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Aplastic Anaemias

Aplastic anaemia (also known as idiopathic aplastic anaemia) is a rare disease, caused by a decrease in the number of all types of blood cells produced by the bone marrow. Normally, the bone marrow produces a sufficient number of new red blood cells (RBCs), white blood cells (WBCs) and platelets for normal body function. If the bone marrow is not able to produce enough blood cells to replace those that die, a number of symptoms, including those due to anaemia, may result.

Symptoms of aplastic anaemia can appear abruptly or can develop more slowly. Some general symptoms that are common to different types of anaemia may appear first and are due to the decrease in number of RBCs. These include:

  • Feeling of tiredness
  • Lack of energy

Some additional signs and symptoms that occur with aplastic anaemia include those due to decreased platelets:

  • Prolonged bleeding
  • Frequent nosebleeds
  • Bleeding gums
  • Easy bruising

and due to a low WBC count:

  • Increased number and severity of infections.

Causes of aplastic anaemia usually have to do with damage to the stem cells in the bone marrow that are responsible for blood cell production. Most often, no obvious underlying cause is found and this is labelled idiopathic aplastic anaemia. Sometimes, specific factors that may be involved with bone marrow damage and that can lead to aplastic anaemia are identified and include:

Rarely, aplastic anaemia is due to an inherited (genetic) disorder such as Fanconi anaemia. (For more on this condition, see the Fanconi Anemia Research web site

Laboratory Tests
The initial test for anaemia, the full blood count (FBC), may reveal many abnormal results.

  • Haemoglobin and/or haematocrit may be low
  • RBC and WBC counts are low
  • Platelet count is low
  • The MCV (average red cell size) may be normal or slightly raised
  • The differential white blood count shows a decrease in most types of cells but not lymphocytes.

Some additional tests that may be performed to help discover the type and cause of anaemia include:

  • Reticulocyte count -result is usually low
  • Erythropoietin - usually increased in aplastic anaemia
  • A bone marrow aspiration and trephine biopsy will show a decrease in the number of all types of mature cells.
  • Tests for infections such as hepatitis, EBV, CMV help to discover the cause
  • Test for arsenic (a heavy metal) and other toxins
  • Iron tests or tests for vitamin B12 may be done to rule out other causes
  • Antibody tests such as ANA to find out if the cause is autoimmune disease

A physical examination or complete medical history may reveal possible causes for aplastic anaemia such as exposure to toxins or certain drugs (for example, chloramphenicol) or prior treatment for cancer.

Some cases of aplastic anaemia are temporary while others have lasting damage to the bone marrow. Treatment depends on the cause. Reducing or eliminating exposure to certain toxins or drugs may help resolve the condition. Medications may be given to stimulate bone marrow production, to treat infections or to suppress the immune system in cases of autoimmune disorders. Blood transfusions and a bone marrow transplant may be needed in severe cases.

Pure red cell aplasia is a disease with some similarities to aplastic anaemia, except only the red blood cell precursors are absent. This can also occur with cancers (especially of the thymus gland) and autoimmune conditions. Infection with parvovirus B19 can cause temporary pure red cell aplasia.

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