polycythemia ve·ra -'vir-ə n chronic polycythemia that is a myeloproliferative disorder of unknown cause characterized by an increase in total blood volume and viscosity and typically accompanied by nosebleed, headache, dizziness, weakness, itchy skin, reddish complexion, distension of the circulatory vessels, and enlargement of the spleen called also erythremia, erythrocythemia, Vaquez's disease
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a myeloproliferative disorder of unknown etiology, characterized by abnormal proliferation of all hematopoietic bone marrow elements and an absolute increase in red cell mass and total blood volume. The skin of the face is often ruddy and swollen, and ecchymoses are common. Most patients have splenomegaly, leukocytosis, and thrombocythemia. Hematopoiesis is also reactive in extramedullary sites (liver and spleen), and in time myelofibrosis occurs. Called also p. rubra or p. rubra vera; myelopathic or splenomegalic p.; and Osler, Osler-Vaquez, Vaquez, or Vaquez-Osler disease. Cf. secondary p.Medical dictionary. 2011.