Arthritides Flashcards
What are Arthritides?
Conditions causing pain + dysfunction related to joints
What is arthritis?
*Inflammation / degeneration of the joint
*Includes osteoarthritis, immune-mediated arthritis, infective arthritis
What is osteoarthritis?
*Degenerative conditions ultimately leading to cartilage breakdown + loss of function (End-stage)
What is a Diarthrodial joint?
*Specialised joint consisting of synovial cavity allowing for articulation between 2 or more bones
*Include ball + socket, hinge or ginglymus, gliding + pivot
Why are joint diseases important to animals?
*Cause pain + suffering - welfare
*COST - drugs, productivity (Milk)
*Loss of function / athletic use - most common cause of euthanasia in horses
*Degenerative joint disease = osteoarthritis
What does a normal synovial joint consist of?
=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
What is the structure of articular cartilage?
*Extracellular matrix with low density of articular chondrocytes
-chondrocytes = maintenance of matrix
*Matrix = collagens (80-90% type II), proteoglycans + water
What tissues contribute to disease progression / clinical signs of osteoarthritis?
*Articular cartilage
*Subchondral bone
*Synovial membrane
*Joint capsule
*Ligaments
*Fat pad
What are predisposing factors of osteoarthritis?
*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
What history should be asked with osteoarthritis?
*Level of exercise
*Onset + progression of disease
*Response to previous medication
What are radiographic signs of osteoarthritis?
*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
What are the main aims of osteoarthritis therapy?
1 Provide analgesia
2. Control articular inflammation
3. Limit damage to articular tissues
4. Promote healing of damaged cartilage***
What needs to be considered with efficacy of treatments?
*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
What are conservative management of osteoarthritic patients?
*Rest / restricted activity - support limb
*Weight loss - reduce strain
*Exercise - beneficial effect on cartilage + bone
What is medical management of osteoarthritis?
*NSAIDs
*+/-multi-modal analgesia
*Intra-synovial corticosteroids
* Intra-synovial Hyaluronic acid
*Pentosan polysulphate
*Bisphosphonates
*‘Biologics’
*Nutraceuticals
What are examples of NSAIDs and what are the concern of using them?
*Meloxicam
*Firocoxib
*Phenylbutazone
*Ketoprofen
*Concerns over gastrointestinal + renal toxicity
What can be used as multimodal analgesia if NSAIDs aren’t enough?
*Paracetamol - unlicenced in dogs + horses
*Tramadol
*Gabapentin - unlicenced in dog+ horses
*Amantadine - unlicenced in dogs
*Bedinvetmab
What does intra-synovial corticosteroids do?
- Inhibit conversion of membrane phospholipids to arachidonic acid precursor
- Bind to cytoplasmic and nuclear receptors = inhibit cytokines
What is the action of intra-synovial hyaluronic acid?
– 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)
What does Pentosan polysulphate sodium do?
=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
What do biphosphonates do?
*Potent inhibitors of bone reabsorption
-inhibit osteoclasts - bone lysis = painful
What are examples of biologics, what do they do?
*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
What does mesenchymal stem cells do in joint disease?
*Bind to fibrillated cartilage, reduce immune cell activity
*Regenerate tissue
*Reduce progression of OA
What are some nutraceuticals and what do they do?
*Polyunsaturated fatty acids
- Stabilisation of cell membranes
-anti-aggrecanase
-Reduce clinical signs of OA
*Glucosamine / Chondroitin sulphate
–reduce lameness, synovial effusion, increase mobility
What can be done for surgical management of OA?
*Arthroscopy - assess damage, debride cartilage defects + flushing inflammatory mediators
*Joint replacement - hip / elbow
*Arthrodesis - destruction of cartilage, bone-bone primary healing
What are common causes of infective arthritis?
*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)
How are septic arthritis diagnosed?
*History
*Clinical signs - lameness, wounds, swelling
*Radiography / ultrasonography
*Differential diagonsis - traumatic joint injury, osteochondrosis, bursitis / hygroma / cellulitis
*Synoviocentesis
How does synoviocentesis work?
*Normal synovial fluid = pale yellow, high viscosity, <10% neutrophils
*Septic synovial fluid = Turbid, reduce viscosity, >90% neutrophils Darker colour
How do you treat septic arthritis?
1.Treat underlying cause
2. Systemic + local antimicrobials - based on culture / sensitivity
3. Remove inflammatory mediators - joint lavage
What breeds are predisposed to immune mediated joint disease?
*Greyhounds
*Shar-pei
*Pedigree cats
What does immune-mediated joint disease present as? What is the prognosis?
Polyarthritis
-Erosive - poor prognosis
-Non-erosive
What occurs with immune mediated joint disease?
*Early changes in synovium
-chronic antigenic stimulation
-antibodies to infective agents = inappropriate immune response
*Development of immune-complexes
What are the clinical signs of IMPA?
*multiple limb joint pain/swelling
*Generalised stiffness
*Shifting lameness
*Neck pain
*Lethargy
How is IMPA diagnosed?
*Synoviocentesis
*Full clinical exam
*Diagnostic imaging
*Clinical signs
How is IMPA controlled / treated?
Corticosteroids - cyclosporine, azathioprine
Why is lyme disease relevant?
Dogs present with inflammatory non-erosive arthropathy with shifting lameness + swollen joints - Similar to polyarthritis
How is lyme disease treated?
Doxycycline for 30+ days
