ALLERGIC ACUTE CORONARY SYNDROME

Abstract

SESSION TITLE: Medical Student/Resident Cardiovascular Disease Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Kounis syndrome describes a unique phenomenon of acute coronary syndrome (ACS) in the presence of allergic or anaphylactic reactions. This syndrome is caused by inflammatory mediators - histamine being the most prominent - inducing coronary artery vasospasm. We present a case of allergic ACS in a patient with mast cell activation syndrome (MCAS). CASE PRESENTATION: A 35-year-old woman with a history of MCAS, chronic urticaria, migraines, severe persistent asthma, and recent DVT on therapeutic enoxaparin, was hospitalized for pain and edema concerning for an acute flare of MCAS. She was treated with oral steroids and a continuous intravenous diphenhydramine infusion. The patient later developed sepsis secondary to a staphylococcus aureus line infection and was started on cefazolin. Overnight, she developed asymptomatic diffuse ST elevations in addition to tachycardia with a rate in the 140s (baseline heart rate 100-130) and was found to have elevated troponins. Her initial troponin measurement was 0.28 and declined to 0.26 and 0.21. On physical exam she had scattered urticaria, tachycardia, normal heart sounds without a pericardial friction rub and was saturating well on room air. She was continued on steroids and diphenhydramine infusion with the addition of famotidine. She had no previous cardiac history and no significant family history of cardiovascular disease. TEE done 6 months prior was negative for mural thrombus and showed normal EF; echo the day after the onset of ST elevations showed no significant findings. DISCUSSION: Histamine induced coronary vasospasm may mimic classic ACS in patients undergoing an allergic reaction. Kounis syndrome is suspected to be largely underdiagnosed and should be considered in patients with anaphylactic or other allergic responses. Our patient likely had histamine-mediated ACS after initiation of cefazolin. Her troponin plateau makes ST-elevation myocardial infarction less likely. Other differentials to consider include myopericarditis given the diffuse ST elevations, however, given the onset in close proximity to new antibiotic initiation, her history is suspicious for an allergy mediated process. Furthermore, Kounis syndrome is more commonly found in individuals with other vasospastic conditions such as migraine. Treatment for allergic ACS includes management of underlying allergic response with corticosteroids and antihistamines; calcium channel blockers can also be considered. ACS protocol can be implemented in patients with underlying cardiac disease, but caution should be used with beta-blockers to avoid exacerbation of vasospasm. CONCLUSIONS: Patients undergoing an allergic reaction may experience classic signs and symptoms of ACS induced by histamine-mediated coronary vasospasm. Kounis syndrome is an important differential to consider in any allergy patient with new-onset ST changes or transient angina with or without concomitant urticaria. Reference #1: Kounis NG. Kounis syndrome: an update no epidemiology, pathogenesis, diagnosis and therapeutic management. CCLM. 2016; 54(10):1545–1559 Reference #2: Kounis NG, Zavras GM. Histamine-induced coronary artery spasm: the concept of allergic angina. Br J Clin Pract. 1991;45(2):121-128. Reference #3: Kounis NG. Kounis syndrome: an update on epidemiology, pathogenesis, diagnosis and therapeutic management. Clin Chem Lab Med. 2016;54(10):1545-1559. doi:10.1515/cclm-2016-0010 DISCLOSURES: No relevant relationships by Jennifer Cortes, source=Web Response No relevant relationships by Kelly Roth, source=Web Response