Anemia
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 vitamin B12 deficiency
- Anemia due to folate (folic acid) deficiency
- Anemia due to iron deficiency
- Anemia of chronic disease
- Hemolytic anemia
- Idiopathic aplastic anemia
- Megaloblastic anemia
- Pernicious anemia
- Sickle cell anemia
- Thalassemia
Iron deficiency anemia is the most common type of anemia.
Elliptocytosis is a hereditary disorder of the red blood cells (RBCs). In this condition, the RBCs assume an elliptical shape, rather than the typical round shape.
Spherocytosis is a hereditary disorder of the red blood cells (RBCs), which may be associated with a mild anemia. Typically, the affected RBCs are small, spherically shaped, and lack the light centers seen in normal, round RBCs.
Sickle cell anemia is an inherited disorder in which abnormal hemoglobin (the red pigment inside red blood cells) is produced. The abnormal hemoglobin causes red blood cells to assume a sickle shape, like the ones seen in this photomicrograph.
Red blood cells (RBCs) are normally round. In ovalocytosis, the cells are oval. Other conditions that produce abnormally shaped RBCs include spherocytosis and eliptocytosis.
This photomicrograph of red blood cells (RBCs) shows both sickle-shaped and Pappenheimer bodies.
These abnormal red blood cells (RBCs) resemble targets. These cells are seen in association with some forms of anemia, and following the removal of the spleen (splenectomy).
Hemoglobin is the most important component of red blood cells. It is composed of a protein called heme, which binds oxygen. In the lungs, oxygen is exchanged for carbon dioxide. Abnormalities of an individual's hemoglobin value can indicate defects in the normal balance between red blood cell production and destruction. Both low and high values can indicate disease states.
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.
Causes
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 that affect how well nutrients are absorbed (for example, celiac disease)
- Poor diet
- Surgery that removes part of the stomach or intestines
Possible causes of anemia include:
- Iron deficiency
- Vitamin B12 deficiency
- Folate deficiency
- 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
- Pregnancy
- Problems with bone marrow such as lymphoma, leukemia, myelodysplasia, multiple myeloma, or aplastic anemia
- Slow blood loss (for example, from heavy menstrual periods or stomach ulcers)
- Sudden heavy blood loss
Symptoms
You may have no symptoms if the anemia is mild or if the problem develops slowly. Symptoms that may occur first include:
- Feeling weak or tired more often than usual, or with exercise
- Headaches
- Problems concentrating or thinking
- Irritability
- Loss of appetite
- Numbness and tingling of hands and feet
If the anemia gets worse, symptoms may include:
- Blue color to the whites of the eyes
- Brittle nails
- Desire to eat ice or other non-food things (pica syndrome)
- Lightheadedness when you stand up
- Pale skin color
- Shortness of breath with mild activity or even at rest
- Sore or inflamed tongue
- Mouth ulcers
- Abnormal or increased menstrual bleeding in females
- Loss of sexual desire in men
Exams and Tests
Your health care provider will perform a physical examination, and may find:
- A heart murmur
- Low blood pressure, especially when you stand up
- Slight fever
- 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
- Complete blood count
- Reticulocyte count
Other tests may be done to find medical problems that can cause anemia.
Treatment
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
Possible Complications
Severe anemia can cause low oxygen levels in vital organs such as the heart, and can lead to heart failure.
When to Contact a Medical Professional
Contact your provider if you have any symptoms of anemia or unusual bleeding.
References
Elghetany MT, Banki K. Erythrocytic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 33.
Lin JC, Benz Jr. EJ. Approach to anemia in the adult and child. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 35.
Means Jr. RT. Approach to the anemias. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 144.
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.
