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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:

Iron deficiency anemia is the most common type of anemia.

Images

Red blood cells - elliptocytosis
Red blood cells - spherocytosis
Red blood cells - multiple sickle cells
Ovalocytoses
Red blood cells - sickle and Pappenheimer
Red blood cells, target cells
Hemoglobin

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:

Possible causes of anemia include:

Symptoms

You may have no symptoms if the anemia is mild or if the problem develops slowly. Symptoms that may occur first include:

If the anemia gets worse, symptoms may include:

Exams and Tests

Your health care provider will perform a physical examination, and may find:

Some types of anemia may cause other findings on a physical exam.

Blood tests used to diagnose some common types of anemia may include:

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:

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.

Related Information

Vitamin B12 deficiency anemia
Folate-deficiency anemia
Iron deficiency anemia
Hemolytic anemia
Glucose-6-phosphate dehydrogenase deficiency
Aplastic anemia
Immune hemolytic anemia
Pernicious anemia
Sickle cell disease
Heart attack

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.

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Review Date: 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.

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