Flashcards in Degenerative joint disease (DJD) Deck (41)
Loading flashcards...
1
What is DJD?
- the end stage of joint disease
- one of the most common orthopaedic conditions vets deal with in practice
- incurable, but ideally temporarily manageable
- degeneration of articular cartilage
- bone changes (OA) -new bone formation and bone lysis
2
Contents - cartilage
- 75% water
- 15% type 2 collagen
- 8% PGs
3
What conditions lead to DJD? 5
- TRAUMA (acute, repetitive)
- INFECTIOUS INFLAMMATION (septic arthritis)
- NON-INFECTIOUS INFLAMMATION
- DEVELOPMENTAL DISEASE (dysplasia, angular limb deformity, flexural limb deformity, osteochondrosis)
- OTHER
4
Outline pathophysiology of DJD
- AC: failure of homeostasis (cartilage breakdown products, MMPs, and catabolic cytokines (IL-1, IL-6, TNF)
- SYNOVIAL MEMBRANE: Pgs, leukotrienes, neuropeptides, cytokines
- SUBCHONDRAL BONE: (chronic remodelling) altered load absorption - cartilage damage, inflammatory mediators (IL-1, TNF)
5
What causes pain in arthritis?
- no pain Rs in cartilage
- pain Rs in joint capsule (synovitis, joint distension)
- exposure of sunchondral bone
6
What is the role of soft tissues in cartilage degradation?
- synoviocytes release mediators and enzymes (PGs, cytokines, MMPs)
- increased levels of inflammatory mediators measured in joint fluid
7
How well do radiographic signs of OA correlate with CS?
poorly
8
What to look for on clinical exam
* weight and BCS
* LAMENESS EXAM:
- ID
- scoring
- localise
- palpation/manipulation of joint
- pain/heat/ swelling/crepitus
- joint thickening/ effusion
- reduced ROM
- mm atrophy
* local analgesia
* synovial fluid analysis (LA often unspecific)
* diagnostic imaging: radiograph (plain/contrast), ultrasound, MRI/CT
- arthroscopy: synovial biopsy sometimes
9
What is more specific than peripheral nn blocks in large animals?
intraarticular analgesia
10
What should you do if you have a positive digital nerve block?
return on 2 separate occasions to block DIPJ and the navicular bursa
11
List radiographic features to look for when suspecting OA - 3
- osteophytes
- soft tissues (soft tissue, effusion)
- subchondral bone sclerosis
12
Goals - arthritis tx
- pain reduction
- stop inflammation (decrease mediator secretion)
- chondroprotection (disease modification = to arrest/slow down cartilage degeneration, but EBVM lacking)
- established OA cannot be fully cured
13
Tx strategies - arthritis
- weight control
- exercise modification/ physio
- strategic analgesia (achieve acceptable level of exercise)
- joint supplements (nutraceuticals, disease modification)
- novel tx concepts
- salvage procedures (if all else fails)
14
Tx - arthritis flare-ups - 3
- initial analgesia (5-10d)
- gradually resume controlled exercise
- swimming/hydrotherapy
15
Medical arthritis tx - large animals
- NSAIDs
- I/A corticosteroids
- GAGs
- sodium hyaluronate
- supplements (chondroitin sulphate, glucosamine)
- IL-1 antagonist protein
- Tiludronate (Tildren): selected conditions
16
What do corticosteroids block?
- PLPA2 (i.e. pain, swelling, cartilage degradation, heat)
- COX
- cartilage-degrading enzymes (MMP-13,3,1 and aggrecanase 1)
17
What do NSAIDs block?
COX
18
What is commonest medication for orthopaedic problems?
NSAIDs (cheap adn efficient)
19
Side effects - NSAIDs
- GI ulcer
- nephritis (with sensitive animals)
- PLE (with chronic ulcers)
- negative influence on cartilage and bone metabolism
20
Why is ketoprofen popular in horses?
because more COX1 selective in horses. used often in foals, v expensive in adults because of dose required
21
Outline corticosteroids in tx of arthritis
- often in horses
- most potent anti-inflammatory drugs (inflammatory cells and humoral mediators)
22
Side effects- IA corticosteroids
- negative effects on cartilage metabolism and healing
- data controversial
- decreased PG synthesis and organisation
- increased risk of iatrogenic joint infections (temporary shut down of inflammatory defence mechanisms)
- laminitis?
23
What dictates drug choice and dose? 4
- joint volume
- severity of inflammation
- # joints to tx
- personal preference
24
List options for IA corticosteroids
- bethamethasone
- triamcinolone acetonide
- flumethasone
- isoflupedone acetate
- methylprednisolone acetate
25
Describe mechanism of polysulphated GAGs in horses - 3
- MMP inhibition
- stimulates HA production
- stimulates matrix synthesis
26
Use of GAGs
- higher concentration
- increased risk of sepsis
- non-septic inflammation (flare)
- licensing
- only licensed for IM injection (use higher dose if going IA)
27
Name 2 types of GAG used in horses for arthritis
- polysulphated GAGs (Adequan) = from bovine lung and trachea
- pentosan polysulphate (Catrophen) = from beechwood hemicellulose
28
Mechanism -pentosan polysulphate
- stimulates cartilage matrix synthesis
- stimulates HA syntehsis
- MMP inhibition
- inhibits inflammatory mediators
- mobilise thrombi and fibrin in synovium
- mobilise lipids and cholesterol in BVs
- inhibits platelet aggregation and clotting
- increase plasma lipase levels
29
Why is sodium hyaluronate good to give to horses?
Major structural component:
- Articular cartilage matrix (from chondrocytes)
- Synovium (by type B synoviocytes)
Anti-inflammatory function (either by steric hindrance or chemotactic response)
30
