Aplastic Anemia

What is aplastic anemia? 

Aplastic anemia is a rare blood disorder that occurs when bone marrow does not make enough blood cells. It is a type of bone marrow failure.

Bone marrow is the soft, spongy tissue at the center of your bones. Stem cells in the bone marrow make new blood cells including red blood cells, white blood cells, and platelets. 

Most often, all 3 types of blood cells are affected (pancytopenia). This causes:

• Low red blood cells, which carry oxygen (anemia)
• Low white blood cells, which fight infections (leukopenia or neutropenia)
• Low platelets, which help the blood to clot and stop bleeding (thrombocytopenia)

Aplastic anemia can develop at any age. It is a severe and life-threatening blood disorder. Treatments include blood transfusions, medicines, and stem cell (bone marrow) transplant. 

Symptoms of aplastic anemia

The bone marrow makes different types of blood cells. Symptoms are caused by low numbers of red blood cells, white blood cells, and platelets. Your child's signs and symptoms depend on which type of blood cell is affected and the severity of their condition.

Causes of aplastic anemia

Aplastic anemia is a type of bone marrow failure. In most cases, aplastic anemia is acquired (not inherited from parents). It is also called idiopathic aplastic anemia.

Acquired aplastic anemia results from an immune system attack and destruction of blood-forming stem cells in the bone marrow. When this happens, the body makes fewer blood cells. The cause for the faulty immune response is not known.

Rarely, aplastic anemia can also be caused by certain viral infections, being around toxic chemicals, taking certain medicines, or having chemotherapy or radiation.

Sometimes, aplastic anemia is diagnosed in the setting of inherited bone marrow failure syndromes that are passed down from parents to children. Inherited disorders that can lead to aplastic anemia include Fanconi anemia, Shwachman-Diamond syndrome, Dyskeratosis congenita, SAMD9 and SAMD9L syndromes, and a number of other rare genetic diseases. These inherited disorders are treated differently than acquired aplastic anemia.

Diagnosis of aplastic anemia

Aplastic anemia is very rare. It only occurs in ~2 people per million in the United States each year. That is approximately 600 new cases across all age groups in the United States.

Diagnosis often involves ruling out other illnesses such as leukemia or inherited bone marrow failure disorders. As soon as aplastic anemia is diagnosed, treatment is started.

Aplastic anemia is diagnosed based on your child’s medical history, physical exam, and lab tests. Lab tests for aplastic anemia may include:

• Complete blood count (CBC) with reticulocytes (immature red blood cells) to measure the number and size of blood cells. Most patients have severe aplastic anemia, which means reticulocytes, hemoglobin, platelets, and neutrophils are very low.
• Bone marrow aspiration and biopsy to look at the number and size of cells found in a bone marrow sample. In patients with severe aplastic anemia, the bone marrow has a very low cell content (hypocellular).
• Genetic testing to check for inherited disorders or gene changes (to rule out inherited bone marrow failure syndromes). Genetic testing is also done to find gene changes that help diagnose acquired aplastic anemia.

How aplastic anemia is classified

Your child’s aplastic anemia can be non-severe (sometimes referred to as “moderate”), severe, or very severe.

• Non-severe (“moderate”) aplastic anemia: Your child has a lower-than-normal number of blood cells in the bone marrow and blood. They might not feel sick or have only mild symptoms.
• Severe aplastic anemia: Your child has a very low number of blood cells in the bone marrow and blood. This classification is the most commonly diagnosed. Severe aplastic anemia is defined as:
  • Bone marrow cellularity (number of cells in the bone marrow) less than 25%
  • Reticulocyte count (number of immature red blood cells) less than 20,000 per microliter of blood 
  • Platelet count less than 20,000 per microliter of blood
  • Absolute neutrophil count (ANC) less than 500 per microliter of blood
• Very severe aplastic anemia: Your child has a very low number of cells in the bone marrow and blood. They meet the criteria for severe aplastic anemia and have an ANC less than 200 per microliter. As the ANC decreases, the risk of infection increases.

Treatment of aplastic anemia 

The right treatment for your child depends on the cause and severity of aplastic anemia and your child’s medical needs. If the condition is not severe, your child may not receive treatment and instead be closely monitored through regular blood tests.

Treatments for aplastic anemia include:

Stem cell (bone marrow) transplant

An allogeneic transplant uses healthy stem cells from a donor who is an HLA-match. HLA (Human Leukocyte Antigens) are proteins on cell surfaces. For a successful bone marrow transplant, doctors need to carefully match these markers between the donor and patient to prevent dangerous immune system reactions and transplant rejection. This treatment is recommended if an HLA-matched sibling bone marrow donor is identified. If a sibling is not a match, an unrelated matched donor may be considered if your child does not respond to immunosuppressive therapy or has severe disease.

A stem cell transplant can cure aplastic anemia for life. A transplant is not an easy process and can have complications including immune system reaction, rejection of donor cells, or infection.

Immunosuppressive therapy

Your child may get medicines to keep the immune system from attacking stem cells. These medicines include cyclosporine and antithymocyte globulin (ATG). This kind of therapy lasts for at least 1 year.

In the beginning, most patients will show a positive response to immunosuppressive therapy with improvement in their blood counts and quality of life. However, only about 1 in 3 patients show long-lasting response. Patients who do not respond to immunosuppressive therapy or whose disease returns will need a stem cell transplant.

Blood transfusions

Your child may receive transfusions of red blood cells or platelets from a healthy donor. This can help treat symptoms but is not a cure.

Bone marrow stimulant medicines

In some situations, medicines such as eltrombopag, romiplostim, or filgrastim (G-CSF) can boost stem cell production to help the body make new blood cells. These medications are rarely given in children with aplastic anemia.

Supportive medication

Patients with aplastic anemia can have very low white blood cell counts and are at a high risk for life-threatening infections. To treat or reduce infection risk, drugs may be given to kill fungi (antifungals), viruses (antivirals), or bacteria (antibiotics).

Prognosis for aplastic anemia 

Most people who get treatment recover from aplastic anemia. Recovery depends on:

• How severe the case is
• Type of treatment and response to treatment
• Your child’s age

Without treatment, aplastic anemia is life-threatening. Complications include severe infections, bleeding, and organ failure due to anemia. With prompt diagnosis and treatment, the overall five-year survival rate is more than 90% for children with aplastic anemia.

With advancements in diagnosis and treatment, the long-term outcomes for children with aplastic anemia patients are continuously improving.

Talk to your doctor before giving your child any medicine

Medicines like aspirin or ibuprofen (Motrin®, Advil®) can keep platelets from working properly. If needed, give acetaminophen (Tylenol®) for headache or pain. Do not give any medication for fever without first contacting your care team.

Know what activities to avoid

If your child has fewer red blood cells, they may get tired more easily or get out of breath. Be sure your child does not overdo physical activity. When platelet counts are low, you child is at higher risk of bleeding. Your child should avoid contact sports, rough play, and activities that could involve falls or injury to the head or stomach.

Talk to your care team before your child:

• Flies in a plane
• Travels to a high-altitude location or mountain area
• Has surgery or a dental procedure

In the beginning of treatment, your child might not be able to attend school in-person. Or your child might need to have an alternate schedule or other classroom accommodations.

Your child’s care team can answer questions about which activities your child might need to avoid.

Questions to ask your care team 

• What treatment does my child need?
• Are there any expected side effects?
• What monitoring or lab tests will my child need?
• What lab test values do I need to know?
• What activities are safe for my child? What activities should my child avoid?
• What symptoms do we need to watch for?
• What should we do if my child has an injury or severe bleeding?
• What should we do if my child has a fever?

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