Abstract
Polycythemia vera (PV) is a primary acquired marrow condition that causes erythrocytosis. It may present with erythromelalgia, pruritus, splenomegaly, and thrombotic events. Secondary causes of polycythemia should be ruled out before labeling a patient as having PV. Serum erythropoietin (EPO) level helps distinguish primary and secondary polycythemia, but it should be aided by further testing such as the JAK-2 gene mutation test. We present a case of a previously healthy 47-year-old female who came to the hospital with a headache and transient left-sided body weakness. She had no similar episodes in the past. Her initial workup showed a high hemoglobin and a high hematocrit level. A plan computed tomography (CT) scan of the head showed evidence of a thalamo-capsular infarct. The serum EPO level was elevated, and a bone marrow biopsy returned positive for JAK-2 mutation indicating the diagnosis of polycythemia vera despite the high EPO level. The World Health Organization (WHO) consensus criteria for diagnosing PV demand the presence of two major criteria and one minor criterion or the presence of the first major criterion and two minor criteria. Decreased EPO is considered a minor WHO criterion for PV diagnosis. A low EPO is also used to discriminate PV from secondary thrombocytosis, as it might be low, as expected, or elevated. Phlebotomy primarily treats PV with low risk with a target hematocrit of less than 45%. PV patients with high risk can benefit from low-dose aspirin. Anticoagulation may be added for patients with thromboembolism. Patients with polycythemia vera can present with a high or low serum EPO level. Further diagnostic tests are usually required to confirm the final diagnosis.