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Polycythaemia vera (PV) is one of a group of conditions known as the myeloproliferative diseases (MPDs).
Myeloproliferative diseases (MPDs)
MPDs are a group of conditions that affect how the bone marrow works. In MPDs, the bone marrow makes too many of one or more types of blood cells.
The main types of MPD are:
Some people with essential thrombocythaemia or polycythaemia vera develop myelofibrosis. This is a condition in which the bone marrow becomes scarred. Rarely, people with MPDs develop leukaemia|.
This information is about polycythaemia vera (PV). We have other information about essential thrombocythaemia and myelofibrosis.
The bone marrow| is the spongy material in the centre of some of our bones. It makes cells known as stem cells. Stem cells are immature cells that develop into three different types of blood cells:
PV is a rare condition that mainly affects people over the age of 40. Typically PV develops very slowly and, in most cases, it doesn’t affect a person’s projected life span.
PV is a myeloproliferative disease, which is caused by changes in the bone marrow. These changes cause too many red blood cells to be made. This raises the haemoglobin (Hb) level and makes the blood thicker than normal. Some people with PV also have increased numbers of white blood cells and platelets in their blood.
Secondary polycythaemia also causes the production of too many red blood cells in the blood, but the cause isn’t due to changes in the bone marrow. It’s the result of a condition somewhere else in the body, such as lung disease or a kidney disorder. The treatment of secondary polycythaemia is very different from PV and involves treating the underlying condition.
Having a high number of red blood cells in the blood doesn't always cause symptoms. Some people are diagnosed with PV following a blood test is taken for other reasons.
Possible symptoms of PV include:
Sometimes symptoms develop due to complications that PV can cause. These include the following.
A small number of people with PV develop gout. This can happen when lots of red blood cells are broken down in the body. It causes inflammation and pain in joints, such as the big toe and sometimes in the ankles, hands or knees.
Having a high level of red blood cells or platelets in the blood increases the chance of blood clots (thromboses). Clots can form anywhere in the body. The symptoms of a blood clot depend on which part of the body is affected.
Possible sites for a clot to form are listed below:
Very occasionally PV can cause abnormal bleeding. This can cause symptoms such as:
PV can cause the spleen to grow bigger than normal. This is because the spleen is involved in breaking down red blood cells. The spleen sits on the left side of your tummy (abdomen) just under the ribs and is normally about the size of a clenched fist. Symptoms of an enlarged spleen may include discomfort on the left side of the tummy and feeling full sooner than usual when eating.
PV is usually diagnosed by a haematologist (a doctor who specialises in blood disorders), following a blood test called a full blood count. This counts the number of red blood cells, white blood cells and platelets.
PV causes a high red blood cell count but other conditions such as lung or kidney problems can also cause an increased red blood cell count (secondary polycythaemia). These conditions need to be ruled out before a diagnosis of PV can be made.
Various tests and investigations may be done to confirm a diagnosis of PV.
This is the most helpful test to diagnose PV. JAK2 is a gene that is important in regulating blood cell production. If a change (mutation) happens in this gene it can cause PV. About 95 out of 100 people with PV (95%) have a mutation in the JAK2 gene. This change in the gene happens during the person's lifetime. It isn't something you’re born with, and you can’t pass it on to your children.
Other tests that may be done include:
All of these tests can be done as an outpatient.
The aim of treatment for PV is to reduce the number of red blood cells in the blood, which reduces the risk of complications occurring. Your treatment will depend on how many red blood cells you have, your fitness level, whether you have symptoms caused by the disease and whether you have a high platelet count. If you have been diagnosed with PV, but it’s not causing you any problems, you may not need any treatment for a while.V
This is one of the simplest ways to reduce the number of red blood cells in your blood, and make your blood less thick. It involves taking about a pint of blood from you.
The procedure is similar to that used when donating blood. A doctor or nurse puts a needle, attached to tubing and a bag, into your vein. Blood flows through the needle and tubing into the bag. When enough blood has been taken the needle is taken out.
Venesections may be done regularly, every few weeks or months, until your blood gets to the right level of thickness. Each time some blood is removed, you will be asked to drink plenty of fluids to replace what you have lost.
Aspirin can help prevent clots because it affects the way platelets 'stick together'. Some people may be prescribed it as part of their treatment. One of the side effects of aspirin is an increased risk of bleeding and ulcers in the stomach.
If you need to take a painkiller while you’re taking aspirin to prevent blood clots, ask your doctor what they advise. Some types of painkillers called NSAIDs (non-steroidal anti-inflammatory drugs) such as ibuprofen may not be suitable.
Chemotherapy| is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. It is most commonly used to treat cancers, but it is sometimes used to treat other conditions. It can be used to reduce the blood cell count.
Hydroxycarbamide| is the most commonly used chemotherapy drug to treat PV. It is taken as a tablet. It can cause side effects, but generally these are mild. Side effects may include lowered resistance to infection|, reduced red blood cell numbers (anaemia), diarrhoea| or constipation.
Hydroxycarbamide may also affect fertility|. People taking it are advised not to get pregnant or father a child, as there may be a risk of harming the developing baby. It is advisable to use effective contraception while taking hydroxycarbamide and also for a few months afterwards.
If hydroxycarbamide is used over a long period of time in combination with other chemotherapy drugs|, it may increase the chance of the PV developing into a leukaemia|.
The chemotherapy drug busulphan| may also be used. However, this drug is used less often than hydroxycarbamide. Busulphan is usually given as a tablet, but it can be given as an injection into a vein. Its side effects are similar to those of hydroxycarbamide.
Interferon| is a natural substance made by the body. It is also made as a medicine. It can be used to reduce the rate at which blood cells are made. Interferon is given as an injection under the skin. Side effects can include flu-like symptoms, headaches, dizziness and tiredness|.
This may be used in some situations. Radioactive phosphorus is given as an injection. It irradiates the bone marrow and can lower the number of blood cells being produced. The effects of a single injection can last from months to years.
Treatment with radioactive phosphorus over many years can cause an increased risk of leukaemia.
This can be used to help prevent gout. It may be given before treatments for PV that work by destroying blood cells, such as chemotherapy. If you do have an episode of gout you may be prescribed allopurinol to take long-term to help prevent further episodes occurring.
Rarely, this intensive treatment is used for younger people with PV that’s developing into myelofibrosis. It involves giving high doses of chemotherapy, and then replacing stem cells (early blood cells) that have been destroyed by the treatment. After chemotherapy, you are given stem cells from a donor| who can be a brother, sister or a volunteer who is a match for you.
Your doctor or nurse will explain your treatment to you and should answer any questions that you have.
Research into treatments for PV is ongoing. Cancer specialists use clinical trials |to assess new treatments. Before any trial is allowed to take place, an ethics committee must approve it and agree that the trial is in the interest of the patients.
You may be asked to take part in a clinical trial. Your doctor will discuss the treatment with you so that you have a full understanding of the trial and what it involves. You may decide not to take part or to withdraw from a trial at any stage. You will still receive the best standard treatment available.
You’ll need to have regular check-ups and blood tests. These will probably be ongoing. If you have any problems, or notice any new symptoms in between these times, you should discuss them with your doctor or haematologist as soon as possible.
You may have many different emotions|, including anger, resentment, guilt, anxiety and fear. These are all normal reactions and are part of the process many people go through in trying to come to terms with their condition.
Everyone has their own way of coping with difficult situations. Adjusting to the news that you have a long-term condition can take time, and it’s important that you get the support that you need. Some people find it helpful to talk to family or friends, while others prefer to seek help from people outside their situation. Some people prefer to keep their feelings to themselves. There is no right or wrong way to cope, but help is available if you need it. Our cancer support specialists| can give you information about counselling in your area.
MPD Voice| is a support network for people with MPDs (myeloproliferative disorders) providing information and support.
Leukaemia CARE| is a national group promoting the welfare of people with leukaemia and other blood disorders. It has regional support groups in many counties.
This information has been compiled using information from a number of reliable sources, including:
With thanks to: Anne Parker, Consultant Haematologist; and the people affected by cancer who reviewed this edition.
Reviewing information is just one of the ways you could help when you join our Cancer Voices| network.
Content last reviewed: 1 January 2013
Next planned review: 2015
For answers, support or just a chat, call the Macmillan Support Line free (Monday to Friday, 9am-8pm)
If you have any questions about cancer, need support or just want someone to talk to, ask Macmillan.
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© Macmillan Cancer Support 2013
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