Tube for glucose analysis

Non-anticoagulated

Tube for other tests

Colorless to pale yellow

Normal synovial fluid appears ____ to ____

Egg, ovum

"Synovial" came from the Latin word for ___

Egg white

Normal viscous synovial fluid resembles ____

Deep yellow

Appearance of synovial fluid when there is presence of noninflammatory and inflammatory effusions

Greenish tinge

Appearance of synovial fluid when there is bacterial infection

Turbidity

Appearance of synovial fluid when there is presence of WBCs

Milky

Appearance of synovial fluid when there is crystals are present

Turbidity

Synovial cell debris and fibrin also produces ___

Hyaluronic acid

The fluid's viscosity comes from the polymerization of the ___ and is essential for the proper joints lubrication

Decrease viscosity

Arthritis affecting hyaluronate production and ability to polymerize

String

Viscosity is determined by the fluid's ability to form a ___from the tip of the syringe (normal: 4 to 6 cm)

Ropes, or mucin clot test

Test measuring Hyaluronate polymerization

2%to 5% acetic acid

Ropes, or mucin clot test is done with the addition of this

Mucin clot test

Not routinely performed, because all forms of arthritis decrease viscosity

Mucin clot test

Can be used to determine questionable fluid as synovial fluid

Good

Mucin clot test reporting: Solid clot

Fair

Mucin clot test reporting: Soft clot

Low

Mucin clot test reporting: Friable clot

Poor

Mucin clot test reporting: No clot

Total leukocyte count

Most frequently performed cell count on synovial fluid

Cell counts

Should be performed as soon as possible to prevent cellular disintegration

Very viscous fluid

Pretreated by adding 1 drop of 0.05% hyaluronidase in phosphate buffer per milliliter of fluid and incubating at 37degC for 5 minutes

Undiluted

Clear fluids care ounted ____

Acetic acid

Traditional WBC diluting fluid cannot be used because it contains ____ that causes the formation of mucin clots

Normal saline

Diluent

Lyse RBC

Hypotonic saline (0.3%) or saline with saponin

Stain WBC nuclei

Methylene blue added to normal saline

Cell count

Recommended technique for ____: line a petri dish with moist paper and place the hemocytometer on two small sticks to elevate it above the moist paper, fill and count both sides of the hematocytometer for compatibility

9

For counts less than 200 WBCs/uL, count all ___ large squares

4

For counts greater than 200 WBCs/uL in the above count, count the ___ corner squares

5

For counts greater than 200 WBCs/uL in the above count, count the ___ small aquares used for RBC count

Hyaluronidase

Incubating fluid with ___ decreases specimen viscosity

Differential count

Should be performed on cytocentrifuged preparations or on thinly smeared slides

Mononuclear cells, monocytes, macrophages, synovial tissue cells

Primary cells seen in normal synovial fluid

Increased neutrophils

Indicates septic condition

Elevated cell count with predominance of lymphocytes

Suggests nonseptic inflammation

Cell abnormalities

Presence of eosinophils, LE cells, Reiter cells (neutrophages - vacuolated macrophages with ingested neutrophils), and RA cells (ragocytes - neutrophils with small, dark cytoplasmic granules consisting precipitated rheumatoid factor)

Lipid droplets

Crush injuries

Pigmented villonodular synovitis

Presence of hemosiderin granules

Neutrophil

Description: Polymorphonuclear leukocyte

Neutrophil

Clinical significance: Bacterial sepsis, Crystal-induced inflammation

Lymphocyte

Description: Mononuclear leukocyte

Lymphocyte

Clinical significance: Nonseptic inflammation

Macrophage (monocyte)

Description: Large mononuclear leukocyte, may be vacuolated

Macrophage (monocyte)

Clinical significance: Normal, Viral infections

Synovial lining cell

Description: Similar to macrophage, but may be multinucleated, resembling a mesothelial cell

Synovial lining cell

Clinical significance: Normal, Disruption from arthrocentesis

LE cell

Description: Neutrophil containing characteristic ingested "round body"

LE cell

Clinical significance: Lupus erythematosus

Reiter cell

Description: Vacuolated macrophage with ingested neutrophils

Reiter cell

Clinical significance: Reactive arthritis (infection in another part of the body)

RA cell (ragocyte)

Description: Neutrophil with dark cytoplasmic granules containing immune complexes

RA cell (ragocyte)

Clinical significance: Rheumatoid arthritis, Immunologic inflammation

Cartilage cells

Description: Large, multinucleated cells

Cartilage cells

Clinical significance: Osteoarthritis

Rice bodies

Description: Macroscopically resemble polished rice