What Is Medullary Aplasia?

What is medullary aplasia? Usually it causes anemia, among other symptoms. We'll explain what it is, what its causes are and how to treat it.
What Is Medullary Aplasia?

Last update: 02 May, 2021

Medullary aplasia is a disease that affects the bone marrow. Bone marrow is the spongy tissue inside the long bones, vertebrae, pelvis, shoulder girdle and others. It’s responsible for producing blood cells, like red blood cells, white blood cells and platelets. So, what is medullary aplasia exactly?

With medullary aplasia, the cells in the bone marrow that produce new blood cells disappear. Therefore, the overall number of blood cells in your body decrease. This can lead to anemia, an increased sensitivity to infection, and clotting problems.

Unfortunately, there are many circumstances that can trigger this disease. In addition, treatment is essential, because it’s a very serious situation. In this article, we’ll explain everything you need to know about this disorder and how to treat it.

What is medullary aplasia?

Medullary aplasia is a bone marrow disease. When you have this disease, your hematopoietic precursor cells either totally or partially disappear. 

These cells create blood cells, like red blood cells, leukocytes, and platelets. Therefore, when they disappear, there’s a decrease in the overall number of cells in your body.

Blood cells are essential for life. Red blood cells are responsible for transporting oxygen to the tissues. In addition, leukocytes are essential for proper immune system function. Platelets (which are larger cell fragments) are responsible for the clotting process. 

Medullary aplasia causes a dysfunction in all of these functions. Therefore, it can lead to an anemic syndrome (called aplastic anemia), bleeding and infection.

Also, medullary aplasia can be partial or total, which also means its severity is variable. According to a study published in the Cuban Journal of Hematology, Immunology and Hemotherapy, experts estimate the incidence is between 2 and 6 people per million inhabitants. 

Blood cells.

Causes of medullary aplasia

There are many situations that can cause medullary aplasia. In general, experts divide these causes into congenital or acquired.

Congenital conditions are those that are present from birth. This group includes Fanconi anemia. It’s a rare, inherited disease that is transferred in an autosomal recessive manner. In addition, it causes a decrease in all types of blood cells. 

On the other hand, there are acquired causes which an article from the Josep Carreras Foundation explains are more common. With these situations, hematopoietic stem cells disappear. This could be due to direct damage to the marrow or because of immune mechanisms. 

In almost 80% of cases, the specialist isn’t able to identify the cause of the aplasia. Because of that, they refer to it as an idiopathic form. Some of the etiologies they usually identify when they can find a cause are the following:

  • Drugs or chemical agents: pesticides or benzene.
  • Viral infections: hepatitis, human immunodeficiency virus, Epstein-Barr virus, and cytomegalovirus.
  • Radiation and chemotherapy treatments: in this case, it’s usually temporary.

Symptoms of medullary aplasia

As we’ve mentioned, medullary aplasia can be partial or total. When it’s partial, there’s still a small production of blood cells. Therefore, the symptoms may be somewhat milder than with a total medullary aplasia.

Also, the symptoms depend on the affected cell line. According to the University of Navarra Clinic, if the red blood cell production is affected, you’ll experience aplastic anemia. This can cause fatigue, shortness of breath, pale skin and tachycardia. In addition, dizziness, vertigo or cramps are common symptoms.

When the condition affects leukocytes, the patient will have a very high susceptibility to infections. These infections are usually from rare germs and they last longer.

Finally, medullary aplasia may involve a change in platelet synthesis. These are the cellular fragments that play a role in the coagulation process. In this case, it’s also common to experience hemorrhages. 


To diagnose this condition, the doctor will need to know the patient’s medical history. It’s essential to let them know if you’ve been undergoing any treatment, if you have any other conditions, and what your symptoms are.

In addition, the specialist will need to carry out certain tests to confirm the diagnosis. Also, blood work is key. Using the blood work, the specialist will be able to quantify the levels of red and white blood cells, as well as platelets. People with medullary aplasia will have below-average quantities.

Another test that can help with diagnosis is a bone marrow biopsy. This consists of extracting a small sample of bone marrow. Normally, they’ll take the sample from the hip bone.

Bone marrow.

Medullary aplasia treatment options

Medullary aplasia can be life-threatening for those who suffer from it. When it comes to a serious case, the patient will likely need to be hospitalized.

One of the techniques doctors usually use is blood transfusions. Although it’s not a curative approach, it can help control some of the anemia and bleeding symptoms. However, repeatedly performing these transfusions can cause certain complications. 

In addition, another option is stem cell transplantation. Since medullary aplasia includes a deficiency of hematopoietic cells, this technique can help to generate new ones.

Also, you have to keep in mind that it’s difficult to find compatible donors. In addition, the body may reject the transplant, which is life-threatening. This is a curative option, but it requires continuous immunosuppression and a long hospital stay. 

Currently, there are medications that act as bone marrow stimulants. For example, one of them is filgrastim. These drugs are usually associated with immunosuppressants, like cyclosporine.

Immunosuppressants are helpful if the cause of the aplasia is an immune system disturbance. They also help keep the patient stable until they can get a bone marrow transplant. 


Medullary aplasia is a serious disease that causes a decrease in blood cells. This condition has many causes. However, in a large number of patients, doctors are not able to figure out the exact cause. 

This disease causes severe anemia, clotting problems, and frequent and long-term infections. Therefore, it’s important to establish a treatment plan as soon as possible. Otherwise, the person is at serious risk of death. 

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