Treatment of muscle disease

Question 1

What is the treatment for Rhabdomyolysis (applies to any myopathy)?
what else do you need to do for severe cases?

Answer 1

• Pain relief and anti-inflammatory effect :
  
  • NSAIDs for 3-6 days: be careful with kidneys! Always monitor plasma creatinine and water intake
  • Acepromazine: Tranquilizer and vasodilation (increase blood supply in affected muscles)
  • Alpha-2+ butorphanol q 4h IM (CRIs ?)
• Moderate-severe cases: Myoglobinuria: IV fluids (isotonic): flush the kidneys!
• Stable rest for 48h, then start walking 5 min 2-3 times a day for 3 days, increase progressively
• Be careful with AM cases: Longer resting periods
• Muscle relaxants (FEI control substances)
  
  • Methocarbamol 5-22mg/kg IV or PO
  • Dantrium Na 2-4mg/kg PO
• Anti-oxidants: Vit E, VitB group, Vit C

Question 2

What is the management protocol for sporatid rhabdomyolysis?

Answer 2

• Re-think training program: slow-down! 15 min exercise/day.
• Maintain diet with Ca:P ratio 2:1
• Keep access to good quality hay: be careful with haylage
• Provide 30-50g day NaCL + 15-25g K-CL either with water or feed
• Do not feed concentrates/grains with more than 15-20% NSC
• Feed 4-8% fat

Question 3

What is the management for Recurrent exertional rhabdomyolysis?

Answer 3

• Manage the environment: reduce stress
  
  • pasture with other horses
  • barn with fewer horses
• Do not hold them back during galloping: race horses
• Daily exercise: min 15 min a day
• Commercial feed: 8-12% NSC and 10-13% fat
• Medication: Be careful with withdrawal times in performance horses!
  
  • Dantrium sodium: 4mg/kg PO 1 hour before exercise
  • Acepromazine 20 min before exercise to reduce stress

nNSC - non-strucural carbohydrates

Question 4

What is the management for PSSM-1?

Answer 4

• Moderate starch and sugar content diet (< 12%) with slightly higher protein content (20%). If higher calorie intake is necessary for performance, energy should be supplemented as fat&raquo_space;> vegetable oil.
• Avoid sweet feed, corn, wheat, oats, barley, and molasses
• Ration balancer with vitamins and minerals (check starch content)
• Consistent exercise, avoid resting: regular exercise enhances glycogen utilization, increases turnover of structural proteins in the muscle and builds mitochondrial enzymes needed to burn energy as fuel.

Question 5

what is the management for myofibrillar myopathy?

Answer 5

• Moderate starch and sugar content diet (< 15%), fat (4-8%) and protein protein content (15%)
• Antioxidants: Vit E and Coenzyme Q
• Branched-amino acids
• Consistent exercise: Particularly important in WB
  • Long warm-up with stretching exercise
  • 30-50 min training max
  • 3 days work and 2 days rest

Question 6

what is the management for HYPP?
what is the difference for moderate cases vs acute/severe cases?

Answer 6

• Limit K intake (max 1%)
  * Test hay (regular quality 1-2% K)
  * Avoid alfalfa and clover hay (high K)
  * Plain oats»> BE CAREFUL WITH STARCH content
• Consistent exercise, avoid resting: exercise increments over 5-7 days

Moderate cases: no paresis
* Karosyrup: insulin mediated K removal
* 2nd or more cut of hay/haylage (less K)
* Small meals of oats/beet pulp over 2 weeks
* Gentle walking

Acute/severe crisis ± paresis
* Epinephrine
* 23% Calcium gluconate
* 5% dextrose

Question 7

What is the treatment for atypical myopathy?

Answer 7

• Limit pigmented nephropathy - IV-fluids
• Replenish Vitamin B2 stores
• Accumulation of partially-metabolized FAs (acyl-carnitines)
  
  • Antioxidants very important: Vit E, Vit B12
• Toxin Binders : charcoal or bio-sponge NGT 1-2 doses
• Correct electrolyte abnormalities: K + Ca +Mg» check electrolytes!
• Analgesia: headache?, myalgia?> NSAID, Paracetamol, CRIs, Morphine
• Be careful with feeding: 25% dysphagia, 90% reduced gut sounds
  
  • Use of glycogen as main energy source: Provide glucose sources: ready to be used: Karosyrup (don’t want to encourage gluconeogenysis as this increases production of the toxic metabolite
• Monitor cardiac function: frequent auscultation, daily ECG?
• Provide thick bedding (ideally straw) in large stable
• Urinary catheterization
• Keep the stable warm (air heaters)

Not a quick fix!: new production of enzymes

Question 8

what is the treatment for immune mediated myopathy?

Answer 8

• IV-fluids if muscle enzymes too high
• Antibiotics: controversial
• Anti-inflammatory/ Immuno-modulatory Therapy: Steroids
  
  • Dexamethasone 0.05mg/kg IM/IV for 3 days
  • Followed by 1mg/kg prednisolone PO for 10 days,
  • then tapered over 1 month

Question 9

What is the treatment of myonecrosis?

Answer 9

• Drain the abscess: and expose to oxygen, fenestration
• Antibiotics: broad spectrum but….
  
  • High dose Penicillin 44 000IU q 12h for 4 days
  • Metronidazole (after culture conformation)
• Control Pain
  
  • Flunixin Meglumine
  • Phenylbutazone