What Is Aplastic Anemia?

Bone marrow
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Aplastic anemia is a disorder of the bone marrow, where our white blood cells, red blood cells, and platelets are made.  Although anemia is in the name, it is much more than anemia.  Essentially, the bone marrow is unable to produce the blood cells in normal amounts.  This is due to some sort of injury to the stem cells, the cells that make all of your blood cells.  

Symptoms of Aplastic Anemia

The symptoms of aplastic anemia are predominantly due to the low blood counts.

 Some people may not have any symptoms.  

  • Pale skin, fatigue, shortness of breath resulting from anemia
  • Bleeding, unexplained bruising or small red dots called petechiae from thrombocytopenia (low platelet counts)
  • Oral ulcers, skin infection from low white blood cell counts called leukopenia/neutropenia
  • Jaundice, if aplastic anemia is triggered by hepatitis, an infection of the liver.

Causes of Aplastic Anemia

  • Inherited:  Some forms of aplastic anemia are inherited and may be referred to as a bone marrow failure syndromes.  These include Fanconi anemia, dykeratosis congenita, or Shwachman Diamond Syndrome.  
  • Acquired:  This simply means that you weren't born with the anemia but rather you acquired it after some sort of injury or exposure.  This may be due to hepatitis, viral infections and certain medications. 
  • Autoimmune:  Your immune system can attack your stems cells, preventing them from making new red blood cells, white blood cells, and platelets.  
  • Unknown:  Sometimes the cause of the aplastic anemia is never identified.  

How is Aplastic Anemia Diagnosed?

Aplastic anemia is initially identified on a complete blood count (CBC), a simple blood test.  It is generally identified by pancytopenia, or decreased white blood cells, red blood cells, and platelets.

 Likely more blood work will be performed to identify a cause.  This will likely include blood work to look for a viral infection as the cause of the aplastic anemia.  This testing may include testing for hepatitis, an infection of the liver.  

To confirm the diagnosis, a bone marrow aspirate and biopsy must be performed.  In this procedure, a needle is used to remove the liquid portion of the bone marrow as well as a small piece of the bone.  A pathologist will review the bone marrow under the microscope.  The bone marrow examination gives valuable information regarding the cause of the aplastic anemia and can rule out cancer as the cause for decreased blood counts.  

Severity of Aplastic Anemia

Aplastic anemia can be categorized based on severity.  This is important as it affects treatment decisions.

  • Severe:  
    • Bone marrow cellularity < 25% (or <50% if < 30% of bone marrow is stem cells)
    • AND 2 of the following:
    • Peripheral blood neutrophil count < 500 cells/microliter 
    • Platelet count < 20,000 cells/microliter
    • Absolute Reticulocyte count < 20,000 cells/microliter
  • Very Severe: As above but with neutrophil count < 200 cells/microliter

Treatment of Aplastic Anemia

Below are several different treatments of aplastic anemia.

 This list does no include all possible treatments.  Treatment is often determined by age at presentation and availability of bone marrow donor.  

  • Blood transfusions:  Red blood cells and platelet transfusions may be given to prevent symptomatic anemia or bleeding from low platelets
  • Antibiotics:  While your neutrophil count is extremely low, every fever will need to be evaluated carefully.  Typically you are admitted to the hospital to receive antibiotics until a serious infection can be ruled out.  
  • Immunosuppressive therapy (IST):  Immunosuppressive medications can be used to prevent your immune system from attacking your stem cells.  The two most common medications used are: antithymocyte globulin (ATG) and cyclosporin.  These are typically administered in the hospital.  
  • Bone marrow transplantation:  Bone marrow transplantation is the only curative therapy for aplastic anemia.  Initially your healthcare team will try to determine if one of your siblings could be your donor.  If a sibling is not a close match, they will look in the bone marrow registry for a match.  


Guinan EC. Diagnosis and Management of Aplastic Anemia. ASH Education Book. 2011:76-81.

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