Hypereosinophilic-syndrome (HES) can lead to multiple organ damage due to direct cytotoxic effects or as a procoagulant and has been associated with neurological complications like stroke, encephalopathy, and sensory polyneuropathy. We present a rare case of stroke presenting as a manifestation of HES.

A 63-year-old Caucasian female with history of hypertension, asthma, nasal polys, and pulmonary endocrine tumor post right upper lobectomy was admitted for fatigue, painful paresthesia, intermittent binocular diplopia, and falls for 2 weeks. She had right facial droop, weakness of left upper extremity and decreased ankle reflexes bilaterally. She had elevated eosinophil-count of 20,000 ul and elevated immunoglobulin-E levels of 925 IU/ml. Infectious workup including blood, urine cultures, Histoplasma, aspergillus and cryptococcal antigen, coccidiosis, Strongyloides, and HIV antibodies were negative. Autoimmune-panel including mitochondrial, c-ANCA, p-ANCA, ANA antibodies were negative. MRI brain showed a right caudate acute infarct. She was started on aspirin, atorvastatin and was discharged to acute rehabilitation. She returned 7 days later with fever and confusion. Repeat MRI showed acute and subacute lacunar infarcts in right frontal and left basal ganglia, along with siderosis, prominent in posterior cerebral hemispheres and left temporal region. Vessel imaging was unremarkable. Cerebrospinal fluid (CSF) analysis was unrevealing with 4 red-blood-cells, 1 nucleated-cell, glucose 61, and protein 36. Her CSF flow cytometry and cytology returned negative for malignancy. She was found to have eosinophilic myocarditis without intracardiac thrombus. She was treated with high-dose prednisone along with aspirin. Her encephalopathy along with her eosinophilia improved thereafter with no recurrent infarcts. The etiology of eosinophilia was not able to be determined and was thought to be idiopathic. 

HES-induced stroke is a rare manifestation of hypereosinophilia and high-dose steroid therapy and/or immunosuppression is recommended to prevent recurrent infarcts. Neurologists must be aware of this rare and treatable potential cause of stroke.