Polycythemia Vera

Polycythemia vera (PV) is a blood disorder that causes your body to produce too many red blood cells. Too many red blood cells can make your blood thick and sluggish and increase your risk of blood clots and complications such as heart attack and stroke. It can also cause vague but irritating symptoms, such as skin itchiness, ringing in your ears, abdominal pain, nose bleeds and blurred or double vision.

Polycythemia vera is a chronic condition with no cure, but medical care can help you manage symptoms and the risk of complications. Other names for polycythemia vera include primary polycythemia, polycythemia rubra vera, erythema and Osler-Vaquez disease.

Is polycythemia vera cancer?

Polycythemia vera is a type of blood cancer known as myeloproliferative neoplasm (MPN). MPNs are a group of various diseases, some of which cause overproduction of different blood cells. A gene mutation that occurs for unknown reasons, usually sometime during the course of your life, causes polycythemia vera. They develop very slowly and often aren’t diagnosed until after the age of 60. This type of cancer usually isn’t fatal by itself. The risk comes from complications of blood clotting, or from the small chance that it would progress more aggressive types of blood cancer.

Who does polycythemia vera affect?

Polycythemia vera is rare. It affects about 50 per 100,000 people in the U.S. It’s most common in people over the age of 60.

How does this condition affect my body?

Polycythemia vera causes your body to produce too many red blood cells. Extra blood cells increase your likelihood of bleeding, bruising and clotting. They thicken your blood and slow your circulation, which means your blood carries less oxygen to your body’s tissues and organs than they need. They also overwork your spleen, which is responsible for filtering your blood and clearing out old blood cells. This can lead it to become swollen and sore (splenomegaly). Over time, you may develop a variety of uncomfortable symptoms as a result of your condition. PV can also lead to several secondary conditions.

What are the risks and complications of polycythemia vera?

PV progresses slowly, but overproduction of blood cells carries immediate risks from blood clots. Over time, polycythemia vera may also induce secondary conditions. It rarely progresses to a more serious kind of cancer.

Blood clots

The most urgent risk from polycythemia vera is the tendency for blood clotting. A blood clot that travels to your heart or brain can cause a heart attack or stroke. A clot that gets stuck in your lungs (pulmonary embolism) can cause pulmonary hypertension, leading to heart failure. A blood clot that blocks a vein (venous thromboembolism) can cause tissue death and chronic venous insufficiency. A clot that blocks the main blood vessel leading to your liver (hepatic vein thrombosis) can cause blood to back up into it (Budd-Chiari syndrome), leading to jaundice and liver failure.

Secondary conditions

High red blood cell turnover also produces high uric acid levels in your body. This contributes to several secondary conditions, including kidney stones (when uric acid builds up in your kidneys) and gout, a painful form of arthritis (when uric acid builds up in your joints). Extra red blood cells also lead to more stomach acid, which can cause stomach ulcers. The extra red blood cells trigger an immune response in your body. Your body releases a chemical called histamine, and your stomach responds by creating more acid to fight off infection. People with PV are four times as likely as others to have peptic ulcer disease.

Leukemia progression

Polycythemia vera is a form of chronic bone marrow disorder/cancer, which usually isn’t an urgent threat. With regular treatment, it can be managed well for many years. But in some people, PV does progress to other more aggressive blood disorders, including, but rarely, acute leukemia.

Stages of polycythemia vera progression

• Early PV: This phase often has no symptoms or only mild symptoms.
• Advancing PV: As polycythemia vera advances, you may begin noticing more uncomfortable symptoms or the development of secondary conditions.
• Spent phase: The so-called “spent phase” of PV occurs when the mutated blood cells that caused the condition have grown so out of control that they’ve taken over your bone marrow, where blood cells grow. As the mutated cells lived out their lives and broke down, they were replaced with scar tissue. When enough of your bone marrow has been replaced with scar tissue, it’ll no longer be able to produce healthy blood cells. Ironically, this leads to anemia — a lack of healthy red blood cells. It also increases your risk of hemorrhage from bleeding.

Post-polycythemia vera blood disorders

• Myelofibrosis: The “spent phase” of polycythemia vera is basically identical to another type of blood cancer called myelofibrosis (MF). Some healthcare providers make no distinction between the two. Myelofibrosis occurs when mutated cells have replaced your bone marrow with scar tissue. The abnormal cells may also begin to spread outside of your bone marrow to other organs in your body. MF is another myeloproliferative disorder. About 10% of MF cases may progress to acute myeloid leukemia.
• Myelodysplastic syndrome: More rarely, PV may turn into a myelodysplastic syndrome (MDS), a kind of disorder in which blood cells don’t fully develop. Whereas PV normally produces an abundance of red blood cells that mature normally, MDS causes blood cells to mature abnormally/improperly, and die early. The inability to form healthy and mature cells causes a lowering of various blood counts (can be one type of low counts or a combination). MDS can occur instead of or simultaneously with myelofibrosis. It’s more aggressive than PV or MF and has a 30% chance of progressing to acute myeloid leukemia (AML).
• Acute myeloid leukemia (AML): About 3% of polycythemia vera cases may progress to acute myeloid leukemia over the course of about 10 years from diagnosis. AML is an aggressive blood cancer that begins in your bone marrow and quickly moves into your bloodstream, where it can spread to other body systems. AML requires more urgent treatment than chronic leukemia, but it has a high survival rate. It accounts for less than 2% of all cancer deaths.