Aplastic anemia
Hypoplastic anemia; Bone marrow failure - aplastic anemia
Aplastic anemia is a condition in which the bone marrow does not make enough blood cells. Bone marrow is the soft, tissue in the center of bones that is responsible for producing blood cells and platelets.
A small amount of bone marrow is removed during a bone marrow aspiration. The procedure is uncomfortable, but can be tolerated by both children and adults. The marrow can be studied to determine the cause of anemia, the presence of leukemia or other malignancy, or the presence of some storage diseases, in which abnormal metabolic products are stored in certain bone marrow cells.
Causes
Aplastic anemia results from damage to the blood stem cells. Stem cells are immature cells in the bone marrow that give rise to all blood cell types (red blood cells, white blood cells, and platelets). Injury to the stem cells leads to a decrease in the number of these blood cell types.
Aplastic anemia can be caused by:
- Use of certain medicines or exposure to toxic chemicals (such as chloramphenicol, benzene)
- Exposure to radiation or chemotherapy
- Autoimmune disorders
- Pregnancy
- Viruses
Sometimes, the cause is unknown. In this case, the disorder is called idiopathic aplastic anemia.
Do you feel tired and listless? Do you find your mind drifting during the day? Do you get dizzy or short of breath whenever you climb the stairs? There are a few possible reasons for the way you feel, but you could have anemia. You could even have anemia without noticing any symptoms at all. Anemia is a problem with hemoglobin, a substance in red blood cells that carries oxygen throughout your body. Without enough hemoglobin, your heart and other organs can't get the oxygen they need to work. When your organs slow down, you slow down and you start feeling tired and listless. Many different health conditions can cause anemia, from heavy blood loss during a woman's period, to pregnancy, to an underactive thyroid gland. Healthy red blood cells are made in your bone marrow, the soft tissue in the middle of your bones. Any disease that damages blood marrow, such as lymphoma or leukemia, can also affect your red blood cell production. Anemia can also be caused by an immune system problem that damages red blood cells, or surgery to the stomach or intestines. How do you know if you have anemia? You may feel tired, dizzy, and have trouble concentrating. You may get sick more often. People with anemia often complain of chest pain, headaches, or shortness of breath. Your skin might look pale, like you haven't seen the sun for months. Because these can also be symptoms of other conditions, your doctor will confirm that you have anemia by taking a blood test to check your red blood cell count and hemoglobin level. Blood tests can also look for problems that may be causing your anemia, such as a vitamin or iron deficiency. If you are anemic, it's very important to treat it. When your body isn't getting enough oxygen, it can starve vital organs like your heart. This can lead to a heart attack. How you treat anemia really depends on the cause. If the problem is with your bone marrow, you may take a medicine called erythropoietin, which will help your bone marrow make more red blood cells. If the problem is a vitamin or mineral deficiency, your doctor may prescribe iron, vitamin B12, or folic acid supplements. Or, you may need a blood transfusion to replace damaged red blood cells with healthy ones. How well you do really depends on what's causing your anemia. Call your doctor if you have any symptoms like fatigue or shortness of breath. Once your doctor can find and treat the cause of your anemia, you should have more energy and start feeling like your old self again.
Symptoms
Symptoms are due to the underproduction of red cells, white cells, and platelets. Symptoms may be severe from the start or gradually worsen over time as the disease progresses.
Low red cell count (anemia) can cause:
- Fatigue
- Pallor (paleness)
- Rapid heart rate
- Shortness of breath with exercise
- Weakness
- Lightheadedness upon standing
Low white cell count (leukopenia) causes an increased risk for infection.
Low platelet count (thrombocytopenia) can result in bleeding. Symptoms include:
- Bleeding gums
- Easy bruising
- Nose bleeds
- Rash, small pinpoint red marks on the skin (petechiae)
- Frequent or severe infections (less common)
Exams and Tests
Blood tests will show:
- Low red blood cell count (anemia)
- Low white blood cell count (leukopenia)
- Low reticulocyte count (reticulocytes are the youngest red blood cells)
- Low platelet count (thrombocytopenia)
A bone marrow biopsy shows fewer-than-normal blood cells and an increased amount of fat.
Treatment
Mild cases of aplastic anemia that do not have symptoms may not require treatment.
As blood cell counts become lower and symptoms develop, blood and platelets may be given through transfusions. Over time, transfusions may stop working, resulting in very low blood cell counts. This is a life-threatening condition.
Bone marrow, or stem cell transplant may be recommended for younger people. It is more likely to be recommended for those 50 years and younger, but people over 50 may receive a transplant if they are healthy enough. This treatment works best when the donor is a fully-matched brother or sister. This is called a matched sibling donor..
Older people and those who do not have a matched sibling donor are given medicine to suppress the immune system. These medicines may allow the bone marrow to once again make healthy blood cells. But the disease may return (relapse). A bone marrow transplant with an unrelated donor may be tried if these medicines do not help or if the disease comes back after getting better.
Outlook (Prognosis)
Untreated, severe aplastic anemia leads to rapid death. Bone marrow transplant can be very successful in young people. A transplant is also used in older people or when the disease comes back after medicines have stopped working.
Possible Complications
Complications may include:
- Severe infections or bleeding
- Complications of bone marrow transplant
- Reactions to medicines
- Hemochromatosis (buildup of too much iron in the body tissues from many red cell transfusions)
When to Contact a Medical Professional
Contact your health care provider or go to the emergency room if bleeding occurs for no reason, or if bleeding is hard to stop. Contact your provider if you notice frequent infections or unusual fatigue.
References
Culligan D, Watson HG. Blood and bone marrow. In: Cross SS, ed. Underwood's Pathology. 7th ed. Philadelphia, PA: Elsevier; 2019:chap 23.
DeZern AE, Brodsky RA. Aplastic anemia and related bone marrow failure states. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 151.
Young NS, Maciejewski JP. Aplastic anemia. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 31.
Version Info
Last reviewed on: 3/31/2024
Reviewed by: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
