A 62-year-old woman presents to the emergency department 6 hours after onset of chest pain. Initial cardiac enzymes were drawn at presentation. Which pattern best fits the expected serum cardiac troponin I behaviour in acute myocardial infarction?
- A Rises by 2 to 4 hours, peaks at about 24 to 48 hours, remains elevated for 7 to 10 days ✓
- B Rises immediately, peaks within 6 hours, normalises by 24 hours
- C Detectable only after 12 hours, peaks at day 5, elevated for 3 weeks
- D Normal for the first 48 hours, rises gradually thereafter over one week
Correct answer: A. Rises by 2 to 4 hours, peaks at about 24 to 48 hours, remains elevated for 7 to 10 days
Explanation
Cardiac troponin I and T are the most specific markers of myocyte death. They become detectable 2 to 4 hours after symptom onset, peak around 24 to 48 hours, and stay raised for 7 to 10 days because contractile protein continues to leach from necrotic myocytes. CK-MB, by contrast, falls back to normal within 2 to 3 days, which is why it was historically used to detect perioperative reinfarction.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
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Written and medically reviewed by the StethoPrep medical team.