Rapid Change in Mental Status in a Patient with Hypereosinophilia

We present the case of a 48-year-old female with acute onset altered mental status, who was found to have eosinophilia, elevated troponin, and embolic strokes. Extensive testing for autoimmune, infectious, and coronary artery etiologies was unremarkable. After a cardiac MRI revealed focal myocardial hyperenhancement, the patient underwent an endomyocardial biopsy with findings consistent with eosinophilic myocarditis. The patient was diagnosed of idiopathic hypereosinophilic syndrome and started on prednisone and apixaban. Our case highlights the importance of considering hypereosinophilic syndrome when eosinophilia is associated with multisystem impairments, as tissue biopsy is usually required to diagnose this rare condition.