Polycythemia vera (PV) is a chronic blood cancer caused by an acquired gene mutation of the blood cells in the bone marrow, which creates an overproduction of blood cells, particularly red blood cells. White blood cell and platelet production may also be increased. An excess amount of red blood cells increases the blood viscosity (thickness), slowing blood flow. As blood flow is restricted, the blood vessels are more susceptible to clotting which can lead to serious conditions such as stroke, heart attack, deep vein thrombosis, and pulmonary embolism. Excess cells can collect in the spleen, causing it to become enlarged. PV is one of a group of rare blood cancers called myeloproliferative neoplasms (MPNs) that develop due to a mutation in the DNA of the stem cells in the bone marrow.
Statistics
- In every 100,000 people, there are approximately 22 cases of polycythemia vera.
- A majority of polycythemia vera cases are diagnosed in people age 60 to 65.
- PV is rarely diagnosed in people under age 30.
Risk Factors
The exact causes of the acquired genetic mutation in polycythemia vera are not yet known. A family history of PV is rarely present in most patients; however, sometimes multiple family members will have the disease. Risk factors may include the following:
- Mutations: Almost all people with PV have the JAK2 gene mutation. Of these, 95 percent have a mutation of JAK-2-V617F (Exon 14) with most of the remainder having mutations in Exon 12. Research is ongoing to determine the link between the disease and gene mutations, or changes in the DNA.
- Gender: Men have a slightly higher risk than women to develop polycythemia vera.
- Age: People over age 60 are more at risk; and it is rarely diagnosed in people under age 30.
- Environment: Exposure to radiation may increase risk.
- Race: PV occurs more often in Jews of Eastern European descent than other European or Asian groups.
- High white blood count increases the risk of blood clotting.
Symptoms
Many patients with PV do not have symptoms when they are diagnosed. Diagnosis often occurs during a routine exam or blood test. However, people who experience any of the following symptoms should consult a physician.
- Headaches
- Sweating and night sweats
- Ringing in the ears
- Blurred vision or blind spots
- Dizziness or vertigo
- Skin with red or purple hue, especially on the palms, ear lobes, nose, and cheeks
- Reddened face
- Unexpected weight loss
- Bleeding or clotting excessively
- Feeling full quickly
- Abnormal discomfort on left side below the ribs
- Itching, especially after a shower
- Burning and redness of the hands or feet
- Fatigue
- Bone pain
- Gout
Prevention
PV cannot be prevented. Research is underway to learn more about how the disease develops.
Treatment
PV is a chronic disease, but can be managed well. PV causes differing reactions in each patient. In some cases, symptoms may not be present, in which case treatment may not be required. However, treatment options usually include phlebotomy (removal of blood) and low-dose aspirin. Drug therapy such as hydroxyurea, anagrelide, ruxolitinib, and interferon are also options. Antihistamines and avoidance of hot showers can help with itching. Clinical trials can also be an important treatment option.