What is polycythemia vera (PV)?
Polycythemia vera (PV) is a type of blood cancer that causes the bone marrow to make too many red blood cells. These cells carry oxygen throughout the body, but when too many of them, the blood becomes thicker and can cause circulation problems, such as blood clots. PV is a rare, slow-onset disease that usually affects people over 50.
Other names for polycythemia vera
Polycythemia vera is also known as primary polycythemia or polycythemia rubra vera. It is sometimes called erythrocytosis, which means having a high concentration of red blood cells in the blood.
How standard is PV?
PV is a rare disease that affects about 2 or 3 people in every 100,000 inhabitants. It is estimated that there are about 15,000 cases in Spain. PV affects men more than women and is more common in people of Jewish descent.
A blood test for other reasons usually detects PV, as many people have no or vague symptoms. The blood test may show an increase in red blood cells, the percentage of red blood cells that comprise the total blood volume (hematocrit), or in platelets or white blood cells. A genetic test can also be done to look for a mutation in the JAK2 gene, which is present in 95% of people with PV.
The symptoms of PV can vary depending on the person and the degree of thickness of the blood. Some common symptoms are:
Headache, dizziness, fatigue, and blurred vision
Itchy skin, especially after a hot bath or shower
Numbness, tingling, burning, or weakness in the hands, feet, arms, or legs
Sensation of fullness or swelling in the abdomen due to an enlarged spleen
Unusual bleeding from the nose or gums
Painful swelling of a joint, usually the big toe
Shortness of breath and difficulty breathing when lying down
Referral to a hematologist
If the diagnosis of PV is suspected or confirmed, the patient should be referred to a hematologist or a doctor specializing in diseases of the blood. The hematologist will conduct more tests and determine the best treatment for each case.
Diagnostic tests for PV include blood tests, bone marrow biopsy, genetic tests, and physical examination.
Blood tests can measure the levels of red blood cells, white blood cells, platelets, and hematocrit (the percentage of red blood cells in your blood).
Bone marrow biopsy can show if your bone marrow produces too many cells. Genetic tests can detect a mutation in the JAK2 gene found in most people with PV.
A physical examination can check for signs of PV, such as an enlarged spleen, red skin, itching, or headaches.
Treatment for PV aims to reduce the number of red blood cells and prevent complications. There is no cure for PV, but treatment can help you manage your symptoms and improve your quality of life.
First-line treatments for PV include phlebotomy and low-dose aspirin.
Phlebotomy is a procedure that removes some of your blood to lower your hematocrit level. You may need regular phlebotomy sessions, depending on your condition.
Low-dose aspirin can help prevent blood clots by making your platelets less sticky.
Additional treatments for PV may be needed if phlebotomy and aspirin are not enough to control your condition. These include hydroxyurea, interferon alpha, ruxolitinib, and anagrelide.
Hydroxyurea and interferon alpha are drugs that slow down the production of blood cells in your bone marrow. Ruxolitinib and anagrelide block the action of the JAK2 gene or reduce the number of platelets in your blood.
Be aware of some possible risks
Polycythemia vera is a disease that affects the blood and causes too many red blood cells to be produced in the bone marrow. This can cause the blood to become thicker and slower, increasing the risk of serious problems, such as blood clots.
Blood clots can affect different parts of the body and cause complications such as:
Deep vein thrombosis (DVT): a clot in a deep vein, usually in the leg or abdomen
Pulmonary embolism (PE): a clot that breaks off and travels to the lungs
Myocardial infarction (MI): a clot that blocks blood flow to the heart
Cerebrovascular accident (CVA): a clot that interrupts the flow of blood to the brain
Minor thrombotic events: small clots that can cause mild or transient symptoms
Transient ischemic attack (TIA): a temporary clot that affects the brain and produces symptoms similar to those of a stroke
Superficial thrombophlebitis: an inflammation of a vein near the surface of the skin, often associated with varicose veins
Erythromelalgia: a condition that causes pain and swelling in the fingers or toes
People with polycythemia vera over 60 or who have had a clot in the past are more likely to have these events. There are also other risk factors for heart attacks and strokes, such as high blood pressure, smoking, diabetes, high cholesterol, obesity, and family background.
Living with PV
The prognosis for PV varies depending on your age, symptoms, complications, and response to treatment.
Some people with PV live for many years without any problems, while others may develop serious complications that affect their survival. The average life expectancy for people with PV is about 15 years after diagnosis.