What Is Polycythemia Vera?
Polycythemia vera (POL-e-si-THE-me-ah VE-ra), or PV,
is a rare blood disease in which your body makes too many red blood cells.
These extra red blood cells make your blood thicker than normal. The thickened
blood flows more slowly through your small blood vessels and can form clots.
These clots can cause
heart
attack and
stroke.
Blood cells are formed in your bone marrowthe
soft tissue inside bones. In addition to red blood cells, your blood contains
two other types of cells: white blood cells to help fight infection and
platelets to help your blood clot. If you have PV, your bone marrow produces
too many red blood cells, but it also can make too many white blood cells and
platelets.
Red blood cells also are called RBCs or erythrocytes
(eh-RITH-ro-sites). Normal red blood cells look like doughnuts without holes in
the center and have an average lifespan of 120 days. Red blood cells contain
hemoglobin (HEE-muh-glow-bin), an iron-rich protein that gives blood its red
color and carries oxygen to the body. Red blood cells also remove carbon
dioxide, a waste product, from cells and carry it to the lungs to be
exhaled.
Important General Information
PV is a rare, chronic disease that can be fatal if
not diagnosed and treated. The cause of PV is not known. It develops slowly and
may not produce symptoms for many years. Sometimes, your symptoms can be vague
and nonspecific. Many people find out they have PV from blood tests done for
other reasons. It is more common in adult males 60 years or older. It is very
rare in people younger than 20 years.
With PV, thicker than normal blood slows down the
flow of blood to all parts of your body. Clots can form more easily, which can
block blood flow through arteries or veins. The slower flow of blood means your
organs dont receive enough oxygen. The shortage of oxygen can lead to
angina,
congestive
heart failure, and gout. Slower blood flow also deprives your arms, legs,
lungs, and eyes of the oxygen they need to perform normally. This can cause
headaches, dizziness, itching, and problems with your vision, such as blurred
or double vision.
PV may also cause you to develop stomach ulcers and
kidney stones.
A small number of people with PV may develop
myelofibrosis (MY-e-lo-fi-BRO-sis), a condition in which your bone marrow is
replaced by fibrous (scar) tissue. The abnormal bone marrow cells may begin to
grow out of control. This abnormal growth can lead to acute myelogenous
(my-e-LOJ-e-nus) leukemia (AML), a disease that worsens very quickly. In AML,
too many immature white blood cells are found in the blood and bone marrow.
Outlook
PV is a serious illness that can lead to death if it
is not treated.
PV can be controlled with treatment, but no cure
exists. If you think you or someone you know might have PV, it is important to
talk to your doctor about it. Some people with PV need only minimal care.
Others will need more intensive treatment. Treatment can control PV and lessen
the risk of blood clots, heart attack, and stroke that can result from the
disease.
Other Names for Polycythemia Vera
- Primary polycythemia
- Polycythemia rubra vera
- Myeloproliferative (MY-e-lo-pro-LIF-er-a-tiv)
disorder
- Erythremia (ER-i-THRE-me-ah)
- Splenomegalic (SPLE-no-me-GA-lic)
polycythemia
- Vaquez disease
- Osler disease
- Polycythemia with chronic cyanosis
(SI-ah-NO-sis)myelopathic (MY-e-lo-PATH-ik) polycythemia
- Erythrocytosis (e-RITH-ro-si-TO-sis)
megalosplenica (MEG-ah-lo-SPLE-ne-kah)
- Cryptogenic (KRIP-to-JEN-ik) polycythemia
What Causes Polycythemia Vera?
Polycythemia vera (PV) also is known as primary
polycythemia. A mutation, or change, in the body's JAK 2 gene causes PV. The
JAK 2 gene makes an important protein that helps the body produce blood cells.
What causes the change in the JAK 2 gene isn't known. PV isn't passed from
parent to child. However, in some families, there may be a tendency for the JAK
2 gene to mutate.
There is another kind of polycythemia not related to
the JAK 2 gene. This is called secondary polycythemia. The cause of secondary
polycythemia is known. It is caused by long-term exposure to low levels of
oxygen. Long-term lack of oxygen can cause your body to produce more of the
hormone erythropoietin (EPO). EPO increases the production of red blood cells
above normal levels, leading to thickening of the blood as in PV. People who
smoke, spend long hours at high altitudes (such as mountaineers and pilots), or
have severe lung or heart disease may develop secondary polycythemia. In some
cases, secondary polycythemia can be cured, depending on whether the underlying
cause can be controlled or cured.
Who Is At Risk for Polycythemia Vera?
Polycythemia vera (PV) is a very rare blood disease.
There are five new cases of PV per year for every 1 million people. It is more
common in adults who are older than 60 years and is rarely found in people who
are younger than 20 years. Men have a greater risk of developing PV than
women.
What Are the Signs and Symptoms of Polycythemia
Vera?
Major Signs and Symptoms
Polycythemia vera (PV) develops very slowly. You may
not see signs and symptoms of PV for years after you have the condition. The
signs and symptoms of PV are the result of the above normal thickness of your
blood. This slows the flow of blood and the oxygen blood carries to all parts
of your body. Without enough oxygen, the parts of your body can have problems
functioning normally.
The most common signs and symptoms of PV include
headache, dizziness, weakness, shortness of breath, difficulty breathing when
youre lying down, feelings of pressure or fullness on the left side of
the abdomen due to enlargement of the spleen, double or blurred vision, blind
spots, itching all over (especially after a warm bath), reddened face, burning
sensation in your skin (especially your hands and feet), bleeding from your
gums, more than normal bleeding from small cuts, and unexplained weight loss.
In rare cases, you may experience pain in your bones if you have PV.
Possible Complications
If you have PV, the above normal thickness of your
blood and slower blood flow can create serious health problems for you. The
most serious complication of PV is that it may cause your blood to form clots.
Blood clots can cause you to suffer a
heart
attack or
stroke. They also can cause your liver and spleen to enlarge.
Blood clots in the liver and spleen can cause sudden and intense pain. The high
levels of red blood cells that cause PV can lead to stomach ulcers, gout, or
kidney stones.
How Is Polycythemia Vera Diagnosed?
You may have polycythemia vera (PV) before signs or
symptoms appear. Many times, doctors discover their patients have PV through
routine blood tests performed for other reasons. If you have no clear symptoms
for PV, but show higher than normal levels of hemoglobin and hematocrit
(he-MAT-o-krit) in your blood test, your doctor may want to do more tests.
Doctors diagnose PV based on symptoms, physical
exam, age, test results, and overall health, including other chronic diseases.
The doctor will find out as much as possible about your medical history. Your
doctor will look for signs of polycythemia during your physical exam, including
enlargement of the spleen, reddened skin on the face, and bleeding from the
gums. If your doctor confirms that you have polycythemia, the next step is to
determine if you have PV or secondary polycythemia.
Often, your medical history and physical exam can
confirm which type of polycythemia you have. If not, your doctor may order
tests that check the level of erythropoietin (EPO) in your blood. Patients with
PV have extremely low levels of EPO. Patients with normal to high levels of EPO
in their blood more than likely suffer from secondary polycythemia.
Specialists Involved
If your primary care doctor suspects you have PV,
you may be referred to a hematologist (a doctor who is an expert in treating
blood conditions).
Diagnostic Tests and Procedures
The doctor treating you may order a number of
different blood tests to diagnose PV. These tests include a complete blood
count (CBC), conducted along with other tests if necessary.
- The CBC counts the numbers of all three types of
blood cellsred blood cells that carry oxygen, white blood cells that
fight infection, and platelets that help clot the blood. If your CBC shows
higher than normal counts of these cells, especially the red blood cells, you
may have PV.
- The CBC also measures hemoglobin, the iron-rich
protein in red blood cells that carries oxygen through the body. A higher than
normal hemoglobin level may be a sign that you have PV.
- The hematocrit part of the CBC measures the
percentage of blood that consists of red blood cells. A higher than normal
hematocrit level may be a sign that you have PV.
Your doctor may order additional blood tests to
confirm a diagnosis of PV:
- A blood smearA sample of your blood is
viewed under a microscope to collect information about the number and shape of
blood cells. Your doctor will examine the smear for the high concentration of
red blood cells seen in PV and for abnormal types of blood cells that are seen
in myelofibrosis and other conditions related to PV.
- Arterial blood gas testA sample of your
blood is taken from an artery to measure the amount of oxygen, carbon dioxide,
and pH (acidity) in the blood. If your test results show a lower than normal
level of oxygen in your blood, it may be a sign you have PV.
- EPO levelYour blood is tested to measure
the level of EPO, a hormone that stimulates bone marrow to produce new blood
cells. If you have PV, this test result will show lower than normal levels of
EPO in your blood.
- Red blood cell massThis test usually takes
place in a hospital in the nuclear medicine department. The health professional
performing the test takes a sample of your blood. A very weak radioactive dye
is mixed with your blood sample. The weak dye attaches itself to the red blood
cells and plasma in your sample. The tagged cells in your sample are injected
back into your bloodstream and spread quickly throughout your body. By taking
another sample of your blood, or using special cameras sensitive to the dye,
technicians can figure out the total number of red blood cells in your body.
Higher than normal red blood cell counts may be a sign you have PV.
In some cases, your doctor may want to do a bone
marrow biopsy or aspiration. A bone marrow biopsy is a minor surgical procedure
your doctor performs to remove a small amount of bone marrow tissue with a
needle from your body. In a bone marrow aspiration, your doctor removes a small
amount of bone marrow fluid through a needle. Bone marrow biopsy or aspiration
tests whether your bone marrow is healthy and producing a normal amount of
blood cells. If the test shows that your bone marrow is producing higher than
normal amounts of blood cells, it may be a sign you have PV.
How Is Polycythemia Vera Treated?
Your doctor may treat your polycythemia vera (PV)
with a number of methods, either separate or in combination. Your treatment
options may include phlebotomy (fle-BOT-o-me), medicines, or biological
therapy.
Goals of Treatment
PV cannot be cured. The goals of treating PV are to
control your symptoms and reduce the risk of complications, especially
stroke or
heart
attack, caused by thickened blood and blood clots. This is done by reducing
the number of red blood cells and hemoglobin in your blood toward normal
levels. Reducing the number of red blood cells and hemoglobin brings the
thickness of your blood closer to normal levels. Blood with normal thickness
flows more easily through the arteries. This reduces the chances that blood
clots will form that could cause you to have a stroke or heart attack. Blood
with normal thickness delivers oxygen more efficiently to all parts of your
body. This can help reduce some of the signs and symptoms PV causes, such as
headaches, vision problems, and itching.
Studies show that treatment of PV greatly improves
your chances of living longer.
Specific Types of Treatment
Phlebotomy
In phlebotomy, your doctor or technician removes
some of your blood from a vein (similar to what is done when you donate blood).
A needle is inserted into your vein, and your blood flows through an airtight
tube into a sterile container or bag. This reduces the number of red blood
cells in your system and begins the process of bringing your blood thickness
closer to normal levels. Typically, a pint (1 unit) of blood is removed each
week until your hematocrit (the measure of what percentage of a tube of blood
consists of red blood cells) approaches a normal level. Then, you may continue
to have phlebotomy performed every few months as needed.
Medicines
Your doctor may prescribe medicines to keep your
bone marrow from making too many red blood cells. You may take hydroxyurea
(hi-DROK-se-u-RE-ah), a chemotherapy medicine, to reduce the numbers of red
blood cells and platelets in your blood. By limiting or reducing the number of
red blood cells in your blood, this medicine helps bring your blood thickness
and blood flow closer to normal levels.
Your doctor may advise you to take aspirin to
relieve bone pain and the burning sensation in hands or feet that you may
experience as a result of PV. Aspirin also reduces the chance of blood
clots.
Biological Therapy (Immunotherapy)
This form of treatment uses substances made
naturally in the body to stimulate your immune response against overproduction
of red blood cells. Your doctor may prescribe substances that your body
normally produces, like interferon-alpha, if you have PV. These substances
reduce the overproduction of blood cells by the bone marrow. This helps keep
your blood thickness and blood flow closer to normal levels, reduces the
chances of blood clots, and may reduce some of the signs and symptoms of
PV.
Other Types of Treatment
If you have itching as a result of PV, your doctor
may prescribe a number of prescription medicines to ease the discomfort you
feel. These include cholestyramine, cyproheptadine, cimetidine, or psoralen.
Your doctor also may prescribe ultraviolet light treatment and antihistamines
to help relieve your itching.
Your doctor may prescribe allopurinol if the level
of uric acid in your blood is higher than normal.
Your doctor may decide to treat you with radioactive
phosphorous (P32) to suppress overactive bone marrow cells. This
helps reduce the number of red blood cells in your blood, and keeps your
bloods thickness and flow closer to normal levels.
How Can Polycythemia Vera Be Prevented?
Polycythemia vera (PV) cannot be prevented. But with
treatment, symptoms and complications can be prevented or delayed.
Secondary polycythemia may be prevented in some
cases by not doing things that deprive your body of normal levels of oxygen for
a long time. Some things, like mountain climbing, living at high altitudes, or
smoking, can be avoided or stopped.
People with serious lung or heart disease may
develop secondary polycythemia. In such cases, your doctor will treat the
disease that deprives your body of oxygen as effectively as possible. Living a
healthy lifestyle that reduces the chances of developing heart and lung disease
will help you prevent secondary polycythemia as well.
Living With Polycythemia Vera
Preventing Complications
You may have polycythemia vera (PV) long before you
see signs or symptoms of the disease. If you have PV, the sooner it is
diagnosed, the sooner your doctor can begin treating you.
Activities such as walking can help improve your
blood circulation if you have PV. Moderate exercise that safely increases your
heart rate improves the flow of blood to the parts of your body. Improving
blood flow reduces the chances that you might develop blood clots. Leg and
ankle stretching exercises also can help improve your blood circulation.
If you have PV, you may experience itchiness all
over as a symptom of the disease. It is important not to damage your skin from
scratching. If bathing or showering causes you to have severe itching, try
using cooler water and gentler soap. Dry your skin carefully and gently after
baths and use moisturizing lotion on the skin.
Due to poor blood flow in the hands and feet that
results from PV, you may be more prone to injury from exposure to cold, heat,
and pressure. If you have PV, it is important for you to avoid prolonged
exposure to extremes in temperature or pressure.
- In cold weather, you should wear warm clothing.
Take particular care with your hands and feet. Warm gloves, socks, and shoes
are very important protection for you.
- Avoid extreme heat. Protect yourself from the
sun. Drink plenty of liquids. Avoid hot tubs, heated whirlpools, or highly
heated baths of any type. Be very careful of tanning booths, sun lamps, or heat
lamps.
- In playing sports or carrying out daily
activities, guard against trauma or situations where your body is put under
pressure. If you are injured, seek treatment as quickly as possible. Tell the
person treating you that you have PV.
- Check your feet regularly and report any sores to
the doctor.
Ongoing Health Care Needs
If you have PV, you will require regular medical
care and monitoring of your condition for the rest of your life. It is
important to see your doctor for any prescribed treatments for your PV. Your
doctor will want to monitor your condition closely. This is important so that
your doctor can detect any changes in your condition and treat them early, if
necessary. Your doctor may need to perform periodic blood tests to determine
the course of the disease. If your doctor prescribes medicine, you will need to
take it as prescribed.
Support Groups
The
Myeloproliferative Disorders Foundation is a foundation that
provides support for and information on PV.
Key Points
- Polycythemia vera (PV) is a rare, chronic disease
in which your body produces too many red blood cells. These extra blood cells
thicken your blood, which can lead to blood clots,
stroke, and
heart
attack.
- Polycythemia vera is also known as primary
polycythemia. A mutation in the JAK 2 gene causes PV, but the cause of the
mutation is not known.
- Secondary polycythemia is caused by long-term
exposure to low levels of oxygen. It is not related to the JAK 2 gene.
- PV is a very rare blood disease. It is more
common in adults older than 60 years and in men.
- The most common signs and symptoms of PV are
pressure or fullness on the left side of the abdomen due to enlargement of the
spleen, headache, double vision, itching all over, reddened face, weakness,
dizziness, and unexplained weight loss.
- PV is diagnosed based on symptoms, physical exam,
age, test results, and overall health.
- The goals of treating PV are to control your
symptoms and reduce the risk of complications caused by thickened blood and
blood clots.
- Treatment may include phlebotomy (removing blood
to reduce the number of red blood cells), medicine, or biological therapy.
- PV cannot be prevented, but treatment can prevent
or delay symptoms and complications. Some cases of secondary polycythemia may
be prevented by not doing things that deprive your body of oxygen for a long
time.
- If you have PV, you will need regular medical
care and monitoring for the rest of your life. It is important to follow the
treatments your doctor prescribes.
Links to Other Information About Polycythemia
Vera
Non-NHLBI Resources
Clinical Trials
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