Degenerative joint disease (DJD) Flashcards Preview

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Flashcards in Degenerative joint disease (DJD) Deck (41)
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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

Mechanism - exogenous sodium hyaluronate in horses

- speculative
- lubrication
- anti-inflammatory activity
- activation of cell receptors
- supplementation of depleted endogenous HA
- stimulation of endogenous HA synthesis
* important that molecular weight is > 5* 10^2kDa