Chem path 14 - Enzyme EMQs (Karim Meeran) Flashcards

1
Q

At what rate do you produce creatinine?

A

At a fixed rate

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2
Q

Where is AST found in heart?

A

Myocytes

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3
Q

How long does it take for AST to go up after MI and how long does it stay up?

A

2-5 days

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4
Q

What are the enzymes which increase following an MI?

A

AST, troponin, CK-MB, LDH, myoglobin

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5
Q

When does LDH peak post MI?

A

5-7 days

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6
Q

When do you measure troponins?

A

2 measurements, 12 hours apart, should go up. A negative troponin is also useful.

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7
Q

How do you prevent the progression to renal failure in rhabdomyolysis?

A

IV bicarbonate which allows them to urinate out all the CK which is the cause of the renal failure

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8
Q

What is the relationship of AST and ALT to either viral hepatitis or chronic alcoholic cirrhosis?

A

ALT higher than AST in pts with viral hepatitis

AST higher than ALT in pts with chronic alcoholic cirrhosis

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9
Q

What is another name for acid phosphatase?

A

PSA

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10
Q

In primary hyperparathyroidism, what happens to the level of vitD?

A

it is low

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11
Q

Why is the level of vit D low in primary hyperparathyroidism?

A

PTH activates 1a hydroxylase meaning that vitamin D is consumed (i.e. it is activated)

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12
Q

What are assays for vitamin D measuring?

A

25-OH cholecalciferol (Calcidiol)

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13
Q

What happens to the urea and creatinine levels in acute and chronic renal failure?

A

In acute renal failure caused by dehydration, UREA will rise the most
In chronic renal failure caused by a fall in GFR, CREATININE will rise the most

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14
Q

what is significant about CKD caused by diabetes?

A

It is much more rapidly progressive than other causes of renal impairment

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15
Q

What creatinine cut off level is significant in diabetes related CKD?

A

A creatinine >200umol/L as you are likely to reach end stage renal failure within a year

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16
Q

Is a high creatinine an indication for dialysis?

A

No

17
Q

What are the indications for dialysis?

A
  • Hyperkalaemia (refractory)
  • refractory fluid overload
  • Acidosis (treated with sodium bicarbonate)
  • Pulmonary oedema
  • Uraemic symptoms (encephalopathy, pruritis, nausea, malaise, pericarditis)
  • CKD Stage 5 (GFR <15l/min)
18
Q

What is a marker for blood glucose control over the last 3 weeks?

A

Fructosamine (useful in pregnancy)

19
Q

Which two markers are increased in Paget’s disease?

A

ALP and osteocalcin due to increased activity in both osetoblasts and osteoclasts

20
Q

what is a key feature of Paget’s disease?

A

A bowed tibia (will be warm as well) (others will be asymptomatic, high risk of fracture)

21
Q

What is the treatment for Paget’s?

A

Bisphosphonates (only if painful disease) - bone formed with calcium bisphosphonate is unable to be degraded by osteoclasts

22
Q

Which scan is performed in all oncology patients to look for bony metastases?

A

Technetium bisphosphonate scan (NOTE: kidneys always show up on this scan as the label is excreted by them)

23
Q

What is a technetium 99 scan and when is it used?

A

It is used to look for iodine uptake by the thyroid gland

24
Q

What is an FDG-PET scan used for?

A

To detect abdominal mets. FDG is a non specific marker as glucose is taken up by every cell but cancer cells are more active so have higher uptake.

25
Q

What does a triple phase CT scan look at?

A

the arterial, portal and venous phase - this involves administering 3x as much radiation

26
Q

If there could be a neuroendocrine tumour, what label is usually superimposed on a CT?

A

Gallium 68 - gallium can be stuck on a somatostatin analogue so that it goes to tissues that have somatostatin receptors e.g. neuroendocrine cells

27
Q

What is another name for a CT scan with superimposed gallium 68?

A

Gallium dotatate

28
Q

Which other organs always show up on a gallium dotatate scan?

A

The kidneys, adrenals and spleen

29
Q

What is an MIBG scan used for?

A

MIBG is a precursor for adrenaline that is used for identifying phaeo metastases

30
Q

Which organs use Sestamibi (Scintigraphy)?

A

Used by parathyroids and myocardium i.e. in MI you get an area with lack of uptake of MIBI

31
Q

What is AST important in ?

A

Gluconeogenesis

32
Q

What liver enzyme is in abundance in zone 1 (Around bile duct in portal triad) ?

A

ALP–> ALP rises most in obstructive jaundice

33
Q

What does alcoholic hepatitis eventually lead to?

A

Nodular cirrhosis –> portal HTN –> varices at sites of porto-systemic anastamosis