What Do You Know About Aplastic Anemia?

The bone marrow, which is the spongy liquid inside your bones, makes stem cells. These stem cells develop into the three main types of blood cells: red blood cells, white blood cells and platelets. Red blood cells are transporters; they carry oxygen from the lungs to the cells and carbon dioxide from the cells to the lungs. White blood cells are part of the body's immune system. Platelets help the blood clot.

The bone marrow in a healthy person continually produces blood cells to replace those that die. According to the NHLBI, a red blood cell lives for about 120 days; a white blood cell, often for less than a day; and a platelet for about six days. In a person with aplastic anemia, blood cell production slows or stops because the stem cells are damaged. Researchers don't know what causes this damage in most cases of aplastic anemia. Occasionally, the disorder is caused by certain medications such as the antibiotic chloramphenicol. Why this happens, researchers do not know.

Red blood cells contain hemoglobin, which carries oxygen from the lungs to all cells in the body. Red blood cells also remove waste carbon dioxide from the cells and carry it to the lungs to be exhaled. If the body has too few red blood cells, too little oxygen reaches the cells and too little carbon dioxide is removed. This condition, called anemia, causes a person to feel tired. The heart must pump harder to make up for the lack of oxygen.

White blood cells are used to fight infections. If the body has too few white blood cells, the person cannot fight off infections as well, and may become ill more often. A low white blood cell count also means illnesses last longer or are more severe than in a person with a normal count.

Platelets help the blood to clot. Having too few platelets raises the risk of bleeding or bruising. With too few platelets, it may be difficult to stop bleeding once it starts. Bleeding can occur even from mild trauma that normally would not be noticed.

Aplastic anemia is rare in the United States. About 900 cases are diagnosed each year, according to the Aplastic Anemia and MDS International Foundation. Although anyone at any age can get this disease, it’s more common in these age groups.

A person with the hereditary form of aplastic anemia is born with the illness. A person with the acquired form -- the more common type -- may develop the illness after exposure to something in the environment. These triggers are thought to include toxic chemicals such as pesticides, chemotherapy drugs used to treat cancer, radiation, autoimmune diseases such as lupus and rheumatoid arthritis, and viral infections such as hepatitis, cytomegalovirus and HIV, the NHLBI says. Often, however, the cause of acquired aplastic anemia isn't known.

These treatments include blood transfusions, drugs to stimulate the bone marrow, immunosuppressant drugs and bone marrow or stem cell transplants. Treatment depends on the severity of the illness. People with mild or moderate aplastic anemia may not need treatment. A health care provider will check blood counts frequently to make sure the illness is not getting worse. Treatment is needed when a person has severe or very severe aplastic anemia. Many people with aplastic anemia can be treated and some can be cured.