Degenerative joint disease (DJD) Flashcards

(41 cards)

1
Q

What is DJD?

A
  • 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
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2
Q

Contents - cartilage

A
  • 75% water
  • 15% type 2 collagen
  • 8% PGs
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3
Q

What conditions lead to DJD? 5

A
  • TRAUMA (acute, repetitive)
  • INFECTIOUS INFLAMMATION (septic arthritis)
  • NON-INFECTIOUS INFLAMMATION
  • DEVELOPMENTAL DISEASE (dysplasia, angular limb deformity, flexural limb deformity, osteochondrosis)
  • OTHER
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4
Q

Outline pathophysiology of DJD

A
  • 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)
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5
Q

What causes pain in arthritis?

A
  • no pain Rs in cartilage
  • pain Rs in joint capsule (synovitis, joint distension)
  • exposure of sunchondral bone
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6
Q

What is the role of soft tissues in cartilage degradation?

A
  • synoviocytes release mediators and enzymes (PGs, cytokines, MMPs)
  • increased levels of inflammatory mediators measured in joint fluid
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7
Q

How well do radiographic signs of OA correlate with CS?

A

poorly

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8
Q

What to look for on clinical exam

A
  • 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
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9
Q

What is more specific than peripheral nn blocks in large animals?

A

intraarticular analgesia

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10
Q

What should you do if you have a positive digital nerve block?

A

return on 2 separate occasions to block DIPJ and the navicular bursa

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11
Q

List radiographic features to look for when suspecting OA - 3

A
  • osteophytes
  • soft tissues (soft tissue, effusion)
  • subchondral bone sclerosis
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12
Q

Goals - arthritis tx

A
  • 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
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13
Q

Tx strategies - arthritis

A
  • 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)
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14
Q

Tx - arthritis flare-ups - 3

A
  • initial analgesia (5-10d)
  • gradually resume controlled exercise
  • swimming/hydrotherapy
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15
Q

Medical arthritis tx - large animals

A
  • NSAIDs
  • I/A corticosteroids
  • GAGs
  • sodium hyaluronate
  • supplements (chondroitin sulphate, glucosamine)
  • IL-1 antagonist protein
  • Tiludronate (Tildren): selected conditions
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16
Q

What do corticosteroids block?

A
  • PLPA2 (i.e. pain, swelling, cartilage degradation, heat)
  • COX
  • cartilage-degrading enzymes (MMP-13,3,1 and aggrecanase 1)
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17
Q

What do NSAIDs block?

18
Q

What is commonest medication for orthopaedic problems?

A

NSAIDs (cheap adn efficient)

19
Q

Side effects - NSAIDs

A
  • GI ulcer
  • nephritis (with sensitive animals)
  • PLE (with chronic ulcers)
  • negative influence on cartilage and bone metabolism
20
Q

Why is ketoprofen popular in horses?

A

because more COX1 selective in horses. used often in foals, v expensive in adults because of dose required

21
Q

Outline corticosteroids in tx of arthritis

A
  • often in horses

- most potent anti-inflammatory drugs (inflammatory cells and humoral mediators)

22
Q

Side effects- IA corticosteroids

A
  • 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
Q

What dictates drug choice and dose? 4

A
  • joint volume
  • severity of inflammation
  • # joints to tx
  • personal preference
24
Q

List options for IA corticosteroids

A
  • 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
31
Administration - sodium hyaluronate
- IA - IV - Per os (unknown bioavailability)
32
Mechanism - neutraceutical supplements
- stimulate cartilage matrix synthesis - MMP inhibition - reduce inflammatory mediators
33
Name 3 matrix GAG supplements
- gluosamine (3 forms; HCl, So4, N-acetyl-D-glucosamine) - chondroitin sulphate (small molecules important for degradation in GIT mucosa) - glucosamine/ chondroitin sulphate combination (effect may be better than individual effect)
34
What is green-lipped mussel extract?
- from edible shellfish (NZ) - neutraceutical supplement - anti-inflammatory - chondroitin sulphate source - unique combination of fatty aas - minerals - vitamins
35
What is methylsulphonylmethan (MSM)?
- sulphur source (usually enough in diet) for collagen and matrix metabolsim - derivate from DMSO - mechanism: unknown, no effect on inflammation, may be analgesic in people
36
What is devil's claw?
= iridoid glycosides MECHANISM: decrease inflammatory mediators in people, no EBVM. Used in traditional african medicine (arthritis, fever, skin conditions, GI disease)
37
What is IRAP?
= IL-1 Receptor Antagonist Protein - for equine OA - directly blocks effects of IL-1 - decreased inflammation in experimental synovitis - no controlled large scale clinical studies (horse) - therapeutic success in many cases refractory to steroids
38
What does IL-1 do?
- key inflammatory mediator in OA | - stimulates cartilage-degrading enzymes (MMPs, aggrecanase)
39
What is ACS?
= Autologous Conditioned Serum - for equine OA - culture patient blood in special syringe (chromium-sulphate soaked glass beeds) - up-regulation of IRAP and other anti-inflammatory mediators - IA administration - serum can be stored frozen (for serial IA injections)
40
What is Tiludronate (Tildren)?
- non-nitrogenous biphosphonate: inhibition of bone resorption (osteoclast apoptosis), anti-inflammatory properties - Europe - licensed for horses, distal tarsal OA, navicular disease, side effect may be colic so give as CRI over 30 mintues
41
Name surgical tx for OA
- excision arthroplasty (SA + small ponies) - arthrodesis (horse pastern, distal tarsus, fetlock, carpus; often salvage procedure) - total joint replacement (SA)