What Is Polycythemia Vera?
Polycythemia vera (PV) is a bone marrow disorder in which
the body produces an excessive amount of red blood cells. Red blood cells are
responsible for carrying oxygen to all parts of the body.
Blood is carried throughout the body by a system of veins
and arteries. When too many red blood cells exist in your blood, they begin to form
clots within the blood vessels. Clots are formed by large amounts of cells
Many people with this condition easily ignore early symptoms
such as fatigue. Untreated PV, on the other hand, cannot be ignored, as serious
symptoms will usually begin to develop due to the blood clots. The clots block
blood from reaching the heart or brain, causing serious damage.
There is no known cure for PV, so treatment focuses on using
medications to prevent serious blood clots. Unfortunately, people with PV who
do not follow treatment regimens have a high likelihood of dying early from
What Causes Polycythemia Vera?
Polycythemia vera is a rare disorder that occurs more often
in men than in women, and rarely in anyone under 40. PV is usually associated
with a gene mutation called JAK2V617F. The JAK2 gene is responsible for making
a protein that helps make blood cells. Mutations are changes or damage in the
body’s DNA. DNA is responsible for all of your physical characteristics, from
eye color to fingerprints.
Red blood cells are made in your bone marrow. This
production of blood cells is supposed to be tightly regulated. If you have PV,
your bone marrow produces too many red blood cells.
What Are the Symptoms of PV?
Early symptoms of PV are common physical ailments and can be
easily ignored by the patient. However, untreated PV may cause blood clots,
which can lead to serious complications.
Early symptoms of PV include:
- tingling in the hands
Significant blood clot complications from untreated PV
- heart attack
- deep vein
Doctors may not discover PV until after a fatal complication
has occurred. Fatal complications include:
- ischemic stroke, a stroke caused
by loss of blood supply to the brain
- pulmonary embolism, a blood clot
in the lung
- hemorrhagic death, death from
bleeding which is usually from the stomach or other parts of the digestive
How Is PV Diagnosed?
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
number of red blood cells, the number of white blood cells, the amount of
hemoglobin (a protein that carries oxygen) in the blood, as well as how much
space is taken up by red blood cells in the blood. If you have PV, an unusually
large percentage of your blood volume will be taken up by red blood cells.
How Is PV Treated?
PV is a chronic illness and can’t be cured. The only way to
treat the disease is through management and prevention. Doctors will treat
patients differently based upon their risk for blood clots.
Patients with a low risk for blood clots include:
- people under 60
without prior history of blood clots
- people with low
blood pressure and low cholesterol
- people who do
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 daily or almost daily and regular CBCs are run until a decrease in
the number of red blood cells is seen. This is basically a wait-and-see
Your doctor may prescribe low-dose aspirin to thin the blood
and prevent blood clots. The low-dose aspirin significantly reduces the risk
for heart attacks and stroke.
Factors that increase your risk of developing blood clots
- a history of
prior blood clots
- increasing age
- high blood
High-risk patients may require more specialized treatment,
using either hydroxyurea or interferon alpha.
Hydroxyurea suppresses the
production of red blood cells. This reduces the risk for clots, but increases
the risk of leukemia.
prevent clots but is expensive and has a high risk of fever and flu-like side
effects. Patients with thyroid and/or mental disorders are to avoid this
In December 2014, the U.S. Food and Drug Administration approved Jakafi
(ruxolitinib) for the treatment of PV. The medication had been previously used
to treat myelofibrosis. Doctors prescribe Jakafi to patients who cannot
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.
What Is the Long-Term Outlook for PV?
PV is a chronic disorder. Treatment works to decrease the
amount of red blood cells being produced by the bone marrow and to prevent
blood clots from forming. Patients who strictly adhere to treatment may be able
to live without complications.