Perth Haematology :: Dr Steven Ward
Aplastic Anaemia (AA) = An acquired disorder of the marrow, characterised by marrow failure causing low blood counts (pancytopenia) without an abnormal infiltrate or increased fibrosis. The marrow is empty of precursor cells, leading to insufficient blood cells in the circulation. The severity can vary greatly, and can change within an individual.
It is rare with an incidence of 0.2/100,000 per year
It is not a form of leukaemia or cancer.
There are other forms of marrow aplasia due to other conditions. These conditions have to be ruled-out in order to make the diagnosis of acquired Aplastic Anaemia.
Causes of AA
Auto-immune reaction: the immune system starts attacking it’s own cells (in this case the marrow stem cells). 75% are of unknown cause (“idiopathic”). The remaining cases have an identifiable trigger-factor such as certain drugs, viruses, chemicals, pregnancy.
There may be no symptoms,
with the disease found incidently
This is based on the low blood counts – usually all three counts are low
reticulocyte count will be low – this measures now juvenile red blood cells
Bone Marrow aspirate and trephine – this will show an “empty” marrow with increased fat and no fibrosis. Often 2 separate marrow studies from different sites are required to confirm the diagnosis. The absence of leukaemia cells is carefully examined
Very Severe AA (VSAA):
Severe AA (SAA):
Non-Severe AA (NSAA)
Blood counts higher than above but below normal.
Hb < 100; Plat <50; ANC < 1.5
Supportive Care: aimed at treating the consequences of low blood counts:
Transfusion of blood (red cells); platelets and antibiotics for infections. The need for transfusion depends on the blood level and the symptoms associated with that level. All transfusions should be very carefully considered as frequent transfusion can lead to antibody formation against the transfused cells, making further transfusion or bone marrow transplant more difficult.
Definitive therapy: aimed at treating the AA itself and restoring marrow function.
Treatment often takes months to reach maximum benefit. The outlook for Severe or Very Severe AA is poor without some form of therapy. Death occurs due to bleeding or infection.
Definitive therapy is aimed at suppressing the immune system, and allowing normal stem cells to develop and form blood cells.