Key Points

• Polycythemia vera (PV) is a rare, chronic disease in which your body produces too many red blood cells. These extra blood cells thicken your blood, which can lead to blood clots, stroke, and heart attack.
• Polycythemia vera is also known as primary polycythemia. A mutation in the JAK 2 gene causes PV, but the cause of the mutation is not known.
• Secondary polycythemia is caused by long-term exposure to low levels of oxygen. It is not related to the JAK 2 gene.
• PV is a very rare blood disease. It is more common in adults older than 60 years and in men.
• The most common signs and symptoms of PV are pressure or fullness on the left side of the abdomen due to enlargement of the spleen, headache, double vision, itching all over, reddened face, weakness, dizziness, and unexplained weight loss.
• PV is diagnosed based on symptoms, physical exam, age, test results, and overall health.
• The goals of treating PV are to control your symptoms and reduce the risk of complications caused by thickened blood and blood clots.
• Treatment may include phlebotomy (removing blood to reduce the number of red blood cells), medicine, or biological therapy.
• PV cannot be prevented, but treatment can prevent or delay symptoms and complications. Some cases of secondary polycythemia may be prevented by not doing things that deprive your body of oxygen for a long time.
• If you have PV, you will need regular medical care and monitoring for the rest of your life. It is important to follow the treatments your doctor prescribes.