Practice Essentials
Polycythemia vera (PV) is a stem cell disorder characterized as a panhyperplastic, malignant, and neoplastic marrow disorder. Its most prominent feature is an elevated absolute red blood cell mass because of uncontrolled red blood cell production. This is accompanied by increased white blood cell (myeloid) and platelet (megakaryocytic) production, which is due to an abnormal clone of the hematopoietic stem cells with increased sensitivity to the different growth factors for maturation.
Signs and symptoms of polycythemia vera
Impaired oxygen delivery due to sludging of blood may lead to the following symptoms:
Headache
Dizziness
Vertigo
Tinnitus
Visual disturbances
Angina pectoris
Intermittent claudication
Bleeding complications, seen in approximately 1% of patients with PV, include epistaxis, gum bleeding, ecchymoses, and gastrointestinal (GI) bleeding. Thrombotic complications (1%) include venous thrombosis or thromboembolism and an increased prevalence of stroke and other arterial thromboses.
Physical examination findings may include the following:
Splenomegaly (75% of patients)
Hepatomegaly (30%)
Plethora
Hypertension
Diagnosis of polycythemia vera
According to 2016 revised World Health Organization (WHO) guidelines, diagnosis of PV requires requires the presence of either all three major criteria or the first two major criteria and the minor criterion.
Major WHO criteria are as follows:
Hemoglobin > 16.5 g/dL in men and > 16 g/dL in women, or hematocrit > 49% in men and > 48% in women, or red cell mass > 25% above mean normal predicted value
Bone marrow biopsy showing hypercellularity for age with trilineage growth (panmyelosis) including prominent erythroid, granulocytic, and megakaryocytic proliferation with pleomorphic, mature megakaryocytes (differences in size)
Presence of JAK2V617F or JAK2 exon 12 mutation
The minor WHO criterion is as follows:
Serum erythropoietin level below the reference range for normal
Management of polycythemia vera
Treatment measures are as follows:
Phlebotomy – To keep hematocrit below 45%
Aspirin – 81 mg daily
Cytoreductive therapy – For patients at high risk for thrombosis
Splenectomy in patients with painful splenomegaly or repeated episodes of splenic infarction
Hydroxyurea is the most commonly used cytoreductive agent. If hydroxyurea is not effective or not tolerated, alternatives include the following:
Interferon alfa
Busulfan – In patients older than 65 years
Ruxolitinib (Jakafi)
Fedratinib (Inrebic)
For discussion of polycythemia in children, see Pediatric Polycythemia vera.