Chempath - enzymes and cardiac markers Flashcards

1
Q

In cell necrosis, which enzymes are released first - cytosolic or sub cellular?

A

Cytosolic first, then subcellular

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2
Q

If an enzyme is released by many different tissues, how can you identify which tissue it is released by?

A

Enzyme isoforms - these can be specific to a tissue

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3
Q

name 4 tissues which release ALP at high concentrations

A

Liver
Bone
Intestine
Placenta

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4
Q

3 ways liver and bone ALP can be differentiated

A

GGT measurement
Electrophoresis
Bone specific ALP immunoassay

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5
Q

2 physiological causes of raised ALP

A

Pregnancy in the 3rd trimester

Growth spurt in childhood

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6
Q

> 5x the upper limit of normal ALP - give 4 pathological causes

A

Bone - PAGETS, OSTEOMALACIA

Liver - Cholestasis, cirrhosis

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7
Q

<5x the upper limit of normal ALP - give 5 causes

A

Bone - Tumours, fractures, osteomyelitis

Liver - infiltrative disease, hepatitis

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8
Q

When is ALP raised in osteoporosis

A

When it’s complicated by fractures

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9
Q

Amylase is raised in acute pancreatitis. Which test is more specific?

A

Lipase

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10
Q

3 forms of creatine kinase - which muscles release them?

A
MM = skeletal
MB = cardiac muscles
BB = brain (activity is minimal)
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11
Q

Risk factors for statin related myopathy

A

High statin dose
Prev Hx of statin related myopathy
Polypharmacy w other drugs also metabolised by CYP3A4

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12
Q

5 causes of a raised CK

A
Myopathy
MI
statin 
severe exercise
Physiological - esp afrocaribbeans
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13
Q

An 82 year old women presented with bone pain, history of fractures and bowing of her tibia. Which enzyme measurement might be helpful with the diagnosis?

A

ALP

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14
Q

A 64 year old man who smokes and has a family history of cardiovascular disease has recently been started on atorvastatin. Three weeks after commencing the tablet, he complains of generalised muscle pain. What is the working clinical diagnosis?

A

Statin related myopathy

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15
Q

What measurement is taken in patients being considered for azathioprine/6-mercaptopurine?

A

TPMT

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16
Q

Current marker of choice for Myocardial injury? When does it start to rise? When does it peak?

A

Troponin

Rise at 4-6 hours
Peak at 12-24 hours

17
Q

When is troponin level measured in chest pain?

A

6 and 12 hours post onset of chest pain

18
Q

How can cardiac biomarker levels help with deciding if MI requires thrombolysis?

A

They don’t rise quickly enough so they can’t. Decision is clinical

19
Q

2 biomarkers in heart failure?

A

ANP

BNP

20
Q

If someone gives a history of an MI from 1 week ago, which biomarker measurement will be most useful?

A

Troponin - remains raised for 3-10 days

21
Q

How do we measure enzyme activity?

A

IU = international unit

Amount of enzyme needed to catalyse a reaction so that 1micromol of substrate is made