Muscle Disorders

Question 1

What are the two types of muscle atrophy and which fiber types are they associated with?

Answer 1

(Myogenic atrophy, type 2 fibers; neurogenic atrophy, type 1 and 2 fibers)

Question 2

What are two etiologies of muscle fasciculations?

Answer 2

(Abnormal recruitment of nerves (can occur in response to nerve root irritation, electrolyte abnormalities, weakness, fatigue, anxiety, and cold) or ion channel defects within the sarcolemma (HYPP))

Question 3

What electrolyte excessively accumulates in muscle cells in relation to rhabdomyolysis that then triggers mitochondria to produce free radicals, proteases, phospholipases, and inflammatory cytokines?

Answer 3

(Calcium)

Question 4

Is creatine kinase better for indicating acute/chronic (choose) injuries?

Answer 4

(Acute, peaks w/in 4-6 hours and returns to normal in 48 hours, severe >4000u/L increases associated with muscle damage)

Question 5

How long does it take for aspartate aminotransferase to return to normal after insults to muscle, liver, RBCs, and other tissue AST is found in?

Answer 5

(Weeks, peaks in 24 hours post injury)

Question 6

What value of serum CK will indicate a positive test in a serum CK exercise response test?

Answer 6

(>3x increase in CK from baseline)

Question 7

What electrolyte changes do you expect to see in severe rhabdomyolysis cases?

Answer 7

(Hyponatremia, hypochloremia, hypocalcemia and hyperkalemia, hyperphosphatemia)

Question 8

Why should you monitor the kidney values in horses with muscle disease?

Answer 8

(Bc myoglobinuria is associated with renal tubular necrosis)

Question 9

What substance should be tested for in foals with severe rhabdomyolysis?

Answer 9

(Selenium)

Question 10

What vitamin should be tested for in horses with generalized muscle atrophy?

Answer 10

(Vitamin E)

Question 11

Of the clinical signs associated with muscle disease in horses, which is not associated with changes on muscle biopsy?

Answer 11

(Muscle fasciculations)

Question 12

Pair the muscle disease with the muscle(s) that should be sampled:

Exertional rhabdomyolysis, PSSM

A - Sacrocaudalis dorsalis
B - Semimembranosus, middle gluteal
C - Gluteal or lumbar

Answer 12

(B)

Question 13

Pair the muscle disease with the muscle(s) that should be sampled:

Immune-mediated myositis

A - Sacrocaudalis dorsalis
B - Semimembranosus, middle gluteal
C - Gluteal or lumbar

Answer 13

(C)

Question 14

Pair the muscle disease with the muscle(s) that should be sampled:

Generalized muscle atrophy

A - Sacrocaudalis dorsalis
B - Semimembranosus, middle gluteal
C - Gluteal or lumbar

Answer 14

(A)

Question 15

What veterinarian should you look up when you’re sending in a muscle biopsy because she’s the best?

Answer 15

(Dr. Stephanie Valberg)

Question 16

What is the main preventative strategy for PSSM episodes?

Answer 16

(Decrease starch in diet/no grain and daily exercise)