What Is Polycythemia Vera?
Polycythemia vera is an uncommon blood disorder characterized by a pathological overproduction of red blood cells, white blood cells, and platelets. Each type of blood cell performs an essential function: red cells carry oxygen, platelets are crucial for clotting, and white cells can engulf infectious agents and thus serve as part of the body’s immune system.
Red cells, platelets, and most types of white cells are produced by the bone marrow and released into the bloodstream as they mature. Normally, the marrow produces only enough new cells to replace the ones that have died.
However, in polycythemia vera new blood cells are produced in excess. The overabundance of red cells increases the viscosity or thickness of blood, resulting in a greater frequency of blood clots in both the arteries and veins. There is also a higher risk of excess bleeding, due to defective platelets or possibly due to blood vessels that are over-engorged with the extra red cells. Late in the disease, the spleen and liver may enlarge markedly.
Polycythemia vera is associated with a greater risk of acute leukemia. Symptoms develop gradually, and the disorder affects people of all ages. Although slightly more common in men than in women, this is not true in patients under age 40.
If left untreated, polycythemia vera may be fatal; stroke and heart attack are the most common causes of death. However, with treatment and control of the disease, the majority of patients survive more than 25 years after their initial diagnosis.
What Causes Polycythemia Vera?
- The cause of polycythemia vera is unknown.
- An ethnic component may be involved; for example, people of Jewish descent appear to be at greater risk of polycythemia vera.
Symptoms of Polycythemia Vera
- Frequent headaches and a feeling of pressure in the head
- Dizziness and ringing in the ears (tinnitus)
- Blurred or double vision
- Flushed or itching skin
- Night sweats
- Shortness of breath
- Itchy or flushed skin
- Frequent nosebleeds and bruises
- Tingling or burning sensation in the hands and feet
Polycythemia Vera PreventionPolycythemia vera cannot be prevented.
Polycythemia Vera Diagnosis
- There are no widely available diagnostic tests for polycythemia vera. Diagnosis is suggested by patient history and physical examination and by blood tests showing an elevation of red cell, white cell, and platelet counts. Initially, only one of these may be elevated (commonly the red cells).
- Because an elevated red cell count can be caused by diseases of the heart, lungs, liver, or kidneys, evaluation of these organs may be necessary to be sure that the elevated count is due to polycythemia vera.
How to Treat Polycythemia Vera
- Phlebotomy, or blood removal, is performed to eliminate excess red cells and to decrease blood viscosity. At first it may be necessary to withdraw a pint of blood every few days; with time, phlebotomy may only be necessary once or twice a year, to keep hemoglobin at certain levels.
- If possible, exposure to chemotherapy agents (alkylating agents such as busulfan) or radioactivity, or x-rays should be avoided as these agents increase the risk of leukemia. Interferon alpha or hydroxyurea may be given to reduce a high white cell or platelet count or shrink an enlarged spleen.
- Medication to prevent heartburn (antacids) or to relieve itching (such as antihistamines) may be prescribed. Allopurinol may be given to prevent kidney stones.
- To lower the platelet counts, a medicine called anagrelide may be given.
- Surgery to remove an enlarged spleen may be necessary if drug therapy fails.
- Ultraviolet-B light therapy can help reduce severe itching.
In December 2014, the U.S. Food and Drug Administration (FDA) approved ruxolitinib (Jakafi) to treat polycythemia vera in people that do not respond to other treatments. This medication inhibits enzymes called Janus Associated Kinase (JAK) 1 and 2 that help regulate blood and immune system function. Jakafi can help reduce the risk for spenomegaly and the need for phlebotomy.
Blood-related side effects of this drug include low red blood cell count (anemia) and low platelets (thrombocytopenia). Other possible effects include constipation, dizziness, and shingles. Jakafi was approved by the FDA in 2011 to treat another bone marrow disorder called myelofibrosis.
When to Call a Doctor
Make an appointment with a doctor if you develop symptoms of polycythemia vera.
Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference
Simeon Margolis, M.D., Ph.D., Medical Editor
Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50
Updated by Remedy Health Media
Updated by Remedy Health Media