Degenerative Joint Disease Flashcards
What is articular cartilage made up of?
Chondrocytes and cartilage matrix
What makes up the joint capsule and synovial membrane?
Type A and type B synoviocytes
What are type A synoviocytes?
Triangular and are like a modified macrophage
What is the function of type B synoviocytes?
Make fluid
What is the cartilage matrix made up of?
75% water, 15% type II collagen fibres, 8% proteoglycans, <1% elastic and reticular fibres, 2% chondrocytes
What are common causes of DJD?
Trauma - acute ligament tear or repetitive such as concussion
Infectious inflammation such as septic arthritis
Non-infectious inflammation
Developmental disease such as dysplasia, angular limb deformity, flexural limb deformity or osteochondrosis
What does a failure of cartilage homeostasis lead to?
Breakdown products, matrix metalloproteinases and catabolic cytokines
What does the synovial membrane release in DJD?
PGs, leukotrienes, neuropeptides and cytokines
What impact does subchondral bone have on DJD?
Alters load absorption leading to cartilage damage and release of inflammatory mediators such as IL-1 and TNF
Where does the pain response come from in DJD?
No pain receptors in cartilage so pain comes from synovitis or joint distension or exposure of subchondral bone
What history needs to be taken when investigating degenerative joint disease?
Duration, specific event started, single/bilateral/multiple limbs, previous treatments and response, behavioural change
What should be noted on a clinical exam with suspected DJD?
Weight, BCS, lameness exam, muscular atrophy
What can be some useful diagnostic tests?
Intra-articular analgesia response
Synovial fluid analysis
Radiography, ultrasound, MRI
Arthroscopy +/- synovial biopsy
What are the treatment goals for DJD?
Pain reduction, stop inflammatory processes and chondroprotection
What conservative treatment options need to be performed along with medical/surgical interventions?
Weight loss and control
Exercise modification
Physiotherapy
How do NSAIDs help with DJD? Side effects?
Most common treatment and inexpensive and efficient
Inhibit COX pathway preventing prostaglandin synthesis
GI ulceration, nephritis, PLE and have had some -ve influence on cartilage and bone metabolism in ex vivo studies
Which species are intra-articular corticosteroids often used in? What is their mode of action? Side effects?
Horses
Most potent anti-inflammatory drugs, inhibit PG synthesis, synthesis of cartilage degrading cytokines and cartilage degrading enzymes
-ve effects on cartilage metabolism and healing, increased risk of iatrogenic joint infections and laminitis
What are drug choice and dose dependent on?
Joint volume, severity of inflammation, number of joints to treat and personal preference
What is polysulphated glycosaminoglycan (Adequan)?
Extract from bovine lung and trachea
MMP inhibition, stimulates HA production and matrix synthesis
What is polysulphated glycosaminoglycan licensed for use in the UK? How else can it be used?
IM at 500mg every 4 days for 28 days
Intra-articular injection resulting in a higher concentration but increased chance of sepsis and non-septic inflammation flare
What is pentosan polysulphate (Cartrophen)?
Extract from beechwood hemicellulose
Stimulates HA synthesis and cartilage matrix synthesis
Inhibits MMPs, inflammatory mediators, platelet aggregation
Mobilises lipids, cholesterol, thrombi, fibrin
What is sodium hyaluronate? What is its mode of action? How can it be administered?
Major structural component synthesised by chondrocytes and type B synoviocytes
Has anti-inflammatory function of steric hindrance and chemotactic response
Can administer IA/IV/PO
What supplements can be used to treat DJD?
Glucosamine, chondroitin sulphate, glucosamine/condroitin sulphate combinations, green-lipped muscle extract, methylsulphonylmethane (MSM), devil’s claw
What is the effect of IL-1 receptor antagonist protein?
Directly blocks effects of IL-1 leading to decreased inflammation in experimental studies but no controlled large scale studies done in horses
How is IL-1 receptor antagonist protein made?
Autologus conditioned serum made by culturing patient blood in a special syringe, up regulates IRAP and other anti-inflammatory mediators which can then be administered IA
What is tiludronate? What is it licensed for?
Non-nitrogenous biphosphonate which inhibits bone resorption and has anti-inflammatory properties
Licensed for use in distal tarsal osteoarthritis and navicular disease
What are some surgical options for treatment of DJD?
Excision arthroplasty
Arthrodesis
Total joint replacement
