Examine the laboratory results for Mr. Garcia. Which labs are consistent with the MI diagnosis? Explain. Why were the levels higher on 12/2?

Question

What will be an ideal response?

Answer 1

The following labs are consistent with the MI diagnosis:
• CPK, CPK-MB, LDH, AST, Troponin I, Troponin T.
• CPK is an enzyme found primarily in heart muscle, skeletal muscle, and the brain.
- When cells are damaged, the enzyme is released and serum levels will increase.
- The CPK-MB isoenzyme specific for myocardial tissue is important in evaluating onset of the myocardial infarction and degree of damage.
• LDH (lactate dehydrogenase) is an enzyme found in many tissues.
- Since LDH is found in many tissues, this lab is not a particularly sensitive measure of an MI.
• AST (aspartate aminotransferase) is also an enzyme found in high concentrations in cardiac tissue.
- Though not specific to an MI, when used in conjunction with the other labs it is useful to determine onset of myocardial damage.
• Troponin T and I are cardiac contractile proteins.
- They are released as myocardial cells die.
- These serum levels can be detected with greater sensitivity and are detectable within 20 minutes of injury.
The levels were higher on 12/2 because:
• CPK and CPK-MB rise 4-8 hours after an MI, peak at 12-24 hours, and return to normal after 72-96 hours.
• LDH rises within 24-72 hours after an MI, and returns to normal after approximately 4 days.
• AST rises within 6-10 hours of an MI, peaks within 24-48 hours, and returns to normal within 3-4 days.