Anemia

A disorder of the red blood cells

Anemia is the broad term used to describe several different blood disorders -- all marked by abnormalities in the number or function of red blood cells. In essence, anemia deprives your body's tissues of oxygen. A lack of oxygen produces the symptoms typical of all anemia types: weakness, fatigue, skin pallor, shortness of breath, and palpitations. Severe anemia can even lead to a stroke, heart attack, or congestive heart failure.

Some types of anemia are health conditions in their own right (iron-deficiency anemia, for example) while others are symptoms of underlying disease (such as hemolytic anemia, resulting from an enlarged spleen or anticancer drugs). Some are easily treated while others are chronic and life threatening.

Pronunciation

a-NEE-me-a

Synonyms

Aplastic anemia

  • Hypoplastic anemia
  • Panmyelophthisis
  • Refractory anemia

Folic-acid-deficiency anemia

  • Megaloblastic anemia

Hemolytic anemia

  • Sickle-cell disease
  • Hemoglobin SC disease
  • Hemolytic anemia due to G6PD deficiency
  • Idiopathic autoimmune hemolytic anemia
  • Nonimmune hemolytic anemia caused by chemical or physical agents
  • Secondary immune hemolytic anemia

Pernicious anemia

  • B-12-deficiency anemia
  • Addison's anemia
  • Megaloblastic anemia due to vitamin B-12 deficiency

Sickle-cell anemia

  • Sickle-cell disease
  • Hemoglobin SC disease
  • Hb S disease
  • S/S disease

Detailed Description

Your red blood cells get their red color from hemoglobin, an iron-rich protein that carries oxygen from the lungs to all other parts of your body. When anemia reduces the number of red blood cells or decreases the amount of hemoglobin the cells can carry, your body tissues become deprived of oxygen. A lack of oxygen to the tissues results in the following symptoms:

  • Weakness
  • Fatigue
  • Skin pallor
  • Shortness of breath
  • Heart palpitations

Anemia is the most common blood disorder. Iron-deficiency anemia is the most common and most curable type. A much lower number of people have the more life-threatening hemolytic types of anemia, such as sickle-cell disease or paroxysmal nocturnal hemoglobinuria.

Certain types of anemia, such as pernicious anemia (vitamin B-12 anemia), may go undetected for some time because our bodies have large stores of vitamin B-12. So a deficiency isn't apparent until the stores are completely depleted.

There are many types of anemia. Following are the most common :

  • Iron-deficiency anemia: The body needs iron to create new hemoglobin, the protein in red blood cells that carries oxygen. A lack of iron leads to iron-deficiency anemia. Iron-deficiency anemia is almost always the result of chronic bleeding such as nosebleeds, hemorrhoids, stomach or intestinal ulcers, polyps or gastrointestinal cancers, or menorrhagia (excessive menstrual bleeding). The body loses huge amounts of iron through excess bleeding. Less typically, iron-deficiency anemia can also develop in elderly people, who sometimes lack sufficient amounts of stomach acid to absorb dietary iron.
  • Aplastic anemia: This is one of the most serious types of anemia. In this serious illness, the body's bone marrow cannot produce enough of certain blood cells: red, white, or platelets. In about half the cases of aplastic anemia, the cause is never known. The known causes range from a hereditary defect, exposure to radiation or toxic chemicals, or effects of certain drugs. Certain viruses and cancers can be the underlying causes as well.
  • Folic-acid-deficiency anemia: The body needs folic acid to create sufficient red blood cells. Without it, red blood-cell production drops and anemia results. This anemia is especially common in alcoholics because alcohol interferes with the absorption and metabolism of folic acid. Other causes might include intestinal disorders, certain malabsorption illnesses, oral contraceptives, and various drugs for cancer and epilepsy.
  • Hemolytic anemia: Uncommon types of anemia result when the body's natural scavengers begin destroying red blood cells prematurely. As a result, the bone marrow compensates by producing new red blood cells at up to 10 times the normal rate. These new cells are small or misshapen, incapable of carrying enough oxygen to the body's tissues. A number of causes of hemolytic anemia exist, ranging from an enlarged spleen to autoimmune diseases to inherited defects of membrane structures or hemoglobin molecules. (Sickle-cell anemia is a type of hemolytic anemia due to abnormal hemoglobin molecules.)
  • Pernicious anemia (vitamin B-12-deficiency anemia): In order to absorb dietary vitamin B-12, the stomach must produce a substance called B-12 intrinsic factor. A lack of intrinsic factor, therefore, can result in a vitamin B-12 deficiency. Since the bone marrow needs vitamin B-12 to produce red blood cells, insufficient amounts result in anemia. This type of anemia is often seen in strict vegetarians who eat no animal products (vegans).
  • Sickle-cell anemia: African-Americans have this inherited type of hemolytic anemia almost exclusively. In this disease, the red blood cells contain an abnormal form of hemoglobin that reduces the oxygen in the cells. As a result, they become crescent- or sickle-shaped, unable to flow smoothly through the smallest blood vessels of the spleen, kidneys, brain, bones, and other organs. Not only do they create blockages that damage these organs, their crescent shape also causes the cells to break up, rendering them unable to deliver oxygen to the tissues. The result is anemia.

Characteristics of Anemia

By the time anemia is apparent, it has usually been at work in the body for some time. Though there are many types of anemia, they all exhibit some common results:

  • Fatigue
  • Muscle weakness
  • Skin pallor
  • Shortness of breath
  • Heart palpitations

In addition, each anemia has its own distinguishing characteristics as follows.

Iron-deficiency anemia

This is a microcytic anemia (characterized by very small red blood cells), and may distinguish itself from other types of anemia in the following ways:

  • Pica (a craving for nonfoods, such as dirt, ice, chalk, or starch)
  • Cracks at the sides of the mouth and in the fingernails
  • Deformity of the fingernails -- they take on a spoon-like shape
  • Irritated tongue

Aplastic anemia

This type of anemia may result in the following:

  • Frequent infections
  • Spots of blood under the skin
  • Bruising without trauma
  • Spontaneous bleeding from the nose, mouth, rectum, vagina, and gums
  • Mouth, throat, and rectal ulcers

Folic-acid-deficiency anemia

This type is characterized by enlarged red blood cells (macrocytic anemia) and may result in the following:

Hemolytic anemia

Hemolytic anemias can be marked by hemolytic crises in which large numbers of red blood cells are destroyed over a short period of time. Such crises include the following:

  • Fever
  • Back and stomach pain
  • Chills
  • Lightheadedness
  • A significant drop in blood pressure
  • Jaundice and darkened urine
  • Abdominal pain resulting from an enlarging spleen

Pernicious anemia

This type of anemia is characterized by enlarged red blood cells (macrocytic anemia), and may result in:

  • Tingling in the extremities
  • Loss of sensation in the legs, feet, and hands, as well as spastic movements
  • Peculiar type of color blindness involving yellow and blue
  • A swollen, sore, or burning tongue
  • Weight loss
  • Darkened skin
  • Diarrhea
  • Confusion
  • Depression
  • Decreased intellectual function

Sickle-cell anemia

Sickle-cell anemia -- a type of hemolytic anemia -- is marked by crises which follow any activities that reduce the amount of oxygen in the blood: vigorous exercise, high altitudes, or an illness, for example. A sudden worsening of the anemia -- pain, fever, and breathlessness -- marks these crises. Abdominal pain may be severe. Children in crisis will often experience severe chest pain.

How Common Is Anemia?

  • Iron-deficiency anemia affects approximately one in 500 people. It is the most common type of anemia, and affects equal numbers of men and women.
  • Aplastic anemia is a less common type of anemia, affecting about one in every 25,000 people per year. It usually affects those between ages 15 and 24 or those over age 60. Both sexes are equally affected.
  • Folic-acid-deficiency anemia is also a less common type of anemia, also affecting about one in every 25,000 people per year. It usually affects people over age 30, and affects more women than men.
  • Hemolytic anemia affects about one in every 25,000 people per year, but can affect people of all ages. This type of anemia also affects more women than men.
  • Pernicious anemia affects about one in every 1,000 people per year. It affects equal numbers of men and women, but usually occurs in adults over age 60.
  • Sickle-cell anemia is most common among African-Americans, affecting approximately one in every 500 African-Americans each year. It affects equal numbers of men and women.

What You Can Expect

Some types of anemia, such as iron-deficiency anemia, can have a very short course followed by full recovery. Others, such as aplastic anemia or sickle-cell disease, can be serious and chronic.

Iron-deficiency anemia

If left untreated, the symptoms of this anemia will only worsen, but with iron supplements, good health can be restored in just weeks. The cause must be identified, however, as this cannot be overcome with dietary supplements alone. Blood counts should return to normal in two months or less.

Aplastic anemia

If left untreated, aplastic anemia leads to rapid death. Bone marrow transplants are more successful in young people, with a survival rate of 80%. This number is lower in older people, ranging from 40% to 70%.

Folic-acid-deficiency anemia

Infants with this anemia may have neurological abnormalities. Untreated, the symptoms of this anemia will only worsen. However, folic acid tablets can relieve symptoms in just weeks. Those who have trouble absorbing folic acid will need supplements for life.

Hemolytic anemia

The expected prognosis for hemolytic anemia depends on the type of condition. These can range from instant recovery in G6PD deficiency anemia to partial control over the disease in immune hemolytic anemia. In general, the prognosis for many types of hemolytic anemia is good. Contact your healthcare provider for details on controlling the primary condition you have.

Pernicious anemia (vitamin B-12-deficiency anemia)

If left untreated, the symptoms of this anemia will only worsen, but with regular B-12 treatments, given orally or by injection, followed by lifelong B-12 supplementation, pernicious anemia can be cured.

Sickle-cell anemia

This type of hemolytic anemia is marked by crises in response to reduced oxygen in the blood (the result of vigorous exercise, altitude, or an illness). People with sickle-cell anemia are more likely to develop infections, which in turn worsen the anemia. Over time, the liver and heart enlarge (often resulting in a heart murmur), and gallstones are common. Skin ulcers may develop, particularly around the ankles, as a result of poor circulation to the skin. Young men may develop priapism (prolonged, painful erections). Older people may experience deterioration of the lungs and kidneys. Death from organ failure frequently occurs in people between ages 20 and 40. Few people with this disorder live past age 50.

Established Causes

Iron-deficiency anemia

This, the most common type of anemia, is caused by an insufficient amount of iron in the diet. It can be brought on by excessive blood loss due to chronic bleeding or during pregnancy. It can also be due to low iron content in the diet, or poor iron absorption by the body. In rarer cases, such as in children, lead poisoning has been shown to be a cause.

Aplastic anemia

Acquired causes (most common):

  • Drugs: dose-related or idiosyncratic. Drugs that are implicated are anticonvulsants, antibacterial drugs, antithyroid drugs, and some drugs used to treat diabetes. Anticancer drugs cause dose-dependent myelotoxicity.
  • Radiation: effects on the bone marrow are dose-related.
  • Benzene and insecticides: Benzene is a component in organic solvents. If you are exposed to benzene, it can cause chemical reactions that are toxic to your bone marrow precursor. DDT and lindane are insecticides that can cause aplastic anemia. Both are currently banned as insecticides in the United States.
  • Viruses: The most common viral infection associated with aplastic anemia is viral hepatitis. Other viruses that can cause aplastic anemia include the Epstein-Barr virus, parvovirus B-19, and HIV.
  • Pregnancy: Some women develop aplastic anemia with pregnancy. In some cases, aplasia is resolved with natural or premature termination of pregnancy.

Genetic cause:

  • Fanconi's anemia: This is a rare type of inherited aplastic anemia caused by an autosomal recessive disorder. May be treated by a bone marrow transplant.

Folic-acid-deficiency anemia

This type of anemia is caused by a deficiency of folic acid. Causes of folic acid deficiency include:

  • Inadequate intake, as in alcoholics
  • Increased demand, as in pregnancy, due to a high demand by the developing fetus
  • Malabsorption, as in sprue (a digestive condition caused by gluten intolerance)

Hemolytic anemia

  • Abnormalities inside the red blood cell
  • Enzyme defects
  • Hemoglobinopathies (sickle-cell disorders)
    • This includes sickle-cell anemia, a genetic condition brought on by an abnormal type of hemoglobin, the oxygen-carrying component of the blood. The blood cells become "sickle" shaped, blocking blood and oxygen flow to vital tissues and organs. The obstruction of small vessels from sickle cells results in repeated infarctions, involving all organs, especially the spleen, lungs, kidneys, and brain.
  • Defects in the Embden-Meyerhof pathway (related to carbohydrate processing)
  • Defects in the hexose monophosphate (HMP) shunt
    • The most common of the congenital shunt defects is the G6PD deficiency. It affects more than 200 million people throughout the world. Like hemoglobin S, it partially protects the person from malaria. People with this disorder experience an acute hemolytic crisis within hours after exposure to the oxidative stress (acute malaria, sulfonamide, nitrofurantoin, etc.).
  • Red blood-cell membrane abnormalities
    • Hereditary spherocytosis: characterized by spherical red blood cells due to molecular defects in the red blood-cell membrane.
    • Hyperspleenism: an enlarged spleen due to lymphomas. This storage disorder may result in an increased destruction of blood cells.
    • Immunologic: antibodies attack the antigens present in the red blood cells. This phenomenon is seen in leukemias, lymphomas, and collagen vascular diseases.

Pernicious anemia

This type of anemia is due to an intrinsic inherited condition that leads to vitamin B-12 deficiency. It can also be caused by malabsorption of this nutrient or a dietary deficiency.

Sickle-cell anemia

This is a genetic conditions almost exclusively affecting African-Americans. For more information, see hemolytic anemia, above.

Risk Factors

There are many risk factors for anemia, depending on the type.

Iron-deficiency anemia

  • Poverty
  • Recent illnesses such as ulcer, gastrointestinal tumors, or bleeding hemorrhoids
  • Malnutrition or eating foods low in iron content
  • Pregnancy

Aplastic anemia

  • Recent illness
  • Genetic factors, such as a family history of anemia
  • Use of certain immunosuppressive and/or anticancer drugs
  • Exposure to toxins
  • Tumors of the thymus
  • Use of other drugs, including anticonvulsants, antibiotics, and antithyroid agents

Folic-acid-deficiency anemia

  • Age, particularly over age 60
  • Poor diet, especially those lacking in vitamin C
  • Alcoholism
  • Pregnancy
  • Smoking
  • Surgical removal of the stomach
  • Use of drugs such as oral contraceptives and anticonvulsants
  • Illness

Hemolytic anemia

  • Family history of hemolytic anemia
  • Hemoglobinopathies (sickle-cell disorders)
  • G6PD deficiency
  • Use of any medication

Pernicious anemia

  • A strict vegetarian diet lacking in vitamin B-12
  • Tapeworm infestation
  • Malabsorption syndromes
  • Thyroid disease
  • Diabetes mellitus
  • Genetic factors: This condition is most common in people of Northern European ancestry. It is rare in African-Americans and Asians.
  • Previous stomach surgery, stomach cancer, or gastritis
  • Bulimia or anorexia nervosa
  • Alcoholism

Sickle-cell anemia

  • African heritage
  • Family history of disease

Symptoms

All forms of anemia share common symptoms, which include the following:

  • Fatigue
  • Shortness of breath
  • Listlessness and weakness
  • Irritability
  • Frequent infection
  • Skin pallor

In addition, specific anemia types may show different symptoms.

Iron-deficiency anemia

This type of anemia progresses slowly. As a result, most people don't notice symptoms until the condition is severe. Signs that you may have iron-deficiency anemia include the following:

  • Spoon-shaped and cracked, brittle nails
  • Pale complexion
  • Smooth tongue
  • Cracks at the corners of the mouth
  • Rapid heartbeat and pulse
  • Abdominal discomfort
  • Pica (cravings for ice, paint, or dirt)

Aplastic anemia

Aplastic anemia symptoms should be checked out quickly. These include the following:

  • Red dots under the skin (which indicate bleeding)
  • Spontaneous bleeding from the nose, mouth, vagina, or gums
  • Unexplained bruising
  • Ulcers in the mouth and throat
  • Weight loss

Folic-acid-deficiency anemia

Like iron-deficiency anemia, folic-acid-deficiency anemia is not usually detected right away. Symptoms include the following:

Hemolytic anemia

Symptoms depend on the primary condition, but generally include the following:

Pernicious anemia

Like other forms of deficiency anemia, pernicious anemia develops slowly and may not be noticed immediately. Symptoms include the following:

  • Sore tongue
  • Numbness and tingling in hands and feet
  • Depression
  • Poor memory
  • Confusion and dementia
  • Difficulty maintaining balance and coordination
  • Congestive heart failure

Sickle-cell anemia

A genetically transmitted type of hemolytic anemia, sickle-cell anemia is generally detected fairly early. Some symptoms include the following:

  • Rapid heart rate
  • Delayed growth and sexual maturity, particularly in boys
  • Ulcers on lower legs
  • Jaundice
  • Bone pain
  • Abdominal pain

Conditions That May Be Mistaken for Anemia

Many different types of anemia exist. Therefore, it's critical that the correct type be diagnosed in order to obtain proper treatment. In addition, different types of anemia may be mistaken for other disorders, including the following:

Aplastic anemia

  • Acute leukemia
  • Disseminated infection
  • Hypersplenism

Folic-acid-deficiency anemia

Pernicious anemia

  • Neurological disorders without B-12 deficiency
  • Liver dysfunction
  • Hypothyroidism
  • Hemolysis or bleeding
  • Drug effects
  • Alcoholism

Sickle-cell anemia

  • Other causes of crises and acute pain

How Is Anemia Diagnosed?

If anemia is suspected, your doctor will typically conduct a detailed work-up that includes questions about your medical and personal history and diet, plus a physical examination and blood tests.

Physical exam

Usually includes a rectal exam and a stool test looking for hidden (occult) blood, since blood loss may be a cause of anemia. If blood is found in the stool, an endoscopy -- in which a flexible device is used to view the gastrointestinal tract -- may sometimes be performed.

Blood tests

Includes a complete blood count (CBC) to establish the population of red blood cells and a blood smear to examine the condition of red blood cells. The blood tests may also be used to determine iron, vitamin B-12, and folic acid levels. Bone marrow tests may sometimes be used in determining certain forms of anemia if other tests prove inconclusive.

Goals of Treatment

Most types of anemia can be cured and all can be treated. For the more serious types, treatment can be prolonged and may involve side effects, but health can be restored. Sickle-cell anemia is quite serious. This disease is sometimes fatal in childhood and those who survive require lifelong treatment.

The primary goal in treating each type of anemia is identifying its particular cause and treating it. Doing so usually results in the lessening or elimination of the anemia symptoms, which can include fatigue, muscle weakness, pallor, shortness of breath, and heart palpitations.

Treatment Overview

In all cases of anemia, your doctor's treatment is required. In nutrient-deficiency instances, such as iron-deficiency anemia, folic-acid deficiency, and pernicious anemia, self-care combined with proper treatment is adequate. Occasionally, blood transfusions are necessary for severe cases of iron-deficiency anemia. In more serious conditions like aplastic, hemolytic, and sickle-cell anemia, closer monitoring and further measures must be taken.

Treatment of the major types of anemia consists of the following:

Iron-deficiency anemia

This type of anemia responds to a fairly simple regimen: iron pills and an iron-rich diet containing plenty of liver and lean red meats. Vegetarians can find plenty of dietary iron in whole grains, dark green vegetables, and legumes. If this anemia results from major blood loss, a blood transfusion may be required.

Aplastic anemia

Aplastic anemia is treated with blood transfusions (in mild cases) and bone marrow transplantation (in severe cases). The immune-su

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