Causes of Lameness: Muscles Flashcards
How do you diagnose muscle injuries?
○ Physical exam
§ Fibrosis, atrophy, inflammation
○ Thermography
○ Ultrasound
§ Hematoma, seroma
○ Nuclear Scintigraphy
§ Soft tissue phase (~15 minutes)
○ Electromyography
§ Record electrical impulse
○ Muscle biopsy
What is muscle atrophy?
○ Atrophy = wasting away or decrease in size
§ Degenerative process
§ Generalized or localized
What are the causes of muscle atrophy?
Denervation
Trauma
Ischemia
Lack of use
Excessive use
What is sweeney?
○ Paralysis of suprascapular nerve –> atrophy of supraspinatus and infraspinatus muscles
What causes sweeney?
Ill-fitting harness
Trauma
What causes fibrotic myopathy?
Repeated trauma and straining of semitendinosus muscle fibers
Acute trauma with resulting scar formation
Repeated IM injections
What are the signs of fibrotic myopathy?
Goose-stepping gait with shortened cranial phase
Limb pulled down before foot hits ground
How do you diagnose fibrotic myopathy?
Signs
Palpation of scar tissue
How do you treat fibrotic myopathy?
Transection of muscle/tendon at scar level or insertion (semitendinosus tenotomy)
What is stringhalt?
Involuntary flexion of the hock when horse moves
Lateral digital extensor muscle/tendon involved?
What are the causes of stringhalt?
Trauma to muscle/tendon (unilateral)
Ingestion of toxic weed (bilateral)
What are the signs of stringhalt?
Mild to severe hyperflexion of hock
□ Spasmodic with every step
Signs exaggerated
□ Horse is backing
□ Cold weather
□ After period of rest
How do you diagnose stringhalt?
Clinical signs
Rule out fibrotic myopathy, shivering, and upward flexion of patella
How do you treat stringhalt?
Conservative - rest, controlled exercise, nutrition changes
Surgery - remove portion of lateral digital extensor tendon (70% improve)
What is shivering?
Involuntary flexion of limbs
Progressive, worsen over time
Hindlimbs > forelimbs
What causes shivering?
Cause unknown
Linked to influenza, strangles, and EPSM
What are the signs of shivering?
Random hyperflexion of any limb
Tail elevated, tail and leg quivers
How do you diagnose shivering?
Clinical signs, backing may exacerbate
What is the treatment for shivering?
Feed high-fat, low-carb diet
What is the prognosis for shivering?
poor because progressive
What is cellulitis?
Subcutaneous bacterial infection
What causes cellulitis?
Wound
Hematogenous/lymphogenous
What are the signs of cellulitis?
Swelling, pain, heat, pitting edema
Fever
Moderate to severe lameness
How do you diagnose cellulitis?
History of wound
Clinical signs
Rule-out fracture
How do you treat cellulitis?
Wound care
Cold hosing
Antibiotics, NSAIDs
DMSO/furacin sweat bandage, nasogastric intubation with DMSO
What are some systemic diseases of muscle?
Tetanus
Botulism
Lyme Disease
Hyperkalemic Periodic Paralysis (HYPP)
Exertional Rhabdomyolysis (ER)
Equine Polysaccharide Storage Myopathy (EPSM)
What is exertional rhabdomyolysis?
AKA Monday morning sickness, tying up, azoturia
What causes exertional rhabdomyolysis?
Return to work after rest
Post-anesthesia
What are some theories for exertional rhabdomyolysis?
Changes in blood supply within muscle
Fluid and/or electrolyte imbalance
Genetic predisposition
Nutritional influence
What are the signs of mild rhabdomyolysis?
Slight change in gait especially hind limbs
Poor performance
Pain or stiffness upon palpation of neck and gluteal muscles
Increased HR, RR, and temp
What are the signs of severe exertional rhabdomyolysis?
Extreme pain
Reluctance to move
Severe stiffness
Sweating
Myoglobinuria
Recumbency
How do you diagnose exertional rhabdomyolysis?
History, clinical signs
Elevated Creatine Kinase (CK) w/ exercise
Muscle biopsy - swollen fibers
How do you treat exertional rhabdomyolysis?
Analgesia
Reduce further muscle damage
□ Don’t move
Restore fluid and electrolyte balances
What is equine polysaccharide storage myopathy?
Disorder of glycogen storage
QHs, WBs, and drafts
Heavily muscled horses with calm demeanor
What are the signs of equine polysaccharide storage myopathy?
Muscle atrophy, abnormal gain, repetitive ER
What is the diagnosis of Equine Polysaccharide Storage Myopathy (EPSM or PSSM)?
Muscle biopsy of semimembranosus/tendinosis
Blood sample
How do you prevent Equine Polysaccharide Storage Myopathy (EPSM or PSSM)?
Replace grain with rice bran/fat
Provide daily exercise
What are the steps of an orthopedic exam?
- Observed the horse from afar and asking history questions
i. How long has it been going on
ii. Signalment
iii. Medical history
iv. What is their job
v. When is it worse?
vi. Owner input, sometimes they say things that could help
vii. Is the horse on medications - Muscular palpation
i. Limbs
ii. Range of motion
iii. Feet - hoof testers - Movement - baseline walk and trot
i. Baseline walk and trot and then canter
1) The transition down from the canter is where lameness pops up - Flexions - a minute longish
