Kounis Syndrome as a Cause of Myocardial Infarction with Nonobstructive Coronary Arteries

Kounis Syndrome, also known as "allergic angina" and "allergic myocardial infarction," is a rare but increasingly recognized clinical entity characterized by acute coronary events triggered by allergic reactions.It was first described in 1991. 1 This syndrome encompasses a spectrum of acute coronary conditions, including angina, myocardial infarction, and stent thrombosis, all of which can be induced by various allergic insults. 1 Assessing the epidemiology of Kounis Syndrome poses challenges.In patients with signs and symptoms suggestive of myocardial infarction, approximately 15% exhibit no obstructive coronary artery disease.Among this group, 30-40% are believed to be associated with coronary artery vasospasm. [2]][4][5] Kounis Syndrome is believed to result from activation of mast cells and basophils during allergic reactions.These activated cells release inflammatory mediators, including histamine, tryptase, leukotrienes, and cytokines, which can lead to coronary vasospasm, endothelial dysfunction, and platelet activation.This process may result in myocardial ischemia and, in severe cases, infarction. 6,7 CASE REPORTA 55-year-old male with a medical history of hypertension, hyperlipidemia, obesity class III, and tobacco use disorder presented to the hospital with acute onset shortness of breath and left-sided chest pressure that woke him from sleep.Initially, he attempted to return to sleep but then experienced diffuse itching, sweating, nausea, and an episode of fecal incontinence.These worsening symptoms prompted him to call emergency medical services.Upon arrival at the emergency department, the patient was found to be tachycardic, tachypneic, and hypotensive.He appeared to be in respiratory distress, with diffuse redness and swelling of his hands and feet.Laboratory results showed leukocytosis with elevated lymphocytes, acute kidney injury, high anion gap metabolic acidosis due to lactic acidosis, and an elevated D-dimer at 0.74 mcg/mL (normal < 0.5 mcg/mL).Troponin-T was mildly elevated at 0.09 ng/mL (normal < 0.01 ng/mL).The initial electrocardiogram showed diffuse ST segment depression with isolated ST segment elevation in aVR (Figure 1).A Code STEMI was initiated, and the patient underwent emergent left heart catheterization.