Synovial fluid

Question 1

What is synovial fluid?

Answer 1

joint fluid, viscous liquid in cavities of movable joints

Question 2

synoviocytes

Answer 2

line the entire membrane, produces hyaluronate (hyaluronic acid)

Question 3

Arthritis

Answer 3

inflammation of a joint. Damage to synovial membranes leads to pain and stiffness. Caused by infection, inflammation, metabolic disorders, trauma, stress or age.

Question 4

Non-inflammatory arthritis

Answer 4

osteoarthritis, loss on synovial fluid production

Question 5

inflammatory arthritis

Answer 5

autoimmune, immunologic, crystal induced

Question 6

septic

Answer 6

infection, usually bacterial

Question 7

hemorrhagic

Answer 7

injury, tumor, hemophilia or coagulation disorder

Question 8

How is synovial fluid collected?

Answer 8

arthrocentesis, three tubes collected if possible. Has hemorrhagic/traumatic tap similar to CSF

Question 9

Normal color of synovial fluid

Answer 9

colorless or pale yellow

Question 10

Deeper yellow color reason

Answer 10

non-inflammatory + inflammatory state

Question 11

green color reason

Answer 11

infection

Question 12

red color reason

Answer 12

hemorrhage or traumatic tap

Question 13

Clarity

Answer 13

clear. decreased clarity could be from WBC’s or debris. Milky could be from crystals

Question 14

Viscosity

Answer 14

should be viscous + form drops 4-6 cm long from Pasteur pipette
Hyaluronidase is added to reduce viscosity for lab testing

Question 15

Clot formation

Answer 15

mucin clot test, if acetic acid is added it should clot
if it does not it is inflammation

Question 16

RBC cell counts

Answer 16

dilute with saline. normal <2000 cells/ul. Hemocytometer or auto counter

Question 17

WBC cell counts

Answer 17

dilute with normal or hypotonic saline. Hemocytometer/auto cell. Differential (categorize). Normal is <200

Question 18

Normal amount of each type of WBC

Answer 18

neutrophils < 25%
lymphocytes <15%
monocytes = 65%

Question 19

Abnormal amount of WBC

Answer 19

neutrophils >80% = septic/crystal
Increase in lymphs= nonseptic, inflammatory
Increase in esinophils= parasite, rheumatic, fever, carcinoma

Question 20

Abnormal cells

Answer 20

LE cells, Reiter cells, Ragocytes, Cartilage cells, rice bodies, lipid droplets, hemosiderin

Question 21

MSU (monosodium urate)

Answer 21

Gout, negative birefringence is yellow. High uric acid, can be intra or extracellular. Needle shaped crystals

Question 22

CPPD (calcium pyrophosphate)

Answer 22

pseudogout, positive birefringence is blue. calcified cartilage breakdown. square rods, rhomboid in shape, intracellular

Question 23

cholesterol

Answer 23

flat plates with notches. extracellular, neg birefringence.

Question 24

corticosteroids

Answer 24

flat plates w/o notch. intracellular from injections

Question 25

calcium oxalate

Answer 25

envelope/diamond. neg birefringence, renal dialysis

Question 26

apatite (caphosphate)

Answer 26

tiny (electron microscope) not birefringence, osteoarthritis

Question 27

chemistry exam

Answer 27

comparison of blood and synovial fluid (should have similar values)

Question 28

glucose test

Answer 28

most valuable, decreased in septic and inflammatory

Question 29

protein test

Answer 29

increased in inflammatory and hemorrhagic arthritis

Question 30

uric acid test

Answer 30

gout diagnosis when no MSU crystals

Question 31

Microbio exam

Answer 31

gram stain and culture are the two most important tests on synovial fluid. Gram stain is on concentrated slide and culture is on chocolate plate.

Question 32

serological exam

Answer 32

blood tested first and then synovial to confirm. Autoantibodies (rheumatoid arthritis or lupis). Antibodies (lyme disease)