Polycythemia vera

Polycythemia vera (PV) is also called polycythemia rubra vera. It is a myeloproliferative neoplasm. It mainly causes the body to make too many (overproduce) red blood cells. Sometimes the body also makes too many white blood cells or platelets. It is called a chronic disorder because it develops slowly over time.

Doctors don’t know why the body makes too many blood cells, but most people with polycythemia vera have a change, or mutation, in the JAK2 (Janus kinase 2) gene. What causes this gene mutation is not known.

The average age of people diagnosed with polycythemia vera is 60–65 years. It is uncommon in people under the age of 40. Polycythemia vera develops more often in men. Most people with polycythemia vera do not have a family history of this disease.

Polycythemia vera may develop into acute myelogenous leukemia (AML) or idiopathic myelofibrosis.

Polycythemia vera may not cause any signs or symptoms in its early stages. Symptoms can develop when too many red blood cells and platelets build up in the blood. These symptoms can cause problems, or complications, as the disease develops. An increase in the number of white blood cells does not usually cause noticeable signs or symptoms but can predict a higher risk of clot formation.

Other health conditions can cause the same symptoms as polycythemia vera. See your doctor if you have these symptoms:

• headache
• dizziness
• fatigue
• ringing in the ears
• vision changes such as blurred vision or blind spots
• shortness of breath or trouble breathing when lying down
• itchy skin, mainly after a warm bath
• reddish or purplish skin, especially on the palms, ear lobes and face
• gout, which causes painful swelling of the joints
• burning feeling in the feet
• abdominal discomfort or feeling of fullness if the spleen is enlarged
• blood clots
• bleeding that is heavier than normal

Diagnosing polycythemia vera usually begins with a visit to your family doctor or when a routine blood test indicates a problem with the blood. Your doctor will ask you about any symptoms you have and do a physical exam to check if your spleen or liver is enlarged. Based on this information, your doctor will order tests to check for polycythemia vera or other health problems.

Some of the same tests used to rule out or diagnose leukemia are also used to diagnose polycythemia vera. These tests include:

• complete blood count (CBC) to measure the number and quality of white blood cells, red blood cells and platelets
• blood chemistry tests to check how well certain organs are working
• reverse transcriptase polymerase chain reaction (RT-PCR) to see if cells in a sample of blood or bone marrow have the JAK2 gene mutation
• bone marrow aspiration and biopsy to confirm whether or not you have polycythemia vera

Find out more about these tests and procedures.

Your healthcare team will create a treatment plan just for you. Treatment is based on your symptoms, how quickly the polycythemia vera progresses, your age and your overall health.

The goal of treatments for polycythemia vera is to control symptoms and lower the risk of complications. Treatments can be done to:

• thin the blood when there are too many red blood cells
• prevent bleeding when you don’t have enough platelets
• help blood clot when you have too many platelets

People with polycythemia vera may be treated with different drugs. For more information on certain drugs, go to sources of drug information.

Phlebotomy is usually the first treatment for people with polycythemia vera. It may be the only treatment needed for many years.

Phlebotomy is used to help make the blood thinner when there are too many red blood cells. It is done in the same way as donating blood. A needle is inserted into a vein to remove blood. Blood is taken every 1–2 weeks, or more often, until the number of red blood cells goes down. Sometimes saline solution is given back into the blood to avoid a drop in blood pressure.

Phlebotomy can cause headache, ringing in the ears and dizziness. These side effects usually go away soon after phlebotomy and can be avoided by coming well hydrated to the phlebotomy appointment.

Drugs may be used to lower red blood cell or platelet counts when phlebotomy alone cannot control the overproduction of these cells. Drugs may also be used when repeated phlebotomy causes an overproduction of platelets.

Drugs are also used to treat complications from bleeding or blood clots. They can help people who have severe symptoms that aren’t relieved by acetylsalicylic acid (ASA, Aspirin, salicylate) or phlebotomy.

The following drugs may be used to treat polycythemia vera:

• hydroxyurea (Hydrea) – most commonly given drug
• interferon alfa (Intron A, Wellferon)
• anagrelide (Agrylin)
• ruxolitinib (Jakavi) – offered if there is a JAK2 gene mutation

Radioactive phosphorus (32p) may be an option for older people who can’t have frequent follow-up and do not tolerate phlebotomy. It is given through a needle in a vein (intravenously). One or 2 doses of radioactive phosphorus may help control blood cell counts for a period of time.

You may be given low doses of Aspirin to lower the risk of a blood clot. Aspirin makes the platelets less likely to stick to the wall of an artery and build up to form a clot. You will likely be instructed to reduce cardiovascular risk factors, most importantly to quit smoking.

Allopurinol (Zyloprim) is used to treat high levels of uric acid, which causes gout (painful swelling of the joints).

Antihistamines and low-dose antidepressants may be given to relieve itchy skin.

Surgery to remove the spleen (called splenectomy) is sometimes done if an enlarged spleen is causing pain.

Follow-up after treatment is an important part of cancer care. Follow-up for polycythemia vera is often shared among the cancer specialists (oncologists) or blood specialists (hematologists) and your family doctor. Your healthcare team will work with you to decide on follow-up care to meet your needs.

Don’t wait until your next scheduled appointment to report any new symptoms and symptoms that don’t go away.