Aplastic anemia

ALSO KNOWN AS: Bone marrow failure

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 making enough new blood cells. The typical life span of red blood cells is 120 days. For platelets, this is about six days, and one day is white blood cells. Bone marrow needs to produce cells continuously to replace the dying cells. Aplastic anemia can be acquired or hereditary. The more commonly acquired aplastic anemia can be a temporary condition caused by exposure to toxic chemicals, pesticides, and benzenes. Other causes come through 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, 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 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 yearly in the United States, according to the Aplastic Anemia & MDS International Foundation. Of patients who are diagnosed with aplastic anemia, 20 percent also have an inherited disorder.

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
• irregular heart rate
• fevers
• frequent infections
• frequent nose bleeds
• oozing gums
• blood in the stool
• bruising
• difficulty in stopping bleeding from a cut
• 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.

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 treatment can be tolerated. Moderate aplastic anemia is not treated, but the physician closely monitors 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.

The most common blood transfusions are red blood cell and platelet transfusions. Red blood cell transfusions help raise the hematocrit and hemoglobin, which improves anemia symptoms. Epoietin alfa, a red blood cell growth factor, can be given to help the bone marrow release immature red blood cells to mature and become functioning red cells. Not all forms of aplastic anemia will respond to growth factors. Platelet transfusions will help the patient 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 with severe infections. Patients with a low white blood cell count may receive filgrastim, a white blood cell growth factor, to stimulate the release of immature white blood cells to 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 drugs. It may take a few months before an improvement in blood counts is apparent. Patients may say they are feeling better before their counts reflect 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, advancements have been made in the treatments available for aplastic anemia, and modern therapy has cured or managed the disease in many patients. One of these treatments is stem cell transplantation. According to 2023 data from The Cleveland Clinic, 96% of patients survived the procedure, and 100% of those treated less than 40 years of age survived beyond five years.

Factors that affect the outcome of aplastic anemia treatments include severity, age, and overall health. 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. Some forms of aplastic anemia can be prevented by avoiding exposure to toxins, radiation, and medication, but other forms cannot be prevented.

Bibliography

"Aplastic Anemia." The Cleveland Clinic, 22 June 2023, my.clevelandclinic.org/health/diseases/16747-aplastic-anemia. 21 June 2024.

"Aplastic Anemia." The Mayo Clinic, 11 Feb. 2022, www.mayoclinic.org/diseases-conditions/aplastic-anemia/symptoms-causes/syc-20355015. Accessed 21 June 2024.

DeZern, Amy E., and Eva C. Guinan. "Aplastic Anemia in Adolescents and Young Adults." Act Haematologica, vol 132, no. 3-4, 2014, pp. 331–39.

Hoffman, Ronald, et al. Hematology: Basic Principles and Practice, 6th ed, Philadelphia, Saunders/Elsevier, 2013.

Klag, Michael J, ed. Johns Hopkins Family Health Book. New York, HarperCollins, 1999.

Korthof, E. T., et al. "Management of Acquired Aplastic Anemia in Children." Bone Marrow Transplantation, vol. 48. no. 2, 2013, pp. 191–95.

Schrezenmeier, Hubert, and Andrea Bacigalupo, eds. Aplastic Anemia: Pathophysiology and Treatment. New York, Cambridge University Press, 2000.

Seladi-Schulman, Jill. "What Factors Influence the Prognosis of Aplastic Anemia in Adults?." Healthline, 5 Jan 2024, www.healthline.com/health/iron-deficiency-anemia/aplastic-anemia-prognosis-in-adults. Accessed 21 June 2024.