When Thyrotoxicosis Meets a Latent Plaque: Unmasking a Type I Myocardial Infarction.

Thyrotoxicosis is a rare but significant precipitant of acute coronary syndrome (ACS), especially in young individuals without traditional cardiovascular risk factors. We present the case of a 36-year-old male with no past medical history who arrived with substernal chest pain, elevated troponins, and sinus rhythm without ST changes on ECG. Thyroid ultrasound revealed a large goiter, and labs confirmed severe thyrotoxicosis. Coronary angiography showed 85% stenosis of the proximal-to-mid left anterior descending artery, managed successfully with stent placement. This case demonstrates how an excess of thyroid hormone may contribute to the development of type I myocardial infarction. Thyrotoxicosis should be included in the differential diagnosis of ACS in young patients without traditional risk profiles to ensure timely diagnosis and targeted therapy.