DefinitionAnemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues.Other types of anemia include:Anemia due to B12 deficiencyAnemia due to folate deficiencyAnemia due to iron deficiencyAnemia of chronic diseaseHemolytic anemiaIdiopathic aplastic anemiaMegaloblastic anemiaPernicious anemia
Sickle cell anemiaThalassemia
Causes, incidence, and risk factorsAlthough 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 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 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 red 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 because:Changes in the lining of the stomach or intestines affect how well nutrients are absorbed (for example, celiac disease)Poor dietSlow 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 medicationsDestruction 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 arthritisSome forms of anemia, such as thalassemia or sickle cell anemia, which can be inherited
PregnancyProblems with bone marrow such as lymphoma, leukemia, multiple myeloma, or aplastic anemia
SymptomsYou may have no symptoms if the anemia is mild. If the problem develops slowly, symptoms that may occur first include:Feeling grumpyFeeling weak or tired more often than usual, or with exerciseHeadachesProblems concentrating or thinkingIf the anemia gets worse, symptoms may include:Blue color to the whites of the eyesBrittle nailsLight-headedness when you stand upPale skin colorShortness of breathSore tongue
Some types of anemia may have other symptoms.
Signs and testsThe doctor will perform a physical examination, and may find:Heart murmurLow blood pressure, especially when you stand upPale skinRapid heart rateSome 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 mineralsRed blood count and hemoglobin levelReticulocyte countOther tests may be done to find medical problems that can cause anemia.
TreatmentTreatment should be directed at the cause of the anemia, and may include:Blood transfusionsCorticosteroids or other medicines that suppress the immune systemErythropoietin, a medicine that helps your bone marrow make more blood cellsSupplements of iron, vitamin B12, folic acid, or other vitamins and minerals
ComplicationsSevere anemia can cause low oxygen levels in vital organs such as the heart, and can lead to a heart attack.
Calling your health care providerCall your health care provider if you have any symptoms of anemia, or any unusual bleeding.
ReferencesBunn HF. Approach to the anemias. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 161.