Chapter 12 Synovial Fluid

where is synovial fluid formed

Synovial fluid is produced as an ultrafiltrate of blood plasma

what is synovial fluid primarily composed of

hyaluronan, lubricin, proteinase, collagenases, and prostaglandins

what are the functions of synovial fluid

•Moistens and lubricates joints

•Reduces friction between bones during joint movement

•Provides nutrients to articular cartilage

•Lessons shock of joint compression

what are the lab findings for Group I Noninflammatory joint disorders

• clear yellow fluid

• good viscosity

• WBCs <1000 uL

• neutrophils <30%

• similar to blood glucose

ex) ganglion cysts

what are the lab findings for Group II inflammatory joint disorders of immunologic origin

• cloudy, yellow fluid

• poor viscosity

• WBCs 2000-75,000 uL

• neutrophils >50%

• decreased glucose level

• possible antibodies present

ex) lupus

what are the lab findings for Group II inflammatory joint disorders of crystal-induced origin

• cloudy or milky fluid

• low viscosity

• WBCs up to 100,000 uL

• neutrophils < 70%

• decreased glucose level

• crystals present

what are the lab findings for Group III inflammatory joint disorders of septic origin

• cloudy yellow-green fluid

• variable viscosity

• WBCs 50,000-100,000 uL HIGHEST WBC

• neutrophils >75%

• decreased glucose level

• positive culture & gram stain

what are the lab findings for Group IV inflammatory joint disorders of hemorrhagic origin

• cloudy red fluid

• low viscosity 

• WBCs equal to blood

• neutrophils equal to blood

• normal glucose level

neutrophils in synovial fluid indicate____?

bacterial sepsis, crystal-induced inflammation

lymphocytes in synovial fluid indicate____?

nonseptic inflammation

macrophages in synovial fluid indicate____?

normal fluid or viral infection

synovial lining cells in synovial fluid indicate____?

normal fluid or disruption from arthrocentesis

LE cells in synovial fluid indicate____?

lupus erythematosus

Reiter cells in synovial fluid indicate____?

reactive arthritis (infection in another part of the body)

RA cell (ragocyte) in synovial fluid indicate____?

rheumatoid arthritis immunologic inflammation

cartilage cells in synovial fluid indicate____?

osteoarthritis

rice bodies in synovial fluid indicate____?

tuberculosis

septic and rheumatoid arthritis

fat droplets in synovial fluid indicate____?

traumatic injury or chronic inflammation

hemosiderin in synovial fluid indicate____?

pigmented villonodular synovitis

what are the most common crystals found in synovial fluid

monosodium uric acid (MSU) and calcium pyrophosphate dihydrate (CPPD)

MSU crystals in synovial fluid indicate____?

gout

CPPD crystals  in synovial fluid indicate____?

pseudo gout

how many tubes are used for synovial fluid specimens

three tubes

1. red stopper tube

2. green or lavender stopper tube

3. green or yellow stopper tube

what is the red stopper tube for synovial fluid used for

1st 4-5mL of synovial fluid

• no coagulants or preservatives added

• observed for clotting

• chemical/immunologic analysis

• must be centrifuged

what is the green stopper tube for synovial fluid used for

2nd 4-5 mL of synovial fluid OR 3rd 4-5mL

• sodium heparin

• cell count, differential count, crystal identification

what is the lavender stopper tube for synovial fluid used for

2nd 4-5mL of synovial fluid

• EDTA 

• cell count, differential count, crystal identification

what is the yellow stopper tube for synovial fluid used for

3rd 4-5 mL of synovial fluid

• sodium polyanethol sulfonate

• microbiological studies

should powdered or liquid anticoagulants be used

liquid; powdered can interfere with crystal anaylsis

what does normal synovial fluid viscosity (String test) look like

jelly-like; should form 4-6 cm long strings from pipette during string test

what does abnormal synovial fluid viscosity (String test) look like

low viscosity; indicates inflammation

what does a normal Rope’s test look like

after addition of acetic acid, a solid or soft ropey mucin clot forms

what does an abnormal Rope’s test look like

after addition of acetic acid, friable (breakable) clot forms OR no clot at all

what does normal synovial fluid look like

colorless and clear, maybe a yellow tinge

what does red, brown, or xanthochromic synovial fluid indicate

hemorrhage into joint

what does yellow/clear synovial fluid indicate

noninflammatory effusion

what does yellow cloudy synovial fluid indicate

inflammation

what does white cloudy synovial fluid indicate

crystals

what do rice bodies in synovial fluid indicate

rheumatoid arthritis or synovium enriched with fibrin

what do free-floating black-colored inclusions that appear similar to ground pepper in synovial fluid indicate

Ochronotic shards

• debris from joint prosthesis

describe what a LE (lupus eryhematosus) cell looks like in synovial fluid

neutrophils that have engulfed a nucleus of a lymphocyte

describe what a Reiter cell looks like in synovial fluid

macrophage containing ingested nuclei of a neutrophil

describe what a RA cell looks like in synovial fluid

isn't a single distinct cell type, but rather refers to neutrophils, which are the predominant inflammatory cells found in rheumatoid arthritis (RA) synovial fluid

what crystal is this and name characteristics/what it signifies

Monosodium urate (MSU)

• needle shaped

• negative birefringence

• appear yellow when oriented parallel to the compensator's slow axis

• gout

what crystal is this and name characteristics/what it signifies

Calcium pyrophosphate dehydrate crystals (CPPD)

• rhomboid, square, rods

• positive birefringence 

• appear blue when parallel to the slow axis

• pseudogout

what crystal is this and name characteristics/what it signifies

cholesterol crystals

• notched, rhomboid plates

• negative birefringence

• chronic inflammation from patients with osteoarthritis or rheumatoid arthritis

what crystal is this and name characteristics/what it signifies

corticosteroid crystals

• flat, variable-shaped plates

• positive and negative birefringence

• present after intra-articular injections

what crystal is this and name characteristics/what it signifies

calcium oxalate crystals

• envelope shaped

• negative birefringence

• seen in patients on renal dialysis

what crystal is this and name characteristics/what it signifies

apatite crystals

• small particles (require electron microscopy)

• no birefringence 

• osteoarthritis or calcified cartilage degeneration

if synovial glucose is < 10 mg/dL than serum glucose levels, this is considered ____ and indicates _____.

normal

if synovial glucose is 10-20 mg/dL less than serum glucose levels, this is considered ____ and indicates _____.

abnormal; osteoarthritis, pigmented villonodular synovitis, trauma

if synovial glucose is 0-40 mg/dL less than serum glucose levels, this is considered ____ and indicates _____.

abnormal; inflammatory disorders

if synovial glucose is 20-100 mg/dL less than serum glucose levels, this is considered ____ and indicates _____.

abnormal; infections and crystal-induced

elevated lactate levels above 9 mmol/L (81 mg/dL) indicate _____?

bacterial arthritis

• GPC or GNB

List four genera of bacteria found most frequently in synovial fluid.

•Staphylococcus

•Streptococcus

•Haemophilus

•N. gonorrhoeae

list 4 microorganisms in synovial fluid that require PCR testing for detection

• Borrelia burgdorferi (tick bite)

• Mycobacterium tuberculosis

• Chlamydia trachomatis

• N. gonorrhoeae

Describe the relationship of serological serum testing to joint disorders

serological testing plays an important role in the diagnosis of joint disorders.

•Most of these tests are performed on serum, synovial fluid is a confirmatory measure