Diseases of joints

Question 1

4 categories of joint diseases

Answer 1

• developmental
• degenerative
• inflammatory
• neoplastic

Question 2

3 types of developmental disturbances

Answer 2

• luxations/subluxations
• hip dysplasia
• arthrogryposis

Question 3

luxation v subluxatin

Answer 3

• luxation: complete dislocation of a joint

- subluxation: partial dislocation of a joint

Question 4

patellar luxations

Answer 4

• common in dogs, sometimes in horses
• most associated with anatomical defects (inherited)
• medial luxations most common (small dogs), lateral luxations in larger dogs and horses

Question 5

hip dysplasia

Answer 5

• large dogs, sometimes cattle
• may be a manifestation of osteochondrosis
• normal at birth, may see microscopic lesions as early as 30 days
• retarded development of craniodorsal acetabular rim –> acetabulum becomes shallow, distorted, wide
• degenerative changes present by 5-8mo, may lead to osteoarthritis

Question 6

lesions in hip dysplasia

Answer 6

• osteophytes
• cartilage ulceration
• eburnation of bone
• distortion of acetabulum, head, neck of femur

Question 7

arthrogryposis

Answer 7

• persistent flexure or contracture of a joint

- cause unclear –> loss of motion of fetus during development

Question 8

osteoarthrosis/itis

Answer 8

• common disorder
• not driven by inflammation
• joint fluid initially normal, chronicity leads to joint deterioration

Question 9

primary arthropathies

Answer 9

• cause is unknown

- ringbone, spavin, navicular, arthropathy of shoulder or stifle

Question 10

secondary arthropathies

Answer 10

• secondary to a known cause

- osteochondrosis, previous trauma

Question 11

vulnerability to degenerative joint disease

Answer 11

• larger joints usually the first to show degenerative changes and are most severely affected
• in individual joints, the areas of cartilage that bear the most stress are the most vulnerable

Question 12

lesions of degenerative joint disease

Answer 12

• fibrillation, clefting, loss of articular cartilage
• increased thickness of subchondral bone (eburnation)
• osteophytes (increased size of joint)
• thickened joint capsule (fibrous tissue) with synovial proliferation

Question 13

ringbone, spavin, navicular

Answer 13

• common horse disorders
• all develop at site of high or sustained mechanical loading
• ringbone: interphalangeal joints
• spavin: intertarsal joints
• navicular: navicular bones
• full thickness necrosis of cartilage covering bone surfaces at sites of sustained compression
• remodeling of subjacent subcondral bone
• penetration of cartilage by granulation tissue arising from remodeling response in subchondral bone

Question 14

arthropathy of canine shoulder

Answer 14

• common in middle aged to old dogs
• bilateral, slow-developing lesions
• cartilage ulceration, eburnation, thickening of joint capsule, villous proliferation of synovium
• osteophytes

Question 15

arthropathy of bovine stifle

Answer 15

• lameness and muscle atrophy in mature dairy cows
• bilateral lesions
• cartilage degeneration, eburnation, osteophyte development
• most severe in medial aspect of distal femur

Question 16

intervertebral disk degeneration

Answer 16

• prolapsed disks
• nucleus pulposus degenerates, replaced with cartilaginous tissue –> increases likelihood of protrusion
• prolapses associated with partial rupture of annulus and bulging of dorsal disk surface
• spinal pain, paresis, paraplegia
• most displacements occur dorsally

Question 17

spondylosis

Answer 17

• common condition of vertebral column
• osteophytes develop at intervertebral space as spurs or as complete bony bridges
• posterior weakness and ataxia, paralysis

Question 18

general considerations of inflammatory joint diseases

Answer 18

• arthritis in inflammatory
• primary and initiating disease process centered in walls of capillaries, driven from the onset by mediators of inflammation
• infectious or noninfectious

Question 19

infectious arthritis - who affected and how

Answer 19

• hematogenous, direct extension, penetrating wound
• dogs/cats: monoarticular, penetrating wounds, adolescent or older animals
• farm animals: polyarticular, hematogenous, neonates

Question 20

infectious arthritis inflammation, steps, etc

Answer 20

• hematogenous is initially polyarticular
• inflammation subsides in many joints, progresses in others
• large joints particularly susceptible to progressive development of inflammation (serofibrinous)
• many causes
• lameness, swelling, fever

Question 21

bursitis

Answer 21

• capped elbow and hock (serous)
• carpal bursitis (hygroma) in cattle
• fistulous withers (supraspinous bursa) and poll evil (atlantal bursa)

Question 22

diskospondylitis

Answer 22

• intervertebral disk inflammation with osteomyelitis of contiguous vertebrae
• dogs and pigs
• usually bacterial
• gray areas of discoloration and disruption
• complete destruction of disk occurs late in disease

Question 23

noninfectious arthritis

Answer 23

• immunologically mediated
• either centered in synovium or centered elsewhere in body
• similar morphologic pattern of joint destruction as infectious arthritis
• joint fluid from infectious arthritis often contains toxic neutrophils

Question 24

erosive arthritis

Answer 24

• ex) rheumatoid arthritis
• episodes of anorexia, depression, and fever with generalized or shifting lameness associated with swelling around joints
• clinical course is progressive

Question 25

tumors of joints

Answer 25

- neoplasms of articular cartilage do not occur - neoplasms of synovial structures are relatively uncommon (synoviomas = benign, synovial sarcomas = malignant) - present as soft tissue masses in joint region, lameness, difficult to remove