muscle

Question 1

What are enzyme IU’s?

Answer 1

Representative of the ACTIVITY of the enzyme

Question 2

What is ALP?

Answer 2

Alkaline Phosphatase - a family of phosphatases that have phosphatase activity in an alkaline environment

Question 3

What is liver ALP?

Answer 3

may be involved in degradation of endotoxin

Question 4

What is Bone ALP?

Answer 4

May be involved in mineralization

Question 5

How are enzymes measured in the chemistry machine?

Answer 5

Serum/plasma is mixed with reagents and the spectrophotometer measures the change in absorbance of a reactant which converts to its concentration.

Question 6

What are 2 reasons enzyme activity would increase in the blood?

Answer 6

Cellular leakage of the enzyme, Increased Synthesis

Question 7

Why would enzymes be leaking?

Answer 7

Cytoplasmic release following plasma membrane damage or fragmentation, Release of cytosol or organelles following necrosis

Question 8

Why would there be an increase in synthesis of enzymes?

Answer 8

Decreased inactivation or clearance of enzyme(renal excretion of amylase), Absorption of maternal enzymes in colostrum(ALP, GGT in certain neonates), Can be by existing cells or by hyperplastic/neoplastic cells

Question 9

What features of enzymes contribute to their diagnostic use?

Answer 9

If the enzyme activity in the target cell is greater than in the blood, Long enough half-life that it accumulates in the blood prior to inactivation, It has access to the blood, directly or through the lymphatics

Question 10

What is an ideal diagnostic test?

Answer 10

High sensitivity - test detects sick patients, High specificity - results will be normal when patient is healthy

Question 11

At what point is an elevation of an enzyme considered clinically significant? What are some exceptions?

Answer 11

2-3 fold increase over upper end of reference. Exceptions: ALP in cats has a short half life, GGT in dogs and cats, SDH

Question 12

What does it mean when enzyme activity is below the reference interval?

Answer 12

Not clinically significant, however, it could be a bad sign(decreased # of target cells due to necrosis or fibrosis). In this case organ function tests would be more reliable

Question 13

What enzymes are considered “leakage enzymes” and why?

Answer 13

CK, AST, LDH - leakage from injured skeletal myocytes.

Question 14

What does an increase in leakage enzymes correlate with?

Answer 14

number of injured cells(not the type of injury)

Question 15

What are 7 causes of myopathies?

Answer 15

Inflammation, Metabolic, Ischemic, Nutritional, Traumatic, Exertional, Degenerative
I-MINTED

Question 16

What are 4 examples of traumatic myopathies?

Answer 16

Hit by car, Downer, Post-op, IM injections

Question 17

What are 4 examples of exertional myopathies?

Answer 17

Exercise, Endurance, Seizures, Trailering

Question 18

What are 3 examples of degenerative myopathies?

Answer 18

Rhabdomyolysis, Senna, Capture myopathy

Question 19

What is an example of an inflammatory myopathy?

Answer 19

Clostridial myositis

Question 20

What is an example of a nutritional myopathy?

Answer 20

Vit E/Se deficiency

Question 21

What is an example of an ischemic myopathy?

Answer 21

Saddle thrombus

Question 22

What is an example of a metabolic myopathy?

Answer 22

Equine Glycogen Storage

Question 23

What type of enzyme is CK?

Answer 23

Leakage

Question 24

Where does CK come from?

Answer 24

skeletal(+cardiac/smooth) muscle, brain

Question 25

How long is the halflife of CK?

Answer 25

Short - hours

Question 26

What is the clinical application for CK?

Answer 26

Highly specific and sensitive for myopathies, but can be overly sensitive

Question 27

What type of enzyme is Aspartate aminotransferase(AST)?

Answer 27

Leakage

Question 28

Where does AST come from?

Answer 28

Skeletal muscle, hepatocytes, and other cells including RBC’s

Question 29

What is the halflife of AST?

Answer 29

hours to days

Question 30

What is the clinical application for AST?

Answer 30

It is sensitive but with a low specificity - you don’t know if its coming from the muscle or liver, so you must use other enzymes to point you in the right direction

Question 31

What type of enzyme is Lactase dehydrogenase(LDH)?

Answer 31

Leakage

Question 32

Where does LDH come from?

Answer 32

skeletal muscle, liver, WBC’s, RBC’s

Question 33

What is the clinical application of LDH?

Answer 33

Not much, it is very sensitive but total LDH provides no specificity(you need isoenzymes) For this reason it is not usually included on chem panels

Question 34

What enzyme, which is generally a liver marker, can sometimes be seen with muscle damage? What are the two situations in which this would occur?

Answer 34

ALT, Young dogs with muscular dystrophy, Dystrophin deficient cats

Question 35

What are uncommon blood changes with massive rhabdomyolysis?

Answer 35

Hyperkalemia, Hyperphosphatemia, Increased Creatinine

Question 36

What tests besides chemistry assays can indicate myopathies?

Answer 36

Urine myoglobin(skeletal), Plasma troponins(skeletal, cardiac), Pro-BNP, Pro-ANP(cardiac)

Question 37

How does myoglobin end up in the urine?

Answer 37

Muscle necrosis releases myoglobin which freely filters into the urine and can be detected on the urine dipstick. Must use clinical signs, enzymes, U/A and CBC to help differentiate whether its myoglobin, blood, or hemoglobin that is being detected on the dipstick

Question 38

What are 4 diseases that Troponin may help detect?

Answer 38

Hypertrophic cardiomyopathy in cats, Cardiac damage in dogs with GDV, Doxirubin-induced cardiotoxicity, Monensin toxicity in horses

Question 39

What are natriuretic peptides?

Answer 39

Peptides that are released in response to cardiac myocyte stretch - vasodilation, natiuresis, Pro-BNP

Question 40

What is Pro-BNP used to monitor?

Answer 40

Causes of dyspnea, Screen occult heart disease, Predict morbidity/mortality with cardiac disease