Treatment of muscle disease Flashcards
General considerations
▪Severity of episode: clinical signs, muscle enzymes and kidney function
▪Pain
▪Suspected aetiology
▪Exercise return speed
▪Nutrition: electrolytes, starch and proteins
Acute-severe rhabdomyolysis tx (but applies to any myopathy)
Analgesia & anti-inflammatories
➢ NSAIDs for 3-6 days:
– be careful with kidneys
– Always monitor plasma creatinine and water intake
– flunixin, bute or meloxicam
➢ Acepromazine: Tranquilizer and vasodilation (increase blood supply in affected muscles)
➢ Alpha-2+ butorphanol q 4h IM (CRIs ?)
– for a short period in extreme cases
Muscle relaxants
➢ Methocarbamol 5-22mg/kg IV or PO
– excellent muscle relaxant with some analgesic effects
➢ Dantrium Na 2-4mg/kg PO
– is a regulator of the calcium entrance into the muscle fibres
➢ FEI controlled substances
Anti-oxidants
➢ Vit E
➢ Vit B group
➢ Vit c
Rest/exercise
➢ 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
➢ Rest important to give enough time for the muscle fibres to recover
Moderate-severe cases - myoglobinuria:
➢ IV fluids (isotonic)
– flush the kidneys
– to prevent pigment nephropathy
Sporadic rhabdomyolysis tx - management
➢ Re-think training program: slow-down 15 min exercise/day
– Gradual exercise program: 10 min walk and trot/day for 7d, then increase 5 min load weekly
– Canter can be included on the 3rd week
– days/week of exercise and increase in intensity depends on the intended activity of the horse
➢ Maintain diet with Ca:P ratio 2:1
➢ Keep access to good quality hay: be careful with haylage (high starch content)
➢ Provide 30-50g day NaCL + 15-25g K-CL either with water or feed
– helps replenish electrolytes stored in the muscles fibres and maintain the horse with correct hydration as encourages drinking
➢ Do not feed concentrates/grains with more than 15-20% NSC
➢ Feed 4-8% fat
– adding fat helps provide healthy fuel stores for the muscles
RER tx
➢ 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
-> helps with the regulation of calcium entry into muscle fibres
-> 2w withdrawal before any FEI competition
– Acepromazine 20 min before exercise to reduce stress
PSSM-1 tx
➢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»> vegetable oil
– Commercial product called relieve that already has these % adjusted
➢Avoid sweet feed, corn, wheat, oats, barley, and molasses
➢Ration balancer with vitamins and minerals (check starch content)
➢Consistent exercise, avoid resting (for long periods): regular exercise enhances glycogen utilization, increases turnover of structural proteins in the muscle and builds mitochondrial enzymes needed to burn energy as fuel.
Myofibrillar myopathy tx
➢Moderate starch and sugar content diet (<15%), fat (4-8%) and protein protein content (15%)
➢Antioxidants: Vit E and Coenzyme Q
➢Branched-amino acids (in the form of a supplement)
➢Consistent exercise: Particularly important in WB ➢Long warm-up with stretching exercise ➢30-50 min training max
➢3 days work and 2 days rest
HYPP tx
➢ 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
Atypical myopathy tx
➢ 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 (with xylazine & butorphanol), Morphine
➢ Be careful with feeding:
–25% dysphagia, 90% reduced gut sounds
–Damage of masseters, tongue and oesophagus , prolonged recumbency
–Use of glycogen as main energy source:
-> Maintain glucose availability
-> Provide glucose sources
➢ Monitor cardiac function: frequent auscultation, daily ECG?
– these horses
➢ Provide thick bedding (ideally straw) in large stable
– some will go through periods of recumbency so try to avoid pressure sores and damage
➢ Urinary catheterization
– necessary for those with bladder atony
➢ Keep the stable warm (air heaters)
– most AM cases occur during autumn and winter in the UK, therefore need to keep the stable warm
– also avoids further muscle crampin
IMM tx
- IV-fluids if muscle enzymes too high
- Antibiotics: controversial
–For those with concurrent streptococcal infection the use of antibiotics is good - Steroids (anti-inflammatory/immunosuppressive)
– Dexamethasone 0.05mg/kg IM/IV for 3 days
– Followed by 1mg/kg prednisolone PO for 10 days,
– then tapered over 1 month
– Use of steroids appears to immediately improve CS and prevent further progression of muscle atrophy
Myonecrosis tx (& clostridial infections)
- Drain the abscess (fenestration)
- Antibiotics: broad spectrum but
– High dose Penicillin 44 000IU q 12h for 4 days
– Metronidazole whilst getting results from culture - Control Pain
– Flunixin Meglumine
– Phenylbutazone
– CRI of alpha2 and butorphanol necessary for severe and extensive cases
Why is rest so important for atypical myopathy cases?
- we don’t have an antidote for Hypoglycin-A, therefore the damage this toxin produces into the dehydrogenases within the mitochondria cannot be counteracted
- Therefore, the body needs enough time and resources to regenerate those enzymes
Why is vitamin B2 important for atypical myopathy cases?
- It will provide the cofactors necessary to regenerate the dehydrogenase
Role of antioxidants in the tx of atypical myopathy
- they help reduce the damage produced by acyl-carnitine that accumulate because of malfunction of the dehydrogenase
Role of toxin binders in the tx of atypical myopathy
- use is a bit controversial BUT is recommended in all cases
- as we don’t know when the animal has ingested the sycamore plant material, we don’t know if they still have some plant material in their GIT
- so the binders would minimise the absorption of the toxin that is still within the GIT
Role of electrolytes in the tx of atypical myopathy
- breaking of the muscle fibres not only releases myoglobin (-> pigment nephropathy) but the stores of electrolytes
- so these should be replenished
- but care taken with K as can trigger cardiac arrhythmias in horses with atypical myopathy
