Polycythemia vera is a disorder of the bone marrow. It mainly causes too much production of red blood cells, although the numbers of white blood cells and platelets are also increased.
It is a rare disease that occurs more often in men than women, and is rare in patients under age 40. It is usually associated with a gene mutation called JAK2V617F. The cause of this mutation is unknown.
The goal of treatment is to reduce the thickness of the blood and prevent bleeding and clotting.
A method called phlebotomy is used to decrease blood thickness. One unit of blood (about 1 pint) is removed weekly until the hematocrit level is less than 45 (males) or 42 (females). Then therapy is continued as needed.
Occasionally, chemotherapy (specifically hydroxyurea) may be given to reduce the number of red blood cells made by the bone marrow. Interferon may also be given to lower blood counts. A medicine called anagrelide may be given to lower platelet counts.
Some patients are advised to take aspirin to reduce the risk of blood clots, though it increases the risk for stomach bleeding. Ultraviolet-B light therapy can reduce the severe itching some patients experience.
The disease usually develops slowly. Most patients do not experience any problems related to the disease after being diagnosed. The condition is often diagnosed before severe symptoms occur.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.