Acute Myocardial Infarction Caused by Thrombotic Occlusion by a Right Coronary Giant Aneurysm in a 6-Year-Old Boy with No History of Kawasaki Disease

Abstract

There are few reports of myocardial infarction in childhood and adulthood caused by a thrombotic obstruction due to a coronary aneurysm (CA), which is considered to be a sequela of Kawasaki disease, in a case in which the history of Kawasaki disease is unknown. Here, we report a case of a 6-year-old boy with no history of Kawasaki disease who developed acute myocardial infarction (AMI) caused by thrombotic occlusion by a right coronary artery (RCA) giant aneurysm. The patient experienced anterior chest pain and vomiting, and was transferred to our hospital because of lethargy. Acute myocarditis was suspected based on an abnormal Q wave and ST depression on an electrocardiogram, and a decrease in left ventricular ejection fraction on echocardiography. Echocardiography revealed a giant RCA aneurysm and a thrombus-like low-intensity region within the aneurysm. Coronary computed tomographic angiography also showed a giant CA and occlusion at the same site. AMI due to thrombotic obstruction by the RCA aneurysm was suspected. Anti-heart failure treatment and anticoagulant therapy were started, and led to recovery of cardiac function. Coronary angiography performed 3 months after onset revealed complete occlusion of the RCA. Collateral circulation from the left coronary artery was confirmed and recommunication between the right coronary arteries was partially observed. In a case of ischemic chest pain and impairment of cardiac function in childhood, careful examination and appropriate treatment are required regardless of the history of Kawasaki disease, based on the possibility of myocardial infarction due to occlusion by a CA.