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. PV is a rare condition. It primarily affects middle-aged and elderly people and it is more common in men. It is rare in children.
Recent research shows that nearly 95% 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.
Polycythaemia vera is also known as:
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:
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:
The aim of PV treatment is to control complications and reduce the number of red cells and platelets in the blood. Venesection 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.
Your haematologist can recommend from several treatments that reduce red cell numbers, including:
In addition to using drugs or venesection, a number of patients take additional treatments.
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:
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:
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 myelofibrosis is about 15% for patients with PV.
If you have PV, your prognosis depends on many factors inclucing 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 myelofibrosis 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. 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.