— 生理適應 · MEDIUM · MCQ —
一位 55 歲高血壓病史病人出現突發性劇烈胸痛並放射至左手臂。哪種心肌酵素是心肌損傷最特異性的指標？
A 55-year-old client with a history of hypertension reports a sudden, crushing chest pain radiating to the left arm. Which cardiac enzyme is the most specific indicator of myocardial injury?
- ALactate Dehydrogenase (LDH)乳酸去氫酶 (LDH)
- BCreatine Kinase (CK-MB)肌酸醯酶 (CK-MB)
- CMyoglobin肌紅蛋白
- DTroponin I✓ 正解肌鈣蛋白 I (Troponin I)
— Explanation · 中文詳解 —
心肌肌鈣蛋白（Troponin I 或 T）在心肌受損後數小時內上升，並持續升高數天，因其僅存在於心肌細胞中，故被視為偵測心肌壞死的黃金標準。肌紅蛋白雖上升早，但特異性差；CK-MB 雖具特異性但回歸正常速度快，LDH 則缺乏診斷價值。
Cardiac troponin (Troponin I or T) rises within hours after myocardial injury and remains elevated for several days. Because it is present only in cardiac muscle cells, it is regarded as the gold standard for detecting myocardial necrosis. Although myoglobin rises early, it has poor specificity; CK-MB has specificity but returns to normal quickly, and LDH has little diagnostic value.
✦ 台美臨床差異
美國醫學中心多已停止測量 CK-MB，全面改用高敏感度肌鈣蛋白；台灣部分中小型醫院仍保留 CK-MB 檢測。