Specific mechanisms of subarachnoid hemorrhage accompanied by ischemic stroke in essential thrombocythemia: two case reports and a literature review

Background: JAK2 V617F mutation increases the risk of thrombosis, and both ischemic and hemorrhagic strokes can occur in essential thrombocythemia (ET). The mechanisms underlying ischemic stroke in ET are diverse, and hemorrhagic stroke has rarely been reported in ET.

Methods: Among 627 stroke patients, those identified as having ET were investigated retrospectively. A comprehensive systemic literature search of the PubMed database was also conducted.

Results: Two cases were extracted with the diagnosis of ET who developed SAH and then ischemic stroke. In Case 1, a 47-year-old woman developed SAH in the left high convexity. Eleven hours later, acute cerebellar infarction suddenly developed due to right vertebral artery dissection. In Case 2, a 70-year-old woman developed SAH in the right high convexity. Magnetic resonance angiography showed multifocal stenotic changes in intracranial arteries. Three days later, she developed acute brain infarcts in the right middle cerebral artery territory. Eight weeks later, multifocal stenotic lesions improved. The literature review revealed 5 patients with hemorrhagic stroke and 40 patients with ischemic stroke associated with ET. Age at onset varied, female gender predominated, and the frequency of JAK2 V617F mutation was high. Atherosclerotic vascular risk factors were more common in ischemic stroke, but not in hemorrhagic stroke.

Conclusions: The current study describes rare cases of SAH accompanied by ischemic stroke secondary to ET along with a review of the current literature, implying specific mechanisms for cerebral artery disorders associated with JAK2 V617F mutation.