Anemia - secondary aplastic
( Acquired aplastic anemia )
Definition - Causes, incidence, and risk factors - Symptoms - Signs and tests - Treatment - Expectations (prognosis) - Complications - Calling your health care provider - Prevention .
Definition
Secondary
aplastic anemia is a failure of the bone marrow to form enough blood cells. All
blood cell types are affected.
Causes, incidence, and risk factors
Secondary
aplastic anemia results from injury to stem cells. Normal stem cells divide and
differentiate into all blood cell types. Thus, when stem cells are injured,
there is a reduction in red blood cells, white blood cells, and platelets.
This condition
can be caused by 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.
The disease may
be acute
or chronic
and is usually gets worse unless the cause is removed.
Symptoms
- A low red blood cell count (anemia) leads to fatigue and weakness.
- A low white blood cell count (leukopenia) leads to frequent or severe infections.
- A low platelet count (thrombocytopenia) may result in easy bruising, nose bleeds, bleeding of the gums, and bleeding of internal organs.
- Other symptoms include shortness of breath on exertion, rapid heart rate, and rash.
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, which shows up as a very low blood-cell count, is a life-threatening
condition. A bone marrow
transplant is indicated for younger patients with 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. 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 - 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
Secondary
aplastic anemia may be an unavoidable consequence of treatments such as
chemotherapy. Avoid toxins such as benzene
and arsenic if possible.
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