Muscle

Question 1

When observing the horse in a PE, what are you looking for when checking the muscles?

Answer 1

size, shape, symmetry. look for muscle fasciculations

Question 2

What does a high creatine kinase (CK) indicate?

Answer 2

Myonecrosis

Question 3

How long does it take after an injury for CK to peak in the serum?

Answer 3

4-6 hours

Question 4

What is the CK elevated to in horses with light training? extreme exercise? colic? rhabdomyolysis?

Answer 4

Light - 400-500 IU/L
Extreme - 1000-8000 IU/L
Colic - <3000 IU/L
Rhabdomyolysis - huge variation (100-100,000’s)

Question 5

What are other causes besides myonecrosis in an increase in serum AST?

Answer 5

hemolysis, muscle, liver, and organ damage

Question 6

How long does it take after an injury for AST to peak in the serum?

Answer 6

24 hours

Question 7

Using clinical pathology skills, what is a good chemistry indicator that myonecrosis is happening?

Answer 7

CK remains persistently elevated

Question 8

What does elevated AST with decreased to normal CK values indicate?

Answer 8

Myonecrosis is not continuing

Question 9

What does elevated CK and AST represent?

Answer 9

Recent or active myonecrosis

Question 10

Besides muscle necrosis, what does an increase in LDH (lactate dehydrogenase) represent?

Answer 10

hepatic necrosis

Question 11

What urinalysis test is used to suggest myoglobinuria?

Answer 11

Hemastix test (must not have hemolysis or RBC in urine)

Question 12

What does renal fractions excretions determine?

Answer 12

FEs determine electrolyte balances in blood and urine

Question 13

What is the purpose of an exercise challenge test?

Answer 13

To see if there is a disease precipitated by exercise

Question 14

When should serum CK samples be taken in an exercise challenge test?

Answer 14

1. ) before

2. ) 4-6 after exercise

Question 15

What would you typically see in serum CK values in a horse with muscle disease?

Answer 15

over 3x increase in CK

Question 16

What will horses with muscle abnormalities show on an electromyography?

Answer 16

spontaneous electrical activity

Question 17

What are electromyographies and nerve conduction velocities used to classify?

Answer 17

Whether the disease is neuropathic or myopathic

Question 18

What does nuclear scintigraphy help do?

Answer 18

Can find areas of muscle damage, particular deep

Question 19

What is sweeney?

Answer 19

When the suprascapular nerve is damage and causes shoulder muscle atrophy

Question 20

How quickly does a denervated muscle lose mass?

Answer 20

2-3 weeks

Question 21

What is myotonia dystrophica?

Answer 21

When the muscles are progressively getting mroe and more contracted with the slightest stimuli

Question 22

How do you definitively diagnose myotonia dystrophica?

Answer 22

electromyography

Question 23

What sound do you hear with EMG in a horse with myotonia dystrophica?

Answer 23

dive bomber sound, high frequency repetitive bursts

Question 24

What treatment has been reportedto be effective in quarter horses with hyperkalemic periodic paralysis and myotonic dystrophy?

Answer 24

Phenytoin

Question 25

What is a non-dystrophic myotonia disease?

Answer 25

Hyperkalemic periodic paralysis

Question 26

What is the cause of HYPP?

Answer 26

inherited defect in the sodium channels of skeletal muscles

Question 27

What are the clinical signs of HYPP?

Answer 27

from asymptomatic to muscle fasciculations and weakness, sweating

Question 28

What are some factors to trigger symptoms of HYPP?

Answer 28

Stress, sudden changes, anesthesia

Question 29

T/F: Exercise does not trigger HYPP clinical signs

Answer 29

True

Question 30

T/F: you can easily diagnose HYPP due to changes to serum CK

Answer 30

False. barely any changes

Question 31

What is the definitive diagnosis for HYPP in horses?

Answer 31

DNA encoding of the sodium channel to show its faultiness

Question 32

How can you control HYPP in a horse?

Answer 32

Decrease potassium in diet and avoid increasing its levels.

Question 33

What does acetazolamide do for horses with HYPP?

Answer 33

stabilizes BG and potassium via increased insulin secretion, so helps with K levels

Question 34

What causes muscle cramping to occur?

Answer 34

Hyperactivity of motor units. Repetitive firing of peripheral and central nervous system

Question 35

What are the dietary issues that may lead to muscle cramping?

Answer 35

Sodium or potassium deficiencies

Question 36

What are some electrolyte abnormalities seen with muscle cramping?

Answer 36

hypochloremia, metabolic alkalosis with hypokalemia, hypomagnesemia,

Question 37

T/F: Muscle cramping will lead to increased values CK, AST, and/or myoglobinuria

Answer 37

False.

Question 38

How do you treat mild muscle cramps?

Answer 38

You don't, self limiting

Question 39

What is the inciting cause for synchronous diaphragmatic flutter? (thumps)

Answer 39

Hypocalcemia

Question 40

What are some causes of thumps?

Answer 40

prolonged exercise, hypocalcemia, GI tract issues, furosemide, trauma, 1ary hypoparathyroidism

Question 41

How do you treat synchronous diaphragmatic flutters?

Answer 41

Give IV calcium and control with supplements

Question 42

What organism causes ear tick muscle cramps?

Answer 42

Otobius megnini

Question 43

T/F: Ear tick muscle cramp cause an increase in serum CK

Answer 43

True. 4000-170,000 IU/L

Question 44

How do you treat eat tick muscle cramps?

Answer 44

locally with pyrethrins. ace can help relieve the pain

Question 45

What are the two forms of nonexertional rhabdomyolysis?

Answer 45

Inflammatory myopathy, nutritional myopathy

Question 46

What bacteria is responsible for nonexertional rhabdomyolysis?

Answer 46

clostridium

Question 47

What are the clinical sigs for clostridial myonecrosis?

Answer 47

rapidly progressive tremors, ataxia, dyspnea, recumbence, coma, death (within 24 hours)

Question 48

Where you see the site of infection with clostridial myonecrosis?

Answer 48

Recent injection sites

Question 49

T/F: Serum CK and AST are definitive diagnostics for clostridial myonecrosis

Answer 49

False

Question 50

How do you treat clostridial myonecrosis?

Answer 50

Aggressive specific therapy with supportive care

Question 51

What organisms causes severe acute generalized rhabdomyolysis?

Answer 51

Streptococcus equi.

Question 52

Besides muscle disorders, what else is effected with severe acute generalized rhabdomyolysis?

Answer 52

blood cells

Question 53

How do you control the pain in a horse with rhabdomyolsis associated strep equi?

Answer 53

CRI lidocaine, detomidine, or ketamine

Question 54

What horse breed is associated with immune-mediated polymyositis?

Answer 54

quarter horses

Question 55

What organism is associated with IMM?

Answer 55

strep. equi

Question 56

What is a good treatment for IMM?

Answer 56

corticosteroids

Question 57

How would you diagnose a seasonal pasture myopathy or atypical myopathy?

Answer 57

Find deficiency in acyl CoA dehydrogenase, or isolate the toxic metabolite methylenecyclopropyl acetic acid (MCPA)

Question 58

What organisms causes seasonal pasture/atypical myopathy?

Answer 58

Seeds of the Acer tree species

Question 59

What are the two forms of postanesthetic myoneuropathy?

Answer 59

1. ) localized myopathy-neuropathy | 2. ) generalized myopathy

Question 60

T/F: Localized myopathy-neuropathies have complicated recoveries despite treatment

Answer 60

False.

Question 61

What can you give to prevent the break down of muscle damage in a horse with generalized anesthetic reactions?

Answer 61

Dantrolene