Anemias

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Anemias

Definition

Anemia is a condition characterized by abnormally low levels of healthy red blood cells or hemoglobin (the component of red blood cells that delivers oxygen to tissues throughout the body).

Description

The tissues of the human body need a regular supply of oxygen to stay healthy. Red blood cells, which contain hemoglobin that allows them to deliver oxygen throughout the body, live for only about 120 days. When they die, the iron they contain is returned to the bone marrow and used to create new red blood cells. Anemia develops when heavy bleeding causes significant iron loss or when something happens to slow down the production of red blood cells or to increase the rate at which they are destroyed.

Types of anemia

Anemia can be mild, moderate, or severe enough to lead to life-threatening complications. More than 400 different types of anemia have been identified. Many of them are rare.

IRON DEFICIENCY ANEMIA. Iron deficiency anemia is the most common form of anemia in the world. In the United States, iron deficiency anemia affects about 240,000 toddlers between one and two years of age and 3.3 million women of childbearing age. This condition is less common in older children and in adults over 50 and rarely occurs in teenage boys and young men.

The onset of iron deficiency anemia is gradual and, at first, there may be no symptoms. The deficiency begins when the body loses more iron than it derives from food. Because depleted iron stores cannot meet the body's red blood cell needs, fewer red blood cells develop. In this early stage of anemia, the red blood cells look normal, but they are reduced in number. Then the body tries to compensate for the iron deficiency by producing more red blood cells, which are characteristically smaller in size. Symptoms develop at this stage.

FOLIC ACID DEFICIENCY ANEMIA. Folic acid deficiency anemia is the most common type of megaloblastic anemia (in which red blood cells are bigger than normal). It is caused by a deficiency of folic acid, a vitamin that the body needs to produce normal cells.

Folic acid anemia is especially common in infants and teenagers. Although this condition usually results from a dietary deficiency, it is sometimes due to inability to absorb enough folic acid from such foods as:

cheese
eggs
fish
green vegetables
meat
milk
mushrooms
yeast

Smoking raises the risk of developing this condition by interfering with the absorption of vitamin C, which the body needs to absorb folic acid. Folic acid anemia can also be a complication of pregnancy, when a woman's body needs eight times as much folic acid.

VITAMIN B₁₂ DEFICIENCY ANEMIA. Less common in this country than folic acid anemia, vitamin B₁₂ deficiency anemia is another type of megaloblastic anemia that develops when the body doesn't absorb enough of this nutrient. Necessary for the creation of red blood cells, B₁₂ is found in meat and vegetables.

Large amounts of B₁₂ are stored in the body, so this condition may not become apparent until as much as four years after B₁₂ absorption stops or slows down. The resulting drop in red blood cell production can cause:

loss of muscle control
loss of sensation in the legs, hands, and feet
soreness or burning of the tongue
weight loss

yellow-blue color blindness

The most common form of B₁₂ deficiency is pernicious anemia. Since most people who eat meat or eggs get enough B₁₂ in their diets, a deficiency of this vitamin usually means that the body is not absorbing it properly. This can occur among people who have had intestinal surgery or among those who do not produce adequate amounts of intrinsic factor, a chemical secreted by the stomach lining that combines with B₁₂ to help its absorption in the small intestine.

Pernicious anemia usually strikes between the ages of 50 and 60. Eating disorders or an unbalanced diet increases the risk of developing pernicious anemia. So do:

diabetes mellitus
gastritis, stomach cancer, or stomach surgery
thyroid disease
family history of pernicious anemia

VITAMIN C DEFICIENCY ANEMIA. A rare disorder that causes the bone marrow to manufacture abnormally small red blood cells, vitamin C deficiency anemia results from a severe, long-standing dietary deficiency.

HEMOLYTIC ANEMIA. Hemolytic anemia is a condition in which infection or antibodies destroy red blood cells more rapidly than bone marrow can replace them. Some people are born with the disease, while others acquire it later in life.

Hemolytic anemia can enlarge the spleen, accelerating the destruction of red blood cells (hemolysis). Other complications of hemolytic anemia include pain, shock, gallstones, and other serious health problems.

THALASSEMIAS. An inherited form of hemolytic anemia, thalassemia stems from the body's inability to manufacture as much normal hemoglobin as it needs. There are two categories of thalassemia, depending on which of the amino acid chains is affected. (Hemoglobin is composed of four chains of amino acids.) In alpha-thalassemia, there is an imbalance in the production of the alpha chain of amino acids; in beta-thalassemia, there is an imbalance in the beta chain. Alpha-thalassemias most commonly affect blacks (25% have at least one gene); beta-thalassemias most commonly affect people of Mediterranean and Southeast Asian ancestry.

Characterized by production of red blood cells that are unusually small and fragile, thalassemia only affects people who inherit the gene for it from each parent (autosomal recessive inheritance).

AUTOIMMUNE HEMOLYTIC ANEMIAS. Warm antibody hemolytic anemia is the most common type of this disorder. This condition occurs when the body produces autoantibodies that coat red blood cells. The coated cells are destroyed by the spleen, liver, or bone marrow.

Warm antibody hemolytic anemia is more common in women than in men. About one-third of patients who have warm antibody hemolytic anemia also have lymphoma, leukemia, lupus, or connective tissue disease.

In cold antibody hemolytic anemia, the body attacks red blood cells at or below normal body temperature. The acute form of this condition frequently develops in people who have had pneumonia, mononucleosis, or other acute infections. It tends to be mild and short-lived, and disappears without treatment.

Chronic cold antibody hemolytic anemia is most common in women and most often affects those who are over 40 and who have arthritis. This condition usually lasts for a lifetime, generally causing few symptoms. However, exposure to cold temperatures can accelerate red blood cell destruction, causing fatigue, joint aches, and discoloration of the arms and hands.

SICKLE CELL ANEMIA. Sickle cell anemia is a chronic, incurable condition that causes the body to produce defective hemoglobin, which forces red blood cells to assume an abnormal crescent shape. Unlike normal oval cells, fragile sickle cells can't hold enough hemoglobin to nourish body tissues. The deformed shape makes it hard for sickle cells to pass through narrow blood vessels. When capillaries become obstructed, a life-threatening condition called sickle cell crisis is likely to occur.

Sickle cell anemia is hereditary. Its rate of incidence is highest among those of African descent, although it can occur in peoples around the world. A child who inherits the sickle cell gene from each parent will have the disease. A child who inherits the sickle cell gene from only one parent carries the sickle cell trait, but does not have the disease.

APLASTIC ANEMIA. Sometimes curable by bone marrow transplant, but potentially fatal, aplastic anemia is characterized by decreased production of red and white blood cells and platelets (disc-shaped cells that allow the blood to clot). This disorder may be inherited or acquired as a result of recent severe illness, long-term exposure to industrial chemicals, and use of anticancer drugs and certain other medications.

SIDEROBLASTIC ANEMIA. Sideroblastic anemia results from an enzyme disorder in which the body has adequate iron but is unable to incorporate it into hemoglobin. In sideroblastic anemia, iron enters a developing red blood cell and builds up in mitochondria of the cell. This build-up of iron gives the cell nucleus a ringed appearance, and the cell is called a ringed sideroblast, the primary sign of siderblastic anemia. Ringed sideroblasts develop poorly or not at all into mature red blood cells, and the red blood cells cannot properly transport oxygen to tissues throughout the body. X-linked sideroblastic anemia is the hereditary form of sideroblastic anemia, also known as iron overload anemia or sideroblastosis. Another, more common type of sideroblastic anemia is called acquired sideroblastic anemia, which can result from prolonged exposure to toxins or nutritional imbalances. Other causes may be inflammatory disease, cancerous conditions such as leukemia and lymphoma, kidney disorders causing uremia, endocrine disorders, or metabolic disorders.

ANEMIA OF CHRONIC DISEASE. Cancer, chronic infection or inflammation, and kidney and liver disease often cause mild or moderate anemia. Chronic liver failure generally produces the most severe symptoms.

Causes and symptoms

Anemia is caused by bleeding, decreased red blood cell production, or increased red blood cell destruction. Poor diet can contribute to vitamin deficiency and iron deficiency anemias in which fewer red blood cells are produced. Hereditary disorders and certain diseases can cause increased blood cell destruction. However, excessive bleeding is the most common cause of anemia, and the speed with which blood loss occurs has a significant effect on the severity of symptoms. Chronic blood loss is usually a consequence of:

cancer
gastrointestinal tumors
diverticulosis
polyposis
heavy menstrual flow
hemorrhoids
nosebleeds
stomach ulcers
long-standing alcohol abuse

Acute blood loss is usually the result of:

childbirth
miscarriage of pregnancy
injury
a ruptured blood vessel
surgery

When a large volume of blood is lost within a short time, blood pressure and the amount of oxygen in the body drop suddenly. Heart failure and death can follow.

Loss of even one-third of the body's blood volume in the space of several hours can be fatal. More gradual blood loss is less serious, because the body has time to create new red blood cells to replace those that have been lost.

Symptoms

Weakness, fatigue, and a run-down feeling may be signs of mild anemia. Skin that is pasty or sallow, or lack of color in the creases of the palm, gums, nail beds, or linings of the eyelids are other signs of anemia. Someone who is weak, tires easily, is often out of breath, and feels faint or dizzy may be severely anemic.

Other symptoms of anemia are:

angina pectoris (chest pain, often accompanied by a choking sensation that provokes severe anxiety)
cravings for ice, paint, or dirt (called pica)
headache
inability to concentrate, memory loss
inflammation of the mouth (stomatitis ) or tongue (glossitis)
insomnia
irregular heartbeat
loss of appetite
nails that are dry, brittle, or ridged
rapid breathing
sores in the mouth, throat, or rectum
sweating
swelling of the hands and feet
thirst
tinnitus (ringing in the ears)
unexplained bleeding or bruising

In pernicious anemia, the tongue feels unusually slick. A patient with pernicious anemia may have problems with movement or balance, tingling in the hands and feet, confusion, depression, and memory loss.

Pernicious anemia can damage the spinal cord. A doctor should be notified whenever symptoms of this condition occur.

A doctor should also be notified if a patient who has been taking iron supplements develops diarrhea, cramps, or vomiting.

Diagnosis

Personal and family health history may suggest the presence of certain types of anemia. Laboratory tests that measure the percentage of red blood cells or the amount of hemoglobin in the blood are used to confirm diagnosis and determine which type of anemia is responsible for a patient's symptoms. X rays and examinations of bone marrow may be used to identify the source of bleeding.

Treatment

Anemia due to nutritional deficiencies can usually be treated at home with appropriate supplements, under a health professional's guidance. People with iron deficiency should take iron supplements. People with folic acid anemia should take oral folic acid replacements. Vitamin C deficiency anemia can be cured by the recommended daily allowance of vitamin C. People with pernicious anemia may be able to self-administer injections of vitamin B₁₂.

Surgery may be necessary to treat anemia caused by excessive loss of blood. Transfusions of red blood cells may be used to accelerate production of red blood cells in the body.

Medication or surgery may also be necessary to control heavy menstrual flow, repair a bleeding ulcer, or remove polyps (growths or nodules) from the bowels.

Patients with thalassemia usually do not require treatment. However, people with a severe form may require periodic hospitalization for blood transfusions or bone marrow transplantation.

Alternative therapies for iron deficiency anemia focus on adding iron-rich foods to the diet or on techniques to improve circulation and digestion. Herbal remedies to improve digestion include Gentian (Gentiana lutea), which is widely used in Europe to treat anemia and other nutritionally based disorders, as well as anise (Pimpinella anisum), caraway (Carum carvi), cumin (Cuminum cyminum), and licorice.

SICKLE CELL ANEMIA. Treatment for sickle cell anemia involves regular eye examinations, immunizations for pneumonia and infectious diseases, and prompt treatment for sickle cell crises and infections of any kind. Psychotherapy or counseling may help patients deal with the emotional impact of this condition.

VITAMIN B₁₂ DEFICIENCY ANEMIA. A life-long regimen of B₁₂ shots is necessary to control symptoms of pernicious anemia. The patient may be advised to limit physical activity until treatment restores strength and balance.

APLASTIC ANEMIA. People who have aplastic anemia are especially susceptible to infection. Treatment for aplastic anemia may involve blood transfusions and bone marrow transplant to replace malfunctioning cells with healthy ones.

SIDEROBLASTIC ANEMIA. X-linked sideroblastic anemia often improves with pyridoxine (vitamin B₆) therapy. In cases of extreme anemia, whole red blood cell transfusion may be required.

If anemia is acquired, removal of the offending agent or treatment for the primary disorder may allow the anemia to disappear.

ANEMIA OF CHRONIC DISEASE. There is no specific treatment for anemia associated with chronic disease, but treating the underlying illness may alleviate this condition. This type of anemia rarely becomes severe. If it does, transfusions or hormone treatments to stimulate red blood cell production may be prescribed.

HEMOLYTIC ANEMIA. There is no specific treatment for cold-antibody hemolytic anemia. About one-third of patients with warm-antibody hemolytic anemia respond well to large doses of intravenous and oral corticosteroids, which are gradually discontinued as the patient's condition improves. Patients with this condition who don't respond to medical therapy must have the spleen surgically removed. This operation controls anemia in about half of the patients on whom it's performed. Immune system suppressants are prescribed for patients whose surgery is not successful.

Self-care

Anyone who has anemia caused by poor nutrition should modify his or her diet to include more vitamins, minerals, and iron. Vitamin C can stimulate iron absorption. The following foods are also good sources of iron:

almonds
broccoli
dried beans
dried fruits
enriched breads and cereals

lean red meat
liver
potatoes
poultry
rice
shellfish
tomatoes

Because light and heat destroy folic acid, fruits and vegetables should be eaten raw, or cooked as little as possible.

Health care team roles

Often, anemia is not discovered until blood tests are run as part of a routine physical examination. Hemoglobin tests are commonly run by medical technologists or other laboratory professionals. Nurses and allied health professionals can play a critical role in the well-being and quality of life of patients at risk for anemia by understanding erythropoiesis, pathophysiology, nursing assessment (including laboratory data assessment), and nursing interventions related to anemia. In particular, nurses should be sure that patients are educated about their disease and about the treatment options available. In cases where anemia may be inherited, they may provide patients with information about genetic testing. They may also refer patients to professional genetic counselors.

Prognosis

Folic acid and iron deficiency anemias

It usually takes three to six weeks to correct folic acid or iron deficiency anemia. Patients should continue taking supplements for another six months to replenish iron reserves and should have periodic blood tests to make sure the bleeding has stopped and the anemia has not recurred.

Pernicious anemia

Although pernicious anemia is considered incurable, regular B₁₂ shots will alleviate symptoms and reverse complications. Some symptoms will disappear almost as soon as treatment begins.

Aplastic anemia

Aplastic anemia can sometimes be cured by bone marrow transplantation. If the condition is due to immunosuppressive drugs, symptoms may disappear after the drugs are discontinued.

Sickle cell anemia

Although sickle cell anemia cannot be cured, effective treatments enable patients with this disease to enjoy longer, more productive lives.

Thalassemia

People with mild thalassemia (alpha thalassemia trait or beta thalassemia minor) lead normal lives and do not require treatment. Those with severe thalassemia may require bone marrow transplantation. Genetic therapy is being investigated and may soon be available.

Hemolytic anemia

Acquired hemolytic anemia can generally be cured when the cause is removed.

Health care team roles

Anemia is often overlooked as a priority associated with quality patient care. Identifying the underlying causes of anemia in patients is critical to positive care outcomes and requires early assessment and intervention. The entire health care team plays a critical role in the well-being and quality of life of patients with anemia by understanding the disease and appropriate treatments, and by providing patients with any materials and education needed to understand the disease and its treatment.

Prevention

Inherited anemias cannot be prevented. Genetic counseling can help parents cope with questions and concerns about transmitting disease-causing genes to their children.

Avoiding excessive use of alcohol, eating a balanced diet that contains plenty of iron-rich foods, and taking a daily multivitamin can help prevent anemia.

Methods of preventing specific types of anemia include:

Avoiding lengthy exposure to industrial chemicals and drugs known to cause aplastic anemia.
Not taking medication that has triggered hemolytic anemia and not eating foods that have caused hemolysis (breakdown of red blood cells).
Receiving regular B₁₂ shots to prevent pernicious anemia resulting from gastritis or stomach surgery.

KEY TERMS

Aplastic— Exhibiting incomplete or faulty development.

Diabetes mellitus— A disorder of carbohydrate metabolism brought on by a combination of hereditary and environmental factors.

Erythropoiesis— Erythropoiesis is the development of mature red blood cells (erythrocytes).

Hemoglobin— An iron-containing pigment of red blood cells composed of four amino acid chains (alpha, beta, gamma, delta) that delivers oxygen from the lungs to the tissues of the body.

Megaloblast— A large erythroblast (a red marrow cell that synthesizes hemoglobin).

Red blood cells— Yellowish, circular, biconcave disks found in the blood, which contain hemoglobin and carries oxygen. Also known as erythrocytes.

Resources

BOOKS

Ramakrishnan, Usha, ed. Nutritional anemias. London: CRC Press, 2001.

Tierney, Lawrence M., Jr., et al., eds. Current Medical Diagnosis & Treatment. Stamford, CT: Appleton & Lange, 1998.

PERIODICALS

Mahoney, Martin C. "Screening for iron deficiency anemia among children and adolescents." American Family Physician 62:3 (August 1, 2000): 671+.

Sheth, Sujit & Brittenham, Gary M. "Genetic disorders affecting proteins of iron metabolism: Clinical implications. Annual Review of Medicine 51 (2000): 443+.

Worrall, L.M., Tompkins, C.A., & Rust, D.M. "Recognizing and managing anemia." Clinical Journal of Oncology Nursing 3:4 (October 1999): 153+.

ORGANIZATIONS

Aplastic Anemia & MDS International Foundation. P.O. Box 613, Annapolis, MD 21404-0613. (800) 747-2820 or (410) 867-0242. ?http://www.aplastic.org?.

Leukemia & Lymphoma Society. 1311 Mamaroneck Ave., White Plains, NY 10605. (914) 949-5213. ?http://www.leukemia-lymphoma.org?.

National Heart, Lung, Blood Institute Information Center. P.O. Box 30105, Bethesda, MD 20824-0105. (301) 592-8573. ?http://www.nhlbi.nih.gov?.

National Organization for Rare Disorders. P.O. Box 8923, New Fairfield, CT 06812-8923, (203) 746-6518 or (800) 999-6673. ?http://www.rarediseases.org?.