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Idiopathic aplastic anemia

Definition

Idiopathic aplastic anemia is a condition in which the bone marrow fails to properly make blood cells. Bone marrow is the soft, fatty tissue in the center of bones.

See also:

• Anemia
• Secondary (acquired) aplastic anemia

Alternative Names

Anemia - idiopathic aplastic

Causes, incidence, and risk factors

Aplastic anemia results from injury to the blood stem cells, immature cells in the bone marrow that give rise to all of other blood cells types. The injury causes a decrease in the number of every type of blood cell in the body -- red cells, white cells, and platelets. Low numbers of red cells, white cells, and platelets is a condition called pancytopenia.

Idiopathic means the cause is unknown. However, idiopathic aplastic anemia is thought to occur when the body reacts against its own cells. This is called an autoimmune disorder.

The disease may be acute or chronic, and may get worse over time. There are no known risk factors.

Aplastic anemia may also be caused by certain medical conditions (such as pregnancy or lupus) or exposure to some toxins or drugs (including chemotherapy). See: Secondary (acquired) aplastic anemia

In some cases, aplastic anemia is associated with another blood disorder called paroxysmal nocturnal hemoglobinuria (PNH).

Symptoms

Symptoms are the result of bone marrow failure and the loss of blood cell production.

Low red cell count (anemia) leads:

• Fatigue
• Pallor (paleness)
• Rapid heart rate
• Shortness of breath with exercise
• Weakness

Low white cell count (leukopenia) causes an increased risk of infection.

Low platelet count (thrombocytopenia) results in bleeding, especially of the mucous membranes and skin. Symptoms include:

• Bleeding gums
• Easy bruising
• Frequent or severe infections
• Nose bleeds

Signs and tests

• Low red blood cell count (anemia)
• Low white blood cell count
• Low reticulocyte count (reticulocytes are immature red blood cell)
• Low platelet count
• Bone marrow biopsy shows an overall decrease in the number of blood cells

Treatment

Mild cases of aplastic anemia may be treated with supportive care or may require no treatment.

In moderate cases, blood transfusions and platelet transfusions will help correct the anemia and the risk of bleeding. However, over time, blood transfusions may stop working.

Too much iron may build-up in the body tissues may occur because of the many transfusions. See Hemochromatosis

Severe aplastic anemia occurs when blood-cell counts are very low, and is a life-threatening condition. Bone marrow transplant or stem cell transplant is recommended for severe disease in younger patients. However, they must have a donor who is a sibling (brother or sister) and a good match. This is called a matched sibling donor.

For older patients, or for those who do not have a matched, related bone marrow donor, anti-thymocyte globulin or other drugs that suppress the immune system may allow the bone marrow to once again make blood cells. A bone marrow transplant with an unrelated donor may be tried if these medications do not help, or if the disease comes back after getting better.

Support Groups

Expectations (prognosis)

Untreated aplastic anemia leads to rapid death. Bone marrow transplant has been successful in young people, with long term survival rates of about 80%. Older people have a survival rate of 40 - 70%.

Complications

• Severe infections or bleeding
• Complications of bone marrow transplant (graft failure or graft-versus-host disease)
• Reactions to medications (patients can have reactions to anti-thymocyte globulin)

Calling your health care provider

Call your health care provider or go to the emergency room if bleeding occurs for no reason, or if bleeding is difficult to stop. Call if you notice frequent infections or unusual fatigue.

Prevention

There is no known prevention for idiopathic aplastic anemia.

References

Castro-Malaspina H, O'Reilly R. Aplastic anemia and related disorders. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 171.