What Is Polycythemia Vera?
Polycythemia (POL-e-si-THE-me-ah) vera (VAY-rah or
VE-rah), or PV, is a rare blood disease in which your body makes too many red
blood cells.
The extra red blood cells make your blood thicker
than normal. As a result, blood clots can form more easily and block blood flow
through your arteries and veins. This can lead to
heart
attack and
stroke.
Thicker blood also flows more slowly to all parts of
your body, preventing your organs from getting enough oxygen. This can cause
other serious complications, such as
angina
(an-JI-nuh or AN-juh-nuh) and
heart
failure.
Overview
Red blood cells carry oxygen to all parts of your
body. They also remove carbon dioxide (a waste product) from your body's cells
and carry it to the lungs to be exhaled.
Red blood cells are made in your bone marrowa
sponge-like tissue inside the bones. White blood cells and platelets
(PLATE-lets) also are made in your bone marrow. White blood cells help fight
infection. Platelets help your blood clot.
If you have PV, your bone marrow makes too many red
blood cells. It also can make too many white blood cells and platelets.
A mutation, or change, in the bodys JAK2 gene
is the major cause of PV. The JAK2 gene makes an important protein that helps
the body produce blood cells. What causes the change in the JAK2 gene
isnt known. PV generally isnt passed from parent to child.
PV develops slowly and may not cause symptoms for
years. Thus, the disease often is found during routine
blood
tests done for other reasons.
When signs and symptoms do occur, theyre the
result of the thick blood that occurs with PV. This thickness slows the flow of
oxygen-rich blood to all parts of your body. Without enough oxygen, many parts
of your body wont work normally.
For example, slower blood flow deprives your arms,
legs, lungs, and eyes of the oxygen they need. This can cause headaches,
dizziness, itching, and vision problems, such as blurred or double vision.
Outlook
PV is a serious, chronic (ongoing) disease that can
be fatal if not diagnosed and treated. PV cant be cured, but treatments
can help control the disease and its complications.
PV is treated with procedures, medicines, and other
methods. You may need one or more treatments to manage the disease.
Other Names for Polycythemia Vera
- Cryptogenic (KRIP-to-JEN-ik) polycythemia
- Erythremia (ER-i-THRE-me-ah)
- Erythrocytosis (e-RITH-ro-si-TO-sis)
megalosplenica (MEG-ah-lo-SPLE-ne-kah)
- Myelopathic (MY-e-lo-PATH-ik) polycythemia
- Myeloproliferative (MY-e-lo-pro-LIF-er-a-tiv)
disorder
- Osler disease
- Polycythemia rubra vera
- Polycythemia with chronic cyanosis
(SI-ah-NO-sis)
- Primary polycythemia
- Splenomegalic (SPLE-no-me-GA-lic)
polycythemia
- Vaquez disease
What Causes Polycythemia Vera?
Polycythemia vera (PV) also is known as primary
polycythemia. A mutation, or change, in the bodys JAK2 gene is the main
cause of PV. The JAK2 gene makes an important protein that helps the body
produce blood cells.
What causes the change in the JAK2 gene isn't known.
PV generally isnt passed from parent to child. However, in some families,
the JAK2 gene may have a tendency to mutate. Other, unknown genetic factors
also may play a role in causing PV.
Secondary Polycythemia
Another type of polycythemia, called secondary
polycythemia, isnt related to the JAK2 gene. Long-term exposure to low
oxygen levels causes secondary polycythemia.
A lack of oxygen over a long period can cause your
body to make more of the hormone erythropoietin (EPO). High levels of EPO can
prompt your body to make more red blood cells than normal. This leads to
thicker blood, as seen in PV.
People who smoke, spend long hours at high
altitudes, or have severe lung or heart disease may develop secondary
polycythemia.
Rarely, tumors can make and release EPO, or certain
blood problems can cause the body to make more EPO.
Sometimes secondary polycythemia can be
curedit depends on whether the underlying cause can be stopped,
controlled, or cured.
Who Is At Risk for Polycythemia Vera?
Polycythemia vera (PV) is a rare blood disease. Only
five new cases occur each year per every 1 million people.
The disease is more common in adults who are older
than 60. PV rarely affects people who are younger than 20. Men are at slightly
higher risk for PV than women.
What Are the Signs and Symptoms of Polycythemia
Vera?
Polycythemia vera (PV) develops slowly. The disease
may not cause signs or symptoms for years.
When signs and symptoms do occur, theyre the
result of the thick blood that occurs with PV. This thickness slows the flow of
oxygen-rich blood to all parts of your body. Without enough oxygen, many parts
of your body wont work normally.
The most common signs and symptoms of PV
include:
- Headache, dizziness, and weakness
- Shortness of breath and problems breathing while
lying down
- Feelings of pressure or fullness on the left side
of the abdomen due to an enlarged spleen
- Double or blurred vision and blind spots
- Itching all over (especially after a warm bath),
reddened face, and a burning feeling on your skin (especially your hands and
feet)
- Bleeding from your gums and heavy bleeding from
small cuts
- Unexplained weight loss
- Fatigue (tiredness)
In rare cases, people who have PV may have pain in
their bones.
Polycythemia Vera Complications
If you have PV, the thickness of your blood and the
slowed blood flow can cause serious health problems.
Blood clots are the most serious complication of PV.
Blood clots can cause
heart
attack and
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 lack of oxygen-rich blood to your organs also
can lead to
angina
(chest pain) and
heart
failure. The high levels of red blood cells that PV causes can lead to
stomach ulcers, gout, or kidney stones.
A small number of people who have PV may develop
myelofibrosis (MY-e-lo-fi-BRO-sis). This is a condition in which your bone
marrow is replaced by scar tissue. 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.
How Is Polycythemia Vera Diagnosed?
Polycythemia vera (PV) may not cause signs or
symptoms for years. Thus, the disease often is found during routine
blood
tests done for other reasons. If the results of your blood tests
arent normal, your doctor may want to do more tests.
Your doctor will diagnose PV based on your signs and
symptoms, your age and overall health, your medical history, a physical exam,
and the results from tests.
During the physical exam, your doctor will look for
signs of PV. He or she will check for an enlarged spleen, red skin on your
face, and bleeding from your gums.
If your doctor confirms that you have polycythemia,
the next step is to find out whether you have primary polycythemia
(polycythemia vera) or secondary polycythemia.
Your medical history and physical exam may confirm
which type of polycythemia you have. If not, you may have tests that check the
level of the hormone erythropoietin (EPO) in your blood.
People who have PV have very low levels of EPO.
People who have secondary polycythemia usually have normal or high levels of
EPO.
Specialists Involved
If your primary care doctor thinks you have PV, he
or she may refer you to a hematologist. This is a doctor who specializes in
diagnosing and treating blood diseases and conditions.
Diagnostic Tests
You may have a number of different blood tests to
diagnose PV. These tests include a
complete
blood count (CBC) and other tests, if necessary.
Complete Blood Count
Often, the first test used to diagnose PV is a CBC.
The CBC measures many different parts of your blood.
This test checks your hemoglobin (HEE-muh-glow-bin)
and hematocrit (hee-MAT-oh-crit) levels. Hemoglobin is the iron-rich protein in
red blood cells that carries oxygen to the body. Hematocrit is a measure of how
much space red blood cells take up in your blood. A high level of hemoglobin or
hematocrit may be a sign of PV.
The CBC also checks the number of red blood cells,
white blood cells, and platelets in your blood. Abnormal results may be a sign
of PV, a blood disorder, an infection, or another condition.
Other Blood Tests
Blood smear. For this test, a small
sample of blood is drawn from a vein, usually in your arm. The sample of blood
is put on a glass slide. A microscope is then used to look at your red blood
cells.
A blood smear can show whether you have a
higher-than-normal number of red blood cells. The test also can show abnormal
types of blood cells that are linked to myelofibrosis and other conditions
related to PV.
Erythropoietin level. This blood
test measures the level of EPO in your blood. EPO is a hormone that stimulates
bone marrow to make new blood cells. People who have PV have very low levels of
EPO. People who have secondary polycythemia usually have normal or high levels
of EPO.
Bone Marrow Tests
Bone
marrow tests are used to check whether your bone marrow is healthy. These
tests also show whether your bone marrow is making normal amounts of blood
cells.
If the tests show that your bone marrow is making
too many blood cells, it may be a sign that you have PV.
How Is Polycythemia Vera Treated?
Polycythemia vera (PV) cant be cured. However,
treatments can help control the disease and its complications. PV is treated
with procedures, medicines, and other methods. You may need one or more
treatments to manage the disease.
Goals of Treatment
The goals of treating PV are to control symptoms and
reduce the risk of complications, especially
heart
attack and
stroke. To do this, PV treatments reduce the number of red
blood cells and the level of hemoglobin (an iron-rich protein) in your blood.
This brings the thickness of your blood closer to normal.
Blood with normal thickness flows better through the
blood vessels. This reduces the chance that blood clots will form and cause a
heart attack or stroke.
Blood with normal thickness also ensures that your
body gets enough oxygen. This can help reduce some of the signs and symptoms
that PV causes, such as headaches, vision problems, and itching.
Studies show that treating PV greatly improves your
chances of living longer.
Treatments To Lower Red Blood Cell Levels
Phlebotomy
Phlebotomy (fle-BOT-o-me) is a procedure that
removes some blood from your body. A needle is inserted into your vein, and
your blood flows through an airtight tube into a sterile container or bag. The
process is similar to the process of donating blood.
Phlebotomy reduces the number of red blood cells in
your system and starts to bring your blood thickness closer to normal.
Typically, a pint (1 unit) of blood is removed each week until your hematocrit
level approaches normal. (Hematocrit is the measure of how much space red blood
cells take up in your blood.)
You may need to have phlebotomy done every few
months.
Medicines
Your doctor may prescribe medicines, such as
hydroxyurea or interferon-alpha, to keep your bone marrow from making too many
red blood cells.
Hydroxyurea is a medicine generally used to treat
cancer. This medicine can reduce the number of red blood cells and platelets in
your blood. As a result, this medicine helps improve your blood flow and bring
the thickness of your blood closer to normal.
Interferon-alpha is a substance that your body
normally produces. It also can be used to treat PV. Interferon-alpha can prompt
your immune system to fight bone marrow cells that are making too many red
blood cells. As a result, this treatment can help lower the number of red blood
cells in your body and maintain blood flow and blood thickness thats
close to normal.
Radiation Treatment
Radiation treatment can help suppress overactive
bone marrow cells. This helps reduce the number of red blood cells in your
blood. It also helps keep your blood flow and blood thickness close to normal.
However, radiation treatment can raise your risk for
leukemia (blood cancer) and other blood diseases.
Treatments for Side Effects
Aspirin can relieve bone pain and burning feelings
in your hands or feet that you may have as a result of PV. Aspirin also thins
your blood, so it reduces the chance of blood clots forming.
Aspirin can have side effects, including bleeding in
the stomach and intestines. For this reason, its important to take
aspirin only as your doctor recommends.
If your PV causes itching, your doctor may prescribe
medicines to ease the discomfort. Your doctor also may prescribe ultraviolet
light treatment to help relieve your itching.
Other ways to reduce itching include:
- Avoiding hot baths. Cooler water can limit the
irritation to your skin.
- Gently patting yourself dry after bathing.
Vigorous rubbing with a towel can irritate your skin.
- Taking starch baths. Add half a box of starch to
a tub of lukewarm water. This can help soothe your skin.
Experimental Treatments
Researchers are studying other treatments for PV. An
experimental treatment for itching involves taking low doses of selective
serotonin reuptake inhibitors (SSRIs). This type of medicine is used to treat
depression. In clinical trials, SSRIs reduced itching in people who had PV.
Imatinib mesylate is a medicine thats approved
for treating leukemia. In clinical trials, it has helped reduce the need for
phlebotomy in people who have PV. It also has helped reduce the size of
enlarged spleens.
Researchers also are trying to develop a treatment
that can block or limit the effects of an abnormal JAK2 gene. (A mutation, or
change, in the JAK2 gene is the major cause of PV.)
How Can Polycythemia Vera Be Prevented?
Primary polycythemia (polycythemia vera) cant
be prevented. However, with proper treatment, you can prevent or delay symptoms
and complications.
Sometimes you can prevent secondary polycythemia by
avoiding things that deprive your body of oxygen for long periods. For example,
you can avoid mountain climbing, living at a high altitude, or smoking.
People who have serious lung or heart diseases may
develop secondary polycythemia. Treatment for the underlying disease may
improve the secondary polycythemia. Following a healthy lifestyle to lower your
risk for heart and lung diseases also will help you prevent secondary
polycythemia.
Living With Polycythemia Vera
Polycythemia vera (PV) develops very slowly. It may
not cause signs or symptoms for years. If you have PV, the sooner its
diagnosed, the sooner your doctor can begin treating you. With proper
treatment, you can prevent or delay complications.
Preventing Complications
Moderate physical activities, such as walking, can
safely increase your heart rate and improve blood flow to your body. Improving
blood flow lowers your risk for blood clots. Leg and ankle stretching exercises
also can help improve your blood flow.
PV may cause itching all over your body. It's
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.
Carefully and gently dry your skin after baths, and use moisturizing lotion on
your skin. Starch baths also may help ease itchy skin.
PV causes poor blood flow in your hands and feet. As
a result, you may be more prone to injury due to cold, heat, and pressure. If
you have PV, avoid long-term exposure to extremes in temperature or pressure.
For example:
- Take extra care of your hands and feet in cold
weather. Wear warm gloves, socks, and shoes.
- Avoid extreme heat, and protect yourself from the
sun. Drink plenty of liquids. Avoid hot tubs, heated whirlpools, or hot baths
of any type. Tanning booths, sun lamps, and heat lamps can damage your skin if
you have PV.
- Guard against trauma or situations where you may
be at high risk of injury, such as during sports or strenuous activities. If
you're injured, seek treatment right away. Tell the person treating you that
you have PV.
- Check your feet regularly and report any sores to
your doctor.
Getting Ongoing Care
If you have PV, you will need lifelong medical care
for the disease. Talk to your doctor about how often to schedule followup
visits.
Routine care will allow your doctor to detect any
changes with your PV and treat them early, if needed. You may need periodic
blood
tests to show whether the disease is progressing.
Follow your treatment plan and take all of your
medicines exactly as your doctor prescribes.
Key Points
- Polycythemia vera (PV) is a rare blood disease in
which your body makes too many red blood cells.
- The extra red blood cells make your blood thicker
than normal. As a result, blood clots can form more easily and block blood flow
through your arteries and veins. This can lead to
heart
attack and
stroke.
- Thicker blood also flows more slowly to all parts
of your body, preventing your organs from getting enough oxygen. This can cause
other serious complications, such as as
angina
(chest pain) and
heart
failure.
- PV also is known as primary polycythemia. A
mutation, or change, in the JAK2 gene is the major cause of PV. This gene makes
an important protein that helps the body produce blood cells. What causes the
change in the JAK2 gene isn't known.
- Another type of polycythemia, called secondary
polycythemia, isnt related to the JAK2 gene. Long-term exposure to low
oxygen levels causes secondary polycythemia.
- PV is a very rare blood disease. Its more
common in adults older than 60, and its slightly more common in men.
- The most common signs and symptoms of PV are
headache, dizziness, weakness, shortness of breath, feelings of pressure or
fullness on the left side of the abdomen (due to an enlarged spleen), double or
blurred vision and blind spots, itching, reddened face, a burning feeling on
the skin (especially the hands and feet), bleeding from the gums, heavy
bleeding from small cuts, unexplained weight loss, and fatigue
(tiredness).
- PV may not cause signs or symptoms for years.
Thus, the disease often is found during routine blood tests done for other
reasons. PV is diagnosed based on your signs and symptoms, age and overall
health, medical history, a physical exam, and test results.
- PV can't be cured. However, treatments can help
control the disease and its complications. PV is treated with procedures,
medicines, and other methods.
- The goals of treating PV are to control your
symptoms and reduce the risk of complications due to thickened blood and blood
clots.
- Primary polycythemia cant be prevented.
However, with proper treatment, you can prevent or delay symptoms and
complications. Avoiding things that deprive your body of oxygen for long
periods may prevent some cases of secondary polycythemia.
- If you have PV, you will need lifelong medical
care for the disease. Talk to your doctor about how often to schedule followup
visits. Routine care will allow your doctor to detect any changes with your PV
and treat them early, if needed. Follow your treatment plan and take all of
your medicines as your doctor prescribes.
Links to Other Information About Polycythemia
Vera
Non-NHLBI Resources
Clinical Trials
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