Ischemic Stroke with Essential Thrombocythemia: A Case Series

Background: Essential thrombocythemia (ET) is considered a rare cause of stroke partly because it is not detected if the platelet count is not elevated. However, early detection of ET is important because thrombosis can recur frequently, unless adequately treated. Methods: We retrospectively collected data from 10 stroke cases with ET. Clinical characteristics, location of stroke, laboratory data (platelet and leukocyte count, hemoglobin, and JAK2 V617F mutation), and treatment were reviewed. Results: The population consisted of 7 women and 3 men aged 18-83 years. Most patients had atherosclerotic risk factors. Half of the patients had a history of ischemic stroke. In 8 patients, ischemic stroke was the first manifestation of ET. Of 13 acute cerebrovascular events, 4 were transient ischemic attacks and 9 were cerebral infarctions. Three patients presented with watershed-type infarcts without large artery stenosis. Two patients had atherosclerotic stenosis of the large artery and experienced atherothrombotic infarction. The mean platelet count was 966 +/- 383 x 10(9)/L. JAK2 V617F mutation was found in 5 of 7 patients. Despite treatment with combined antiplatelet and cytoreductive therapy in all patients, 3 experienced recurrent ischemic stroke. Conclusions: These findings suggest that ET is an adjunctive risk factor for stroke and the patients with ET are subject to watershed-type infarcts even in the absence of large artery stenosis. Early diagnosis of ET and strict management of vascular risk factors may help prevent additional cerebrovascular events. (C) 2015 by National Stroke Association