Equine Lameness Flashcards
What background history should we initially collect for a potentially lame patient?
Signalment Use Duration of ownership Recent management - work/exercise, feeding, shoeing, housing Previous medical problems
What specific history should we collect about a potentially lame horse?
Limb(s) affected Timing and nature of onset of signs Associated events or incidents Details of any areas of swelling/heat/pain Progression of signs since onset Treatments/management employed to date Current state of problem
What are the aims of the initial lameness workup?
Is horse actually lame? If so: Identify the limb(s) affected Score the severity of lameness Try to identify source/cause Implement treatment plan
What does the initial lameness workup generally include?
Physical examination Focused exam of MSK system Gait evaluation - walk/trot/lunge Flexion tests Further exam of affected limb Further workup - nerve/joint blocks, diagnostic imaging
How do we carry out a lameness physical examination?
General clinical exam General body condition Conformation of body, limbs and feet Posture and weightbearing on limbs Skeletal and soft tissue symmetry Localised swellings/thickenings Detailed evaluation - inspection/palpation/manipulation
What do we want to establish when evaluating gait?
Is there a gait abnormality? Is this due to lameness or something else (e.g. neurological)? What degree of lameness? Which limbs are affected? What exacerbates the lameness?
How do we carry out a gait evaluation?
Different surfaces - soft or hard
Start with walk - if obviously lame at walk then will not trot
Trot up in a straight line
Move on to lunging (soft and hard surface)
What considerations should we have when trotting up a horse?
PPE - hard hat, steel toe-capped boots, overalls, gloves Location - safe, flat surface, weather Contained? How lame? Temperament of horse Restraint - headcollar +/- bridle
How do we recognise forelimb lameness?
Assess as the horse is walking/trotting towards you
Head nod
Head lifts UP as the LAME leg hits the ground or vice versa
How do we recognise hindlimb lameness?
Assess as horse is walking/trotting away from you
Harder to recognise and identify than forelimb
Hindquarters as a whole pushed up by sound limb and sink during stance phase of lame limb
‘Hip’ of the lame limb will rise and fall through a greater range of motion than the sound side
What other aspects are we assessing in gait evaluation?
Relative lengths of phases of stride
Arc of foot flight
Path of foot flight (medial/lateral)
Foot placement
How do we grade lameness?
Two different grading systems used commonly - out of 10 or out of 5
Most useful for individual clinician to assess improvement
Why do we use provocative (flexion) tests?
To demonstrate occult lameness in ‘sound’ horse
To exacerbate a mild lameness
To aid localisation of source of lameness
How do we carry out a flexion test?
Limb held in flexion for about 1 minute
Horse trotted away as soon as limb released
Allowed a few lame strides
Horse should be standing ready to trot away
Attempt to flex only the joints you are testing
What are the limitations of the flexion test?
Lack of specificity to site
Inconsistency
Lack of hard criteria for ‘positive’
False positives and negatives
How do we lunge a horse?
Lameness often exacerbated on a circle
Usually exacerbates lameness with lame leg on the inside
Can be performed on hard or soft ground - hard usually exacerbates more
What considerations should we have for lunging a horse?
PPE - hard hat, steel toe-capped boots, gloves, overalls
Correct equipment - lunge line, lunge whip, bridle/lunging cavesoon, boots for horse
Does the horse lunge well?
Location - soft e.g. school, arena, lunging pen / hard e.g. hospital area
Is location flat, large, secure, safe, appropriate surface?
How do we carry out nerve blocks?
Start distally and work up
Clean area with chlorhex and spirit +/- clipping
Usually unsedated - consider safety
Left 10 mins then trot up to check for improvement
What are common sites and equipment for nerve blocks?
Palmar/plantar digital, abaxial sesamoid, low 4 point
23-25G, 5-8” needles, 2ml syringes
Other nerve blocks if need to go higher up limb
How do we carry out joint blocks?
Intrasynovial admin - sterility is key!
Sterile skin prep - chlorhexidine and spirit
Evaluated at 10 mins and then later
How do we radiograph horses?
Remember PPE - lead gowns, thyroid protectors
Usually sedate horses - keep them still
Useful for identifying bony change
Why do we use ultrasound on lame horses?
Distinguishes tendon/ligament injuries from peritendinous swelling
Defines which tendon/ligament is injured
Evaluates the type and degree of damage
Monitors healing
How do we carry out ultrasound on horses?
Clip area if required
Clean to remove dirt
Apply ultrasound gel to area
May require sedation
What are we looking for on lameness ultrasounds?
Increase in tendon/ligament size
Change in internal architecture - hypoechoic core lesions, heterogenous pattern, loss of longitudinal fibre alignment
Indistinct margination
Peritendinous fluid in tendon sheaths
Why do we use diagnostic arthroscopy?
Direct visualisation of joint cavities, including - articular cartilage, synovial membrane, intra-articular ligaments, menisci
Why do we use MRI on lame horses?
Simultaneous demonstration of bone and soft tissue structures
Potential for evaluation of tendons/ligaments and other soft tissues
What lesions can be detected using nuclear scintigraphy?
Stress fractures
Arthropathies
Enthesiopathies
How do we carry out nuclear scintigraphy?
Lunged/exercised prior to injection to increase uptake if safe to do so
IV catheter placed
Horses will be radioactive for period of time after injection!
PPE - lead gowns etc.
Urine will need to be collected during image acquisition
Must be kept in isolation until no longer radioactive - no handling/mucking out etc.
Be aware of specific protocol
What is synovial sepsis?
Bacterial contamination of synovial structure
Usually wounds in adults
Causes septic arthritis and chronic lameness if not treated
How can we investigate synovial sepsis?
Synoviocentesis and analysis of synovial fluid
May inject sterile saline into the joint and check for egress
Contrast radiography?
How do we carry out arthrocentesis?
Sterile prep of site - chlorhex 5min minimum scrub, wipe with surgical spirit
Needle requirement depends on joint
Sedation usually
What is the role of the nurse during arthrocentesis?
Prep the site (vets may choose to do this themselves)
Non-sterile assistant during procedure
Have equipment/spares ready (needles, syringes, sterile gloves, tubes/pots for collection)
Monitoring for lameness/deterioration in lameness in post 48hrs
How can we analyse arthrocentesis samples?
Cytology - TNCC and neutrophil %
Protein concentration
Lactate (slow to rise in first 24hrs)
May take blood sample for SAA
What is laminitis?
Inflammation of laminae/lamella in the hoof
Dermal/epidermal separation
Very painful!
Can lead to structural changes/failure in foot - rotation/sinking of P3
What are the phases of laminitis?
Developmental - between trigger and clinical signs
Acute - onset of clinical signs, 72hrs, may become chronic or subacute after this
Subacute - from 72hrs, 2-3 months repair
Chronic - structural failure
What are the clinical signs of laminitis?
Stilted, pottery gait Increased, bounding digital pulses Leaning back on heels Recumbency Worse on hard ground Struggle to turn Reluctance to pick up feet
What are the possible causes of laminitis?
Endocrinopathies e.g. PPID, EMS
Excessive carbohydrates e.g. grain overload, pasture
Excessive weightbearing
Endotoxaemia/SIRS
Corticosteroids?
Pathogenesis not precisely understood, potentially multiple mechanisms
What is endocrinopathic laminitis?
Underlying endocrinopathy - Equine Metabolic Syndrome (EMS) or Pituitary Pars Intermedia Dysfunction (PPID)
Pathophysiology not known but likely hyperinsulinaemia and insulin toxicity
Describe the other causes for laminitis.
Supporting limb laminitis - excessive weightbearing, particularly when non-weightbearing on one limb e.g. fractures, cellulitis
Endotoxinaemia - secondary colic, colitis, retained foetal membranes
What are some risk factors for laminitis?
History of laminitis Obesity Endocrinopathies - PPID, EMS, insulin resistance Season Heavy horses Native ponies Excessive weightbearing Excessive carbohydrates At risk of endotoxaemia - colitis, post-op colics, RFM
How can we intervene and try to prevent development of clinical signs of laminitis?
At-risk patients e.g. endotoxic, RFMs, supporting limb
Cold therapy - ice boots to reduce perfusion
NSAIDs to reduce inflammation
Support for feet - frog supports, deep shavings bed
Treat underlying endocrinopathy and discuss long-term management
How can we manage acute laminitis patients?
Strict and complete box rest Deep (shavings) bed Frog supports/Styrofoam pads NSAIDs - analgesia and anti-inflammatory Increase perfusion - ACP? Treat underlying cause Address diet if endocrine-related (reduce carbohydrates gradually) Once more comfortable - farriery
How do we manage subacute and chronic laminitis patients?
Subacute - gradually withdraw treatment as long as improving, keep on strict box rest
Farriery - shorten toe over time, remedial shoeing e.g. heart bars, silicone, glue-on shoes
What specific considerations should we have for radiographing laminitis patients?
Lateromedial and dorsopalmar/plantar projections
Measuring rotation and sinking, prognostic indicators
Comfort - pick up feet and stand on blocks
Metal marker on dorsal hoof wall - coronary band downwards
How can we try to prevent laminitis?
Control risk factors
Particularly for endocrinopathies - treat underlying, exercise if possible to increase insulin sensitivity, weight loss/promote ideal BCS
Diet - restrict carbohydrates, soaking hay + balancer
Grazing restricted - not just by time!
What is box rest?
Stabling the horse
Confined rest
No exercise, no turnout
What GI considerations should we have when box resting a horse with laminitis?
Management changes - colic
Reduced exercise - gut motility, impactions
Diet - sudden change = colic
Ulcers - reduction in eating time, omeprazole?, smaller holed haynets
What behaviour considerations should we have for box resting horses with laminitis?
Behaviour - stereotypies, stable mates, used to stabling?
Increased energy? - misbehaviour, try to escape/climb up/excitable in stable
What nursing can we provide for box resting laminitis patients?
Monitor faecal output / colic signs / appetite / signs of stress
Mirrors, company
Watch out for behaviour - more keen to escape, more difficult to handle
How do we take a laminitis horse off box rest?
Gradual changes in management
Gradual changes in diet
Behaviour when turned out - gradual return to turnout
Slow reintroduction to work
