DJD (bolt) Flashcards Preview

Locomotor > DJD (bolt) > Flashcards

Flashcards in DJD (bolt) Deck (43):
1

Terminology used for DJD?

OA
DJD
Osteoarthrosis
Arthrosis

2

What is the purpose of the menisci?

Compensate for incongruency of joint (stifle)

3

2 types of synoviocytes?

A (modified epithelial cells)
B (metabolically active, produce hyaluronic acid)

4

What is the ECM of hyaline cartilage mainly composed of?

Secreted by chondrocytes
- type 2 collagen
- GAGs(aggrecan)
- water
- very small amount of elastic and reticular fibres and chondrocytes

5

Are immune mediated joint disease seen in endorse?

Nooo

6

What is DJD?

- multi factorial disorder of joints
- degeneration of articular cartilage
- bone changes (OA)
- lysis and new bone formation

7

Common conditions causing DJD?

> trauma
- acute
- repetitive
> infectious inflam
- septic
> non-infectious inflam (VERY COMMON HORSES)
> developmental dz
- dysplasia
- angular /flexural limb deformity
- OCD

8

What is bone spavin?

DJD of the TMT/DIT

9

Outline the pathophysiology of DJD LOOOK UP

> failure of homeostasis of articular cartilage
- cartilage breakdown products
- matrix metalloproteinases (MMP2,3,4... Etc)
- catabolic cytokines
> synovial membrane
- PGs, LTs
- neuropeptides and cytokines
> subchondral bone
- altered load absorption: cartilage damage
- inflammatory mediators (IL-1, TNFa)

10

How is pain caused with DJD?

No pain fibres in the articular cartilage
- pain fibres in synovium (joint capsule)
- pain fibres in subchondral bone (exposure bad)

11

How do soft tissues affect pathophysiology of DJD?

> synoviocytes release mediators and enzymes (PGs, cytokines, MMPs)

12

Do radiographic signs correlate well with clinical signs?

No

13

Is intra-articular medication cheap?

No!

14

What should be looked at in PE for DJD?

> weight BCS
> lameness exam
- identify and loacalise
- scoring
- palap and manipulatio nof joint
- pain, heat, swelling, crepitus
- reduced ROM
- joint effusion
> muscular atrophy

15

Further Dxx for joint dz?

> imaging
- rads
- ultrasound
- MRI/CT
> nerve blocks
> synovial fluid analysis (rare in horses, usually normal, unless suspect iatrogenic sepsis)
> arthroscopy (rarely for 1* DJD investigation, only to debride etc)
- synovial biopsy possible

16

Why may intra-articular analgesia be more specific? Why are there limitations to intra-articular analgesia in the distal limb?

Close proximity of DIP joint, navicular bursa and distal recess of digital synovial sheath
- more specific than peripheral nerve blocks otherwise

17

Osteophytes

- see rads

18

Soft tissues

eg. meniscal tear and protrusions, can become 2* mineralised, effusions

19

Subchondral bone sclerosis

thickened radiodensity

20

Tx goals for DJD?

- pain
- stop inflammatory process (all DJD comes from inflam)
- V production inflam mediators
- chondroprotection ("disease modification" arrest or slow down cartilage degeneration, usually not drugs, (called Neutroceuticals but NOT as no nutritional value) supplement type things)
* OA can not be cured, just managed *

21

Tx strategies LOOK UP

>maintenance
- weight loss
- excercise mod/physio
- stratgetic analgesia
> control flare ups
- initial analgesia (5-10d)
- gradual resume excercise
- swimming/hydrotherapy
- joint supplements ("neutraceuticals" / for disease modificiation)
> salvage/new tx options

22

Potential medical Tx of DJD in large animals?

- NSAIDs
- intraarticular steroids
- analgesia
- GAGs
- sodium hyaluronate
- supplemetns
> chondroitin sulphate
> glucosamine
- IL1 receptor antagonist protein
- Tiludronate "Tildren" (bisphospohate)

23

Most common medication for orthopeadic problems? Side effects?

>NSAIDs
- inexpensive
- efficient
- mechanism = inhibition of COX, prevent PG
> side effects
- GI ulceration
- nephritis
- PLE
- negative influence of bone and cartilage metabolism?!!

24

Look at lecture for table of NSAIDs

-

25

Why is ketoprofen good? Bad?

- good for foals, COX specific
- $$$$$

26

Most potent anti inflam Tx?

Intra articular corticosteroids
- inflam cells and humoral mediators
> mechanism
- inhibits PG synthessis by blocking PLA and COX pathways
- inhibit synthesis of cartilage degrading cytokines (IL1, TNFa)
- inhibit cartilage degrading enzymes themselves (MMP, aggrecanase)

27

Potential side effects of coritcosteroids ?

> negative effects on cartilage healing? (Not seen clinically, very effective!)
> ^ risk of iatrogenic joint infection
- immunosuppressive
> laminitis
- check max doses

28

Which 2 drugs are used most commonly for Tx DJD in horses?

- Triamcinolone acetinonide
- methylprednisolone acetate

29

When is the term OA used?

Only when radiographic signs of underlying bone involvement

30

What GAG products are available for horses? What is it's mechanism and recommedned dose?

> "Adequan" Polysulfated GAG
- extract from bovine lung and trachea $$$
- mechanism: MMP inhibition, HA production stimulator, matrix synthesis stimulator
- IA injection
- ^ risk of sepsis or non septic inflam (flare)
- licensing?
- Dose: 500mg IM q4d for 28d
> "Cartrophen" Pentosan Polysulphate
- extract from beechwood hemicellulose
- mechanism: stimulates cartilage matrix and HA synth, MMP and inflam inhibition, mobilises thrombi and fibrin in synovium, lipids and cholesterol in vessels, inhibits platelet aggregation and clotting, ^ plasma lipase levels
- Dose: 3mg/kg SC 4x q5-7d

31

What is sodium hyaluronate and how can it be administered? What effects do supplements have?

- major structural componenet (articular cartilage matrix synthesis by chondrocytes, synovium synthesis by btype B synoviocytes)
-> viscoelasticity, concentration, polymerisation, boundary lubrication
-> anti-inflammatory function (steric hinderance, chemotactic response)
> IA/IV/PO
- may supplement depeleted HA or stimulate endogenous HA synthesis (unknown)

32

What is the difference between cheap and expensive HA supplements?

Molecular weight in kDa - bigger the better

33

What effects can supplements have on DJD?

= neutraceuticals (feed additives)
- dz modification
- mechanism: stim cartilage matrix synthesis, MMP inhibition, reduce inflam mediators
- often administered without vet prescription

34

Egs. of matrix GAGs? Are these commonly used?

> glucosamine
- bioavailability variable
> chondroitin sulphate
- molecular weight: SMALLER the better!!
- degradation in GI mucosa
> glucosamine/chondroitin sulphate combo may be better?
> most horses will be on some kind of supplement!!

35

WHere is chondroitin sulphate found naturally?

- Green-lipped mussell extract!!!
- Perna canaliculus (edible shellfish in NZ)
+ anti-inflam via leukotriene pathway
+ fatty amino acids
+ minerals
+ vitamins

36

What is MSM?

Methylsulphonylmethane
> sulphur source
- collagen
- matrix metabolism
> derived from DMSO
> Mechanism (no convincing efficacy data, no effect on inflam)
- analgesic (human studies)

37

What is Devil's claw?

- harpagophytum Procumbens (Iridoid Glycosides)
- decreses inflam mediators in people but no science in horses
-used in traditional african medicine (arthritis, fever, skin conditions, GI dz)
- not cheap but good alternative if allergic to bute

38

What is IRAP? How is it used?

= IL1-R antagonist protein
- IL1 key inflam mediator in OA
- stimultes cartilage degrading enzymes (MMPs, aggrecanases)
> IRAP diectly blocks IL1, v inflam but no controlled large scale studie sin horses
- therapeutic sucess in cases refractory to steroids
> autologous conditioned serum (ACS) used byu culturing patient blood in special syringe with chromium sulphate soaked glass beads
-> upregulation of IRAP and other anti-inflam mediators
- IA administration
- serum can be stored frozen

39

What is Tildren? What drug is similar?

Tiludronate (Non-nitrogenous Biphosphonate)
- inhibits bone resorption by osteoclast apoptosis
- anti-inflam
> Europe LIC for horses
- distal tarsal OA
- navicular dz
- ?clinical efficacy
- side effects.. colic?
> DOse: 1mg/kg IV CRI over 30 mins
- may require NSAID premed ??
> ~=Osphos (IM version)

40

What surgical tx are possible for DJD?

> Excision arthroplasty (SA)
> Arthrodesis
- horse pastern, distal tarsus, fetlock, carpus (often slavage procedure)
> Total joint replacement (SA)

41

What is high ring bone?

DJD of the pastern (DIP)

42

Tx high ring bone? Prog?

Arthrodesis (40% return to work in FL, 70% HL)

43

Which steroids are best for high motion joints? Which for low motion?

> TMA high motion (fetlock)
> Methylprednisolone low motion or 2nd line
- can cause reaction @ injection site (hock/back)