Polycythemia vera (PV) is a rare bone marrow
disorder in which your body produces too many red blood cells. Red blood cells
are responsible for carrying oxygen to all parts of your body.
Blood is carried throughout your body by a
system of veins and arteries. When there are too many red blood cells in your
blood it becomes thicker and flows more slowly. The red blood cells can begin to
form clots within the blood vessels. In PV, clots are formed when large amounts
of red blood cells clump together.
PV can lead to life-threatening complications
if it’s not treated. Slower flowing blood and blood clots can keep oxygen from reaching
your heart, brain, and other vital organs. As blood clots it can cause serious
damage to your organs.
There is no known cure for PV, but the
condition can be managed with treatment. Treatment focuses on routine blood
draws and using medications to prevent serious blood clots. It’s important to talk
to your doctor if you’re at risk for PV and experience any of its symptoms.
Polycythemia vera symptoms
Early symptoms of PV often cause common
physical ailments that may be easy to overlook them. But untreated PV may cause
blood clots, which can lead to serious complications.
Common symptoms of PV include:
- difficulties with activity
- difficulties with concentration
- abdominal discomfort
If the early symptoms of PV aren’t noticed,
doctors may not discover the condition until a blood clot causes a serious
complication. In these cases, the complication is the first sign that something
Polycythemia vera causes and risk factors
Polycythemia vera is a rare blood disorder
that occurs more often in men than in women. It’s rarely seen in anyone under age
40. PV is usually associated with a gene mutation called JAK2 V617F. The JAK2
gene handles production of a protein that helps make blood cells. About 95 percent of people with PV have this
Mutations are changes or damage in the body’s
DNA. DNA is responsible for all of your physical characteristics, from eye
color to fingerprints. The mutation that causes PV can be acquired, which means
something has damaged the DNA (instead of being born with it) and passed on within families. More
research needs to be done to understand what causes the genetic mutation behind
If you have PV, the genetic mutation causes
your bone marrow to produce too many red blood cells. The production of red
blood cells within your bone marrow is normally tightly regulated. Having too
many red blood cells in your bloodstream can cause the blood to clot and lead
to dangerous complications.
If you have PV, your risk for developing
serious complications depends on how likely you are to develop a blood clot.
Factors that increase your risk of developing
blood clots in PV include:
Polycythemia vera diagnosis
If your doctor suspects that you might have
PV, they will order a blood test called a complete
blood count (CBC). A CBC measures the following
factors in your blood:
- the number of red blood cells
- the number of white blood cells
- the number of platelets
- the amount of hemoglobin (a protein that carries oxygen)
- the percentage of space taken up by red blood cells in the blood,
known as the hematocrit
If you have PV, you will have a higher than normal
hemoglobin and hematocrit. Along with other blood tests, you may also need a bone marrow biopsy to confirm
PV is a chronic condition and can’t be cured.
The only way to treat the disease is through management and prevention. Your
doctor will prescribe a treatment based your risk for developing blood clots.
In low-risk people
Treatments for those at low risk include
regular phlebotomy and low-dose aspirin. Phlebotomy is the removal of
blood through a vein. Blood is withdrawn regularly and CBCs are run until there
is a decrease in the number of red blood cells.
Your doctor may also prescribe low-dose
aspirin to decrease the risk of life-threatening blood clots.
In high-risk people
In addition to regular blood draws and
aspirin, high-risk people may require more specialized treatment, using medications
Hydroxyurea: Hydroxyurea is a
chemotherapy drug that suppresses
the production of red blood cells. This reduces the risk for clots and manages
the disease, but can also increase the risk of leukemia. Over time, for about 1
in 4 individuals this drug can lose its effectiveness.
Using hydroxyurea for managing PV is
off-label drug usage. It remains the recommended treatment for this condition
in both the United States and Europe. Using a drug off-label means that the drug has been approved by the FDA for one
purpose and is being used for a different purpose. Off-label use of drugs occurs
when doctors have found them to be effective in patients. So, your doctor can
prescribe a drug however they think is best for your care, especially when
there is evidence that the drug works for a particular condition.
Interferon alpha: Interferon
alpha can also be used off-label to manage PV, but it’s expensive and has a high risk of fever and
flu-like side effects. Patients with certain mental health conditions should
avoid this medication. It can also cause thyroid abnormalities.
In December 2014, the U.S. Food and Drug Administration (FDA) approved ruxolitinib (Jakafi) for the treatment of
PV. This is currently the only FDA approved drug for PV. Doctors prescribe
Jakafi to people who can’t tolerate hydroxyurea or whose blood counts have not
responded to hydroxyurea. The medication works by inhibiting growth factors
responsible for creating red blood cells and immune system functioning. Side
effects may include:
- lowering blood counts too much
- increased risk of certain skin cancers
- high cholesterol
Polycythemia vera complications
Doctors may not discover PV until after a
blood clot causes a serious complication. These can be fatal. Blood clots can
form in both arteries and veins. Complications of PV can include:
- heart attack
- deep vein
- ischemic stroke, a stroke caused by loss of blood supply to
blood clot in the lung
- hemorrhagic death, death from bleeding, usually from the stomach
or other parts of the digestive tract
- portal hypertension, increased blood pressure within the liver
Polycythemia vera life expectancy and outlook
PV is a chronic disorder. Treatment works to
decrease the amount of red blood cells in the body, the amount to red cells
being produced by the bone marrow, and to prevent blood clots from forming. People
with PV who stick to their treatment may be able to live for many years without
complications. However, untreated PV can be fatal.
Preventing and managing blood
clots with polycythemia vera
You can manage PV by sticking strictly to
your treatment plan and by reducing your risk factors for blood clots. People
with a low risk for blood clots include those who have normal blood pressure,
normal cholesterol, do not have diabetes and don’t smoke.