WEEK 4 LOCOMOTION- DJD Flashcards
How does the function of Type A and Type B synvoicocytes differ?
Type A: Macrophages- phagocytic function Type B: formation of Synovial fluid
Bone changes with osteoarthritis
-New bone formation -Bone lysis
Where does Pain come from is DJD / Osteoarthritis
->No pain receptors in cartilage. ->Pain receptors in joint capsule. Synovitis/ Joint Distention. ->Exposure of subchondral bone
Mechanism of NSAIDs in treatment of OA
Inhibition of cyclooxygenase pathway/ prevent prostaglandin synthesis - Decrease synovitis - Reduce cartilage degradation Side effects: Nephritis/ GI ulceration Negative influence on cartiladge/ bone metabolism
Phenylbutazone routes of administration
IV/ PO
Why is intraarticular corticosteroids more effective than NSAIDs at treating osteoarthritis
Corticosteroids. Mechanism: Inhibit prostaglandin synthesis (block phospholipase a2/ cycloosygenase pathways) INHIBITS SYNTHESIS OF CARTILAGE-DEGRADING CYTOKINES (TNF-alpha) Inhibits cartilage - degreading enzymes (metalloprotinases)
Which drugs have a negative effect on cartilage healing and metabolism
NSAIDs/ Corticosteroids
How do Glycosaminoglycans work?
Horses Mechanism: 1. MMP inhibition (also inhibited by corticosteroids) 2. Stinulates HA production 3. Stimulates matrix synthesis
Cartrophen works via
Glycosaminoglycans (GAGs) 1. MMP inhibition 2. Stimulates HA production 3. Stimulates matrix synthesis
Surgical treatment of osteoarthritis
Athrodesis. Surgical formation of joint aka ankalosis
Synovial fluid from the right carpus of a 5 year old FN Weimaraner, one of several effused joints shows lots of neutrophils. Most likely Diagnosis
Weimaraners are one of the breeds in which polyarthritis-meningitis syndrome has been reported (although it may be seen in many breeds). Therefore neck pain may also be present. The CSF may also show neutrophilic inflammation. INFECTIOUS DISEASE MAY ALSO LEAD TO POLYARTHRITIS
Infectious diseases may also lead to polyarthritis, and may consider testing for these,
Erlichia and Borrelia. If considering Rhumatoid arthritis then ANA test (SLE)
Sites for Osteosarcoma
Proximal humerus, distal radius, distal femur and proximal and distal tibia in dogs. Cats have no preferential sites. Heads in horses and cattle. DOGS: LARGE/GIANT BREEDS ARE PREDISPOSED
Cranial cruciate rupture signs on radiograph
Positive Cranial Draw. Osteophyte formation in distal aspect of the patella, fabellas, proximal tibia and femoral trochlea. Joint effusion.
Flattening of the caudal aspect of the humeral head in a lame 7 month old Newfoundland is indicitive of
Osteochonrosis dessicans
Comminuted fracture
Avulsion fracture.
Differentiate between Oblique fracture and Spiral fracture
Which type of fractures are a) easy to neutralise with a cast b) difficult to neutralise witha cast
a) Easy to neutralise with cast: Bending/Rotational forces
b) Compression/Shear are difficult to neutralise.
Olecranon fractures/ Fractures of greater trochanter difficult to control with cast (use sling)
Distraction forces are caused by muscle _____ and poorly neutralised by external coaption. What is the best way to neutralise?
Olecreanon fractures/ Fractures of greater trochanter.
Sling to decrease weight bearing, reduce muscle tension, reduce tension forces.
Compression/Shear also difficult to neutralise with a cast
Basic guidelines for coaptation with regard to joints
Joints above and below have to be immobalised therefore can’t be used above stifle/ elbow
Spica splints to immobalise hip/shoulder
If using a cast to support internal fixation when should it be done?
3-5 days, less swelling reduce before place cast.
Immediately post surgery use robert jones swelling to decrease swelling
Number of neutrophils in a) normal joint b) degenerative joint disease in arthrocentesis
a) normal joint <5%
b) Degenerative joint disease <10%
Treatment of Septic arthritis in a) small animal b) horse
a) Small animal: Amoxicillin / Clavulanitc acid (6 weeks) 94% will resolve. Medical just as good as Surgery
b) Horse: ACUTE INFECT = EMERGENCY. Mostly caused by iatrogenic. Eliminate organisms from joint. Intra-articular- Penicillin and Gentamycin. Also oral AB. Resample every 48 hrs.
How does Aetiology of IMPA and IMPA (Erosive) differ?
IMPA:
Ag/ab complex [page21image1368] formation of inflammatory products
Host IgG and M bind to altered autologous IgG
Ag/Ab complex deposited on synovium neutrophil/macrophage chemotaxis
IMPA EROSIVE:
Cellular or humoral immunopathogenic factors
Release of chondrodestructive collagenases/proteases
Failure of self-tolerance or production of immunogenic immunoglobulins
Immune mediated arthritis is what type of hypersensitivity reaction
Type III.
Immune-complex formation
Synovial fluid analysis is negative for culture- what is the diagnosis?
Synovial fluid analysis can help distinguish septic arthritis (+ve culture) from immune-mediated HOWEVER NEGATIVE CULTURE does not mean sterile (50% will have -ve culture but septic arthritis)
Degenerate neutrophils= septic
Non-degenerate= immune mediated
Difference between Type I and Type IV hypersensitivity reactions
Type I: Immediate/ anaphylactin reaction. IgE–> mast cells
Type IV: Cell-mediated/ delayed type reaction .
Type II: Ab-dependend (IgG or IgM against cell surface component)
Arthritis in 1 joint likely to be…
Septic arthritis,.
Immune-mediated arthritis is more likely to be polyarticular i.e. 6+ joints. or pauciarticular (2-5) VERY RARELY MONOARTICULAR
4 types of Non-erosive polyarthritis
Type I: uncomplicated idiopathic 50%
Type II: Associated with remote infections (reactive) e.g. endocarditis
Type III: Associated with GI disease/ hepatic
Type IV: Associated with remote neoplasia
Signs often most severe in Type I, II and milder in III, IV
Reactive polyarthrtisis = Type II, III, IV
4 other causes of non-erosive polyarthritis
- Systemic Lupus Erythematous
- Lyme Disease (Borrelia)
- Doberbmanns + Sulphonamides
- Calcivirus
- Steroid responsive meningitis-arthritis
- IBD
- Immune-mediated
Pathogenesis of Erosive arthritis
On radiography = collapse of joint space.
Chronic synovitis leads to production of proliferative granulation tissue = pannus
Pannus invades articular cartilage and can erode sub-chondral bone.
Pannus + inflamed synovium produce enzymes including proteases/collagenanses = further joint destruction.
Similar changes to septic artheritis
Examples of erosive joint diseases
- Rheumatoid arthritis
- Periosteal proliferative polyarthritis in CATS
- Polyarthritis of Greyhounds (Felty’s Syndrome)
- Felty’s Syndrome (RA, splenomegaly and neutropenia)
Felty’s Syndrome
Rhematoid arthritis
Splenomegaly
Neutropenia
A dog has raised RF, what test is used to differentiate between rhumatoid arthritis and SLE (both cause increase in RF)
Anti-nucelar antibody test (ANA)
+VE in SLE
Deposition of immune complexes in the skin
Skin lesions
Symmetric or focal skin lesions - redness, scaling, ulcers, depigmentation, and/or hair loss
Ulceration of mucocutaneous junctions and oral mucosa may develop
TYPE III immune complex formation
Disease-modifying antirheymatic drugs
lefunomide, methotrexate, gold therapy= treatment for Rheumatoid arthritis = erosive TYPE iii immune complex formation
Mainstay of treatment for polyarthritis (immune-mediated)
Prednisalone - taped dose. Initially 2-4mg/kg daily.
+/- cytotoxic drugs (bone marrow suppression)
cyclophosphamide (haemorrganic cystitis in cats)
azothioprine (not cats)
Monitoring of treatment for im polyarthritis
Response often within 7 days.
Substanial decrease in WBCs/ neutrophils is a good prognostic indicator
4 types:
1: uncomplicated idiopathic
2. associated with remote infections
3. associated with gi disease/ hepatic
4. associated with remote neoplasia
Crystal based arthritis treatment
Main Ddx for reptiles/ birds(lack enzyme)
Tx: Fluid therapy, avoid meds that increase renal excretion
Indications for Femoral Head and Neck Excision (FHNE)
Hip dysplasia (juvenile pain)
Intractable osteoarthrits / DJD
Femoral head and neck fractures/ acetabular fractures
Persistant luxation
Legg-Calve0Perthes disease (avascular necrosis of the femoral head)
Best outcome post FHNE surgery is achieved in dogs <
Dogs <30kg = best prog.
Some restriction in ROM will affect FULL athletic performance.
Aftercare vital to outcome: early return to CONTROLELD exercise (analgesia, physio, hydro)
GENERAL PRACTICE PROCEDURE,.
Surgical technique for FHNE
Want to remove removal neck as well.
Leave LESSER TROCHANTER (as Ipsilosoas m. inserts here)
Ideal patient for total hip replacement
Skeletally mature, large breed dog (>20kg)
Sensible, well trained dog
£4000
CAGE REST FOR 6 WEEKS POST-OP (c.f. FHNE exercise encouraged)
How does the aftercare vary between Total Hip replacement and FHNE surgery?
Hip replacement: 10% severe complications, CAGE REST FOR 6 WEEKS.
FHNE: Low risk of minor Cx. Activity encouraged asap.
Function: THR= EXCELLENT/ NORMAL (>30kg)
FHNE: Reduced but acceptable (<20/30kg)
Mechanically it is better to loose a ____ limb
Better to loose a pelvic limb rather than thoracic limb.
BEFORE AMPUTATION- CHECK CONTRALATERAL LIMB IS HEALTHY!!
- Neoplasia
- Trauma (ischemia)
- paralysis (brachial plexus avulsion)
- Unmanageable joint condition
- Client finances
Why is it better to loose a pelvic limb than thoracic limb
Thoracic limb: 60% weight bearing
Pelvic limb: 40% weight bearing
Better to loose pelvic limb.
Before amputation CHECK CONTRALTERAL LIMB IS HEALTHY
How does amputation site differ in cows from small animals
Cattle: Proximal interphalangeal joint with cartilage removal in cattlwe
Digtal p1 or p2 in small animal.
Bog Spavin =
Tx=
Laymans terms for osteoarthritis in horses
Most common cause of HL lameness in horse
Tx: Intra articular corticosteroids (methylprednisalone acetate)- not cartilage friendly! Consider arthrodesis (ankalosis) x=
Presentation of common calcanean tendon injury. Which breeds are predisposed
Dobermans / German Shepherds are predisposed.
Extended stifle and Hyperflexion of digits
Common calcaneal injurys
Extension of stifle
Hyperflexion of digits = pathopneumonic for common calcanean injury
Dobermans / GSDs
How many patella ligaments do horses have
medial, middle and lateral
Dog with CrCL tear prognosis for contralateral limb
40-60% will develop tear in contralateral limb.
Majority have concurrent medial meniscal damadeg
Treatment for CrCL damage
Do not try and fix ligament as already too damaged.
Have to change biomechanisms of knee joint i.e. osteotomy (bone cut) techniques to affect quadricep mechanics.
Tibial Plateau Leveling Osteotomy (TPLO) involves making a circular cut around the top of the tibia and rotating its contact surface (tibial plateau) until it attains a near level orientation (approximately 90 degrees) relative to the attachment of the quadriceps muscles (Figure 2). This renders the knee more stable, in the absence of the CrC
Two surgical techniques for CrCL damage
TPLO or Tibeal Tuberostity Advancement (TTA) or suture https://www.acvs.org/small-animal/cranial-cruciate-ligament-disease
Target for % lameness in cow herd
<5% (but majority of farms ++++)
Most common foot lesion affecting cows feet
30% sole ulcers
22.5% white line disease
Digital dermatitis
Score 0 dairy cow
Walks with even weight bearing and rhythm on all four feet, with a flat back.
Long fluid strides
C.F. Score 1: Steps uneven, shortened strides
Score 2 cow mobility
uneven weight bearing on a limb that is immediately identifiable and/or obviously shortened strides (usually with an arch to the centre of the back)
Cow walks swinging right hind leg through much quicker than left hind. Cow is probably lame on ____
Lame on contralateral limb to the one being swung through quickly. Cows moves limb through quickly to take weight off lame limb.
In score 2 cow the dew claws of the hind limb will sink low on the ____limb
Dew claws will sink lower when weight is placed on the healthy limb (more weight bearing) when compared to affected limb
Score 3 cows
Walk slower than walking speed. Can’t keep up with herd.
90:90:90 rule
90% lameness hind , 90% feet, 90% lateral
Dutch 5 step foot trim
- Create foot angle of 52 degrees
- Create balance between claws
- Transfer weight from sole onto wall, toe and heal
- Remove weight from painful claw
- Remove loose/ sharp horn
Step 1 of Dutch 5 step foot trimming technique is to create an angle of
52 degrees,
Measure 7.5cm from cornary band (cut 1)
Cut 2: Trim sole until white line just appears at tip of toe (5-7mm step at toe)
Which claw to start on for step 1 Dutch foot trim
Start at most normal claw.
Inner hind claw
Outer fore claw
Cut 1: 7.5cm
Cut 2: 5-7mm step at toe
Haemorrhage in horn is roughly ___ months historic
Hamorrhage in the horn is roughly 2 months historic.
When would systemic antibiotics be indicated for sole ulcers?
Normally just topic.
If swelling above coronary band systemic antibiotics are indicated
What causes sole ulcers?
Laminitis is a controversial foot condition in cattle.
Acidosis does not appear to directly cause claw horn lesions.
Most claw horn disease STEMS FROM ENVIRONMENTAL CONDITIONS.
Body condition score and claw horn growth rates may be important in sole ulcer pathogenesis.
Biotin may improve claw horn quality
What two things are thought to decrease sole ulcers
1, Biotin
- Feeding higher dry matter intake (much probably due to drier drug)
i. e. ENVIRONMENTAL
Why are sole ulcers more likely around calving?
Decreased digital cushion (comprised of fat therefore decrease BCS = no digital cushion)
Poor foot angle, trauma, more growth, less weear.
Treponemes???
Exostoses
Caused by chronic injury/ damage
Calcification on the surface of bone
Potential aetiology of Sole ulcer (with loss of fat pad, loss of laminar suspetion around calving, poor foot angle)
Pathogenesis of White Line Disease
Soft claws during high rainfall?
Loss of fat pad
Thin soles
Rough, stoney tracks
Brusing from long standing times
Sharp turns on concrete
Sequalae: wall ulcers
White line disease.
Biotin deficiency, soft claws during high rainfall,
Aetiology of Digital dermatitis
Three familys of Treponeme, gaining entry through hair follicles.
Sequale: interdigital hyperplasia.
Digital dermatitis scoring
M1: Ulcerative (<2cm)
M2: Ulcerative (>2cm)
M3: Regressing
M4:.1 Reactivating
M4: Hyperkaratotic
DD treatment (M1,M2,M3,M4)
M1: Clean,dry, topical oxytet for 3 days
M2: As above but debride and consider bandaging
M4: Debulk/Debride under local, badage with antibacterial
Foul in the foot
An acute bacterial infection of the subcutaneous tissues characterised by symmetrical swelling, separation of the claws and interdigital skin necrosis yielding a pungent odour
Fusobacterium necrophorum
Aetiological theories for Foul-in-foot
- Fusobacterium necrophorum
- Foreign body through skin.
Sequale: interdigital hyperplasia
Procedure for cow claw amputation
Should be culled? Barren? Sound medial claw?
Tornique Block (procaine/ antibiotics)
- Incise into interdigital space 2-3cm
- Embrotomy wire up and obliquly outwards
- Melolin pressure bandage
- Redress every 48 hours, 96 hours, 7 days then leave open
- BLOCK UNAFFECTED DIGIT (NORMALLY MEDIAL UNAFFECTED)
Which local anaesthetic is licenced for a) cows b) horses
a) cows= procaine ((adrenocaine)
b) horses= lidocaine
Claw amputation needs to be done proximal to ___
If can’t find vein tornquie prox to hock = bigger veins
Want to amputate prox to P2 otherwise will cut off blood supply and form a sequestrum
Causative agent of lameness in a) piglets b) growers
a) 2days to weaning = arthritis (dog sitting)- e coli, staph, strep) Bacteriology from PM - penicillin/ampicillin/lincomycin
b) Growers: Osteochondrosis dessicans/ infectious (mycoplasma hyosynvovia, erisepothrax)
Sheep Scald
Interdigital hyperplasia. Red, wet interdigital space. Loss of hair in interdigital space.
Primarily caused by Fusobacterium necrophroum (presence in faeces)
Foot rot requires what extra bacteria?
D. nodosus
CODD is caused by treponemes
Toe Granuloma normally iatrogenic (farmers + vets)
The risk of scald progressing to footrot is determined by…
Whether D.nodosus is on the farm
The virulence and dose of the D.nodosus
The susceptibility of the sheep
Whether the sheep is treated promptly before separation of the hoof horn occurs
ROUTINE TRIMMING NOT REQUIRED
Management of foot rot and scald
The most important action is the early treatment with parenteral antibiotics and a topical spray, with NO foot trimming
Treatment of Footrot
Oxytetracycline spray a clean foot
Long acting parenteral antibiotic
•
Oxytetracycline
•
Amoxicillin
Allow sheep to stand on clean concrete
Clean up the area
Ideally isolate the sheep 14 days
Prognosis: 90% recover in 5 days
Treatment of Scald
Ewes: Treat as footrot
Lambs: Oxytetracycline spray, stand in clean area and re spray5 days if nec
When to cull sheep with scald/ footrot
If still lame after 2 antibiotic treatments or if misshaped claws
Footbathing concentration for a) ZnSO4 b) Formalin c) CuSO4
a) ZnSO4: 10% > 2 mins standing
b) Formalin: 3%
c) DON’T USE
Stand sheep for 1 hr afterwards
Aetiotogy and Treatment of Contagious Ovine Digital Dermatitis
Same treponemes that cause bovine digital dermatitis.
Use Tilmacosin (Mycotil)
Footbath: Lincomycin / Tylocin
Where does the cranial cruciate ligament run?
The cranial cruciate (red) runs from proximal and lateral to distal and medial, the caudal cruciate runs in the opposite direction
How long for ligament damage to regain a) 50% of original strength b) 90% of strength
50%: 6 weeks
90%: 1 year
Post operative care for CCL repair
No hydrotherapy initially.
Lead walks for 6-8 weeks.
Cold packs
Vitiligo
Hypopigmentation
c.f. Lentigo = hyperpigmentation
