Kounis syndrome due to angiotensin converting enzyme inhibitor

Abstract

A 51-year-old African-American female presented to the emergency room with tongue swelling. She denied any chest pain, shortness of breath, orthopnea, paroxysmal nocturnal dyspnea, lower extremity edema, palpitations, dizziness or syncope. She developed angioedema due to angiotensin converting enzyme inhibitor (ACE-I) 5 months previously, and was advised never to take it again. Two weeks prior to the current admission, she decided to restart ACE-I on her own. Past medical history included hypertension, diabetes mellitus, and tobacco use. She had no prior history of coronary artery disease or cardiomyopathy. On examination, her pulse rate was 80 beats per minute, blood pressure was 171/84 mmHg, temperature of 36.7 C, and oxygen saturation was 98 % on room air. Cardiovascular examination was unremarkable. She was found to have vocal cord and arytenoid edema and was intubated to protect her airway. Electrocardiogram demonstrated symmetrical, deep T-wave inversions in anterolateral leads (Fig. 1a). Peak troponin-I was 0.24 ng/ml, confirming a non-ST-segment elevation myocardial infarction. Chest X-ray was unremarkable. Her white blood cell count, including polymorphonuclear leukocyte and eosinophil counts, was normal. The differential diagnosis included coronary artery disease, stress cardiomyopathy (Takotsubo syndrome) and allergic myocardial infarction (Kounis syndrome). Echocardiogram showed normal left and right ventricular systolic function, and thus excluded takotsubo syndrome. There was no clinical suspicion for an occult infection. Cardiac catheterization demonstrated normal coronary arteries (Fig. 1b, c). She had an uneventful recovery and was discharged 7 days later. Follow-up electrocardiogram showed resolution of T-wave inversions (Fig. 1d). Allergic reactions as a cause of acute coronary events was first described in 1950 [1]. Kounis et al. [2] described ‘‘Kounis syndrome’’ (‘‘Allergic angina’’ which may progress to ‘‘allergic myocardial infarction’’) in 1991. Kounis syndrome is of two types. Type I presents as coronary vasospasm with no atheromatous disease. Type II patients have pre-existing atheromatous disease in whom acute allergic episode can induce plaque erosion or rupture manifesting as an acute myocardial infarction. Many drugs including antibiotics, analgesics, proton pump inhibitor, antineoplastics, and anesthetics have been implicated as etiological factors. Others include intravenous contrast, bee stings, and food allergies [3]. More recently, allergic reaction to metal is thought to play a role in acute and late stent thrombosis and reaction after amplatzer septal occluder has been described. Mast cell degranulation and release of powerful coronary vasoconstrictors such as histamine, and leukotrienes can cause vasospasm and lead to type I Kounis syndrome. Release of metalloproteinase activators such as tryptase and chymase can trigger degradation of collagen and induce plaque erosion or rupture leading to type II Kounis syndrome [4]. The allergy workup should include assays for serum histamine, tryptase, IgE antibody, and complement proteins (C4 and C1-esterase inhibitor levels) and eosinophil counts. However, histamine and tryptase have very short R. Movva V. M. Figueredo (&) D. Lynn Morris Einstein Heart and Vascular Institute, Einstein Medical Center, 5501 Old York Road, Philadelphia, PA 19141, USA e-mail: FigueredoV@einstein.edu