What is Aplastic Anemia?

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.

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?"