Synovial Fluid

Question 1

Where is a synovial fluid produced?

Answer 1

Tissue: Synovium

Question 2

Role of synoviocyte

Answer 2

Active phagocytes and synthesize hyalaurate

Question 3

Synovial fluid is formed by…

Answer 3

the ultrafiltration of plasma across the synovial membrane

Question 4

Viscous fluid in joints

Answer 4

sole nutrient source for the metabolically active articular cartilage

Question 5

In the fasting patient, compare synovial fluid and plasma

Answer 5

Equivalent: glucose and uric acid

Question 6

Physical of synovial fluid: Color

Answer 6

Normal: Colorless - Slightly pale yellow
Class 1: Pale yellow: non-inflammatory
Class 2: Deep yellow: Inflammatory
Hemorrhagic: Red
Bacterial infection: Green tinge

Question 7

Physical of synovial fluid: Clarity

Answer 7

Normal: translucent
WBC or Synovial cell debris: turbid
Crystal: milky, opaque
Fibrinogen: clotting
Fractured joint: Fat on side/on top of bloody layer
Necrotic tissue: Rice body

Question 8

Physical of synovial fluid: Texture

Answer 8

Normal: Egg white
Arthritis: decreased viscosity
Pus: purulent (septic arthritis –> shake to see if clots are present)
Cholesterol: purulent if high conc.
White sodium urate crystals: opaque gouty effusion (chronic gouty arthritis)

Question 9

Synovial fluid sample collecting

Answer 9

Arthrocentesis

Question 10

Handling sample of SF

Answer 10

Remove needle first –> Record: color, clarity –> Check volume for next steps tests

Question 11

Tube for Synovial

Answer 11

Liquid anticoagulant (Sodium heparin/Green top)
EDTA (lavender), Citrate (blue)
Other chemistry tests (red)

Question 12

Synovial Fluid Classification

Answer 12

G1: Non-inflammatory
G2: Inflammatory
G3: Septic (bacterial infection)
Hemorrhagic

Question 13

Symmetrical arthritis

Answer 13

The same joints are affected both sides –> Inflammatory

Question 14

Asymmetrical arthritis

Answer 14

Only one side –> a degenerative or non-inflammatory arthritis

Question 15

Degenerative arthritis

Answer 15

the breakdown of cartilage

Question 16

Erosion

Answer 16

breakdown of bone (of joints)

Question 17

Osteoarthritis

Answer 17

Non-inflammatory, asymmetrical.
Spongy cushions of cartilage, “wear and tear” (bones of joints rub together)
Morning stiffness relieve less than 30 min
Reason: heredity, obesity, overuse, age
Treatment: chiropractor, water exercise, physical therapy

Question 18

Rheumatoid arthritis

Answer 18

Inflammatory, symmetrical
Morning stiffness lasts longer than 30 min
Red, swollen, painful –> lead to permanent deformity & erosion
The body immune system attacks synovium lining
No cure, use pain reliver.

Question 19

Infectious (septic)

Answer 19

Caused by Staph., TB
The spread from open wounds, surgery, bites, etc.
Treatment: antibiotics, tissue removal. fluid drainage

Question 20

Hemorrhage

Answer 20

Bleeding to the joints (can be caused by tumor)
Occur after injuries, surgical procedures
Bleeding causes damage to synovium, cartilage,
Treatment: Draining blood, synovectomy, or drug for clotting factor

Question 21

Calcium Pyrophosphate Dihydrate (CPPD)

Answer 21

• Rod, square with blunt, angulated ends
• Weakly birefringent (blue parallel)
• Examined under a polar microscope (compensator to have dark background)
• Found in pseudogout (caused by CPPD instead of urate crystal), degenerative arthritis: cartilage calcification and elevated calcium levels.

Question 22

Monosodium urate (MSU)

Answer 22

• Fine, needle-shape, rod-shape
• Negative birefringent (yellow parallel)
• Wet mount (the best examination) or Wright stained slide
• Disease: Gout, impaired metabolism of purines, high purine diet, alcohol, chemotherapy

Question 23

Calcium oxalate

Answer 23

Bipyramid shaped
No birefringent
Rare to see in synovial fluid

Question 24

Corticosteroids

Answer 24

Rod-shaped and aggregates present
Variable birefringent
Mostly be injected into the joint, but can be confused with pathological

Question 25

Cholesterol

Answer 25

Flat, square, notch corner
No birefringent
Seen in chronic inflammation and inflammatory effusion
Milky/white specimens can indicate

Question 26

Calcium phosphate

Answer 26

Requires electron microscopy as it’s very tiny
Rod-shaped
Not birefringent
Seen in osteoarthritis (assoc. with calcified cartilage degeneration)