Diagnostic testing for horses with muscle diseases Flashcards
What are the 2 non-specific markers of muscle damage
CK - creatinine kinase
AST- Aspartate aminotransferase
when does CK activity peak after acute myopathy
6 hours and returns to normal quickly (24 hours)- if there is no further muscle damage
How does AST respond to acute myopathy
AST activities increase more slowly (18-24 hours) and return to normal slowly (20 days)
what can happen to urine if there is severe muscle damage
myoglobinuria
how can we use CK to measure muscle damage
we can look at the change over time - take a sample, exercise the animal and then another 6 hours later - if the increase is over double then this is significant
List 5 indications for muscle biopsy
Repeated bouts of clinical disease, poorly managed
Cases with doubling of baseline CK activity
Suspicion of underlying storage myopathy
If seeking a definitive diagnosis
Poor performance work-up with suspicion of muscle disease
List 2 contraindications for a muscle biopsy
The diagnosis is clearly evident (atypical myopathy)
Condition is successfully managed with husbandry changes and symptomatic treatment (equine rhabdomyolysis)
what muscle should we biopsy to look for exertional myopathies
semi-membranous muscle
how do we test for PSSM on muscle biopsies
amylase digestion (removes normal accumulation of glycogen), then Periodic acid Schiff stain to test for abnormal accumulation of resistant glycogen
how can we test for myofibrillar myopathy on muscle biopsy
desmin stain - looks for abnormal accummulation of desmin
how can we test for recurrent equine rhabdomyolysis on muscle biopsy
H&E staining
what is the best way to test for PSSM-1
genetic testing
how can we test for atypical myopathy
test for hypoglycin A on blood or serum
How can we test for PSSM-2
You can’t - lots of unvalidated tests avaliable
