Metamizole-Induced Type I Kounis Syndrome.

Kounis syndrome (KS) is defined as acute coronary syndrome (ACS) triggered by mast cell and platelet activation in the setting of allergic or anaphylactic insults. KS is a unique and complex cause of ACS and many cases may be missed due to its highly variable clinical manifestations. In this report, we present a case of KS type I triggered by metamizole in the absence of a previous history of allergy to this drug. Following the administration of metamizole, the patient developed generalized acute urticaria, chest pain and diaphoresis. Electrocardiography (ECG) showed ST-segment elevation suggestive of myocardial infarction complicated by ventricular tachycardia. No coronary disease was observed on coronary angiography. The cardiac manifestations of KS may be life-threatening, and so it is important to appropriately recognize and treat this condition. LEARNING POINTS: Kounis syndrome (KS) diagnosis requires a high index of suspicion and should be considered in patients who present with acute coronary syndrome (ACS) soon after the administration of a new medication or possible allergic stimulus.Treatment should be administered carefully, since some drugs used to treat the cardiac manifestations of KS can worsen the allergic reaction.The prognosis is generally good with appropriate treatment, but some complications may occur, such as malignant arrhythmia. © EFIM 2021.