Aplastic anemia is a rare disease caused by a decrease in, damage to marrow stem cells and dysfunction to the microenvironment within the marrow basically replacing marrow cells for the production of all three blood cell types (erythrocytes, lymphocytes and platelets) with adipose tissue. The term “aplastic” refers to the incapability of the stem cells of the marrow in generating mature blood cells.
The precise etiology of aplastic anemia is relatively unknown, but it is hypothesized that the body’s T-cells mediate an inappropriate attack against the bone marrow, seriously hindering and suppressing the marrow’s production of blood cells from becoming mature, resulting in what was earlier mentioned as bone marrow aplasia (marked reduced blood cell production). Therefore, in addition to severe anemia, there is also a significant decrease in platelets and white blood cells.
Pathophysiology of aplastic anemia
Aplastic anemia can be congenital or acquired, but in most cases the cause can be attributed as idiopathic (without apparent cause). Infections and pregnancy can trigger it or it may be caused by certain medications, chemicals or effects from exposure to radioactive substances. Agents that regularly produce marrow aplasia include benzene and benzene derived materials and certain toxic materials such as arsenic and several inorganic pesticides have also been implicated as possible causes of this condition. Furthermore, this condition mostly affects the very young, adolescent population as well as elderly adults.
Clinical manifestations of aplastic anemia
The signs and symptoms of aplastic anemia are generally observed to be slowly progressive and insidious. Complications resulting from bone marrow failure may happen even before a definitive diagnosis can be properly established. Typical complications are infections and general symptoms of anemia (fatigue, pallor, difficulty in breathing). Superficial bruising may develop later prompting individuals to undergo a complete blood cell count evaluation. If the individual has already recurrent throat infections, cervical lymphadenopathy may be observed. Enlargement of the spleen and other lymphadenopathies as well as retinal bleeding are common complications of this disorder.
Medical management of aplastic anemia
It is presumed that the white blood cells of individuals with aplastic anemia does not recognize the between self and non-self material in the body wherein existing lymphocytes destroy stem cells in the bone marrow seeing it as a non-self/foreign material consequently impairing the production of all other blood cells along with it. Despite its severity, this condition can be treated in most people. The most common treatment approach is the use of immunosuppressive agents where it acts on mature lymphocytes preventing them from attacking stem cells so as the marrow can continue producing mature blood cells.
Another common yet invasive treatment for this disorder is bone marrow transplantation, wherein an individual is transplanted with new marrow from a compatible donor to replace the severely compromised stem cells destroyed by the host body’s lymphocytes. The risk for acquiring infection and donor cell rejection is comparatively higher with the latter treatment of aplastic anemia although immunosuppressive therapy still predisposes patients from infection in a much lesser degree.
Just like other forms of anemia, aplastic anemia generally compromises susceptible individuals with the inability to maintain healthy amounts of blood cells necessary for oxygen transport and immune function. Since patients with aplastic anemia are vulnerable to problems related to all blood cell deficiencies, supportive therapy plays a vital role in the management of aplastic anemia.