Secondary aplastic anemia

Secondary aplastic anemia

Definition:

Secondary aplastic anemia is a failure of the blood-cell forming capacity of the bone marrow that affects all blood-cell types.

Alternative Names:

Anemia - secondary aplastic; Acquired aplastic anemia

Causes, incidence, and risk factors:

Secondary aplastic anemia is a condition that is a result of injury to the stem cell, a cell that gives rise to other blood cell types when it divides and differentiates. Consequently, there is a reduction in all types of blood cells: red blood cells, white blood cells, and platelets (which is called pancytopenia).

Causes of secondary aplastic anemia include chemotherapy, drug therapy to suppress the immune system, radiation therapy, toxins such as benzene or arsenic, drugs, pregnancy, and congenital disorders. When the cause is unknown, it is then referred to as idiopathic aplastic anemia.

Symptoms arise as a consequence of bone-marrow failure. Anemia (a low red blood cell count) leads to fatigue and weakness. A low white blood cell count (leukopenia) causes an increased risk of infection. A low platelet count (thrombocytopenia) may result in bleeding of the mucus membranes, internal organs, and skin. The disease may be acute or chronic and is usually progressive unless the causative agent is removed.

Symptoms:

Fatigue
Pallor
Shortness of breath on exertion
Rapid heart rate
Rash
Easy bruising
Nose bleeds
Bleeding of the gums
Prolonged bleeding
Frequent or severe infections

Signs and tests:

A complete blood count (CBC) shows low hematocrit and hemoglobin levels (anemia).
The reticulocyte count is low.
The platelet count is low.
The white blood cell count is low.
A bone marrow biopsy shows very few cells.

Treatment:

In secondary aplastic anemia, removal of the causative agent is critical, and in some cases can lead to recovery.

Mild cases of aplastic anemia may be treated with supportive care or may require no treatment. Blood transfusions and platelet transfusions will help correct the abnormal blood counts and relieve some symptoms, in moderate cases.

Severe aplastic anemia, as evidenced by very low blood-cell counts, is a life-threatening condition. A bone marrow transplant for younger patients is indicated in a severe case of the disease. For older patients, or for those who do not have a matched bone marrow donor, antithymocyte globulin (ATG) is the alternative treatment.

ATG is a horse serum that contains antibodies against human T cells, and it is used in an attempt to suppress the body's immune system, allowing the bone marrow to resume its blood-cell generating function. Other medications to suppress the immune system may be used, such as cyclosporine and Cytoxan (cyclophosphamide). Corticosteroids and androgens have also been used.

Expectations (prognosis):

Untreated aplastic anemia is an illness that leads to rapid death. Bone marrow transplantation has been successful in young people with a long-term survival rate of 80%. Older people have a survival rate of 40 to 70%.

Complications:

Infection
Cerebral hemorrhage
Death caused by bleeding, infectious complications of bone marrow transplant, rejection of bone marrow graft, or severe reaction to antithymocyte globulin (ATG)

Calling your health care provider:

Call your health care provider if bleeding occurs for no reason.

Prevention:

This may be an unavoidable consequence of treatments such as chemotherapy. Avod toxins such as benzene or arsenic if possible.

Review Date: 10/10/2001
Reviewed By: Rebecca Elstrom, M.D., Division of Hematology-Oncology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network.

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