What is aplastic anemia?
Before knowing about aplastic anemia, we should know the normal function of blood cells and bone marrow. Bone marrow is the factory producing all the blood cells continuously. Our body needs continuous production of red cells, white cells and platelets which are constantly released into the blood stream from the bone marrow. In the blood, these cells live for few days and lose their function and so they have to be constantly replenished. Red cells carry oxygen throughout the body. White cells fight against infection. Platelets prevent against minor bleeding from the blood vessels.
When the bone marrow stops working for some reasons, it is called aplastic anemia.
What are the causes of aplastic anemia?
This can be due to varied causes such as viral infections, chemicals, drugs, toxin exposure or inherited genetic damage etc. In a particular individual, it may be difficult to find out the cause.
Can the bone marrow function be replaced by transfusing blood?
No, not completely.Red cells can be transfused as blood. But even the blood if it is transfused repeatedly, it can cause lot of problems such as iron overload.White cells cannot be transfused unless in exceptional circumstances.Platelets can be transfused but can be present in the blood for few days only. In some individuals, due to antibody formation, platelets are destroyed rapidly within few hours in the body.
What are the complications in these patients?
Normally white cells are the policemen of our body, providing protection from various infections entering our blood from within our body (such as intestine, lungs etc) or outside our body through contamination of water, hand shaking or airborne infections. Without white cells, the bacteria or viruses are not easily killed in the blood and they proliferate rapidly and hence these patients have high risk of succumbing to infections. Also, they can get unusual infections like fungus and other rare bacteria which sometimes may need expensive antibiotics and antifungal treatments.
The platelets seal the holes formed in our blood vessels. Normally since the blood flows rapidly, numerous holes can be formed in the blood vessels on a continuing basis. They have to be sealed constantly to prevent minor or major bleeding from the blood vessels. Even though platelets can be transfused separately, on the long run, many patients develop antibodies to the transfused platelets. This is a big problem in aplastic anemia patients, as after repeated platelet transfusions, they become refractory to therapy due to antibody formation. Even though the normal platelet count is around 150-400, any platelet count of more than 20-30 is quite safe in the sense, spontaneous bleeding is uncommon with that level.
Due to the absence of production of red cells, these patients develop anemia. Even though this can be easily corrected by packed cell transfusions, too many transfusions can cause lot of problems, in the sense it will lead to iron overload. Iron overload can affect heart and other organs in the body.
Then how is aplastic anemia treated?
Aplastic anemia has to be treated according to the cause and severity. Genetic causes of aplastic anemia can be treated differently from acquired aplastic anemias.
In young individuals with severe aplasia, allogenic stem cell transplantation has to be carried out as soon as possible.
In patients who do not have a HLA match, or in older patients, intense immunosuppressive therapy is another option. Immunosuppressive therapy can be with Antithymocyte globulin (ATG) and cyclosporine or using cyclosporine alone.
How will I know whether I am progressing well or benefitted from treatment?
It will take usually 3-4 months for a response to occur. Till then you will need blood products and contact the doctor whenever you have fever or infections.
Can the disease come back even after treatment?
Unfortunately it can, in people who have immunosuppressive therapy. In those patients immunosuppressive therapy can be repeated again.
However there are certain indicators which will tell us the chances that you will benefit from immunosuppressive treatment. Your doctor will let it know.