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. Each type of cell enters the blood stream, circulates and then dies within a certain time frame. For example, the normal lifespan of RBCs is about 120 days. 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, fatigue
- lack of energy
- prolonged bleeding
- frequent nosebleeds
- bleeding gums
- easy bruising
and due to a low white blood cell count (WBC):
- 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. Some factors that may be involved with bone marrow damage and that can lead to aplastic anaemia include:
- exposure to toxic substances such as arsenic, benzene or pesticides
- cancer therapy (radiation or chemotherapy)
- autoimmune disorders such as lupus or rheumatoid arthritis
- viral infections such as hepatitis, EBV, HIV, CMV, or parvovirus B19
Rarely, aplastic anaemia is due to an inherited (genetic) disorder such as Fanconi anaemia. For more on this condition, see the Faconi Anemia Research Fund.
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.
- Red blood cell indices are usually normal.
- 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 determine the type and cause of anemia include:
- Reticulocyte count — result is usually low.
- Erythropoietin — usually increased in aplastic anaemia.
- A bone marrow aspiration will show a decrease in the number of all types of mature cells.
- Tests for infections such as hepatitis, EBV, CMV help to determine 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 determine 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.