A type of anaemia caused by failure of the bone marrow to generate new blood cells of all types
The blood normally contains red blood cells, white blood cells, and platelets. These components are produced either entirely or mostly in the bone marrow. However, in aplastic anaemia, the bone marrow does not produce stem cells, the initial form of these components, resulting in abnormally low numbers of all these blood cells.
In many cases of aplastic anaemia, the cause is unknown. However, the condition may result from an autoimmune disorder in which antibodies are produced by the immune system that act against and destroy the body’s own stem cells. In rare cases, aplastic anaemia is due to an inherited abnormal gene. When the cause of the condition has been established, the term secondary aplastic anaemia is used.
Secondary aplastic anaemia sometimes occurs following a severe viral infection, such as a hepatitis virus infection (see Acute hepatitis). The disorder may also develop after chemotherapy or radiotherapy, as both treatments may reduce the production of blood cells by the bone marrow. Exposure to certain chemicals, such as benzene, and to some antibiotics, such as sulphonamides, may also trigger secondary aplastic anaemia.
Aplastic anaemia may lead to the following symptoms, common to all anaemias and due to the lack of red blood cells:
Tiredness and a feeling of faintness.
Shortness of breath on mild exertion.
Lack of platelets, the tiny cells involved in blood clotting, may cause symptoms such as easy bruising and excessive bleeding, often from the gums or nose. A deficiency of white blood cells, which form an important part of the immune system, may increase susceptibility to bacterial and fungal infections, which may become life-threatening due to the inadequate immune response.
To confirm the diagnosis, your doctor may arrange for blood tests to measure blood cell levels and a bone marrow aspiration and biopsy to obtain cell samples for examination.
Treatment of the underlying cause may allow the bone marrow to recover. Immunosuppressant drugs or corticosteroids may be used to treat autoimmune disorders. During recovery, blood transfusions and antibiotics may be needed to prevent or treat infection. If these treatments are ineffective, you may be offered a stem cell transplant.
If treated early, a person with aplastic anaemia may make a complete recovery. However, in some cases the condition may be fatal. A successful stem cell transplant can be life-saving.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.