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Flashcards in Equine MSK diseases 3 Deck (100)
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1
Q

Discuss the use of scintigraphy in the diagnosis of back pain in horses

A
  • Extremely sensitive for bone lesions incl. fractures, new bone, infective processes and bone tumours
  • Often unrewarding for back soft tissue injuries
  • Good for pelvic disorders
2
Q

Discuss the use of ultrasonography in the diagnosis of back pain in horses

A
  • Imaging of supraspinous ligament
  • Imaging of spinous processes
  • Identification of overriding dorsal spinous processes (kissing spine)
  • Poor for muscle injuries
  • Good for pelvis, esp. ilial fracures
3
Q

Describe the ultrasonographic appearance of overriding dorsal spinous processes in horses

A
  • Tips of spines appear very close together
    Marked narrowing at the affected interspinous spaces
  • Pseudoarthrosis may be visible: anechoic area surrounded by well-defined capsule
4
Q

List the tests, other than imaging, that can be used for the diagnosis of back pain in horses

A
  • Lab tests (muscle enzyme activities - AST, CK, lactate)
  • Local anaesthetic blocks
  • Infiltration of steroids
  • NSAIDs
  • Electrical stimulation of epaxial musculature (rare)
5
Q

Why is trial treatment with NSAIDs useful in the diagnosis of back pain in horses?

A

Confirmation of presence of pain - differentiate between behaviour and pain

6
Q

Outline the management of a horse with back pain

A
  • Conservative: box rest, physiotherapy
  • Surgical for some causes e.g. kissing spine, some fractures
  • Keep horse as light as possible, diet altered accordingly
  • May need to consider effect of rider (poor rider, or heavy)
7
Q

Discuss the prognosis for chronic soft tissue injuries causing back pain in horses

A
  • Guarded prognnosis
  • Difficult to confirm
  • Need to start treatment including rest, controlled, exercise and physio for several months before declaring unfit for work
8
Q

List possible causes of lameness originating the equine foot

A
  • Solar/white line infection
  • Thrush
  • Solar bruising/solar pain
  • Hoof wall lesions
  • Wounds
  • Laminitis
  • Foot imbalance/caudal foot pain
  • Navicular disease
  • DIP joint pain/DJD
  • Foot penetrations
  • Fractures
9
Q

List the key features of the initial observation in a lameness examination of the horse

A
  • Weight bearing or not? (Stance)
  • Foot balance (conformation)
  • Uneven wear of hoof/shoe
  • Compare left and right foot
  • Shoeing (type, when shod)
10
Q

Which tendons are affected by a palmar imbalance in horses?

A

More pressure on flexor tendons

11
Q

Outline the key features of the physical examination of a lame horse relating to the feet

A
  • Palpate for heat, pain, swelling, digital pulses
  • Check show and nail position
  • Check sole surface
12
Q

List the conditions that commonly cause heat, pain, swelling of the foot and palpable digital pulses in the horse

A
  • Laminitis
  • Infection
  • Sole bruising
  • Fractures
  • Joint effusions
13
Q

Outline the typical findings on physical examination in a case of laminitis

A
  • Hot feet, bounding digital pulses
  • Can be single limb (overload laminitis), both FLs, or all 4 limbs
  • Other systemic signs e.g. tachyC and sweating may be present
14
Q

Outline the typical findings on physical examination in a case of infection in the equine foot

A
  • Hot foot, bounding digital pulses

- Usually unilateral (sole or white line infections)

15
Q

Outline the typical findings on physical examination in a case of solar bruising in a horse

A
  • Hot foot, bounding digital pulse
  • Usually unilateral, can be bilateral
  • Usually FL (takes more weigh)
  • Hoof testers/paring away hoof reveals bruising/haemorrhage
16
Q

Outline the typical findings on physical examination in a cause of foot fractures in a horse

A
  • Hot foot, bounding pulse

- If P2 may have swelling and palpable crepitus

17
Q

What are the key considerations for when evaluating the movement of a horse in a lameness examination

A
  • Degree of lameness
  • Limb/limbs affected
  • Effect of surface
  • Effect of load (left reign vs right reign)
  • Effect of flexion of distal limb
  • Need to rule out fractures prior to trotting horse
18
Q

List the contraindications for diagnostic anaesthesia in a lameness examination in a horse

A
  • Suspected fractures
  • Severe soft tissue injuries e.g. DDFT rupture
  • Risk of infection e.g. current infection at injection site such as mud fever, or if cannot be performed sterile
19
Q

List the options for diagnostic anaesthesia for the diagnosis of lameness originating in the equine foot

A
  • Perineural anaesthesia
  • Intra-articular anaesthesia
  • Distal interphalangeal joint
  • Navicular bursal block
  • Digital flexor tendon sheath block
20
Q

What is the main difficulty with diagnostic anaesthesia in the equine foot?

A

Communication and overlap between different areas is inconsistent between horses e.g. DIP is up against navicular bursa, sometimes communicates allowing perfusion of local anaesthetic between structures, sometimes does not

21
Q

For which conditions of the equine foot is radiography the first line of diagnostics

A
  • Suspected fracture
  • Laminitis
  • Suspected bone lesions/foot penetrations
22
Q

What are the standard views of the equine foot?

A
  • Lateromedial
  • Upright pedal
  • Upright navicular
  • Flexor navicular
23
Q

What is the first line diagnostic test for synovial sepsis?

A

Arthrocentesis - no nerve blocks, no radiographs

24
Q

When is use of ultrasonography indicated in equine foot lameness?

A

Only soft tissue lesions, limited value due to hoof

25
Q

When is use of gamma scintigraphy indicated in equine foot lameness?

A
  • Used in non-displaced pedal bone fractures (non radiographic signs)
  • May not see much
26
Q

Discuss the use of MRI in the diagnosis of equine foot lameness

A
  • Very useful, allows assessment of all structures in the foot
  • Good for soft tissues e.g. DDFT insertion on P3, collateral ligs of DIP joint
  • Expensive
27
Q

Outline the aetiology of laminitis

A
  • Ischaemic necrosis → vasoconstriction
  • Damage to interlaminar bodies, loss of epidermal/dermal junction, separation of laminae
  • → separation of P3 from hoof wall
28
Q

Outline the clinical signs of acute laminitis

A
  • Uni/bi/quadrilateral lameness possible
  • Hot foot, bounding pulse, characteristic stance
  • TachyC, hypertension, sweating
  • Severe: depression at coronary band, protrusion/haemorrhage at sole at toe region
29
Q

Outline the diagnosis of laminitis

A
  • Radiography
  • Lateromedial view with markers on sole and coronary band, and dorsal hoof wall
  • Divergence of hoof wall and dorsal P3 measured
  • Remodelling in toe area in chronic cases
30
Q

Discuss the prognostic factors for laminitis

A
  • <5˚ separation = good prognosis
  • > 15˚ separation = poor prognosis
  • Rapid deviation = poor
  • Slow = better
31
Q

Outline the treatment for laminitis

A
  • Treat underlying cause
  • Vasodilators and NSAIDs
  • Frog supports, soft deep bedding
  • Dorsal wall resection(stop rotation, release seroma fluid)
32
Q

Outline the importance and treatment of foot balance abnormalities

A
  • Predisposes to other conditions e.g. navicular pain, palmar heel pain, DDFT lesions, DIP joint disease
  • Corrective farriery
33
Q

What is meant by navicular disease and how does it occur?

A
  • Pain in navicular region; bone, bursa or soft tissues

- Biomechanical use

34
Q

Which horses are predisposed to navicular disease?

A

Middle aged horses, esp. TB and Warmbloods

35
Q

Outline the clinical signs of navicular disease in the horse

A
  • Usually FL
  • Uni/bi lateral
  • Chronic, progressive lameness
  • Worse on hard ground
  • Periods of box rest may trigger episodes
  • +/- Toe point when resting
  • Chronic cases have smaller, upright feet
36
Q

Outline the diagnosis of navicular disease

A
  • Bilateral lameness (short striding or obvious when lunged)
  • Positive flexion tests
  • Positive to palmar digital nerve block, +/- positive to DIP joint block, positive to navicular nerve block
  • Lameness may become more apparent in contralateral limb following nerve block
  • Radiography: LM, DPr-60PaDi upright, PaPr-PaDi oblique
  • +/- gamma scintigraphy, MRI
37
Q

Outline the radiographic appearance of navicular disease

A
  • Radiographic signs may not be present, or may be present in abscence of lameness
  • New bone formation (lateral and medial wings)
  • Loss of corticomedullary junction
  • Irregular/cyst like radiolucencies
  • Remodelling of distal border (upright pedal) or flexor surface (flexor view), incl. fractures
  • Calcification of soft tissues
38
Q

Outline the conservative treatment options for navicular disease

A
  • Correction of foot balance and farriery
  • Avoid rest, need to encourage movement
  • Intra-bursal steroid injections
  • Systemic NSAIDs
  • Isoxuprine
  • Bisphosphonates
39
Q

Outline the surgical treatment options for navicular disease

A
  • Endoscopy of navicular bursa and DDFT
  • Suspensory lig. desmotomy
  • Neurectomy
40
Q

Discuss the use of neurectomy in the treatment of navicular disease

A
  • Cut nerves to prevent pain but can still work
  • Ethical issue - condition will worsen but will not be felt
  • Illegal in some competitions
  • Risk of damage to other foot structures
41
Q

What may cause DIP joint pain the horse?

A
  • Synovitis
  • Degenerative joint disease
  • Trauma/fractures
  • Infectious arthritis
42
Q

Outline the clinical signs of distal interphalangeal joint disease resulting from synovitis or DJD

A
  • Insidious onset
  • Uni/bilateral lameness
  • Usually FLs
  • Lameness worsened by increased workload, hard ground
  • Joint effusion palpable
  • Often related to foot balance
43
Q

Outline the diagnosis of distal interphalangeal joint disease in horses

A
  • Positive to flexion tests
  • Worse when lunged on hard ground, affected limb inside
  • Full/partial response to palmar digital nerve blocks, positive to abaxial sesamoid nerve block, positive to DIP joint block
  • Radiography
  • MRI
44
Q

Outline the radiographic appearance of DIP joint disease in horses

A
  • Radiographic signs (osteophytes) seen on joint margins (extensor process of P3, distal P2 on LM view)
  • Radiographic changes can be subtle
45
Q

Discuss the significance of finding radiographic signs in DIP joint disease in a horse

A

Signs of DJD associated with a poor prognosis for return to soundness

46
Q

Outline the treatment of DIP joint disease in horses

A
  • Identify and treat underlying cause
  • Correct foot balance (farriery)
  • Treat inflammatory/degenerative cycle
  • systemic NSAIDs, intra-articular steroids
  • Modify exercise (work on soft ground, gentle, keep regular, may need weight loss)
47
Q

List uncommon causes of lameness originating from the equine foot

A
  • Penetrations
  • Cysts in pedal and navicular bone
  • Pedal osteitis
  • Keratoma
  • Sidebone
  • Quittor
  • Canker
48
Q

What is a keratoma in the equine foot a key differential for?

A

Recurrent infection

49
Q

What is “sidebone” in horses?

A

Ossification of collateral cartilages, usually no clinical significance

50
Q

What is quittor in a horse?

A
  • Uncommon

- Infection of collateral cartilages of pedal bone leading to coronary band and hoof wall pathology

51
Q

What is canker in a horse?

A
  • Uncommon
  • Soft caseous discharge from frog and heel bulb region
  • Difficult to manage and treat
52
Q

List the main causes of lameness associated with the equine forelimb

A
  • Foot pain
  • Cellulitis/lymphangitis
  • Pastern degenerative joint disease
  • Fetlock DJD
  • Splints
  • Tendon and ligament injuries
  • Carpal DJD
  • Synovial sepsis, fractures, luxations
  • Neoplasia
53
Q

List the causes of limb swelling in a horse

A
  • Cellulitis and lymphangitis
  • Pupura haemorrhagica (strangles)
  • Equine viral arteritis
  • Hypoproteinaemia/fluid overload/cardiac failure
54
Q

What is innervated by the radial nerve in a horse?

A
  • Extensors of elbow, carpus and digits

- Skin sensation on craniolateral aspect of limb

55
Q

What is innervated by the median nerve in a horse?

A
  • Flexors of carpus and digit

- Skin sensation on palmar aspect and dorsal digit

56
Q

What is innervated by the ulna nerve in the horse?

A
  • Flexors of carpus and digit

- Caudal aspect of forearm, lateral and dorsal digit

57
Q

Which forelimb nerves are the key ones to be blocked for a lameness examination in a horse?

A

Median and ulna

58
Q

Outline your initial approach to the lameness examination for the equine forelimb

A
  • Observation (conformation etc.)
  • Palpation (asymmetry, heat, swelling, pain)
  • Range of movement
59
Q

Outline the use of diagnostic tests in the diagnosis of forelimb lameness in the horse

A
  • Radiography (first line of diagnostics, before nerve block)
  • Ultrasonography for suspected soft tissue lesions
  • Arthrocentesis if suspect joint sepsis
  • Perineural anaesthesia unless # or tendon/ligament
  • MRI, CT for some difficult lesions, complicated fractures/bone lesions
60
Q

When is the use of ultrasonography indicated as the first test for the diagnosis of equine forelimb lamaness?

A

When soft tissue lesion is suspected e.g. tendonitis, bursal swellings

  • Swollen, hot, painful indicates tendonitis
  • Do not block/trot suspected tendonitis until know severity by ultrasonography
61
Q

What is cellulitis and how does it occur in the horse?

A
  • Inflammation of subcut tissues
  • +/- infection
  • Site of bacterial entry may be wound, skin infection e.g. mud fever, or deeper infection
  • May be localised around the wound, or spread throughout limb
62
Q

Outline the clinical signs of cellulitis in the horse

A
  • Heat, pain, swelling
  • Usually diffuse swelling, can have localised abscesses as well
  • +/- pyrexia
  • Varying degree of lameness
  • Elevated white cell count
63
Q

Outline your approach to a case of suspected cellulitis in the horse

A
  • Identify underlying cause
  • Rule out complicating factors e.g fractures, snynovial sepsis, osteomyelitis
  • Treat underlying cause (incl. establishing drainage for pockets of infection)
  • Antibiotics and anti-inflammatories
64
Q

Discuss the antibiotic selection for a case of cellulitis in the horse

A
  • Systemic required (spread through tissues)
  • Penicillin, cephalosporins, potentiated sulphonamides effective: good for skin contaminants, good penetration of skin/soft tissues
  • But cephalosporins and TMPS ineffective against anaerobes
65
Q

What is lymphangitis and how does it develop in the horse?

A
  • Inflammation of lymphatic system of the limb
  • Impaired lymph drainage leads to build up of fluid in limb
  • May be trigger by infection, once affected horse may be predisposed to repeats
66
Q

Outline the clinical signs of lymphangitis in the horse

A
  • HL more common than FL
  • Bi or uni lateral
  • Diffuse soft tissue swelling
  • Prominent lymphatics
  • Can progress to serum oozing through skin
  • May have abrasions/site of infection
  • Similar appearance to cellulitis
67
Q

Outline the treatment of lymphangitis in the horse

A
  • Identify and treat underlying cause
  • Antibiotics and steroids (Dex IM followed by oral pred, NSAIDs if owner worried)
  • Physical therapy: cold hosing, bandaging, walking exercise
  • Need to treat aggressively, prone to recurrence, may get chronic limb swelling
68
Q

Discuss the development of pastern DJD in the horse

A
  • Low motion joint, disease may be advanced before clinical signs
  • May have inciting causes e.g. sepsis, fracture, bone cysts/OCD
  • Repeat concussion/turning forces
69
Q

What may be felt in a horse with pastern DJD?

A

New articular bone growth palpable as a bony swelling

70
Q

Describe the diagnosis of pastern DJD in the horse

A
  • Blocked by abaxial sesamoid nerve block
  • Intra-articular anaesthesia
  • Radiography to rule out underlying causes and monitor progression
71
Q

Outline the treatment of mild pastern DJD in the horse

A
  • No radiographic changes
  • Intra-articular anti-inflammatories (e.g. hyaluronic acid, PsGAGs)
  • If pain free, continue riding
72
Q

Outline the treatment of pastern DJD in the horse where radiographic signs are present

A
  • Disease will continue to progress, hyaluronic acid no use
  • NSAIDs to manage pain
  • Surgical arthrodesis if cannot be managed with NSAIDs, weight loss and exercise
73
Q

What are the 4 main causes of fetlock joint disease in the horse?

A
  • Developmental (OCD and bone cysts)
  • Trauma/repetitive injury
  • Articular fragments
  • Major fractures that extend to joint
74
Q

What are the main causes of fetlock lameness in growing horses?

A
  • OCD
  • Bone cysts
  • Angular limb deformities
  • Flexural deformities
75
Q

List less common causes of fetlock lameness in the horse

A
  • Soft tissue injuries
  • Sepsis
  • Luxations
76
Q

Outline your diagnostic approach to a fetlock lameness in the horse

A
  • History and palpation
  • Nerve blocks (unless suspect #): abaxial sesamoid, low 4 point, intra-articular (confirm joint involvement)
  • Radiography (also contralateral limb): 4 oblique views + specialised obliques
77
Q

Outline the treatment of fetlock lameness in the horse (consider articular fragments, OCD, bone cysts, subchondral bone disease, synovitis, osteoarthritis)

A
  • Removal of articular fragments if small
  • Stabilise large fragments with plate and screws
  • Remove/debride OCD lesions
  • Debride bone cysts
  • Rest horses with subchondral bone disease
  • Intra-articular anti-inflammatories for synovitis
  • Anti-inflammatories and analgesia for chronic OA
78
Q

What is meant by “splints” as a cause of lameness in the horse?

A

Enlargement of the region of the 2nd and 4th metacarpal and metatarsal bones

79
Q

How does “splints” develop in the horse?

A
  • Ligament between splint bones and 3rd metacarpal/tarsal can be torn
  • Thought to be caused by trauma and subperiosteal haemorrhage
80
Q

Outline the clinical signs of splints in the horse

A
  • Usually younger horses starting/increasing work
  • FL more than HL
  • 2nd metacarpal more than 4th
  • Some but not all cause lameness
81
Q

What type of conformation may predispose to the development of splints in the horse?

A

Bench knee

82
Q

What is the most likely cause of lameness in a young horse, where physical examination demonstrates heat, pain, swelling around proximal splint bone

A

Splints

83
Q

Outline the diagnosis of splints in the horse

A
  • Usually based on clinical signs

- can confirm on radiography or use nerve blocks to confirm site of pain

84
Q

Outline the treatment of splints in the horse

A
  • Swelling will persist following treatment, but may not be clinically significant if not causing pain
  • Anti-inflammatories
  • Reduce/stop work until lameness settles
  • Cold hosing
  • May require surgical removal if new bone impinges on suspensory ligament (rare)
85
Q

What is the most common cause of lameness originating in the carpus of horses?

A

Osteoarthritis

86
Q

Outline the clinical signs of osteoarthritis in the carpus of a horse

A
  • Lameness
  • Joint effusion
  • Bony swelling
  • Reduced ROM
  • Pain on flexion
87
Q

Outline your diagnostic approach for suspected osteoarthritis in the carpus of a horse

A
  • Joint effusion and pain on palpation indicates need for radiography
  • Nerve blocks if fracture ruled out (intra-articular if localising signs present: middle carpal and carpometacarpal as one, middle and antebrachiocarpal as separate blocks)
88
Q

Outline your treatment approach for osteoarthritis in the carpus of a horse

A
  • Anti-inflammatories
  • Analgesia
  • Removal of articular fragments if present
89
Q

Discuss the prognosis of osteoarthritis in the midcarpal and antebrachiocarpal joints in the horse

A
  • Are high motion joints
  • Radiographic signs in these joints indicate poor prognosis for return to athletic function due to presence of irreversible damage
90
Q

List the main causes of hindlimb lameness in the horse

A
  • Cellulitis/lymphangitis
  • DJD of small tarsal joints/Spavin
  • Meniscal disease of the stifle
  • Subchondral bone cysts of the stifle
  • OCD of the stifle and hock
  • proximal suspensory desmitis
  • Synovial sepsis
  • Fractures
  • Luxations
  • Tendon ruptures
  • Luxations (less common)
91
Q

What is spavin?

A

Degenerative joint disease of the small tarsal joints in the horse

92
Q

Discuss the distribution of joints affected in spavin in the horse

A
  • Tarsometatarsal and distal intertarsal usually
  • Sometimes proximal intertarsal
  • Worst affected if tarsocrural joint is affected
93
Q

Describe the lameness seen with spavin in the horse

A
  • Can be uni or bilateral
  • If bi, may appear stiff, or gait problem esp. in canter
  • Lameness can be mild or severe
  • Often pain on flexion e.g. when being shod
94
Q

Outline your diagnostic approach for a case of suspected spavin

A
  • Conformation, palpation, lameness evaluation, flexion tests
  • Intra-articular anaesthesia: TMT and DIT separately, PIT (will also block tarsocrural as these communicate) - required for definitive diagnosis
  • +/- Perineural anaesthesia (tibial and peroneal nerve block)
  • Radiography of hock showing signs of joint disease
95
Q

Outline the use of radiography in the diagnosis of spavin in the horse

A
  • LM and DP views of hock, D45LPM and D45MPL obliques
  • Radiographic signs: narrowing of joint space, periarticular osteophyte formation, subchondral bone sclerosis, subchondral bone lucency
  • Severity of radiographic signs does not always relate to severity of the lameness
96
Q

Outline the treatment of spavin in a case where there are no radiographic changes

A

Intra-articular anti-inflammatories only

97
Q

Outline the treatment of spavin in a case where there are radiographic changes

A
  • Intra-articular anti-inflammatories
  • Conservative: intra-articular steroids 1-3 months, systemic NSAIDs, continue to work horse
  • Surgical: arthrodesis of joint (can be chemical or surgical), will be pain free after fusion
98
Q

Briefly outline how chemical arthrodesis works in the management of spavin

A
  • MIA (monoiodoacetate) or ethanol
  • Inject into joint: damages cartilage, kills nerves
  • Exercise as much as possible to encourage fusion of bones
99
Q

List the common causes of lameness originating in the tarsus of horses

A
  • OCD
  • Synovitis of tarsocrural joint
  • OA of tarsocrural joint
  • Intra-articular fragments
  • Luxations and collateral ligament injuries
  • Sepsis of the joint
100
Q

Discuss the location of synovial sepsis in the tarsus and the importance of this

A
  • Tarsocrural joint common site
  • Small tarsal joints can be affected, are difficult to flush
  • Need to consider other synovial structures e.g. tarsal sheath and calcaneal bursa
  • Tarsocrural joint communicates with the PIT