Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues.
Different types of anemia include:
- Anemia due to B12 deficiency
- Anemia due to folate deficiency
- Anemia due to iron deficiency
- Anemia of chronic disease
- Hemolytic anemia
- Idiopathic aplastic anemia
- Megaloblastic anemia
- Pernicious anemia
- Sickle cell anemia
Although many parts of the body help make red blood cells, most of the work is done in the bone marrow. Bone marrow is the soft tissue in the center of bones that helps form all blood cells.
Healthy red blood cells last between 90 and 120 days. Parts of your body then remove old blood cells. A hormone called erythropoietin (epo) made in your kidneys signals your bone marrow to make more red blood cells.
Hemoglobin is the oxygen-carrying protein inside red blood cells. It gives red blood cells their color. People with anemia do not have enough hemoglobin.
The body needs certain vitamins, minerals, and nutrients to make enough red blood cells. Iron, vitamin B12, and folic acid are three of the most important ones. The body may not have enough of these nutrients due to:
- Changes in the lining of the stomach or intestines affect how well nutrients are absorbed (for example, celiac disease)
- Poor diet
- Slow blood loss (for example, from heavy menstrual periods or stomach ulcers)
- Surgery that removes part of the stomach or intestines
Possible causes of anemia include:
- Certain medicines
- Destruction of red blood cells earlier than normal (which may be caused by immune system problems)
- Long-term (chronic) diseases such as chronic kidney disease, cancer, ulcerative colitis, or rheumatoid arthritis
- Some forms of anemia, such as thalassemia or sickle cell anemia, which can be inherited
- Problems with bone marrow such as lymphoma, leukemia, myelodysplasia, multiple myeloma, or aplastic anemia
You may have no symptoms if the anemia is mild or if the problem develops slowly. Symptoms that may occur first include:
- Feeling grumpy
- Feeling weak or tired more often than usual, or with exercise
- Problems concentrating or thinking
If the anemia gets worse, symptoms may include:
Exams and Tests
The doctor will perform a physical examination, and may find:
- A heart murmur
- Low blood pressure, especially when you stand up
- Pale skin
- Rapid heart rate
Some types of anemia may cause other findings on a physical exam.
Blood tests used to diagnose some common types of anemia may include:
- Blood levels of iron, vitamin B12, folic acid, and other vitamins and minerals
- Red blood count and hemoglobin level
- Reticulocyte count
Other tests may be done to find medical problems that can cause anemia.
Treatment should be directed at the cause of the anemia, and may include:
- Blood transfusions
- Corticosteroids or other medicines that suppress the immune system
- Erythropoietin, a medicine that helps your bone marrow make more blood cells
- Supplements of iron, vitamin B12, folic acid, or other vitamins and minerals
Severe anemia can cause low oxygen levels in vital organs such as the heart, and can lead to a heart attack.
When to Contact a Medical Professional
Call your health care provider if you have any symptoms of anemia or unusual bleeding.
Bunn HF. Approach to the anemias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 158.
Marks PW. Approach to anemia in the adult and child. In: Hoffman R, Benz EJ Jr, Silberstein LE, Weitz JI, Anastasi J, eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 32.
Update Date 2/13/2015
Updated by: Rita Nanda, MD, Assistant Professor of Medicine, Section of Hematology/Oncology, University of Chicago Medicine, Chicago, IL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.