What Is Aplastic Anemia?
Aplastic anemia (a-PLAS-tik uh-NEE-me-uh) is a blood
disorder in which the body’s bone marrow doesn’t make enough new
blood cells. Bone marrow is a sponge-like tissue inside the bones. It makes
stem cells that develop into red blood cells, white blood cells, and platelets
(PLATE-lets).
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. White blood cells help your body fight
infections. Platelets are blood cell fragments that stick together to seal
small cuts or breaks on blood vessel walls and stop bleeding.
It's normal for blood cells to die. The lifespan of
red blood cells is about 120 days. White blood cells live less than 1 day.
Platelets live about 6 days. As a result, your bone marrow must constantly make
new blood cells.
If your bone marrow is unable to make enough new
blood cells, a number of health problems can occur. These include
arrhythmias
(ah-RITH-me-ahs), an enlarged heart,
heart
failure, infections, and bleeding. Severe aplastic anemia can even cause
death.
Overview
Aplastic anemia is a type of
anemia.
The term "anemia" usually refers to a condition in which your blood has a lower
than normal number of red blood cells. Anemia also can occur if your red blood
cells don't contain enough hemoglobin (HEE-muh-glow-bin). This iron-rich
protein helps carry oxygen to your body.
In people who have aplastic anemia, the body
doesn’t make enough red blood cells, white blood cells, or platelets. This
is because the bone marrow's stem cells are damaged. (Aplastic anemia also is
sometimes called bone marrow failure.)
A number of diseases, conditions, and factors can
cause damage to the stem cells. These causes can be acquired or inherited.
"Acquired" means you aren’t born with the condition, but you develop it.
"Inherited" means your parents passed the gene for the condition on to you.
In more than half of the people who have aplastic
anemia, the cause is unknown.
Outlook
Aplastic anemia is a rare, but serious disorder. In
the United States, about 500–1,000 people develop this type of anemia each
year. The disorder is two to three times more common in Asian countries.
Aplastic anemia can develop suddenly or slowly. It
tends to get worse over time, unless its cause is found and treated. Treatments
for aplastic anemia include
blood
transfusions,
blood
and marrow stem cell transplants, and medicines.
With prompt and proper care, many people who have
aplastic anemia can be successfully treated. Blood and marrow stem cell
transplants may offer a cure for some people who have aplastic anemia.
What Causes Aplastic Anemia?
Damage to the bone marrow's stem cells causes
aplastic anemia. When stem cells are damaged, they don't grow into healthy
blood cells.
The cause of the damage can be acquired or
inherited. Acquired aplastic anemia is more common, and sometimes it's only
temporary. Aplastic anemia that’s inherited is rare.
In more than half of the people who have aplastic
anemia, the cause of the disorder is unknown. Some research suggests that stem
cell damage may occur because the body's immune system attacks its own cells by
mistake.
Acquired Causes
A number of diseases, conditions, and factors can
cause aplastic anemia, including:
- Toxins, such as pesticides, arsenic, and
benzene
- Radiation and chemotherapy (treatments for
cancer)
- Medicines, such as chloramphenicol (an antibiotic
rarely used in the United States)
- Infectious diseases, such as hepatitis,
Epstein-Barr virus, cytomegalovirus (si-to-MEG-a-lo-VI-rus), parvovirus B19,
and HIV
- Autoimmune disorders, such as lupus and
rheumatoid arthritis
In some cases, cancer from another part of the body
can spread to the bone and cause aplastic anemia.
Inherited Causes
Certain inherited conditions can damage the stem
cells and lead to aplastic anemia. Examples include
Fanconi
anemia, Shwachman-Diamond syndrome, dyskeratosis congenita, and
Diamond-Blackfan anemia.
Who Is At Risk for Aplastic Anemia?
Aplastic anemia is a rare, but serious blood
disorder. In the United States, about 500–1,000 people develop this type
of anemia each year. The disorder is two to three times more common in Asian
countries.
People of all ages can get aplastic anemia. However,
it's most common in adolescents, young adults, and the elderly. Men and women
are equally likely to have it.
Your risk for aplastic anemia is higher if you
have:
- Been exposed to toxins
- Taken certain medicines or had radiation or
chemotherapy treatment (treatments for cancer)
- Certain infectious diseases, autoimmune
disorders, or inherited conditions
For more information, see
"What Causes Aplastic Anemia?"
What Are the Signs and Symptoms of Aplastic
Anemia?
Low numbers of red blood cells, white blood cells,
and platelets cause most of the signs and symptoms of aplastic anemia.
Signs and Symptoms of Low Blood Cell Counts
Red Blood Cells
The most common symptom of a low red blood cell
count is fatigue (feeling tired or weak). Not having enough hemoglobin in the
blood causes fatigue. Hemoglobin is an iron-rich protein in red blood cells
that carries oxygen to the body.
A low red blood cell count also can cause shortness
of breath; dizziness, especially when standing up; headache; coldness in your
hands or feet; pale skin, gums, and nail beds; and chest pain.
If you don't have enough hemoglobin-carrying red
blood cells, your heart has to work harder to circulate the reduced amount of
oxygen in your blood. This can lead to
arrhythmias,
heart
murmur, an enlarged heart, or even
heart
failure.
White Blood Cells
White blood cells help fight infections. Signs and
symptoms of a low white blood cell count include fevers, frequent infections
that can be severe, and flu-like illnesses that linger.
Platelets
Platelets stick together to seal small cuts on blood
vessel walls and stop bleeding. People who have low platelet counts tend to
bruise and bleed easily, and the bleeding may be hard to stop.
Common types of bleeding linked to a low platelet
count include nosebleeds, bleeding gums, pinpoint red bleeding spots on the
skin, and blood in the stool. Women also may have heavy menstrual bleeding.
Other Signs and Symptoms
Aplastic anemia can cause signs and symptoms that
aren’t directly related to low blood cell counts. Examples include nausea
(feeling sick to your stomach) and skin rashes.
Paroxysmal Nocturnal Hemoglobinuria
About one-third of people who have aplastic anemia
have a condition called paroxysmal nocturnal hemoglobinuria (PNH). This is a
red blood cell disorder. Most people who have PNH don’t have any signs or
symptoms.
If symptoms do occur, they may include:
- Shortness of breath
- Swelling or pain in the abdomen or swelling in
the legs caused by blood clots
- Blood in the urine
- Headache
- Jaundice (a yellowish color of the eyes or
skin)
In people who have aplastic anemia with PNH, either
condition can develop first.
How Is Aplastic Anemia Diagnosed?
Your doctor will diagnose aplastic anemia based on
your medical and family histories, a physical exam, and test results.
Once your doctor knows the cause and severity of the
condition, he or she can create a treatment plan for you.
Specialists Involved
If your primary care doctor thinks you have aplastic
anemia, he or she may refer you to a hematologist. A hematologist is a doctor
who specializes in treating blood diseases and disorders.
Medical and Family Histories
To learn about your medical history, your doctor may
ask a number of questions. He or she may ask whether:
- You've had
anemia
or a condition that can cause anemia
- You have shortness of breath, dizziness,
headaches, or other signs and symptoms of anemia
- You've been exposed to certain toxins or
medicines
- You've had radiation or chemotherapy (treatments
for cancer)
- You've had infections or signs of infections,
such as fever
- You bruise or bleed easily
Your doctor also may ask whether you have family
members who have ever had anemia or other blood disorders.
Physical Exam
Your doctor will do a physical exam to check for
signs of aplastic anemia. He or she will try to find out how severe the
disorder is and what’s causing it.
The exam may include checking for pale or yellowish
skin, signs of bleeding, and signs of infection. Your doctor may listen to your
heart and lungs for abnormal heartbeats and breathing sounds. He or she also
may feel your abdomen to check the size of your liver and feel your legs for
swelling.
Diagnostic Tests
A number of tests are used to diagnose aplastic
anemia. These tests help:
- Confirm a diagnosis of aplastic anemia, look for
its cause, and find out how severe it is
- Rule out other conditions that may cause similar
symptoms
- Check for paroxysmal nocturnal hemoglobinuria
(PNH)
Complete Blood Count
Often, the first test used to diagnose aplastic
anemia is a
complete
blood count (CBC). The CBC measures many different parts of your blood.
This test checks your hemoglobin and hematocrit
(hee-MAT-oh-crit) levels. Hemoglobin is an 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 low level of hemoglobin or hematocrit is a
sign of anemia.
The normal range of these levels varies in certain
racial and ethnic populations. Your doctor can explain your test results to
you.
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 aplastic anemia, an infection, or another condition.
Finally, the CBC looks at mean corpuscular
(kor-PUS-kyu-lar) volume (MCV). MCV is a measure of the average size of your
red blood cells. The results may be a clue as to the cause of your anemia.
Reticulocyte Count
A reticulocyte (re-TIK-u-lo-site) count measures the
number of young red blood cells in your blood. The test shows whether your bone
marrow is making red blood cells at the correct rate. People who have aplastic
anemia have low reticulocyte levels.
Bone Marrow Tests
Bone
marrow tests show whether your bone marrow is healthy and making enough
blood cells. The two bone marrow tests are aspiration (as-pi-RA-shun) and
biopsy.
Bone marrow aspiration may be done to find out if
and why your bone marrow isn't making enough blood cells. For this test, your
doctor removes a small amount of bone marrow fluid through a needle. The sample
is examined under a microscope to check for faulty cells.
A bone marrow biopsy may be done at the same time as
an aspiration or afterward. For this test, your doctor removes a small amount
of bone marrow tissue through a needle.
The tissue is examined to check the number and types
of cells in the bone marrow. In aplastic anemia, the bone marrow has a lower
than normal number of all three types of blood cells.
Other Tests
Other conditions can cause symptoms similar to those
of aplastic anemia. Thus, other tests may be needed to rule out those
conditions. These tests may include:
- X ray, computed tomography (CT) scan, or
ultrasound imaging tests. Your doctor may use these tests to look for enlarged
lymph nodes in your abdomen. Enlarged lymph nodes may be a sign of blood
cancer. These tests also may be used to examine the kidneys and the bones in
the arms and hands, which are sometimes abnormal in young people who have
Fanconi
anemia. This type of anemia can lead to aplastic anemia.
- Chest
x ray. This test creates pictures of the structures inside your chest, such
as your heart and lungs. A chest x ray may be used to rule out infections.
- Liver tests and viral studies. These tests are
used to check for liver diseases and viruses.
- Tests that check vitamin B12 and folate levels in
the blood. These tests can help rule out anemia due to vitamin deficiency.
Your doctor also may recommend blood tests for PNH
and to check your immune system for antibodies. (Antibodies in the immune
system that attack your own bone marrow cells may cause aplastic
anemia.)
How Is Aplastic Anemia Treated?
Treatments for aplastic anemia include
blood
transfusions,
blood
and marrow stem cell transplants, and medicines. These treatments can
prevent or limit complications, relieve symptoms, and improve quality of
life.
In some cases, a cure may be possible. Blood and
marrow stem cell transplants may cure the disorder in people who are eligible
for a transplant. Removing a known cause of aplastic anemia, such as exposure
to a toxin, also may cure the condition.
Who Needs Treatment
People who have mild or moderate aplastic anemia may
not need treatment as long as the condition doesn’t get worse. People who
have severe aplastic anemia need medical treatment right away to prevent
complications.
People who have very severe aplastic anemia need
emergency medical care in a hospital. Very severe aplastic anemia can be fatal
if it's not treated right away.
Blood Transfusions
People who have aplastic anemia may need blood
transfusions to keep their blood cell counts at acceptable levels.
A blood transfusion is a common procedure in which
blood is given to you through an intravenous (IV) line in one of your blood
vessels. Transfusions require careful matching of donated blood with the
recipient’s blood.
Blood transfusions help relieve the symptoms of
aplastic anemia, but they’re not a permanent treatment.
Blood and Marrow Stem Cell Transplants
A blood and marrow stem cell transplant replaces
damaged stem cells with healthy ones from another person (a donor).
During the transplant, which is like a blood
transfusion, you get donated stem cells through a tube placed in a vein in your
chest. Once the stem cells are in your body, they travel to your bone marrow
and begin making new blood cells.
Blood and marrow stem cell transplants often cure
aplastic anemia in people who are eligible for this type of transplant. The
transplant works best in children and young adults with severe aplastic anemia
who are in good health and who have matched donors.
Older people may be less able to handle the
treatments needed to prepare the body for the transplant. They’re also
more likely to have complications after the transplant.
If you have aplastic anemia, talk to your doctor
about whether a bone and marrow stem cell transplant is an option for you.
Medicines
If you have aplastic anemia, your doctor may
prescribe medicines to:
- Stimulate your bone marrow
- Suppress your immune system
- Prevent and treat infections
Medicines To Stimulate Bone Marrow
Man-made versions of substances that occur naturally
in the body can stimulate the bone marrow to make more blood cells. Examples of
these types of medicines include erythropoietin (e-RITH-ro-PO-e-tin) and
colony-stimulating factors.
These medicines have some risks. You and your doctor
will work together to decide whether the benefits of these medicines outweigh
the risks. If this treatment works well, it can help you avoid the need for
blood transfusions.
Medicines To Suppress the Immune System
Research suggests that some cases of aplastic anemia
may occur because the body’s immune system attacks its own cells by
mistake. For this reason, your doctor may prescribe medicines to suppress your
immune system.
These medicines can allow your bone marrow to start
making blood cells again. These medicines also may help you avoid the need for
blood transfusions.
Medicines that suppress the immune system don’t
cure aplastic anemia. However, they can relieve its symptoms and reduce its
complications.
These medicines often are used for people who
aren’t eligible for a bone and marrow stem cell transplant or who are
waiting for a transplant.
Three medicines—often given together—can
suppress the body’s immune system. They are antithymocyte globulin (ATG),
cyclosporine, and methylprednisolone.
It may take a few months to notice the effects of
these medicines. Most often, as blood cell counts rise, symptoms lessen. Blood
cell counts in people who respond well to these medicines usually don’t
reach normal levels. However, the blood cell counts often are high enough to
allow people to do their normal activities.
People who have aplastic anemia may need long-term
treatment with these medicines.
Medicines that suppress the immune system can have
side effects. They also may increase the risk of developing leukemia
(lu-KE-me-ah) or myelodysplasia (MI-e-lo-dis-PLA-ze-a; MDS). Leukemia is a
cancer of the blood cells. MDS is a condition in which the bone marrow makes
too many faulty blood cells.
Medicines To Prevent and Treat Infections
People who have aplastic anemia may be at risk for
infections due to a low number of white blood cells. Your doctor may prescribe
antibiotic and antiviral medicines to prevent and treat infections.
Living With Aplastic Anemia
With prompt and proper care, most people who have
aplastic anemia can be successfully treated, and some may be cured.
Most people who have the disorder are able to go
back to their normal routines after treatment. However, it may take some time
to get good results from treatment. You may need repeated treatments, or you
may need to try several treatments to find one that works.
It's important to get ongoing medical care to make
sure the disorder doesn't return and to check for possible complications.
Ongoing Care
Treatment for aplastic anemia may cause side effects
or complications. Talk to your doctor about how to cope with these issues.
People who have aplastic anemia may be at higher
risk for infection due to low white blood cell counts. Talk to your doctor
about ways to lower your risk for infection. For example, you may want to:
- Stay away from people who are sick and avoid
large crowds of people.
- Avoid certain kinds of foods that can expose you
to bacteria, such as uncooked foods.
- Wash your hands often.
- Brush and floss your teeth and get regular dental
care to reduce the risk of infection in your mouth and throat.
- Get a yearly flu shot and
pneumonia
vaccine. Ask your doctor whether these shots will benefit you.
It's important to know the signs of infection, such
as fever. Call your doctor right away if you think you have an infection.
Physical Activity
Talk to your doctor about what types and amounts of
physical activity are safe for you. You may want to avoid activities that cause
chest pain or shortness of breath. You also may want to stay away from
activities that could result in injuries and bleeding, such as contact
sports.
Support Groups
You or your family members may find it helpful to
know about resources that can give you emotional support and information about
aplastic anemia.
Your doctor or hospital social worker may have
information about counseling and support services. They also may be able to
refer you to support groups that offer help with financial planning, because
treatment for aplastic anemia can be costly.
Key Points
- Aplastic anemia is a blood disorder in which the
body's bone marrow doesn't make enough new blood cells.
- This can lead to a number of health problems,
such as
arrhythmias,
an enlarged heart,
heart
failure, infections, and bleeding. Severe aplastic anemia can even cause
death.
- Aplastic anemia is a type of
anemia.
The term "anemia" usually refers to a condition in which your blood has a lower
than normal number of red blood cells. Anemia also can occur if your red blood
cells don't contain enough hemoglobin, an iron-rich protein that helps carry
oxygen to your body.
- In people who have aplastic anemia, the body
doesn't make enough red blood cells, white blood cells, or platelets. This is
because the bone marrow's stem cells are damaged.
- A number of diseases, conditions, or factors can
cause damage to the stem cells. These causes can be acquired or inherited. In
more than half of the people who have aplastic anemia, the cause is
unknown.
- Aplastic anemia is a rare, but serious blood
disorder. People of all ages can get aplastic anemia, but it's more common in
adolescents, young adults, and the elderly.
- Low numbers of red blood cells, white blood
cells, and platelets cause most of the signs and symptoms of aplastic anemia.
Signs and symptoms may include fatigue (tiredness); shortness of breath;
dizziness; headache; coldness in your hands and feet; pale skin, gums, and nail
beds; chest pain; infections; and bleeding.
- Your doctor will diagnose aplastic anemia based
on your medical and family histories, a physical exam, and test results.
- Treatments for aplastic anemia include
blood
transfusions,
blood
and marrow stem cell transplants, and medicines. These treatments can
prevent or limit complications, relieve symptoms, and improve quality of life.
- Blood and marrow stem cell transplants may offer
a cure for some people who have the disorder. Removing a known cause of
aplastic anemia, such as exposure to a toxin, also may cure the condition.
- With prompt and proper care, most people who have
aplastic anemia can be successfully treated. It's important to get ongoing
medical care to make sure the disorder doesn't return and to check for possible
complications.
Links to Other Information About Aplastic
Anemia
NHLBI Resources
Non-NHLBI Resources
Clinical Trials
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