Hypereosinophilic Syndrome Complicated by Eosinophilic Myocarditis: Embolic Stroke or Eosinophilic Stroke? A Case Report.

Hypereosinophilic syndrome (HES) is traditionally described as chronic peripheral eosinophilia with involvement of various organs and systems, including the heart and nervous system. In this report, we describe cardiac involvement and border zone stroke in a patient with idiopathic HES. A 37-year-old woman presented with sudden right-sided weakness and slurred speech, which began four days before admission, accompanied by palpitations, retrosternal exertional chest discomfort, dry cough, and progressive shortness of breath over approximately two months. Preliminary studies showed an increased number of white blood cells with eosinophilia. Further diagnostic investigation revealed apical thrombosis in both ventricles of the heart and moderate left ventricular systolic dysfunction. Magnetic resonance imaging of the brain indicated multifocal infarctions in the anterior and posterior border zones, as well as both cerebellar hemispheres, predominantly on the left side. Consequently, the patient was diagnosed with idiopathic HES and treated with corticosteroids, cyclophosphamide, anticoagulants, and medications for heart failure. She responded well both clinically and hematologically. Our case highlights the importance of multiple imaging modalities in diagnosing eosinophilic endomyocarditis and the impact of timely medical treatment to prevent disease progression.