What is aplastic anaemia?

What causes aplastic anaemia?

Aplastic anaemia can be inherited, but more commonly this is an acquired disease that develops at some stage in an individual’s life.

It is believed that in many cases, acquired aplastic anaemia results from the bone marrow stem cells being damaged by an autoimmune reaction in the body. An autoimmune reaction is where the body’s immune system fights against its own cells because it mistakenly believes them to be damaged or faulty. When this happens, the bone marrow function starts to slow down.

This results in an underproduction of all types of blood cells. Autoimmune reactions can have an underlying cause – about one in ten people with aplastic anaemia have experienced a recent viral infection. Other potential triggers have been identified as exposure to certain drugs or chemicals and also radiation exposure.

However, in many cases, the cause remains unknown. When there is no obvious reason for the immune system to damage your stem cells in this way, it is known as idiopathic aplastic anaemia

What are the symptoms?

The most common symptoms of aplastic anaemia will be anaemia caused by a reduction in red blood cells, with associated feeling of fatigue, shortness of breath, headaches and, occasionally, chest pains.

A lack of white blood cells can lead to infections, such as sinus or throat and chest infections.

Low platelets cause a tendency to bleed easily, for example, from the nose or gums, may lead to unexplained bruising, blood blisters in the mouth, but also serious bleeding, for example in the brain or in the gut.

Different types of aplastic anaemia

Aplastic anaemia in most cases is acquired, with no known cause. It is becoming increasingly recognised that inherited types of aplastic anaemia are more common than previously thought and can present in adults as well as children.

Aplastic anaemia classification

Aplastic anaemia can be very severe, severe, moderate or non-severe, depending on how low the numbers of the essential blood cells are. 

Very severe

• Neutrophils - less than 0.2 x 109/L
• Platelets - less than 20 x 109/L
• Bone marrow activity - less than 30 per cent

Severe

• Neutrophils less than 0.5 x 109/L
• Platelets less than 20 x 109/L
• Bone marrow activity less than 30 per cent

Non-severe

• All cases which do not follow the above classification.

Types of the relatively more common inherited aplastic anaemia are fanconi anaemia and dyskeratosis congenita .

Paroxysmal nocturnal haemoglobinuria (PNH) is closely linked to aplastic anaemia.