Path - Joints

Question 1

Components of synovial joints

Answer 1

Joint space - lines joint cavity & articulating bones w layer of cartilage
Articular cartilage - hyaline cartilage, 70-80% water
Synoviocytes - produce fluid for synovial fluid
Chondrocytes - cells within cartilage; collagen - structural proteins & glycans - non structural proteins

Question 2

Morphologic features of articular cartilage

Answer 2

Hyaline cartilage
Chondrocytes : collagen & glycans
TM : tide marker, junction between articulate & calcified cartilage

Question 3

Morphologic features of subchondral bone

Question 4

Morphologic features of synovium

Question 5

Traumatic joint injury

Question 6

Example of traumatic joint injury

Question 7

Arthrogryposis

Answer 7

Congenital joint contracture, infant animal is born with limbs and joints splayed in various directions due to lack of movement & joint configuration in the womb

Question 8

Pathogenesis of arthrogryposis

Answer 8

Sporadic - random/unknown
Intrauterine viral infection
- akabane virus
- blue tongue virus (Culicoides)
- schmallenberg virus
Hereditary CNS disease
Toxins - lupine plants & poison hemlock

Question 9

Pathogenesis of degenerative joint disease

Answer 9

Chronic, destructive disease of synovial joints
Common sequel to various forms of joint injury

Question 10

Inciting causes of degenerative joint disease

Answer 10

Age
Conformational defects : hip dysplasia, patellar luxation, osteochrondrosis
Excessive wear/use : athletic animals
Joint inflammation : synovitis, arthritis

Question 11

Complex path of DJD

Answer 11

Damage to Chondrocytes
Proteoglycan depletion = dehydration
Loss of normal articular cartilage viscosity
Progressive loss of cartilage due to normal biomechanial forces (movement)
Release of cytokine/GF = inflammation, 2nd response
Cartilage matrix degradation > repair

Question 12

Eburnation

Answer 12

“Like ivory”
Degeneration/wear in subcondylar bone, whitening appearance & polishing

Question 13

Fibrillation of cartilage

Answer 13

Fissure is damage or a tear in cartilage, fibrillation is the sub acute or chronic condition with multiple fissures present in cartilage

Question 14

What DJD is common in horses?

Answer 14

Navicular syndrome
Degenerative arthropathy of navicular bone
Common in fore limbs or abnormal foot conformation

Question 15

What animal is osteophytes commonly found w DJD?

Question 16

Ankylosing spondylosis is commonly found in what animal?

Answer 16

Dogs

Question 17

Intervertebral disc disease is common in w hat animal

Question 18

Pathogenesis of infectious arthritis

Answer 18

Hematogenous = poly arthritis, multi joint
Common in young animals
Direct extension - due to penetrating wound or adjacent soft tissue infection
Prognosis & outcome depend on degree of cartilage damage
Infection elim before Cartilage damage -> normal function
Cartilage damage occurs -> DJD, synovial fibrosis

Question 19

Common Infections that lead to arthritis in pigs

Answer 19

Strep suis, haemophilus parasuis, mycoplasma, Trueperella pyogenes, E. coli, erysiplothrix rhusipathiae

Question 20

Common infections that lead to arthritis in cattle

Answer 20

Trueperella pyogenes, e. Coli, strep spp, histophilus somni, mycoplasma bovis, salmonella, borrelia burgdoferi

Question 21

Common infections that could cause arthritis in sheep

Answer 21

Mycoplasma, strep, chlamydophilia, E. coli

Question 22

Common infections that could cause arthritis in goats

Answer 22

Caprine arthritis-encephalitis virus

Question 23

Common infections that could cause arthritis in horses

Answer 23

Actinbacillus equuli, strep, e Coli, salmonella, borrelia burgdoferi

Question 24

Common infections that can cause arthritis in dogs

Answer 24

Borrelia burgdoferi

Question 25

Pathogenesis of suppurative diskospondylitis

Answer 25

Purulent inflammation of intervertebral disks, brucella infection

Question 26

Non-infectious erosive arthritis pathogenesis

Answer 26

Rheumatoid arthritis
Chronic immune mediated disease
Pannus formation - migration of inflammation over the articular cartilage

Question 27

Non-infectious non-erosive arthritis

Answer 27

Systemic lupus erythematosus
Anti-nuclear antibody, anemia, thrombocytopenia, glomerulonphritis, dermatitis

Question 28

Path of idiopathic poly arthritis

Answer 28

Concurrent with chronic disease

Question 29

Path of primary joint neoplasia

Answer 29

Synovial cell sarcoma
From synovial lining cells, can occur in joints/tendon sheaths
Locally invasive & destructive, moderate to low distant metastatic potential

Question 30

Path of articular/ periarticular histocytic sarcoma

Answer 30

Within or adjacent to joints (stifle, elbow)
More common than SCS in dogs
Distant metastasis more likely than SCS