MSK pt 3 Flashcards
what happens with articular cartilage is damaged?
hyaline cartilage replaced by fibrocartilage
What is the synovial fossa?
normal clefts in non-weight bearing cartilage surfaces in horses, pigs, ruminants
articular cartilage has limited blood supply, which means that there is limited _____ capacity
regenerative
what are erosions?
superficial defects that persist/won’t fill in
what are ulcerations?
full-thickness defects where mesenchymal cells can access site of injury, leading to it being filled with fibrocartilage
if you have a joint injury and feel pain, what does that mean?
that the articular cartilage is not the only thing that is impacted. If only articular cartilage is affected, there is no pain. There must also be injury to the synovium or subchondral bone for pain to be present
Describe the positive feedback loop of injury to articular cartilage
- injury (sterile or infectious)
- stimulates an increase in enzymes, cytokines, prostaglandins, and other molecules
- destruction of cartilage matrix
- injury (cycle starts over)
what is the role of subchondral bone and where is it located?
located immediately below articular cartilage
supports articular cartilage and dissipates forces
describe the pathogenesis of how damage to or loss of articular cartilage leads to subchondral bone sclerosis
- damage/loss of articular cartilage
- increase in concussive forces reach subchondral bone
- response in accordance to Wolff’s law
- increase in bone formation with decrease in bone resorption
- net bone thickening –> subchondral bone sclerosis
What is eburnation?
complete ulceration of articular cartilage with exposure of subchondral bone
what is the name of the lesion in this picture
eburnation
why does eburnation look “shiny”?
exposure of the subchondral bone leads to increased bone density, and it is polished from bone-to-bone contact
you find these gnarly things in the synovium. what are they? what do they mean?
villous hypertrophy/hyperplasia
they mean injury/inflammation of the synovial membrane
Name the lesion labeled F and the lesion that looks like rumen papillae.
F: eburnation
the other stuff is villous hypertrophy or hyperplasia
Define these terms:
1. synovitis
2. arthritis
3. arthropathy
4. polyarthritis
5. hygroma
6. ankylosis
- inflammation of the synovial membrane, likely a response to cartilage debris within the joint
- generic term for joint inflammation
- generic term for joint disease
- inflammation of multiple joints
- fluid-filled sac that develops in areas of high pressure, including adjacent to joint
- joint fusion
what is an osteophyte? what causes is?
proliferative new bone along joint margins
response to inflammation and/or joint instability
what are the arrows pointing to?
osteophytes
What are the two classifications of arthritis, and what is the difference between them?
inflammatory and osteoarthritis
osteoarthritis is not caused by inflammation, and inflammatory arthritis is caused by inflammation
What are the 5 ways in which bacteria can enter joints?
- hematogenous
- extension from osteomyelitis
- spread from ST infection
- iatrogenic
- penetrating injury
What is suppurative arthritis?
joint inflammation associated with bacterial infection with purulent exudate in synovial fluid
what are the gross lesions of suppurative arthritis? tell me specifically about how the articular cartilage changes.
synovial fluid is turbid (pus) ± synovial membrane proliferation ± fibrin in joint
articular cartilage changes based on the chronicity:
- acute: normal to slightly thin
- chronic: severe erosions/ulcerations
what is “the great pus former” and something that causes suppurative arthritis in animals?
Truperella pyogenes
what is the lesion?
suppurative arthritis
this is a joint of an animal (idk what lol). the fluid in the syringe is synovial fluid. what is the lesion?
suppurative arthritis
suppurative polyarthritis of neonatal calves, foals, and lambs can start as what disease process?
embolic suppurative osteomyelitis of the growth plate that spreads into joint
can also start at epiphyseal/joint cartilage (site of epiphyseal growth)
what is fibrinous arthritis?
joint inflammation associated with bacterial infection with fibrinous exudate in synovial fluid
what are the gross lesions of fibrinous arthritis? tell me specifically about the articular cartilage changes.
synovial fluid containing fibrin, severe synovial membrane proliferation ± cartilage damage
articular cartilage changes with chronicity:
- acute: normal to slightly thin
- chronic: may develop cartilage damage erosions/ulcerations but not consistently
This is a joint. what is the lesion?
fibrinous arthritis
We have to know 5 examples of bacterial species that cause fibrinous arthritis. Name them and tell me which species is impacted.
Escherichia coli (cattle & pigs)
Haemophilus parasuis (pigs)
Streptococcus bovis (cattle)
Histophilus somni (cattle)
Streptococcus suis (pigs)
“Emmett Has Such Hot Stifles”
We have to know 5 examples of bacterial species that cause fibrinous arthritis. Name them and tell me what disease they cause (other than fibrinous arthritis lol)
Escherichia coli – bacterial septicemia
Haemophilus parasuis – Glasser’s Disease
Streptococcus bovis – Bacterial septicemia
Histophilus somni – Thrombotic meningoencephalitis
Streptococcus suis – bacterial septicaemia
“Emmett Has Such Hot Stifles”
This is a stifle joint. What is the lesion?
fibrinous arthritis
Histophilus somni can wreak havoc on cows. Name the 4 associated lesions that we should know.
- fibrinous arthritis
- myocarditis (remember boxing glove cut?)
- fibrinous pleuritis
- meningoencephalitis
There are different outcomes to both fibrinous and suppurative arthritis depending on if the inflammation is mild or severe. What is the outcome if the inflammation is mild?
resolution of lesions
There are different outcomes to both fibrinous and suppurative arthritis depending on if the inflammation is mild or severe. What is the outcome if the inflammation is severe?
enzymes, cytokines, prostaglandins, and other molecules –> damage cartilage and synovium –> osteoarthritis/degenerative joint disease
joint rigidity, loss of function, ankylosis
Borrelia burgdorferi is another example of a bacteria that causes joint disease. What disease does it cause and in what species?
dogs – associated with fibrinosuppurative polyarthritis
Mycoplasma spp. cause what type of joint disease? Which Mycoplasma species affect pigs, and which affect cattle?
fibrinous to pyogranulomatous arthritis
M. hyorhinis & M. hyosynoviae = pigs
M. bovis = cattle
is viral arthritis rare or common in animals?
rare
viral arthritis in turkeys and chickens is seen sometimes. What specific pathologies did the prof mention?
reovirus arthritis & tenosynovitis
viral arthritis in goats is seen sometimes. what is the ethology of this pathology and what are the lesions?
Caprine arthritis and encephalitis virus
fibrinous arthritis, carpal hygroma, synovial hyperplasia, bursitis
Systemic Lupus Erythematosus (SLE):
1. what is it?
2. how is articular cartilage affected?
3. what are the lesions?
4. what cell type is in the synovial fluid?
- autoimmune disease of dogs; formation of antinuclear autoantibodies
- not affected (non-erosive)
- villus hyperplasia & synovitis of synovial membrane
- neutrophil
Crystal deposits in articular cartilage & other joint tissues stimulate _____. what are 2 examples of crystals?
inflammation
urates & calcium molecules
what is gout?
urate crystal deposits in/around joints
visceral organs may also be affected
who does gout affect?
birds, reptiles, primates
what are the gross lesions of gout?
gross lesions: white, caseous material within joints
This is a chicken joint. the white material you see has quite a chalky texture. what is the lesion?
gout
Osteoarthritis is also known as what?
degenerative joint disease or osteoarthrosis
what is osteoarthritis?
destructive condition of articular cartilage in synovial joint
an end stage disease that is caused by a variety of insults that initiate joint/cartilage damage
Name 6 things that can cause osteoarthritis.
suppurative/fibrinous arthritis
chronic gout
advanced age
joint instability
poorly aligned fractures
osteochondrosis
what is the pathogenesis of osteoarthritis?
- inciting cartilage damage
- decrease in proteoglycans in cartilage
- water retention and chrondromalacia (cartilage softening)
- abnormal wear
- cartilage erosion and ulceration
what is the main lesion in osteoarthritis?
what are the accompanying changes?
main: articular cartilage roughening (fibrillations) progressing to fissures/grooves, erosions/ulcerations, and eventually exposure of the subchondral bone (eburnation).
accompanying:
- subchondral bone sclerosis
- synovitis (mild compared to inflammatory arthritis)
- joint capsule fibrosis (thickening)
- osteophytes
- joint stiffness
- ankylosis
what is the lesion?
osteoarthritis
are linear lines on articular cartilage normal?
no
Canine hip dysplasia:
1. breed dispositions?
2. what is it?
- large & giant dog breeds
- congenital joint laxity leads to chronic subluxation and severe osteoarthritis
what are the lesions associated with canine hip dysplasia?
- articular cartilage erosion & ulceration (femoral head and acetabulum)
- bone moedling of the acetabulum and femoral head/neck
- advanced disease: eburnation and flattening of femoral head and periarticular osteophytes
This is the femoral head and pelvis from a dog. What is the lesion?
canine hip dysplasia that lead to osteoarthritis
Ankylosing spondylosis:
1. results from what?
2. which bones are most often affected?
3. signalment?
4. is it usually incidental?
- intervertebral disk disease
- caudal thoracic and cranial lumbar vertebrae
- old age condition of many species
- yes
what is the pathogenesis of ankylosing spondylosis?
- nucleus pulposus dehydrates and increases collagen content + weakening of annulus fibrosus
- herniation of nucleus pulposus dorsally (site of thinner annulus fibrosus)
- collapse of disk space
- osteoarthritis and perihstreal new bone formation (spondylosis)
- ankyloses
- ankylosing spondylosis
these are vertebrae. what is the lesion?
ankylosing spondylosis
True or false. Joint neoplasia is relatively rare.
true
true or false. joint neoplasia arises from the synovial membrane.
true
What is osteochondrosis?
common lesions of the growth cartilage caused by abnormal endochondral ossification = cartilage fails to calcify and is not replaced by bone
where does osteochondrosis occur?
metaphyseal growth plate & junction of articular cartilage and epiphysis (articular-epiphyseal cartilage complex)
True or false. Osteochondrosis is NOT often bilaterally symmetrical.
False. it is usually bilaterally symmetrical
what is the gross lesion of osteochondrosis?
focal growth cartilage retention
osteochondrosis:
1. species?
2. predilection sites?
- mainly horses, dogs, pigs
- vary by species
What is the lesion? This is a horse.
Osteochondrosis (OCD)
What is the cause of osteochondrosis?
multifactorial disease, causes include genetics, rapid growth, vascular factors, and trauma
describe the pathogenesis of osteochondrosis.
- vascular injury in growth cartilage
- cartilage undergoes ischemic necrosis
- fails to mineralize and is not replaced by bone
- articular cartilage damaged because subchondral bone is not there to support it
what is osteochondrosis latens?
microscopic area of necrotic cartilage
what is osteochondrosis manifesta?
grossly-visible retained necrotic epiphyseal cartilage. prone to cleft formation through necrotic cartilage
what is osteochondrosis dissecans (OCD lesions)?
grossly-visible retained necrotic epiphyseal cartilage with cleating through necrotic cartilage and extending up through articular cartilage. exposed subchondral bone is painful = lameness
cleating from retained cartilage up through articular cartilage with exposure of subchondral bone – flaps may form composed of cartilage or cartilage with bone
true or false. most cases of osteochondrosis are subclinical and will resolve without cleft formation.
true
The type of osteochondrosis dissecans (OCD) is associated with _____ disease. Name 4 of these.
clinical.
1. pain (lameness)
2. joint effusion (extra fluid in joint)
3. synovitis
4. arthritis
what the heck are joint mice?!
free-floating flaps within joint that can interfere with movement.
basically with osteochondrosis dissecans, the flap actually lifts off and lives in the joint
what is the lesion?
osteochondrosis dissecans (OCD)
What is Wobbler’s Syndrome? AKA what? who does it affect?
AKA cranial cervical stenotic myelopathy
affects horses and dogs
osteochondrosis suspected to be an underlying cause to vertebrae abnormalities
abnormal cervical vertebrae –> spinal cord injury (myelopathy) –> neurological deficiencies
what’s this
Wobbler’s syndrome
fill in this chart to tell me the differences b/t osteochondrosis and osteoarthritis.
What is arthrogryposis?
congenital contraction of joints, usually bilaterally symmetrical
what are the causes of arthrogryposis?
cattle & sheep: intrauterine viral infection (bluetongue virus, Akabane virus, etc –> motor neurone damage)
hereditary
toxic plants
what is the pathogenesis of arthrogryposis?
- inciting cause
- decrease in fetla motion during development
- joints lack flexibility
True or false. With arthrogryposis, other than their lack of flexibility, the joints are abnormal.
false. they are otherwise normal
what is wrong with this piglet ?
arthrogryposis
where do tendon injuries usually occur?
at sites of anatomic weakness or excessive stretch forces
what is the pathogenesis of tendon injuries?
- tendon stretch
- ruptured collagen fibres & capillaries
- fibrin exudation
- myofibroblasts stimulated to form scar collage (type III vs type I collagen = less stretchy)
tell me what happens with:
1. severe tendon rupture
2. acute tendon injury
3. chronic tendon injury
- tendon necrosis, sequestration, irregular scar tissue with adhesions to tendon sheath
- tendon swollen, warm, painful
- tendon is thicker and possible longer than normal
what is wrong with this horse’s leg?
bowed tendons
