Recurrent cardiac arrests caused by Kounis syndrome without typical allergic symptoms

Kounis syndrome is a rare disease in which coronary spasm or acute coronary syndrome is induced by type I allergy. Concurrence of allergic reaction and chest pain are important clues to establish diagnosis. We report a rare case of Kounis syndrome without obvious signs of allergy.A 52-year-old woman experienced abdominal pain followed by ventricular fibrillation (VF) storm. Ten months earlier, the patient underwent subcutaneous implantable cardioverter-defibrillator implantation based on the previous diagnosis of idiopathic VF. In both episodes, the patient was given dental treatment and administered loxoprofen before VF onset. After we performed loxoprofen provocation test, electrocardiogram revealed ST-segment elevation in leads II, III, and aVF. Moreover, the patient developed VF again. An emergency coronary angiography after recovery showed no significant findings. However, myocardial scintigraphy presented a perfusion-metabolism mismatch in the inferior wall. Furthermore, laboratory test results after provocation revealed increased histamine level. Based on these findings, we diagnosed the patient with Kounis syndrome.Kounis syndrome without typical allergic symptoms is challenging to diagnose. Therefore, suspecting the possibility of allergic reactions and detailed history taking are important, particularly when confronted with recurrent coronary spasm, acute coronary syndrome, and inexplicable cardiac arrest.

Kounis syndrome is a rare coronary disease with vasospasm or plaque rupture, induced by type I allergy. Since Kounis syndrome without typical allergic symptoms is challenging to diagnose, a high index of suspicion is necessary. Detailed history taking can provide important clues to establish diagnosis, particularly when confronted with recurrent coronary spasm, acute coronary syndrome, and inexplicable cardiac arrest.