Synovial Fluid

Question 1

what cells line joints, tendon sheaths, and bursa?

Answer 1

synoviocytes

Question 2

what cells are primarily in synovial fluid?

Answer 2

non-phagocytic mononuclear cells
low cellularity

Question 3

what do synoviocytes type B secrete?

Answer 3

hyaluronate

Question 4

how viscous is synovial fluid?

Answer 4

high viscosity

Question 5

what are some indications for fluid analysis on synovial fluid?

Answer 5

joint effusion
lameness
fever of unknown origin
trauma/lacerations

Question 6

what color is healthy synovial fluid?

Answer 6

colorless to pale straw
clear

Question 7

what is bloody synovial fluid usually?

Answer 7

artifact of collection

Question 8

when might synovial fluid clot?

Answer 8

blood contamination
intraarticular hemorrhage
protein exudation

Question 9

what can cause decreased viscosity of synovial fluid?

Answer 9

inflammatory or non-inflammatory diseases
hyaluronidase produced by bacteria
enzymes released from inflammatory cells
dilutional effects of an effusion
dilution with excess anticoagulant

Question 10

what do we analyze in synovial fluid?

Answer 10

physical features
total nucleated cell count
total protein determination
microscopic examination

Question 11

do cell counts vary a lot in synovial fluid?

Answer 11

yes: between animals and even between joints

Question 12

how can you estimate a cell count on a direct smear?

Answer 12

average number of cells per field multiplied by the objective power squared

Question 13

can eosinophils or mast cells be in healthy synovial fluid?

Answer 13

no

Question 14

what are the categories for synovial fluid analysis (abnormal)?

Answer 14

non-inflammatory arthropathy
mild, mixed inflammation
inflammatory arthropathy
hemarthrosis

Question 15

what does non-inflammatory arthropathy result from?

Answer 15

trauma or degenerative changes in articular surfaces

Question 16

what is cellularity usually in non-inflammatory arthropathy?

Answer 16

usually normal or mildly increased
predominance of mononuclear cells

Question 17

when might cartilage fragments and osteoclasts be found in non-inflammatory arthropathy?

Answer 17

if damage to articular cartilage is severe enough and osteoid is exposed

Question 18

what is cellularity in mild mixed inflammation?

Answer 18

above normal, generally <10,000/microliter

Question 19

what is the cellularity in inflammatory arthropathy?

Answer 19

moderate to marked increase: >10,000/microliter
often 100,000-200,000/microliter

Question 20

how prevalent are neutrophils in inflammatory arthropathy?

Answer 20

40-100% of the nucleated cells

Question 21

what is the main differential in small animals for inflammatory arthropathy?

Answer 21

non-infectious arthropathies

Question 22

what are non-infectious arthropathies often caused by?

Answer 22

immune-mediated disease

Question 23

what are ragocytes?

Answer 23

neutrophils with phagocytized immunocomplexes or nuclear chromatin

Question 24

what is the main differential for inflammatory arthropathy in large animals?

Answer 24

septic arthritis

Question 25

what should you do when septic arthritis is a possibility?

Answer 25

culture the joint fluid

Question 26

macrophages show _______________ unless hemorrhage is peracute (<45’)

Answer 26

erythrophagia

Question 27

what is the most common tumor of the canine synovium?

Answer 27

histiocytic sarcoma