Abstract Body (Do not enter title and authors here): Kounis syndrome (KS) is a dangerous and rare acute coronary syndrome elicited in the setting of an allergic, hypersensitivity, or anaphylactic reaction. The syndrome is caused by mast cell activation leading to a release of proinflammatory mediators that can promote coronary vasospasm, atheromatous plaque erosion with rupture, or both.

We present the case of a 48-year-old female with a past medical history of type 2 diabetes, hypertension, and chronic kidney disease stage 3 who presented via ambulance with anaphylaxis following an unknown allergen exposure. She was immediately given intramuscular epinephrine with resolution of symptoms, but she continued to have chest discomfort with radiation to her back. Initial EKG showed deep ST depressions in numerous leads (mainly the inferior and anterolateral leads) with ST elevations in leads V1 and aVR, consistent with diffuse subendocardial ischemia (Figure 1). Initial troponin was 2,122 which peaked at 5,328. Coronary angiogram was immediately obtained which showed patent coronary arteries with minimal narrowing of the distal left anterior descending artery. Because of this, cardiac MRI was obtained which showed subendocardial delayed enhancement at the basal and mid left ventricle with associated subendocardial perfusion defects and myocardial edema. These were felt to be in the distributions of the left circumflex and left anterior descending arteries and likely due to vasospasm, so the patient was initiated on diltiazem. Allergy evaluated the patient and felt her symptoms represented KS. They recommended outpatient workup to identify an allergy trigger and discharge with an epinephrine pen.

KS is a rare presentation of acute coronary syndrome in the setting of an allergic, hypersensitivity, or anaphylactic reaction. Clinicians must be aware of this phenomenon to be able to promptly diagnose and evaluate these patients as late diagnosis can lead to significant morbidity and mortality.