Cerebral arteriolar thromboembolism in idiopathic hypereosinophilic syndrome.

OBJECTIVE: To describe imaging findings as well as postmortem brain and cardiac pathology in a patient with fulminant idiopathic hypereosinophilic syndrome.

DESIGN: Case report.

SETTING: University hospital.

PATIENT: A 48-year-old right-handed man with hypereosinophilia, rapidly progressive encephalopathy, and focal neurological deficits who died 22 days after presentation.

MAIN OUTCOME MEASURES: Physical examination, radiologic, and neuropathologic examination results.

RESULTS: Imaging of the brain revealed bihemispheric ischemic changes in and beyond the watershed distributions. Pathology review demonstrated mural cardiac thrombus that likely caused cardioembolism as well as diffuse microangiopathy despite resolution of the hypereosinophilia.

CONCLUSIONS: Timely recognition of idiopathic hypereosinophilic syndrome may enable aggressive treatment prior to widespread cardioembolism and degranulation that result in devastating cerebrovascular complications.