Arthritides

Question 1

What are Arthritides?

Answer 1

Conditions causing pain + dysfunction related to joints

Question 2

What is arthritis?

Answer 2

*Inflammation / degeneration of the joint
*Includes osteoarthritis, immune-mediated arthritis, infective arthritis

Question 3

What is osteoarthritis?

Answer 3

*Degenerative conditions ultimately leading to cartilage breakdown + loss of function (End-stage)

Question 4

What is a Diarthrodial joint?

Answer 4

*Specialised joint consisting of synovial cavity allowing for articulation between 2 or more bones
*Include ball + socket, hinge or ginglymus, gliding + pivot

Question 5

Why are joint diseases important to animals?

Answer 5

*Cause pain + suffering - welfare
*COST - drugs, productivity (Milk)
*Loss of function / athletic use - most common cause of euthanasia in horses
*Degenerative joint disease = osteoarthritis

Question 6

What does a normal synovial joint consist of?

Answer 6

=Diarthrodial joints
*Hyaline cartilage covered bones - articular cartilage + subchondral bone
*Synovial fluid (plasma + protein= hyaluronic acid)
*Fibrous joint capsule - synovial membrane, nerves + blood vessels, supportive ligaments / tendons

Question 7

What is the structure of articular cartilage?

Answer 7

*Extracellular matrix with low density of articular chondrocytes
-chondrocytes = maintenance of matrix
*Matrix = collagens (80-90% type II), proteoglycans + water

Question 8

What tissues contribute to disease progression / clinical signs of osteoarthritis?

Answer 8

*Articular cartilage
*Subchondral bone
*Synovial membrane
*Joint capsule
*Ligaments
*Fat pad

Question 9

What are predisposing factors of osteoarthritis?

Answer 9

*Exercise / trauma / biomechanics - soft-tissue injury
*Developmental orthopaedic disease - hip + elbow dysplasia
*Obesity - weight stress
*Genetics - cruciate ligament disease (Newfoundlands)
*Sepsis - sequel to joint sepsis
*Repeat medications - corticosteroids
*Ageing - wear + tear

Question 10

What history should be asked with osteoarthritis?

Answer 10

*Level of exercise
*Onset + progression of disease
*Response to previous medication

Question 11

What are radiographic signs of osteoarthritis?

Answer 11

*Soft tissue swelling
*Osteophytosis - bony lumps growing around joints
*Enthesiophytosis - bony spur forming from ligament / tendon insertion to bone
*Subchondral bone sclerosis
*Intra-articular mineralisation
*Fragmentation / joint mice
*Collapsed joint space
*Subchondral bone cysts

Question 12

What are the main aims of osteoarthritis therapy?

Answer 12

1 Provide analgesia
2. Control articular inflammation
3. Limit damage to articular tissues
4. Promote healing of damaged cartilage***

Question 13

What needs to be considered with efficacy of treatments?

Answer 13

*Heterogeneity of disease
*Inter-animal variation
*Poor correlation between imaging and disease process
*Lack of reliable indicators of disease process
*In vivo versus in vitro
*High expectations of owners

Question 14

What are conservative management of osteoarthritic patients?

Answer 14

*Rest / restricted activity - support limb
*Weight loss - reduce strain
*Exercise - beneficial effect on cartilage + bone

Question 15

What is medical management of osteoarthritis?

Answer 15

*NSAIDs
*+/-multi-modal analgesia
*Intra-synovial corticosteroids
* Intra-synovial Hyaluronic acid
*Pentosan polysulphate
*Bisphosphonates
*‘Biologics’
*Nutraceuticals

Question 16

What are examples of NSAIDs and what are the concern of using them?

Answer 16

*Meloxicam
*Firocoxib
*Phenylbutazone
*Ketoprofen

*Concerns over gastrointestinal + renal toxicity

Question 17

What can be used as multimodal analgesia if NSAIDs aren’t enough?

Answer 17

*Paracetamol - unlicenced in dogs + horses
*Tramadol
*Gabapentin - unlicenced in dog+ horses
*Amantadine - unlicenced in dogs
*Bedinvetmab

Question 18

What does intra-synovial corticosteroids do?

Answer 18

1. Inhibit conversion of membrane phospholipids to arachidonic acid precursor
2. Bind to cytoplasmic and nuclear receptors = inhibit cytokines

Question 19

What is the action of intra-synovial hyaluronic acid?

Answer 19

– Mechanical effect (improves viscosity)
– Anti-inflammatory
– Chondroprotection (reduces chondrocyte apoptosis)
– Mitigates synovial hypertrophy
– Stimulates proteoglycan synthesis from chondrocytes
– Limits subchondral bone changes
– Analgesia (bind to nerve endings)

Question 20

What does Pentosan polysulphate sodium do?

Answer 20

=Disease modifying osteoarthritic drug
– Enhances proteoglycan synthesis
– Reduction in articular cartilage fibrillation
– Fibrinolytic - improves joint perfusion
– Improves SF viscosity
– Increases release of free radical scavengers

Question 21

What do biphosphonates do?

Answer 21

*Potent inhibitors of bone reabsorption
-inhibit osteoclasts - bone lysis = painful

Question 22

What are examples of biologics, what do they do?

Answer 22

*Autologous conditioned serum - reduce effect of IL-1
*Platelet-rich plasma = increased growth factors - treat ligament/tendon injuries
*Mesenchymal stem cells = used in bone repair, tendon/ligament injuries, wound healing + joint disease

Question 23

What does mesenchymal stem cells do in joint disease?

Answer 23

*Bind to fibrillated cartilage, reduce immune cell activity
*Regenerate tissue
*Reduce progression of OA

Question 24

What are some nutraceuticals and what do they do?

Answer 24

*Polyunsaturated fatty acids
- Stabilisation of cell membranes
-anti-aggrecanase
-Reduce clinical signs of OA

*Glucosamine / Chondroitin sulphate
–reduce lameness, synovial effusion, increase mobility

Question 25

What can be done for surgical management of OA?

Answer 25

*Arthroscopy - assess damage, debride cartilage defects + flushing inflammatory mediators
*Joint replacement - hip / elbow
*Arthrodesis - destruction of cartilage, bone-bone primary healing

Question 26

What are common causes of infective arthritis?

Answer 26

*Haematogenous
- infection e.g umbilicus, pneumonia, diarrhoea, septicaemia
-Neonates - failure of passive transfer
*Trauma / wound
-cat bites, adjacent infection, distal limb wounds
*Iatrogenic - post joint/fracture surgery (more common in SA surgery)

Question 27

How are septic arthritis diagnosed?

Answer 27

*History
*Clinical signs - lameness, wounds, swelling
*Radiography / ultrasonography
*Differential diagonsis - traumatic joint injury, osteochondrosis, bursitis / hygroma / cellulitis
*Synoviocentesis

Question 28

How does synoviocentesis work?

Answer 28

*Normal synovial fluid = pale yellow, high viscosity, <10% neutrophils
*Septic synovial fluid = Turbid, reduce viscosity, >90% neutrophils Darker colour

Question 29

How do you treat septic arthritis?

Answer 29

1.Treat underlying cause
2. Systemic + local antimicrobials - based on culture / sensitivity
3. Remove inflammatory mediators - joint lavage

Question 30

What breeds are predisposed to immune mediated joint disease?

Answer 30

*Greyhounds
*Shar-pei
*Pedigree cats

Question 31

What does immune-mediated joint disease present as? What is the prognosis?

Answer 31

Polyarthritis
-Erosive - poor prognosis
-Non-erosive

Question 32

What occurs with immune mediated joint disease?

Answer 32

*Early changes in synovium
-chronic antigenic stimulation
-antibodies to infective agents = inappropriate immune response
*Development of immune-complexes

Question 33

What are the clinical signs of IMPA?

Answer 33

*multiple limb joint pain/swelling
*Generalised stiffness
*Shifting lameness
*Neck pain
*Lethargy

Question 34

How is IMPA diagnosed?

Answer 34

*Synoviocentesis
*Full clinical exam
*Diagnostic imaging
*Clinical signs

Question 35

How is IMPA controlled / treated?

Answer 35

Corticosteroids - cyclosporine, azathioprine

Question 36

Why is lyme disease relevant?

Answer 36

Dogs present with inflammatory non-erosive arthropathy with shifting lameness + swollen joints - Similar to polyarthritis

Question 37

How is lyme disease treated?

Answer 37

Doxycycline for 30+ days