Enzymes and Cardiac Markers

Question 1

What are enzymes primarily used to determine?

Answer 1

Diseases that result in abnormalities of enzyme concentrations /function

Tissue da mage

Question 2

Where are enzymes usually found

Answer 2

Intracellularly

may be cytoplasmic / sub cellular (in organelles)

Question 3

What occurs as necrosis becomes more severe?

Answer 3

You go from just cytoplasmic enzymes being released

To intro-organellar enzymes also being released

Question 4

What organs is All Phosph found in?

Answer 4

Liver
bone
intestine
placenta

Question 5

How does ALP change with age?

Answer 5

High in newborn

Second spike at puberty

Question 6

What organs are pathological increases in ALP due to ?

Answer 6

Bone

Liver

Question 7

When is ALP increased in osteoporosis?

Answer 7

ONLY if there is a fracture

Otherwise normal

Question 8

What enzyme should you measure if suspecting liver disease in a patient with high ALP?

Answer 8

GGT

Question 9

What method do you use to separate out ALP isoenzymes?

Answer 9

Electrophoresis

Question 10

What are physiological causes of ALP rise?

Answer 10

Pregnancy (third trimester, from placenta)

Childhood (growth spurt)

Question 11

What are pathological causes of ALP?

Answer 11

MORE THAN x5 normal

• bone : Paget’s disease, osteomalacia
• liver: cholestasis, cirrhosis

LESS THAN x5 normal

• Bone: tumours, fractures, osteomyelitis
• Liver: infiltrative disease, hepatitis

Question 12

What organ is ALT mainly found in?

Answer 12

The LIVER

But not very sensitive (also present in other organs like kidney, pancreas)

Question 13

When is GGT raised?

Answer 13

Hepatic or biliary disease

Question 14

What drugs up regulate GGT

Answer 14

alcohol
rifampicin
phenytoin

Question 15

What is LDH a good marker for?

Answer 15

Tumours (lymphoma, seminoma)

Haemolysis, myositis

Question 16

How much is amylase raised by in acute pancreatitis?

Answer 16

x10

Question 17

What other organ produces amylase?

Answer 17

salivary glands

Question 18

What is creatine kinase a general marker of?

Answer 18

Muscle damage

Question 19

what are the three forms of CK?

Answer 19

MM - skeletal muscle
MB - cardiac muscle
BB - brain

Question 20

What is a side effect of statins in terms of raised markers=

Answer 20

Raised CK

Question 21

What causes raised CK in statin patients?

Answer 21

Myalgia, rhabdomyolysis

Question 22

What are risk factors to statin related myopathy?

Answer 22

Polypharmacy (esp other drugs metabolised by CYP3A4)
High dose
Genetic
Previous history of myopathy with another statin
Vitamin D deficiency

Question 23

What are other causes of raised CK other than statins?

Answer 23

Muscle damage from any cause 
Myopathy e.g. Duchenne muscular dystrophy 
MI 
severe exercise 
Physiological

Question 24

What are 3 old fashioned enzymes for MI monitoring, and what is the order in which they rise?

Answer 24

CK > AST > LDH

Question 25

What is the main marker now used to identify MI?

Answer 25

Troponin

Question 26

What is the first enzyme to rise in MI? why?

Answer 26

Myoglobin | Because it is loose in the cytoplasm

Question 27

Why are there two peaks of troponin?

Answer 27

FIRST PEAK due to free cytosolic pool of troponin | Second peak due to breakdown of troponin in the contractile apparatus

Question 28

When does troponin rise after MI?

Answer 28

4-6h post MI

Question 29

When does Troponin peak after MI?

Answer 29

12-24h

Question 30

How long does troponin remain elevated after MI?

Answer 30

3-10 days

Question 31

When should troponin be measured after an MI?

Answer 31

at 6 h | at 12 h after onset of chest pain

Question 32

What are biomarkers of cardiac failure?

Answer 32

ANP - atria BNP - ventricles HIGH SPECIFICITY (if negative, confirm NO HF)

Question 33

What is unit of enzyme activity?

Answer 33

Unit/Litre

Question 34

what levels of BNP let you include / exclude cardiac failure

Answer 34

<100: exclude | >400: include

Question 35

which cardiac marker is NOT an enzyme

Answer 35

TROPONIN