Anemia

Definition

Anemia is a condition characterized by a lower than normal level of red blood cells, which leads to iron deficiency.

Description

The World Health Organization (WHO) defines anemia as a hemoglobin level lower than 13 g/dL in men and lower than 12 g/dL in women. Hemoglobin is a protein found in red blood cells (RBCs). It has an active site called a heme that contains iron. The heme iron binds oxygen in the lungs for transport to the rest of the body where it releases the oxygen. A decrease of RBCs means a decrease of hemoglobin and a decrease of iron levels. Iron is essential to most life forms and to human health. A deficiency of iron impairs oxygen delivery to cells, resulting in fatigue, poor physical performance, and decreased immunity.

Demographics

According to WHO , iron deficiency is the most important nutritional disorder in the world. WHO estimates that 80% of the world's population may be iron deficient, and that 30% may have iron deficiency anemia . The prevalence of vitamin B12 deficiency among the geriatric population is estimated at 5–15%.

Anemia has become a serious senior health concern with incidence and prevalence increasing with age. While estimates vary, nearly 25% of community based octagenerians (people in their 80s) and 50% of the chronically ill elderly have Hb levels low enough to satisfy a diagnosis of anemia. It affects 3 million people in the United States aged 65 years and older and is associated with a wide range of complications, including increased risk of mortality,heart disease , kidney disease, reduced bone density, increased falls and fractures, and longer hospitalization for other conditions. Although the prevalence of anemia is greater in women than men aged less than 75, by age 75, male prevalence surpasses female prevalence by about 5%.

Causes and symptoms

Causes of anemia

Some direct causes of anemia include blood loss (from injury or surgery), and blood disorders such as sickle cell anemia, thalassemia, aplastic anemia, and sideroblastic anemia. Other diseases such as cancer , kidney disease or human immunodeficiency virus (HIV), and medical treatments such as chemotherapy or AZT can also cause anemia. Although anemia is primarily defined as an iron deficiency condition, it can also result from folate and/or vitamin B12 deficiency, two vitamins required to produce and maintain the health of new cells. When caused by vitamin B12 deficiency, the anemia is calledpernicious anemia.

Anemia is not an inevitable consequence of aging, a cause is identified in about 80% of elderly patients. In seniors, the most common cause of anemia is blood loss or nutritional iron or vitamin deficiencies (34%), followed by anemia of chronic disease (ACD) or renal failure (32%). With ACD, there is enough iron s tored in the body, but the bone marrow cannot incorporate it into the RBCs. ACD is associated with a wide range of chronic malignant, autoimmune, inflammatory, and infectious diseases . Other causes of anemia in older adults include aplastic anemia, thalassemia, sideroblastic anemia, and hemolytic anemia due to abnormal breakdown of RBCs.

Symptoms of anemia

Common symptoms of anemia include:

• weakness
• pale skin
• fast, irregular heartbeat
• shortness of breath
• chest pains
• dizziness
• coldness in extremities
• headache

Diagnosis

Anemia is diagnosed by taking the medical history of the patient, performing a physical exam and doing complete blood count (CBC) to check the number of RBCs, white blood cells, and platelets in the blood. The hematocrit test that measures the percentage of blood that consists of RBCs is particularly useful to screen for anemia or to determine the extent of anemia, since anemic persons have fewer or smaller than normal RBCs. Further blood work may be done to evaluate iron, vitamin B12, and folate levels, and a serum iron test to measure the total iron binding capacity (TIBC) of the blood. A bone marrow biopsy and aspirate may also be performed to help determine the cause of the anemia.

Treatment

Treatment for anemia depends on what is causing the anemia:

• Iron deficiency anemia is usually treated with iron supplements, prescribed for several months or longer.
• Pernicious anemia is treated with injections of vitamin B12.
• Folate deficiency anemia is treated with folic acid supplements.
• ACD can be treated with epoetin, a synthetic erythropoietin that stimulates the production of RBCs, but the focus is on treating the underlying disease.
• Aplastic anemia may be treated with blood transfusions to increase levels of red blood cells, or bone marrow transplants if the bone marrow cannot produce healthy blood cells.
• Hemolytic anemia is treated by managing related infections and drugs that suppress the immune system (immunosuppressants).
• Sickle cell anemia treatment may include the administration of oxygen, pain-relieving drugs, and fluids to reduce pain and prevent complications.

Nutrition/Dietetic concerns

Iron deficiency anemia has been associated with a low dietary intake of iron. There are two forms of dietary iron: heme and nonheme. Heme iron is the best source of iron and is found in animal foods such as red meats, fish, and poultry. Nonheme iron is found in plant foods such as lentils and beans, and is also the form of iron added to iron-enriched foods. Folate is found in citrus juices and fruits, dark green leafy vegetables, legumes and fortified breakfast cereals. Vitamin B12 requirements are met by eating meat and dairy products.

Therapy

In addition to iron, vitamins, and medicines prescribed to treat the underlying causes of anemia or to increase the production of RBCs, blood transfusions may be prescribed in some cases, as well as surgery to stop serious or life-threatening bleeding when it is causing anemia, for example, to control chronic bleeding from a stomach ulcer.

Prognosis

The forms of anemia that can be treated by correcting deficiencies with a healthy diet and supplements are reversible with good outcomes. Approximately 70% of nutritional deficiency anemias in older individuals are reversible. Overall, treatment of anemia in the elderly has been shown to improve outcomes. For instance, if the underlying cause of ACD is cured, the anemia also resolves. Outcomes for aplastic anemia can be good if prompt and appropriate treatment is obtained. Some people with aplastic anemia can be cured with a bone marrow transplant. As for hemolytic anemia, it can often be successfully controlled, but outcomes depend on the cause and the severity of the anemia. The symptoms and complications of sickle cell anemia can often be treated, but there is no cure for the condition.

Prevention

Even though some forms of anemia cannot be prevented, iron deficiency and vitamin deficiency anemias can be avoided by eating a healthy, varied diet that includes foods rich in iron, folate and vitamin B12.

Caregiver concerns

Anemia can have a significant impact on the quality of life of seniors. Anemia from iron deficiency often results from poor nutrition in this age group. Caregivers need to focus on the age-related physiologic changes underlying this condition and whether anemia correction can improve quality of life. The prevalence of blood loss/iron deficiency as a cause of anemia in the elderly points to the importance of recognizing this diagnosis in these patients.

KEY TERMS

Anemia of chronic disease (ACD) —Blood disorder that results from a medical condition that affects the production and lifespan of red blood cells.

Aplastic anemia —Rare and serious blood disorder in which bone marrow stops making enough new blood cells.

AZT —A drug that inhibits the human immunodeficiency virus (HIV).

Erythropoietin —Hormone that stimulates production of red blood cells.

Hematocrit —A laboratory test that determines the percentage of packed red blood cells in a given volume of blood.

Hemoglobin —Iron-containing protein found in red blood cells that carries oxygen to tissues.

Heme iron —Iron that is bound to four nitrogen atoms in the center of a ring system of carbon atoms called a porphyrin.

Human immunodeficiency virus (HIV) —The virus that causes acquired immunodeficiency syndrome (AIDS).

Immunosuppressant —A medicine that blocks the body's immune response.

Infectious disease —Disease resulting from infection by a pathogen microorganism that subsequently grows and multiplies in the body.

Red blood cell (RBC) —A cell found in blood that contains haemoglobin to bind oxygen and carry it to all parts of the body.

Sickle cell anemia —Blood disorder in which the body produces abnormally shaped red blood cells that look like a crescent or sickle and also contain an abnormal form of hemoglobin, which interferes with oxygen delivery to tissues.

Sideroblastic anemia —Disorder in which the body has adequate iron but is unable to incorporate it into hemoglobin.

Thalassemia —Inherited blood disorder characterized by abnormal red blood cells that are unable to carry enough oxygen throughout the body.

Resources

BOOKS

Anemia of Chronic Disease., edited by Gunter Weiss, et al.

London: Informa Healthcare, 2005.

Anemia in the Elderly, edited by Lodovico Balducci, et al.

New York: Springer, 2007.

Bridges, Kenneth. Anemias and Other Red Cell Disorders.

New York: McGraw-Hill, 2007.

Gomez, Joan. Anemia in Women: Self-Help and Treatment.

Alameda, CA: Hunter House Publishers, 2001.

Iron Disorders Institute. The Iron Disorders Institute Guide to Anemia. Nashville, TN: Cumberland House Publishing, 2003.

Ross, Allison J. Everything You Need to Know About Anemia. New York: Rosen Publishing Group, 2000.

PERIODICALS

Carmel, R. “Anemia and Aging: An Overview of Clinical, Diagnostic and Biological Issues. “Blood Reviews 15, no. 1 (March 2001): 213–226.

Eisenstaedt, R., et al. “Anemia in the Elderly: Current Understanding and Emerging Concepts. “Blood Reviews 20, no. 4 (July 2006): 213–226.

Guralnik, Jack M., et al. “Anemia in the Elderly: A Public Health Crisis in Hematology. “Hematology (January 2005): 528–532.

Haas, J. D., and T. Brownlie. “Iron Deficiency and Reduced Work Capacity: A Critical Review of the Research to Determine a Causal Relationship. “Journals of Nutrition 85 (2001): S75–S80.

Miret, S., et al. “Physiology and Molecular Biology of Dietary Iron Absorption. “Annual Reviews of Nutrition 23 (2003): 283–301.

Penninx, B. W. “Anemia in Old Age is Associated with Increased Mortality and Hospitalization. “The Journals of Gerontology A 61, no.5 (May 2006): 474–479.

Spivak, J. L. “Iron and the Anemia of Chronic Disease. “Oncology 16, no. 9, suppl. 10 (September 2002): 25–33.

OTHER

“Aging and Anemia?”Cleveland Clinic Center for Consumer Health Information. January 13, 2005 [cited April 9, 2008]. Cleveland Clinic. http://www.clevelandclinic.org/health/health-info/docs/2100/2127.asp?index=8964.

“Anemia.”MayoClinic.com. February 21, 2007 [cited April 9, 2008]. Mayo Foundation for Medical Education and Research. http://www.mayoclinic.com/health/anemia/DS00321.

“Anemia: What Is Anemia?” National Heart Lung and Blood Institute Diseases and Conditions Index. December 2007 [cited April 9, 2008]. http://www.nhlbi.nih.gov/health/dci/Diseases/anemia/anemia_whatis.html.

Bailey, Lynn B., et al. Dietary Supplement Fact Sheet: Folate. NIH Office of Dietary Supplements, Fact Sheet. August 22, 2005 [cited April 9, 2008]. http://ods.od.nih.gov/factsheets/folate.asp

Beard, John, et al. Dietary Supplement Fact Sheet: Iron. NIH Office of Dietary Supplements, Fact Sheet. August 24, 2007 [April 9, 2008]. http://ods.od.nih.gov/factsheets/iron.asp.

Carmel, Ralph, et al. Dietary Supplement Fact Sheet: Vitamin B12. NIH Office of Dietary Supplements, Fact Sheet. April 26, 2006 [cited April 9, 2008]. http://ods.od.nih.gov/factsheets/vitaminb12.asp.

Matsui, William. “Anemia of Chronic Disease.”MedlinePlus. February 6, 2007 [cited April 9, 2008].http://www.nlm.nih.gov/medlineplus/ency/article/000565.htm

ORGANIZATIONS

National Anemia Action Council (NAAC), 555 E. Wells St., Suite 1100, Milwaukee, WI, 53202, (414) 225–0138, (414) 276–3349, [email protected], http://www.anemia.org.

National Heart Lung and Blood Institute, P.O. Box 30105, Bethesda, MD, 20824–0105, (301) 592–8573, (240) 629–3246, [email protected], http://www.nhlbi.nih.gov.

Monique Laberge Ph.D.