Aplastic Anemia

(Aregenerative Anemia, Panmyelopathy, Hypoplastic Anemia, Toxic Paralytic Anemia)

The Facts

The blood that circulates throughout the body performs a number of critical functions. It delivers oxygen, removes carbon dioxide, and carries life-sustaining nutrients. By acting as the vehicle for long-distance messengers such as hormones, blood helps the various parts of the body communicate with each other. This is carried out by blood cells working in partnership with the liquid part of the blood (plasma).

Most of the cells that make up your blood are red blood cells (RBCs; erythrocytes). Also present are white blood cells (WBCs; leukocytes), which defend the body against foreign matter, including infections, viruses, and fungi.

Anemia is a condition where the number of healthy RBCs in the blood is lower than normal. RBCs transport oxygen throughout the body, so a shortage of these cells can lead to serious health problems.

In aplastic anemia, the bone marrow drastically cuts down on its production of all types of blood cells (red, white, and platelets). Aplastic actually means "a failure in development." Aplastic anemia, acute or chronic, is a rare and serious condition that can occur spontaneously or be triggered by exposure to certain medications or toxins.

Dr. Paul Ehrlich, a famous German pathologist, first identified the condition in 1888 after studying the case of a pregnant woman who died of bone marrow failure. In 1904, the disorder was termed aplastic anemia.

Aplastic anemia isn't restricted to any age or gender. There are approximately 3 to 8 new cases for every million people worldwide each year, though this rate tends to be higher in East Asian countries . A very rare form of aplastic anemia, Fanconi anemia (a type of hereditary aplastic anemia with bone abnormalities and brown pigmentation in the skin), occurs in some children with abnormal chromosomes.

The Causes

Most of the causes of aplastic anemia are unknown. Certain cancer treatments, such as high doses of chemotherapy or radiation treatment, can cause aplastic anemia. Other possible causes include chemicals (such as benzene-based compounds), certain prescription medications, radiation, viruses, immune diseases, pregnancy, street drugs, and environmental toxins (such as insecticides and pesticides). Fanconi anemia is an inherited condition.

Symptoms And Complications

Symptoms of aplastic anemia occur because of the low blood cell counts. Because of fewer RBCs present, people may have pale skin and feel tired, weak, or short of breath. The low platelet count may cause bruising and bleeding to easily occur, and people with aplastic anemia may be more likely to get bacterial infections because of the low number of WBCs, which fight infection. Cases of infection and hemorrhaging (excessive bleeding) are emergencies and must be treated quickly.

Other symptoms may include a waxy pallor to the skin and mucous membranes, bleeding gums, and a lack of energy during exercise. Premenopausal women may have an increased menstrual flow and duration. Massive bleeding is unusual.

Generally, the symptoms of aplastic anemia begin weeks or months after exposure to a toxin, but they may occasionally start sooner.

Making A Diagnosis

To diagnose aplastic anemia, your doctor will conduct a complete physical exam to check for paleness, bruising, oozing gums, and other unusual signs. They will order blood tests to get a complete blood cell count and will probably also arrange for a sample of your bone marrow so it can be checked for abnormalities.

Treatment And Prevention

The first and most important step of treatment is to find out and treat the cause of the aplastic anemia. People with aplastic anemia must do everything they can to avoid getting infections. If any develop, the infections are treated aggressively with antibiotics. Transfusions of red blood cells (RBCs) and platelets may be considered, but they are not the first option for treatment since they create a risk of rejection for a person who may later receive a transplant.

In mild or moderate cases of aplastic anemia, a colony-stimulating factor medication called eltrombopag* (or EPAG) is often used. It works by stimulating the bone marrow, causing it to produce healthy RBCs, and comes in the form of an oral tablet. Immunosuppressive therapy is used to treat aplastic anemia in someone who is not a suitable candidate for a transplant, or if there is no matching donor. This usually involves a combination made of a medication called cyclosporine, and a type of antibody called horse antithymocyte globulin (or hATG), which are both used along with EPAG.

Bone marrow transplantation*, *also called a stem cell transplant or hematopoietic cell transplant, replaces defective bone marrow with healthy cells from a normal donor, and may cure aplastic anemia. For people under the age of 40, immunosuppressive therapy is usually skipped entirely, and they instead directly undergo bone marrow transplantation. However, immunosuppressive therapy is often preferred instead for those over the age of 40 to avoid the risk of complications from surgery, or for patients waiting for a transplant donor, which can take several months.

Blood transfusions are used to replace the blood cells that are not being produced by the bone marrow the way they should be. Transfusions can replace RBCs and platelets, but white blood cells (WBCs) are harder to transfuse. People with aplastic anemia can receive blood transfusions for many years, but there are some complications that can develop from this treatment. RBC transfusions contain iron that builds up in the body and can damage normal tissues. Proteins on the transfused blood cells stimulate the immune system, and over time antibodies may be produced that destroy the transfused RBCs or platelets.

Because aplastic anemia can be life-threatening, quick diagnosis and treatment is crucial. Most people with the disorder can be effectively treated.