Chempath 23: Enzymes And Cardiac Markers Flashcards

1
Q

Which 2 organs are most commonly associated with ALP rise in case of pathology ?

A

Liver

Bone

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2
Q

When does bone release excess ALP ?

A

In pathologically high Osteoblast activity

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3
Q

How can you differentiate if the pathology is in the liver or Bone when ALP is high?

A

Measure GGT. If also high it suggests that the liver has the pathology.

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4
Q

List 2 physiological causes of high ALP ?

A

Pregnancy (ALP is released by the placenta)

Growth spurts in children (bone)

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5
Q

Which 2 bone diseases produce a high ALP (> 5X upper limit) ?

A

Osteomalacia

Paget’s disease

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6
Q

List 2 pathologies of the liver that cause a high ALP (> 5X upper limit) ?

A

Cholestasis

Cirrhosis

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7
Q

Which of these causes a high ALP but not more than 5X the upper limit ?

A) Bone fracture
B) Osteomyelitis 
C) Hepatitis 
D) Bone tumours
E) Alcoholic Liver Cirrhosis
A

E) Alcoholic liver cirrhosis

Cirrhosis of the liver causes a high ALP > 5X the upper limit

The rest are all causes of a high ALP but < 5X the upper limit

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8
Q

Which test would you do to confirm acute pancreatitis ?

A
Serum Amylase (10x upper limit)
Pancreatic Lipase

(salivary glands also produce an amylase isoenzyme - can be raised in parotitis)

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9
Q

Which disease that is normally vaccinated against can cause a high Amylase?

A

Mumps

Causes parotid swelling (parotitis) which releases amylase

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10
Q

Which form of Creatine kinase is specific for the heart ?

A

CK-MB

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11
Q

Which form of Creatine kinase is specific for skeletal muscle?Which one is specific for the brain ?

A

CK-MM

CK-BB

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12
Q

Which drug used in treatment of cardiovascular disease can causes myalgia or even Rhabdomyelisis and also raised creatine kinase?

A

Statins

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13
Q

How many hours post MI do troponins start to rise?

A

4-6 hours

They peak at 12-24 hours and remain elevated for 3-10 days

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14
Q

Are cardiac markers used to influence decisions about thrombolysis ?

A

No they are too slow to rise

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15
Q

List 2 cardiac markers that are useful in heart failure ?

A

ANP (from the atria)

BNP (from the ventricles)

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16
Q

List 3 enzymes that are biomarkers for MI ?

A

Myoglobin
Troponin (best markers)
CK-MB

17
Q

Which enzyme cardiac biomarker rises earliest after an MI ?

A

Myoglobin

But not very specific

18
Q

Which biomarker is most useful to detect re-infarction after a very recent MI.

A

CKMB

19
Q

Which liver enzyme is raised in an MI ?

A

AST

20
Q

Where are most enzymes found

A

Intracellularly

21
Q

In what order are enzymes released

A

Cytosolic then sub-cellular

22
Q

Where is alkaline phosphatase found in high concentrations

A

Liver
Bone
Intestines
Placenta

23
Q

What pathologies cause a rise in ALP <5x the upper limit

A

Bone - tumours, fractures, osteomyelitis

Liver - infiltrative disease, hepatitis

24
Q

RF for statin-related myopathy

A
polypharmacy (esp fibrates, cyclosporin)
high dose
genetic predisposition
previous hx of myopathy associated with other statins 
vitamin D deficiency
25
Q

What are other causes of raised CK

A
muscle damage
myopathy (DMD)
MI
severe exercise
physiological (Afro-caribbeans)
26
Q

When would you measure TPMT activity

A

before starting patients on a thiopurine ( azothioprine, 6-MP)
marker of therapeutic response/drug toxicity

27
Q

Where are different cardiac enzymes found

A

Myoglobin - cytosolic
CK-MB - mitochondria and nucleus
Troponins - contractile apparatus

28
Q

What is the diagnostic criteria for MI

A
Either:
- Rise and fall of troponin or more rapid rise and fall of CK-MB and at least one of...
- Ischaemic symptoms
- Pathological Q waves on ECG 
- ECG changes indicative of ischaemia
- Coronary artery intervention 
OR
- Pathological findings of an acute MI
29
Q

Define one international unit (U) of enzyme activity

A

the quantity of enzyme that catalyses the reaction of 1 micromol of substrate per minute