Polycythemia vera (PV) is a very rare chronic cancer of the bone marrow that involves the overproduction of blood cells (myeloproliferation), and leads to abnormally high quantities of circulating red cells in the blood. When this occurs, the blood thickens, a condition known as hyperviscosity, causing it to stall in small blood vessels. This leads to a variety of symptoms, including headaches, fatigue, weakness, dizziness, itchy skin, an enlarged spleen (splenomegaly), a variety of gastrointestinal issues, and the risk of blood clot formation, which may prevent blood flow to vital organs.
PV may eventually “burn out”, causing scar tissue to replace the marrow, and this disorder resembles idiopathic myelofibrosis. When this happens, the marrow no longer produces blood cells, resulting in anemia, low platelet count (thrombocytopenia), and low white cell count (leukopenia). In rare cases, PV may eventually progress into acute myeloid leukemia.
The treatment of PV is intended to reduce the number of red blood cells and prevent complications, especially blood clot formation (thrombosis). Treatment options include:
- Phlebotomy or venesection (drawing blood), which may be done regularly (every few weeks or months) until the blood gets to the right level of thickness.
- Low dose aspirin, to reduce the chances of blood clots.
- Interferon alpha.
- Radioactive phosphorus (32P).
- Stem cell or bone marrow transplant.
Information taken from Mayo Clinic.