Aplastic Anemia

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is aplastic anemia?

Aplastic anemia is a type of bone marrow failure, the result of damage to stem cells in the bone marrow. All types of blood cells—red blood cells, white blood cells, and platelets—develop from these early stem cells. Without enough stem cells, the bone marrow cannot supply the body with an adequate and diverse blood cell inventory. So, aplastic anemia causes low red blood cells (anemia), low white blood cells (leukopenia), and low platelets (thrombocytopenia). However, the few blood cells the bone marrow produces and releases to the body are normal.

Some people with aplastic anemia have a low number of stem cells in the bone marrow (hypoplastic). Others have bone marrow that is basically empty (aplastic). The severity of the lack of stem cells will affect symptoms. In moderate cases, there may be enough normal blood cells that symptoms are not noticeable. When symptoms occur, they can include fatigue, frequent infections, and uncontrolled bleeding.

Aplastic anemia is very rare. Less than 1,000 Americans are diagnosed with the disease each year. It can occur at any age, but is more common in very young children, young adults in their early 20s, and senior adults. It affects both sexes equally.

When people develop aplastic anemia, it is usually idiopathic—meaning the cause is unknown. The main theory is that it is an autoimmune disease—the immune system attacks the bone marrow as if it were a foreign invader. Genetics often plays a role in children with aplastic anemia.

Aplastic anemia can be life-threatening. Treatments may include medicines, blood transfusions, and stem cell transplants. For some people, a stem cell transplant can cure aplastic anemia. See your doctor promptly for persistent symptoms, such as fever, cuts that will not heal, or weakness. Seek immediate medical care for bleeding that will not stop.

What are the different types of aplastic anemia?

Doctors classify aplastic anemia using blood counts. Using a standard blood draw, a laboratory determines the number of different types of cells circulating in your blood, including:

  • Neutrophil, a type of white blood cell

  • Platelet, a blood cell “fragment” required for blood to clot

  • Reticulocyte, an immature red blood cell

Moderate aplastic anemia

Moderate aplastic anemia has the following characteristics:

  • Lower-than-normal blood cell counts, but not as low as severe aplastic anemia

  • No symptoms or very few or mild symptoms

  • Watchful waiting and monitoring blood counts may be all that is necessary

Severe aplastic anemia

Severe aplastic anemia has the following characteristics:

  • Neutrophil count is less than 500 per microliter

  • Platelet count is less than 20,000 per microliter

  • Reticulocyte (immature red blood cell) count is less than 20,000 per microliter
     

Very severe aplastic anemia

Very severe aplastic anemia has the following characteristics:

  • Neutrophil count is less than 200 per microliter

  • Platelet and reticulocyte counts are the same as for severe aplastic anemia

What are the symptoms of aplastic anemia?

It is possible to have moderate aplastic anemia and not have symptoms. When symptoms occur, they depend on the type or types of blood cells the disease affects the most. Symptoms can develop suddenly or slowly over a period of time.

Common symptoms of aplastic anemia

Common symptoms of aplastic anemia include:

Serious symptoms that might indicate a life-threatening condition

In some cases, aplastic anemia can be life-threatening. Seek immediate medical care (call 911) for bleeding that will not stop. Seek prompt medical treatment for any symptoms of aplastic anemia that persist or worsen. When aplastic anemia is severe, hospital treatment is often necessary to prevent potentially fatal complications.

What causes aplastic anemia?

Aplastic anemia is either hereditary or acquired. Hereditary aplastic anemia is less common. It occurs when a parent passes a gene to their child and usually shows up during childhood. Damage to the stem cells occurs as the result of a genetic condition such as:

  • Daimond-Blackfan anemia

  • Dyskeratosis congenita

  • Fanconi anemia

  • Shwachman-Diamond syndrome

  • Telomere diseases

Acquired aplastic anemia accounts for most cases of aplastic anemia. It is acquired because it develops later in life for some other reason (not inherited). Most of the time, there is no clear cause—it is idiopathic. Most experts believe an autoimmune process is the underlying cause of idiopathic aplastic anemia. In an autoimmune disease, the immune system mistakenly attacks the body’s own tissues as if they were foreign. In this case, the bone marrow stem cells are the target.

In the remaining cases of acquired aplastic anemia, doctors can identify a cause, which may include:

  • Cancer chemotherapy or radiation treatment

  • Accidental radiation exposure from the environment

  • Certain medications, such as some antibiotics, antiseizure medicines, gold salts, and NSAIDs (nonsteroidal anti-inflammatory drugs)

  • Viral infections, such as cytomegalovirus (CMV), Epstein-Barr virus, hepatitis, HIV, and parvovirus B19

  • Pregnancy

  • Toxins, such as arsenic, benzene, heavy metals, insecticides, and pesticides

What are the risk factors for aplastic anemia?

Aplastic anemia affects males and females equally. While it can occur at any age, it is most likely to develop between the ages of 2 to 5 years, 20 to 25 years, and after age 55. In addition, it is more common in Asian Americans.

A number of other factors increase the risk of developing aplastic anemia including:

  • Exposure to certain medications, chemicals and toxins

  • Family history of certain genetic disorders

  • Personal history of autoimmune disorders or certain viral infections

  • Pregnancy (a rare cause)

  • Previous chemotherapy or radiation treatment for cancer

Reducing your risk of aplastic anemia

Reducing your risk of a disease relies on changing risk factors that are under your control. Unfortunately, you cannot change most of the risk factors for aplastic anemia. Therefore, it is usually not possible to prevent it. If you work with pesticides or other chemicals, follow the safety precautions for handling each individual substance.

If a child has hereditary aplastic anemia, it is important to test any siblings for the disease. While this will not prevent the disease, it will allow doctors to treat it early.

What are some conditions related to aplastic anemia?

There are two closely related conditions to aplastic anemia. The first is myelodysplastic syndromes (MDS). This group of rare disorders are like aplastic anemia in that damage to the bone marrow stem cells results in low blood cell counts. However, unlike aplastic anemia, any blood cells the bone marrow is able to produce are abnormal. Blood cells do not function properly, so they are unable to do their jobs at all. MDS is more common in older adults and strikes men twice as often as women.

The other related condition is paroxysmal nocturnal hemoglobinuria (PNH). PNH is an acquired stem cell disorder where red blood cells break down prematurely. This results in repeated episodes of blood in the urine. It is common to have very dark or bloody urine in the morning, when urine is more concentrated. PNH can develop from aplastic anemia or lead to it.

How do doctors diagnose aplastic anemia?

To diagnose your condition, your doctor will take a medical history, perform a physical exam, and order testing. Questions your doctor make ask include:

  • What symptoms are you experiencing?

  • When did your symptoms first start?

  • Are your symptoms constant or do they come and go?

  • What, if anything, seems to make your symptoms better or worse?

  • What do you do for a living? Are you around chemicals?

  • What medications do you take?

  • What other medical conditions do you have? Have you ever been treated for cancer?

Based on your history and physical exam, your doctor may order testing including:

  • Blood tests, specifically a complete blood count to look at levels of all three types of blood cells. Your doctor may also order tests to check levels of iron, folate, vitamin B12, and erythropoietin—a hormone that stimulates red blood cell production.

  • Bone marrow biopsy, a necessary procedure if blood cell counts are low, to confirm a diagnosis of aplastic anemia. The bone marrow biopsy will also tell your doctor how well your bone marrow is working.

What are the treatments for aplastic anemia?

Treatment of aplastic anemia depends on the severity. For moderate disease, treatment may not be necessary. Instead, doctors may recommend monitoring the disease to make sure it does not get worse. Severe aplastic anemia requires treatment to avoid complications. Often, this means hospitalization to manage the disease.

Aplastic anemia treatments may include:

  • Antibiotics or antivirals to treat fever and infections, which can quickly become life-threatening in people with aplastic anemia
  • Blood transfusions to relieve symptoms of aplastic anemia by replacing blood cells
  • Growth factors that stimulate the bone marrow to make different kinds of blood cells, such as epoetin alfa (Epogen/Procrit), filgrastim (Neupogen) and pegfilgrastim (Neulasta), sargramostim (Leukine), and eltrombopag (Promacta)
  • Immunosuppressants to suppress the immune system, such as cyclosporine (Gengraf, Neoral, Sandimmune), antithymocyte globulin (ATG), and corticosteroids
  • Stem cell transplant to rebuild the bone marrow with donor stem cells. This option offers a cure for some people. The best candidates for stem cell transplant are young patients with a matching donor, most likely a sibling. 

There are risks with each treatment option. Like all healthcare decisions, finding the right treatment involves weighing these risks against the benefits of treatment. Discuss your options with your doctor and make sure you understand the risks and benefits with each one.

In addition to active treatments, people with aplastic anemia may need to be in isolation to prevent infection.

At-home care for aplastic anemia

Lifestyle habits and home remedies may help you manage the symptoms and protect yourself. Self-care strategies include:

  • Avoiding contact sports and other activities that put you at risk of bleeding

  • Eating a healthy balanced diet to ensure proper nutrition

  • Getting adequate rest and taking breaks when necessary

  • Reducing your risk of infection by practicing good hygiene, washing your hands frequently, and staying away from people who are sick and large crowds

What are the potential complications of aplastic anemia?

Aplastic anemia can cause serious and even life-threatening complications. When any of the types of blood cells get too low, complications are possible including:

  • Heart failure due to severely low levels of red blood cells

  • Severe or life-threatening infections due to very low levels of white blood cells (neutrophils)

  • Spontaneous internal bleeding due to extremely low platelet levels

In addition, people with aplastic anemia have an increased risk of acute myeloid leukemia (AML).

Does aplastic anemia shorten life expectancy?

Left untreated, aplastic anemia has a high fatality rate. About 70% of people will die within a year if they do not get treatment. Even with treatment, the disease was often fatal in the past. However, with today’s treatments, the survival rate is vastly better. Standard treatment with immunosuppressants or a stem cell transplant allows about 80% of aplastic anemia patients to recover.

Your prognosis depends on several factors, including disease severity and your response to treatment. Your doctor is the best source of information about your future outlook.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jul 26
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