UNIT 9. SYNOVIAL FLUID

Joint fluid

a viscous fluid found in a cavities of movable joints (diarthroses)

Comes from the latin word for egg.

smooth articular cartilage

synovial fluid

Bones in synovial joint are lined with ___ & separated by cavity containing the __

synoviocytes

Joint is enclosed in fibrous joint capsule lined by synovial membrane (__).

Hyaluronic Acid

viscosity

Synoviocytes secrete __, responsible for the _ of SF

Arthritis

pain and stiffness in joints caused by damage to articular membrane

arthritis

Less viscous hyaluronic acid → Collision of bones → inflammation → ___

F

they are AVASCULAR

T or F

Smooth articular cartilages lining the bone ends are vascular (lined by blood vessels)

synovial membrane

This synovial cavity is also referred to as __ which is lined with cells called synoviocytes.

<3.5 mL

normal volume of SF

colorless to pale yellow

normal color of SF

able to form 4-6 cm long string

normal viscosity of SF

<200 cells/uL

normal leukocyte count of SF

<25% of the differential

normal neutrophils count of SF

<10 mg/dL lower than the blood glucose

normal glucose:plasma difference of SF

<3g/dL

normal total protein of SF

Arthrocentesis

method of collection of SF through needle aspiration

• Tube 1: 1-3 mL, Sodium fluoride, Glucose testing

• Tube 2: 2-5 mL, Heparin/Liquid EDTA, Hematology

• Tube 3: 3-10, Sterile heparinized, SPS, Microbiology

SF SPECIMEN DISCTRIBUTION

• Tube 1:

• Tube 2:

• Tube 3:

• powdered EDTA

• oxalate

• lithium heparin

[POL]

ENUMRATE

Anticoagulants not used for SF (produce artifacts)

centrifuged

Non-anticoagulated tubes must be ___ → separated → prevent cellular elements interferes w/ chemical

8 hrs fasting

Fasting rq for glucose testing

refrigerate

For crystal analysis: do not __ for it produces additional crystals

• NSS

• 1% saponin

• 0.1N HCL

ENUMERATE

Synovial diluents

fibrinogen

Normally, synovial fluid does not clot because it do not contain __.

plain tube

centrifuge

special tests

If there is excess from what is collected, put it in an ___ → ___ immediately → used for ___

henoch schonlein purpura

• characterized by joint pain and abdominal pain and is often associated with bleeding

• red synovial fluid

Contains acetic acid → precipitation of SF

Why is hematology WBC diluent not used for synovial fluid?

Non-inflammatory (Arthritis)

Clear, deep yellow SF signifies?

Inflammatory (Arthritis)

Cloudy, deep yellow SF signifies?

Hemarthrosis (Henoch-Schonlein purpura)

Even distribution among 3 tubes of Red Brown SF signifies?

Traumatic tap

Uneven distribution among 3 tubes of Red Brown SF signifies?

Bacterial Infection

Green SF signifies?

Crystals

White/cloudy/milky SF signifies?

VISCOSITY

Comes from the Polymerization of Hyaluronic Acid

production & polymerization of hyaluronate

Arthritis affects both the ___ → decrease viscosity

Mucin Clot Test/ Ropes test

• test for Hyaluronate polymerization measurement

• integrity of hyaluronic acid-protein matrix/mucin

• Principle: the rgt has the capacity to clot synovial fluid when there is normal amount of hyaluronic acid

• Normal: forms solid clot surrounded by clear fluid

2-5% Acetic acid

Mucin Clot Test/ Ropes test reagent

• Normal: forms solid clot surrounded by clear fluid

• Good (solid clot)

• Fair (soft clot)

• Poor (Friable clot)

• Very Poor (no clot at all)

ENUMRATE

Manner of reporting for the Ropes test

• 1 pinch of hyaluronidase to 0.5 ml fluid

• 1 drop of 0.05% hyaluronidase in PO4 buffer/ml of fluid

• incubate at 37 C for 5 minutes

Specimen preparation for total leukocyte count (to make spx less viscous)

• hypotonic saline (0.3%)

• Saline + saponin

Used to lyse RBC for leukocyte count of SF

Methylene Blue

Used to stain WBC nuclei for leukocyte count of SF

F

Do not dilute CLEAR spx, dilute only the BLOODY/TURBID ones.

T or F

Always dilute clear specimens.

9 large square.

If < 200 WBC/ ul, you must count in all the __

4 corner square

If > 200 WBC/ ul than the above, use the __.

5 small squares used for RBC count.

If > 200 WBC/ ul than the 2nd, use the __

• Normal amount of WBC in synovial fluid: < 200 WBC/ ul.

• In case of infection such as syphilis: >100,000 WBC/ul.

• Normal amount of WBC in synovial fluid:

• In case of infection such as syphilis:

cytocentrifuged prepared, thin smeared

hyaluronidase

Differential count is performed on ___ slides incubated in ___

Mononuclear cells

• monocytes

• macrophages

• synovial tissue cell

normal primary cells seen in differential count

• Neutrophil: <25% : Increased in Septic Inflammation

• Lymphocytes: <15% : Increased in Non-Septic Inflammation

DIFFERENTIAL COUNT

• Neutrophil: ___ : Increased in ___

• Lymphocytes: ___ : Increased in ___

Reiter cells/Neutrophages

• Vacuolated macrophages w/ ingested neutrophils

• Reiter Syndrome, Reactive Arthritis

Rheumatoid Arthritis cells / Ragocyte

• Neutrophil with dark cytoplasmic granules, with immune complex

• Precipitated Rheumatoid factor

• Rheumatoid Arthritis, Immunologic inflammation

Lipid droplets / Fat droplets

• Refractile intra- & extracellular globules w/c stained w/ sudan dyes

• Traumatic injury, Chronic inflammation

Hemosiderin

• Inclusions w/n clusters of synovial cells

• Pigmented Villonodular Synovitis

Synovial lining

• Similar to macrophage resembling mesothelial cells

• Disruption from arthrocentesis (normal)

Lupus Erythematosus cell

• Neutrophil containing characteristic ingested round body

• Lupus Erythematosus

Cartilage cell

• Large, multinucleated

• Osteoarthritis

Rice bodies

• Macro: resembles polished rice

• Micro: Collagen & fibrin

• TB, Septic arthritis, Rheumatoid arthritis, Osteoarthritis

Ochronotic shards

• Debris from metal & plastic joint prosthesis

• Look like Ground Pepper

Septic inflammation

__ means there is a bacterial infection causing the inflammation of your synovial joints.

pinocytic

While lymphocyte, when it exceeds 15%, then it is ___ in nature.

rheumatoid factors

These are immune cell complexes that appear darkly stained inside ragocytes.

Synovial lining / Synoviocytes

Cells that are very common for those individuals who have synovitis.

Crystals

caused by metabolic disorders, ↓ renal excretion, degeneration of cartilage and bones, corticosteroids

MONOSODIUM URATE (MSU/URIC ACID)

• Crystal located extracellular or within cytoplasm of neutrophil

• Related to gout

CALCIUM PHOSPHATE DEHYDRATE

• Located within vacuoles of neutrophil

• Causative agent of pseudogout

PSEUDOGOUT

Degenerative arthritis, producing of cartilage calcification, endocrine disorders that produce ↑ calcium level

Monosodium Urate

• Needle shaped crystals

• Negative birefringence (yellow)

• Gout

Calcium Pyrophosphate Dihydrate

• Rhomboid, square, Short rods

• Positive birefringence (blue)

• Pseudogout

Hydroxyapatite (Basic Calcium Phosphate)

• Small particles

• No birefringence

• Calcified cartilage degeneration, osteoarthritis

Cholesterol Crystals

• Notched, rhomboid plates

• Negative birefringence

• Chronic inflammation

Corticosteroids

• Flat, variable-shaped plates

• Positive & negative birefringence

• Injections of corticosteroids

Calcium Oxalate

• Envelope-shaped

• Negative birefringence

• Renal Dialysis

T

T or F

Crystals are not normally present in the synovial fluid.

POLARIZING MICROSCOPE

To differentiate the MSU and CPPD, we often make use of ___.

Frist-order Red compensator

CRYSTAL POLLARIZATION:

• placed between the crystal and analyzer.

• It produces a red background and helps determine whether a crystal is positively or negatively birefringent.

• The compensator has a slow axis and a fast axis.

compensated polarized light microscopy

Crystal analysis uses ___ to identify crystals in synovial fluid, especially MSU & CPPD.

bethamethasone acetate corticosteroid

Control slide for MSU polarization

Positive Birefringence

Longitudinal axes are Perpendicular to the axis of the compensator (Slow vibration)

Negative Birefringence

Longitudinal axes are Parallel to the axis of the compensator (Slow vibration)

Monosodium urate

• Negative birefringence

• Parallel to slow axis: YELLOW

• Perpendicular to slow axis: BLUE

Calcium pyrophosphate dihydrate

• Positive birefringence

• Parallel to slow axis: BLUE

• Perpendicular to slow axis: YELLOW

10 mg/dl lower than the blood glucose level

Normal Synovial Fluid Glucose

< 3 g/dl

Normal Protein Level of SF

• Staphylococcus

• Streptococcus

• Haemophilus

• N. gonorrhoeae

ENUMERATE

Bacteria that infect synovial fluid

Direct serologic testing

Serologic testing that targets antigens (microorganism)

Indirect serologic testing

Serologic testing that targets antibodies produced by the organism

• lactate

• acid phosphatases

• antibodies

[ALA]

What are elevated in Rheumatoid arthritis

rheumatoid factor (IgM)

Antibody seen in RA

Non-Inflammatory Arthritis

Inflammatory Arthritis (Immunologic)

Inflammatory Arthritis (Crystal-Induced)

Septic Arthritis

Hemorrhagic Arthritis