Dhir Teena, Jiang Ning
14511 Pine Court, Riverside, CA, 92503, USA;
Int J Biomed Sci. 2013 Jun;9(2):107-11.
Elevations of cardiac enzymes are commonly used to indicate myocardial ischemia, but they can be elevated due to other conditions. Different forms of Troponin (cTnT, sTnT, cTnI), can cause cross-reactivity in the Troponin T assay, leading to false positives. This report describes a patient with polymyositis who had elevated Troponin T, but no cardiac abnormalities. The purpose is to show that Troponin T, which is believed to be solely from cardiac muscle breakdown, can be seen in inflammatory muscle disease, so Troponin I should be used instead.
This is a case report of a 70-year-old woman with a history of diabetes, hypertension, gout and polymyositis, who presented with one-day history of lightheadedness and abdominal pain. To rule out myocardial ischemia, cardiac enzyme testing was ordered which showed elevated CK, CK-MB, and Troponin T. A full cardiac workup was performed which showed no signs of ischemia. Troponin I was <0.05 ng/mL, (normal).
In inflammatory myositis, there are elevations in many cardiac markers due to non-cardiac causes, which could be related to muscle regeneration and gene expression. This is not seen certain isoforms of Troponin I, specifically cardiac Troponin I.
In patients with history of diabetes and other comorbidities, silent myocardial ischemias should be ruled out. Non-cardiac elevations in Troponin T can be seen in patients with inflammatory, so Troponin I should be ordered to get an accurate interpretation. Patients with inflammatory myopathies can have elevations in CK, CK-MB, and Troponin T, but not Troponin I.
心肌酶升高常用于指示心肌缺血，但其他情况也可导致其升高。不同形式的肌钙蛋白（cTnT、sTnT、cTnI）可在肌钙蛋白T检测中引起交叉反应，导致假阳性。本报告描述了一名患有多发性肌炎的患者，其肌钙蛋白T升高，但无心脏异常。目的是表明，被认为仅源于心肌分解的肌钙蛋白T也可见于炎性肌肉疾病，因此应改用肌钙蛋白I。
这是一例70岁女性的病例报告，该患者有糖尿病、高血压、痛风和多发性肌炎病史，出现头晕和腹痛1天。为排除心肌缺血，进行了心肌酶检测，结果显示肌酸激酶（CK）、肌酸激酶同工酶（CK-MB）和肌钙蛋白T升高。进行了全面的心脏检查，未发现缺血迹象。肌钙蛋白I<0.05 ng/mL（正常）。
在炎性肌炎中，由于非心脏原因，许多心脏标志物会升高，这可能与肌肉再生和基因表达有关。肌钙蛋白I的某些同工型，特别是心肌肌钙蛋白I则不会出现这种情况。
对于有糖尿病和其他合并症病史的患者，应排除无症状心肌缺血。炎性疾病患者可出现肌钙蛋白T的非心脏性升高，因此应检测肌钙蛋白I以获得准确的解读。炎性肌病患者的CK、CK-MB和肌钙蛋白T可能升高，但肌钙蛋白I不会升高。
