Secondary aplastic anemia

Causes and Risks:
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 differentiates. Consequently, there is a reduction in all types of blood cells with this anemia : 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 , congenital disorders, infectious hepatitis , and systemic lupus erythematosus . The cause may be unknown, and 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 (neutropenia) causes an increased risk of infection. A low platelet count ( thrombocytopenia ) results in bleeding of the mucus membranes, internal organs, and skin. The disease may be acute or chronic and is always progressive. The risk factors are unknown. The incidence is 4 out of 100,000 people.

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

Symptoms:



Signs and Tests:
A physical examination may reveal enlarged spleen , tenderness of the sternum, and an irregular heart rate . The lymph nodes may be enlarged (rare).



Treatment:
Mild cases of aplastic anemia are 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 people 40 and under is indicated in a severe case of the disease. For adults over 40, 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 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.

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)



Call Your Healthcare Provider:
Call your health care provider if bleeding occurs for no reason.


A small amount of bone marrow is removed during a bone marrow aspiration. The procedure is uncomfortable, but can be tolerated by both children and adults. The marrow can be studied to determine the cause of anemia, the presence of leukemia or other malignancy, or the presence of some "storage diseases" in which abnormal metabolic products are stored in certain bone marrow cells.