Locker G J, Kotzmann H, Frey B, Messina F C, Sterz F R, Weissel M, Laggner A N
Department of Internal Medicine I, University of Vienna, Austria.
Thyroid. 1995 Dec;5(6):465-7. doi: 10.1089/thy.1995.5.465.
Myocardial ischemia is a rare but severe and possibly life threatening manifestation of hyperthyroidism, but does not usually result in persistent ischemia. We report on a 71-year-old woman who had undergone total thyroidectomy with subsequent irradiation because of follicular carcinoma 3 years ago. Since then, she had been maintained on oral levothyroxine replacement therapy at a dose of 0.15 mg alternating with 0.2 mg daily. When latent hypothyroidism became evident despite replacement therapy, the dose of levothyroxine was increased to 0.3 mg a day. Three weeks later, the patient suffered from an acute posterior myocardial infarction, although she had no previous history of coronary artery disease. Subsequent coronary arteriograms revealed no evidence of disease of the major vessels. Myocardial scintigraphy 3 weeks after infarction still revealed a persistent perfusion defect. Since it is known that thyroid hormones increase oxygen demand, the rapid elevation of oxygen utilization caused by thyrotoxicosis factitia is likely to be responsible for this patient's myocardial infarction. The case illustrates that a sudden increase in levothyroxine replacement dose should be avoided.
心肌缺血是甲状腺功能亢进症的一种罕见但严重且可能危及生命的表现，但通常不会导致持续性缺血。我们报告一例71岁女性，3年前因滤泡癌接受了甲状腺全切除术及后续放疗。从那时起，她一直口服左甲状腺素替代治疗，剂量为每日0.15 mg与0.2 mg交替。尽管进行了替代治疗，但当隐匿性甲状腺功能减退变得明显时，左甲状腺素剂量增加至每日0.3 mg。三周后，该患者发生急性后壁心肌梗死，尽管她既往无冠状动脉疾病史。随后的冠状动脉造影未发现主要血管病变的证据。心肌梗死后3周的心肌闪烁显像仍显示持续的灌注缺损。由于已知甲状腺激素会增加氧需求，人为甲状腺毒症导致的氧利用迅速升高可能是该患者心肌梗死的原因。该病例表明应避免突然增加左甲状腺素替代剂量。
