Synovial Fluid Analysis

Chapter 11

what is synovial fluid?

fluid within the joint cavity

function of synovial fluid

lubricates the joints, reduces friction, cushions bones, delivers nutrients to the articular cartilage ( which doesnt have capillaries)bone

What produces the degregadtive enzymes and hyularondate of the synovial fluid?

synoviocytes

Synovial fluid in genral is a combination of ultrafiltration of “—” in conjunction with the secreted products from “——” cells

plasma ultrafiltration and synoviocytes

what components of the synovial fluid are equivalent to that of blood plasma? what components are half or ¼ of the plasma composition?

glucose and uric acid concentrations are the same as in plasma, protein and Ig are ½ to ¼ plasma

Non-Newtonian behavior

thinner under rapid movement and thicker under slow or weight-bearing conditions

What are the 4 categories synovial fluid can be classified as?

noninflammatory, inflammatory, septic, hemorrhagic

why should the pateint fast for 4 to 6 hours pre arthrocentesis?

take time for glucose to stabalize between the blood and joint ( allows for other chemiscal constituients to equilibrate between blood and synovial fluid)

what ammount of synovial fluid is drawn out?

0.4 mL to 3.5mL

first portion of fluid obtained ( tube 1) should be placed in what kind of tube?

red top tube NO anticoagulant

the redtop tube with no anticoagulant is used for what?

chemical and immunological studies

the next portion of fluid collected ( tube 2) should be placed in what kind of tube?

anticoagulent tube with EDTA or Heparin

What is tube 2 used for?

microscopic examination- cell count, crystal ID, diff

the last portion of the synovial fluid collected should be put into what kind of tube?

sterile no anticoagulant tube ( plain red top)

which two anticoagulants are chosen for synovial fluid because they do not form crystals?

liquid EDTA or sodium heparin

What will happen to the specimen if we do not analyze it within 1-2 hours?

decreased cell count because cells deteriorate

can we refredgerate and or freeze synovial fluid?

we can put it in the fridge id delays are unavoidable , but we should NOt freeze synovial fluid

What is the percent makeup of each different type of cell on a synovial diff?

monos and macros- 60%

lymphs- 30%

neutrophils- 10%

Color

pale-yellow

clarity

clear

Viscosity

high! we like to see strings 4-6 cm tall

spontaneous clot?

no

erythrocyte count

less than 2000 cells per microliter

leukocyte count

less than 200 cells per microliter

glucose

equivalent to plasma

uric acid

equivalent to plasma

total protein

½ to ¼ of total plasma conc ( 1-3 g/dL)

lactate

9-33 mg/dL

hyaluronate

0.3-0.4 g/dL

what does a pink- red color of synovial fluid inficate

blood due to traumatic collection

what does yellow synovial fluid indicate?

noninflammatory process

what does yellow-white fluid indicate

inflammatory process

what does yellow- green color indicate?

infection or septic joint

red or brown color of synovial fluid indicates…

hemorrhagic condition

what substances can all affect the clarity of synovial fluid?

WBC RBC synoviocytes—- crystals, fat droplets— fibrin, cellular debris, rice bodies

what clinically significant subsatnces can be seen in synovial fluid without microscopic evaluation?

onchronotic shards and rice bodies

rice bodies

white, free- floating substances made up of collagen covered by fibrinous tissue. they are commonly observed with arthritic conditions, especially RA

onchronotic shards

dark, pepper looking flakes from individuals with ochronotic arthropathy( a rare joint disorder classified by alkaptonuria.) pigmented cartliage that has eroded and broken lose into the fluid

Why does synovial fluid have high viscosity?

mucoprotein hyluronate

what can happen to alter viscosity of synovial fluid

• depolymerization of hylaurondate via hyluronidase eznyme in some bacteira and some neutrophils

• diseases that inhibit production and secretion of hylaurondate by synoviocytes

in what cases would synovial fluid clot?

when there is an abnormal presence of fibrinogen. ( fibrinogen has HMW and shouldnt pass through membrane)

what test should you preform on synovial fluid to test for the integretiy of the membranes inclosing the synovial cavity? ( helpps ID inflammatory or non inflammatory)

mucin clot formation

effusions that are induced by ____ or ___ are the ones that frequently form fibrin clot

infections or crystal formation

how do we preform the mucin clot formation test?

synovial fluid + acetic acid → incubate → observe clot formation

what happens to the hyaluronic acid when we add acetic acid?

it precipitates out, forming a clot

how could in vivo inflammation affect the quality of the hyalauronic clot in the micin clot formation test?

neutrophils release enzymes that destroy hyalauuroninc acid in vivo

what does no clot in the mucin clot formation text indicate?

gout ot gonorrhea

what does a low, friable clot in the mucin clot formation test indicate?

lupus, RA`

where would we see an increased plasma/ synovial glucose difference in 10-20 mg/dL

noninflamatory and hemorrhageic joint disorder

where would we see a decrease in synovial glucose so large that the diffrence between plasma and synovial glucose levels differ in 20-40 mg/dL?

inflammatory conditions

where would we see a decrease in synovial glucose so large that the diffrence between plasma and synovial glucose levels differ greater than 40 mg/dL?

septic conditions

when do we see increased levels of uric acid ?

gout

gout is frequently diagnosed wit “—-” crystals in the synovial fluid

monosodium urate

an increased amount of protein in the synovial fluid results from changes in the “——” of the synovial membrane or from increased synthesis within the joint or from inflammatory process within the joint

permeability

why would there be an increased amount of lactate within the synovial joint?

anaerobic glycolysis in the synovium

severe inflammatory condtions= indcreased demand for energy=???

tissue hypoxia

“——” is associated with significantly increased lactate in synovial fluid

septic arthritis