What is aplastic anemia?

Related conditions:
Thrombocytopenia (low platelet count), neutropenia (low white count)

Definition:
The bone marrow is responsible for producing all of the blood cells in the body. Aplastic anemia is a life-threatening condition caused when the bone marrow stops producing enough new cells to create new blood cells. The typical life span of red blood cells is 120 days, platelets about six days, and white blood cells about one day. The bone marrow needs to produce cells continuously to replace the dying cells. Aplastic anemia can be acquired or hereditary. The more common acquired aplastic anemia can be a temporary condition caused by exposure to toxic chemicals, pesticides, and benzenes. Common causes for the cancer patient are chemotherapy and radiation. Hereditary aplastic anemia is rare and can be associated with Fanconi anemia, Shwachman-Diamond syndrome, and dyskeratosis congenita.

Etiology and the disease process: Although the cause of most aplastic anemia is unknown, those cases induced by chemotherapy and radiation result from the therapy’s suppression of bone marrow function. The bone marrow is not able to manufacture the cells that are needed to create red blood cells, platelets, and white blood cells.

Incidence: Aplastic anemia is a rare condition with only about 600 to 900 new cases each year in the United States, according to the Aplastic Anemia & MDS International Foundation. Of patients who are diagnosed with aplastic anemia, 20 percent have an inherited disorder as well.

Symptoms: The signs and symptoms of aplastic anemia may be seen immediately or can be slow to develop and be dependent on the blood counts themselves. Common symptoms include fatigue, dizziness, an irregular heart rate, fevers, frequent infections, frequent nose bleeds, oozing gums, blood in the stool, bruising, difficulty in stopping bleeding from a cut, and petechiae (similar to a red pinpoint rash, located on the arms, legs, and trunk). Patients may also complain of severe shortness of breath even while at rest.

Screening and diagnosis: Aplastic anemia is typically found when patients complain of fatigue to their physicians. The physical assessment includes looking for pale or yellow-tinted skin; listening to the heart, lungs, and breathing patterns; feeling the liver and spleen for enlargement; and checking for signs of bleeding. The physician may also assess the patient’s environment to determine whether exposure to toxic chemicals or other triggers has occurred. Diagnostic testing includes analysis of blood, urine, and stool samples, and bone marrow aspiration and biopsy. The patient may also have images taken (X rays, computed `tomography scans, and ultrasound) to look for enlarged organs. Once testing is complete, the aplastic anemia is staged according to how many cells are seen in the bone marrow. The three stages are moderate, severe, or very severe.

Treatment and therapy: The treatment for aplastic anemia depends on the severity and the patient’s symptoms. The patient’s overall health also determines what type of treatment can be tolerated. Moderate aplastic anemia is not treated, but the physician keeps a close eye on the blood counts and the patient’s symptoms. If the aplastic anemia is caused by chemotherapy or radiation, the patient is treated with transfusions and growth factors.

Transfusions of red blood cells and platelets are the most common. Red blood cell transfusions help raise the hematocrit and hemoglobin, which improves the anemia symptoms. Epoietin alfa, a red blood cell growth factor, can be given to help the bone marrow release immature red blood cells from the bone marrow to mature and become functioning red cells.

Not all forms of aplastic anemia will respond to growth factors. Platelet transfusions will help the patient be able to form clots to stop bleeding. White blood cells are not typically transfused because of their short life span; however, they may be given to patients who have a severe infection. Patients with a low white blood cell count may receive filgrastim, a white blood cell growth factor, to stimulate the release of the immature white blood cells so that they can mature and fight off infections. Like the red cell growth factor, filgrastim may not be applicable for all forms of aplastic anemia.

Patients may receive medications such as antithymocyte globulin (ATG), cyclosporine, and methylprednisolone. Traditional therapy consists of the patient taking all three medications. It may take a few months before an improvement in blood counts is apparent. Patients may say that they are feeling better before their counts actually reflect an improvement. Antibiotics and antivirals may also be given to prevent infection.

Bone marrow transplants are more commonly used with younger patients to replace damaged bone marrow. Research is ongoing to develop additional treatments for aplastic anemia.

Prognosis, prevention, and outcomes: Historically aplastic anemia has had a poor prognosis. However, great strides have been made on the treatments available for aplastic anemia, and modern therapy has cured or managed the disease in many patients. Treatment can be effective but may take months before results are seen. Patients may also need to try different therapies to find one that works for them. Some forms of aplastic anemia can be prevented by avoiding exposure to toxins, radiation, and medication, but other forms cannot be prevented.

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