Anemia - idiopathic aplastic
Definition - Causes, incidence, and risk factors - Symptoms - Signs and tests - Treatment - Expectations (prognosis) - Complications - Bone marrow aspiration .
Definition
Idiopathic
aplastic anemia is a failure of the bone marrow to properly form all types of
blood cells.
Causes, incidence, and risk factors
Idiopathic
aplastic anemia is a condition that results from injury to the stem cell, a
cell that gives rise to other cell types after it divides. Consequently, there
is a reduction in all cell types -- red blood cells, white blood cells and
platelets -- with this type of anemia,
which is called pancytopenia.
The cause of
idiopathic aplastic anemia is unknown, but is thought to be an autoimmune
process (the body reacting against its own cells). Causes of other types of aplastic
anemia may be chemotherapy,
radiation
therapy, toxins,
drugs, pregnancy, congenital disorder, or systemic
lupus erythematosus.
Symptoms arise
as the consequence of bone marrow failure. Low red blood cell count (anemia)
leads to fatigue and weakness. Low white blood cell count (leukopenia) causes
an increased risk of infection. Low platelet count (thrombocytopenia)
results in bleeding, especially of mucus membranes and skin.
The disease may
be acute
or chronic,
and is almost always progressive. Risk factors are unknown.
Symptoms Returnto top
- Fatigue
- Pallor
- Shortness
of breath on exertion
- Rapid
heart rate
- Easy
bruising
- Nose
bleeds
- Bleeding
gums
- Prolonged
bleeding
- Frequent
or severe infections
- Enlarged
lymph nodes (rare)
- Low red
blood cells (anemia)
- Low
white blood cell count
- Low
reticulocyte count (red blood cell precursors)
- Low
platelet count
- Bone
marrow biopsy shows few blood cells
Mild cases of
aplastic anemia are treated with supportive care. Blood transfusions and
platelet transfusions help correct the abnormal blood counts and relieve some
symptoms.
Severe aplastic
anemia, as evidenced by very low blood cell counts, is a life-threatening
condition. Bone
marrow transplant is indicated for severe disease in younger patients.
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 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.
Expectations (prognosis)
Untreated
aplastic anemia is an illness that leads to rapid death. Bone marrow
transplantation has been successful in young people, with long term survival of
80%.
Older people have a survival rate of 40 - 70%.
Complications
Severe
infections or bleeding may develop
Complications of
treatment may include graft failure or graft vs. host disease, and an
autoimmune disease, after bone marrow transplant. Patients can have reactions
to ATG.
Bone marrow aspiration
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.
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