Anemia
Description
An in-depth report on the types, diagnosis, treatment, and prevention of anemia.
Alternative Names
Iron deficiency; Pernicious anemia
Complications
Most cases of anemia are mild, including those that occur as a result of chronic disease. Nevertheless, even mild anemia can reduce oxygen transport in the blood, causing fatigue and a diminished physical capacity. Moderate to severe iron-deficiency anemia is known to reduce endurance. Some studies indicate that even iron deficiency
without
anemia can produce a subtle but still lower capacity for exercise.
Complications of Severe or Prolonged Anemia
Because a reduction in red blood cells decreases the ability to absorb oxygen from the lungs, serious problems can occur in prolonged and severe anemia that is not treated. Anemia can lead to secondary organ dysfunction or damage, including heart arrhythmia and heart failure.
Certain inherited forms of anemia, including thalassemia major, pernicious anemia, and sickle-cell anemia can be life-threatening. Thalassemia major and sickle-cell anemia affect children and are particularly devastating.
Effects of Anemia in Pregnant Women
Pregnant women who are anemic have an increased risk for poor pregnancy outcomes, particularly if they are anemic in the first trimester.
Complications from Anemia in Children and Adolescents
One study reported a higher incidence of ear infections in infants with iron deficiency anemia. Some experts have also identified an anemia in children that may be caused by inflammation from ear, urinary tract, and other infections.
In children, severe anemia can impair growth and motor and mental development. One small, well-conducted trial suggested that iron therapy in anemic children younger than 2 years may help reverse some of these problems. Iron deficiency in vegetarian children without anemia may cause mental impairment, but it appears to be temporary.
A long-term study reported that 11 - 15-year-old children who had been severely iron-deficient during their infant years scored lower than normal children cognitive and motor test scores, but particularly in written expression. They also tended to have more behavioral, general health, and emotional problems. Another study reported that teenage girls with iron deficiency, even without anemia, may have temporary memory and concentration loss.
Effects of Anemia in the Elderly
Anemia is common in older people and can have significantly more severe complications than anemia in younger adults. Some studies have reported higher mortality rates in anemic individuals 85 and older compared to their non-anemic peers. (The rates were higher in anemic men than in women.) The following are examples of its effects from different studies:
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Anemia may have adverse effects on the heart and increase the severity of cardiac conditions, including reducing survival rates from heart failure and heart attacks. Elderly patients who are anemic for more than 2 days before heart surgery may have a greater risk for complications and death.
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Anemia may predict the development of other serious problems. In one study, 13% of elderly people with anemia developed cancer over a 10-year period compared to 5% of non-anemic individuals. Rates of infection and peptic ulcer rates were also higher in anemic patients.
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Elderly people with lower levels of hemoglobin are at an increased risk of death.
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Anemia may be associated with an increased incidence of falls.
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There may be an association between anemia and vascular dementia. This form of dementia is caused by lack of oxygen to the brain and is not related to Alzheimer's disease. Even mild anemia may possibly lead to cognitive impairment. A 2006 study of elderly women found that mild anemia worsened problem-solving abilities and other cognitive functions.
Effects of Vitamin B12 Deficiencies and Pernicious Anemia
In addition to anemia, vitamin B12 deficiency can cause neurologic damage, which can be irreversible if it continues for long periods without treatment. In addition to being at risk for neurologic damage, people with pernicious anemia, which results in an inability to absorb vitamin B12, also have a higher risk for stomach cancer and possibly cancer of the throat and mouth.
Anemia in Patients with Cancer
Anemia is particularly serious in cancer patients. In people with many common cancers, the presence of anemia is associated with a shorter survival time. Anemia may worsen the toxicity of chemotherapy in elderly cancer patients.
Anemia in Patients with Kidney Disease
Anemia is associated with higher mortality rates and possibly heart disease in patients with kidney disease.
Anemia in Patients with Heart Failure
The combination of anemia and heart failure can increase the risk of hospitalization or death by 30 - 60%. Patients with heart failure whose hemoglobin levels decline do worse than patients with stable levels.
Effects of Excess Iron
Iron overload occurs when there is too much iron in the blood. It can be as serious a problem as iron deficiency. Iron overload is usually caused by:
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Blood transfusions
. Patients with certain types of anemia require frequent blood transfusions. These transfusions can cause iron overload. Patients are treated with iron chelation therapy, which uses a drug that binds to iron. Excess iron is then eliminated by the kidneys. The standard drug for iron chelation therapy, deferoxamine (Desferal), is injected intravenously through an infusion pump. The treatment can be difficult for many patients. In 2005, a new drug, deferasirox (Exjade), was approved to treat iron overload due to blood transfusions. It is taken once a day by mouth. Patients dilute the pills in liquid and drink the mixture.
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Hemochromatosis
. Hemochromatosis is a hereditary condition in which the intestinal tract absorbs too much iron from food. Over time this excess iron leads to damaged organs and joints. To reduce dangerous iron levels, blood is regularly removed from the patient's body. This procedure is called phlebotomy. It is similar to donating blood. Some patients also need iron chelation therapy. Deferoxamine is currently used for iron chelation therapy in patients with hemochromatosis. Researchers are investigating deferasirox for chelation treatment of this genetic condition.
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Review Date: 1/17/2007
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Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital
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