An 81-year-old male with hypertension and diabetes was brought to the ED after 3 days of immobility secondary to left-sided hemiparesis. Initial labs revealed platelet count of 1.3 M/uL, WBC count 22,000 /uL and CPK of 12,000 IU/L. CT and MRI findings were consistent with acute to subacute infarct within the right external capsule extending into the corona radiata. MRA showed mild-moderate atherosclerotic disease. Intravenous fluids were given for rhabdomyolysis secondary to prolonged immobility and lack of oral intake. There was rapid improvement in leukocytosis and renal function but persistent platelet count >1 M/uL. Peripheral smear demonstrated thrombocytosis with no blasts or overt dysplasia. JAK2 V617F mutation was positive. Bone marrow biopsy was negative for PV, PMF, MDS or CML. Patient was started on aspirin 81mg and hydroxyurea for essential thrombocythemia. He was discharged to rehab with modest improvements in left-sided weakness with plan for outpatient hematology follow-up.
Discussion: Essential thrombocythemia (ET) is a myeloproliferative disorder characterized by reactive thrombocytosis in the absence of other chronic myeloid disorders. Despite elevated platelet counts, formed platelets are defective with abnormal morphology and function. This places patients at elevated risk for both bleeding and thrombosis; however, patients are generally asymptomatic for months to years. Other complications, such as clonal evolution or myelofibrosis, can occur but are less common. It is important to risk stratify patients with ET to identify those at an elevated risk of thrombosis which determines treatment strategy. Age > 60, co-morbid cardiovascular conditions, previous stroke and a positive JAK2 mutation are all individual risk factors that contribute to a higher risk for thrombotic events. If no more than one of these factors is present, the annual risk of thrombosis including CVA, TIA, MI, or DVT approximates 1 percent. Our patient has 3 risk factors, thus placing him at a high risk of 3.5 percent/year. The mainstay of treatment in high-risk patients is pharmacologic therapy with hydroxyurea, which has been shown to significantly reduce the risk of thrombotic events. Treatment with low-dose aspirin is also associated with less thrombosis. Our patient was started on both aspirin and hydroxyurea. Hematologic profile was closely followed to allow medication titration to maintain platelet counts between 100-400 k/uL and to monitor for the development of neutropenia or anemia.
Conclusions: Essential thrombocythemia may initially present with ischemic stroke. Once ET is suspected, it is essential to first rule out other myeloproliferative disorders. Subsequently, risk stratification and individualizing the treatment strategy is necessary to prevent thrombosis in high-risk patients.
To cite this abstract:Hachey B, Paje D. Essential Thrombocythemia Presenting As Acute Ischemic Stroke: A Case Report. Abstract published at Hospital Medicine 2015, March 29-April 1, National Harbor, Md. Abstract 535. Journal of Hospital Medicine. 2015; 10 (suppl 2). https://www.shmabstracts.com/abstract/essential-thrombocythemia-presenting-as-acute-ischemic-stroke-a-case-report/. Accessed April 7, 2020.