Chemical Pathology 17 - EMQs on Enzymes, Chemistry

Question 1

What type of technetium is used in bone scans vs thyroid scans?

Answer 1

Bone scans: Tc bisphosphonate

Thyroid scans: Tc pertechnate

Question 2

Which type of nuclear medicine test is most useful for identifying Ca cells themselves?

Answer 2

FDG-PET

Question 3

Which type of nuclear medicine test is most useful for identifying primary neuroendocrine tumours (eg insulinomas)?

Answer 3

Gallium 68 dotatate PET and CT (identifies somatostatin receptor)

Spleen, kidneys and adrenals may appear “hot” as well due to large number of somatostatin receptors in them.

Question 4

Which type of nuclear medicine test is most useful for parathyroid scans?

Answer 4

Sesta MIBI scan

Question 5

Which type of nuclear medicine test is most useful for investigating for a phaeochromocytoma?

Answer 5

MIBG (looks for phaeo mets)

Question 6

Recall the timeline of elevation of troponin I, AST and LDH elevation post-MI

Answer 6

Troponin I - first few hours
AST - first day
LDH - over first 5 days

Question 7

Which LFT result will be most deranged in obstructive jaundice?

Answer 7

ALP

Question 8

Descrine the pathophysiology of alcoholic hepatitis causing portal hypertension

Answer 8

Alcoholic hepatitis –> hepatocyte death
The person becomes ill and recovers, and the hepatocytes regenerate. However, rather than regenerating as before, they form a NODULE
This nodule disrupts hepatic micro-architecture between the portal vein and the central vein
If enough nodules appear, this increases pressure in the portal vein –> portal HTN

Question 9

Which enzymes are most elevated by gallstones vs viral hepatitis and why?

Answer 9

Gallstones: ALP - stones tend to cause most damage near portal triad, where more ALP is made

Viral hepatitis - ALT - the virus tends to affect hepatocytes around the central vein the most, where ALT is predominantly produced