First Report of Moxifloxacin-Induced Type II Kounis Syndrome: A Case Study and Comprehensive Literature Review

Background Kounis syndrome is a distinct form of acute coronary syndrome that is precipitated by allergic or hypersensitivity reactions. Although this syndrome is infrequently observed in clinical practice, it can result in severe cardiovascular events and represents a significant threat to patient life when it occurs. Consequently, enhancing the understanding, diagnosis, and management of this condition is essential. We present a case of Type II Kounis syndrome induced by intravenous moxifloxacin. Case Summary A 71-year-old female patient with no prior history of coronary artery disease developed hypotension and chest pain thirty minutes after the intravenous administration of moxifloxacin. Electrocardiography revealed T-wave inversion in leads I and aVL, accompanied by elevated levels of troponin I. Coronary angiography indicated 80% stenosis in the mid-segment of the left anterior descending artery (LAD), 99% stenosis at the ostium of the diagonal branch, and localized 60% stenosis in the proximal segment of the left circumflex artery (LCx). Subsequent echocardiography demonstrated segmental wall motion abnormalities, with a left ventricular ejection fraction (LVEF) of 52%. The diagnosis was moxifloxacin-induced Type II Kounis syndrome, presenting as acute non-ST-segment elevation myocardial infarction. Conclusion Kounis syndrome is a potentially life-threatening emergency that necessitates prompt intervention. Although primarily documented in case studies, the actual incidence of Kounis syndrome may be underreported. Clinicians should remain vigilant for the possibility of allergic reactions in patients presenting with acute coronary syndrome (ACS). For patients with known allergies, particularly those suspected of experiencing systemic allergic reactions, it is crucial to monitor for cardiac symptoms, perform electrocardiograms, conduct cardiac enzyme tests, and, if indicated, carry out coronary angiography. Early recognition and appropriate management of Kounis syndrome can significantly enhance patient prognosis.