What is polycythaemia vera (PV)?
People with polycythaemia vera (PV) produce more red blood cells than normal. PV may also affect the production of your other blood cells, for example your body may also produce too many platelets and white blood cells. Recent research shows that nearly 97% of people with PV have a mutation (or change) in a protein called JAK2, a protein that is part of the mechanism which regulates blood cell production in our bodies. The cause of this mutation is unknown but may result from viral infections or radiation damage, but more research needs to be done to determine the causes of PV.
Other names for polycythaemia vera
Polycythaemia vera is also known as:
- Primary polycythaemia
- Polycythaemia rubra vera
- Splenomegalic polycythaemia
- Vaquez’’s Disease
- Osler’’s Disease
- Polycythaemia with chronic cyanosis
- Myelopathic polycythaemia
- Erythrocytosis megalosplenica
- Cryptogenic polycythaemia
- The US spelling of polycythaemia is ““polycythemia””
How common is PV?
PV is considered to be a rare disease. The number of people diagnosed each year with PV will be two cases per 100,000 and is more common in men than women. It primarily affects middle-aged and elderly people and it is hardly diagnosed in children.
In the early stages, PV patients may not exhibit any signs of the disorder but as the condition progresses a patient may exhibit some of the following symptoms:
- Redness of skin (plethora)
- Blurred vision and headaches
- Bleeding and/or clotting
- Skin itchiness (pruritus)
- Joint pain or gout
- Dizzy spells
- Unexplained weight loss
- Shortness of breath
- Chest pain
- Fullness/bloating in the left upper abdomen due to enlarged spleen
Referral to a haematologist
If you have a high red cell count you may be referred to a haematologist, a doctor who specialises in treating blood diseases. The haematologist will look for clues to the diagnosis of PV or other causes of a high red cell count. The haematologist will examine you and ask you about your health, medications, lifestyle and family history.
Several tests are used to confirm the diagnosis of PV and to help your haematologist to understand your condition. You may need the following tests:
- Full blood count (blood test): Your haematologist may repeat this test for verification if the test was previously done by your GP.
- JAK2 test: Your haematologist can test your blood to see if you have a change (or mutation) called JAK2 V617F. Approximately 95% who have PV have this mutation. A further 2% of patients have a mutation in another part of the JAK2 gene called exon 12.
- Chest x-ray
- Liver, kidney tests: These tests are done on your blood but a urine sample may also be needed.
- EPO test: Measurement of your erythropoietin (EPO) level via a blood test.
- Iron, folate and vitamin B12: Tested on your blood these vitaminsand minerals are needed for healthy red blood cell production.
- Oxygen: Measurement of oxygen levels in the blood using a finger probe.
- Abdominal ultrasound: If you have PV, your spleen may be enlarged. This is because in PV your spleen may begin to produce blood cells, and these collect inside the spleen. The ultrasound is a painless test. Spleen examination can also be done by feeling your tummy.
- Bone marrow biopsy (BMB): A bone marrow biopsy is a test of your bone marrow that is done in the hospital. You will not need to stay overnight in the hospital, and you will generally just need local anaesthesia. Your haematologist will give you some medication to prevent pain, and then he or she will extract some bone marrow from your hip bone using a needle. The bone marrow tissue can then be examined in a laboratory so that your haematologist see how the cells in your bone marrow are functioning.
You may need additional tests including:
- Lung function test
- A red cell mass test
- Blood test measuring haemoglobin binding to oxygen
- An ECG (echocardiogram) to examine the heart
- Genetic testing of the erythropoietin receptor
- A sleep study
The aim of PV treatment is to control complications and reduce the number of red cells and platelets in the blood. Venesection (a process or removing blood from the body), and drug therapy can be used to reduce the number of red cells and to slow their production. Your haematologist will determine your treatment for you individually based on your age, how well you tolerate venesection, your red blood cell count, and your history of clotting or bleeding complications.
First line treatments
Your haematologist can recommend several treatments that reduce red cell numbers, including:
- Melphalan, busulphan and radioactive phosphorous
- Interferon alpha
- Anagrelide (Anagrelide is used in PV to lower the red blood cell count by reducing the size of the red blood cell-producing cells. In Europe, Anagrelide is only licensed as a second line treatment for essential thrombocythaemia, but it may also be used to treat polycythaemia vera.)
- Ruxolitinib (a JAK inhibitor) was approved for PV patients who are no longer able to take or are not responding to hydrocycarbamide.
In addition to using drugs or venesection, a number of patients take additional treatments, including:
- Aspirin can be used to reduce the likelihood of complications. Aspirin may increase your bleeding, especially from the gut, although this bleeding is unlikely if your blood count is well controlled and you have no pre-existing ulcer or bleeding history.
- Allopurinol for gout. People with PV can sometimes experience gout. Your risk of gout can be controlled by reducing your red cell count and by using the drug allopurinol. Acute attacks of gout can be treated with painkillers.
- Ranitidine: Itching can be a particularly difficult problem to control. Patients can use creams and ranitidine to ease the symptoms.
People with PV are at a high risk of blood clots (thrombosis) and bleeding (haemorrhagic) events. The chance of both bleeding and clotting complications of PV can be reduced with medication to reduce blood stickiness and also lower the red blood cell and platelet counts. Clotting episodes are more common than bleeding episodes and they have a significant impact on survival. Examples of the different types of blood clots include:
- Deep vein thrombosis (DVT)
- Pulmonary embolism (lung clot)
- Myocardial infarction (heart attack)
- Cerebrovascular accident (stroke)
- Minor thrombotic events (minor clots)
- Transient ischaemic attack (TIA – minor stroke)
- Superficial thrombophlebitis (varicose veins)
- Erythromelalgia (painful and swollen finger/toe)
People with PV who are over age 60 or have had a clot in the past are at higher risk for these events. There are other risk factors for heart attacks and strokes that are important too:
- High blood pressure
- Cigarette smoking
- High cholesterol
- Family history
Bleeding can appear in a variety of forms, from easy bruising and nosebleeds, to bleeding from the gut and sometimes in the head.
Less common complications include a risk of developing acute myeloid leukaemia (AML) or myelofibrosis (MF). The risk of developing MF is about 15% for patients with PV.
If you have PV, your prognosis depends on many factors including your age, other illnesses you have, and PV complications you may develop with PV. Blood clots (thrombosis) are common and are frequently serious; the risk of these events increases with age and previous episodes. The goal of PV treatment is to reduce the risk of complications and prolong your life.
Patients who do not suffer from other diseases (especially MF or leukaemia) have a normal to slightly reduced life expectancy.
About 15% of people with PV develop a complication of the disease known as myelofibrosis (MF). Please visit our Myelofibrosis page for more information about this disorder.
Some patients with PV transform to acute myeloid leukaemia (AML). The onset of AML is rare but can have a poor outlook, as this form of leukaemia is often resistant to treatment. If this is a concern for you, please discuss this with your haematologist.
Your guide to Polycythaemia Vera (PV)
Information and advice about causes, symptoms and management. Download a copy of our booklet here…