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Lifespan's A - Z Health Information Library |
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AnemiaHighlightsErythropoiesis-Stimulating Drugs In 2006, the Food and Drug Administration (FDA) issued an advisory regarding treatment targets for erythropoiesis-stimulating drugs. These drugs include epoetin alfa (Procrit, Epogen, and Eprex) and darbepoetin alfa (Aranesp). They are used to treat severe anemia caused by other diseases, such as chronic kidney disease. Two 2006 studies in the New England Journal of Medicine indicated that aggressive dosing to completely normalize anemia (hemoglobin levels of 13.5 g/dL) provided no greater benefit than lower dosing to partially correct anemia (hemoglobin levels of 10 – 12 g/dL). Higher dosing and higher hemoglobin levels increased the risk for heart failure, heart attack, and stroke. In response to these studies, the FDA recommends that patients who take these drugs should:·
Anemia in the Elderly Mild anemia may cause difficulties with problem-solving abilities and other cognitive functions, suggests a 2006 study in the Journal of the American Geriatrics Society. Diagnosing Fetal Anemia Doppler ultrasonography may be better and safer than amniocentesis for diagnosing fetal anemia, according to a 2006 study in the New England Journal of Medicine. Doppler ultrasonography is a non-invasive imaging test. Investigational Drugs Eculizumab, an investigational monoclonal antibody drug, may help improve anemia in patients with paroxysmal nocturnal hemoglobinuria (PNH), indicates a 2006 study in the New England Journal of Medicine. PNH is a rare and severe form of hemolytic anemia. There are few treatment options for this condition. IntroductionAnemia is an abnormal reduction in red blood cells. ![]() This photmicrograph shows normal red blood cells (RBCs) as seen in the microscope after staining. Anemia is a global problem, at its worst in developing countries. But it is by no means absent in industrialized nations. An estimated 3.4 million Americans suffer from anemia. Anemia is not a single disease but a condition, like fever, with many possible causes and many forms. Causes of anemia include nutritional deficiencies, inherited genetic defects, medication-related side effects, and chronic disease. It can also occur because of blood loss from injury or internal bleeding, the destruction of red blood cells, or insufficient red blood cell production. The condition may be temporary or long term, and can manifest in mild or severe forms. As it is impossible to discuss all types of anemia, this report focuses on three of the most common forms:
Some less common causes and types of anemia are included in a table in this report.
Iron Deficiency AnemiaIron deficiency anemia occurs when the body lacks mineral iron to produce the hemoglobin it needs to make red blood cells. In general, there are three stages leading from iron deficiency to anemia:
Most of the iron used in the body can be recycled from blood and reused. Nevertheless, iron deficiency can occur from a number of conditions. Iron-Poor Diets. A healthy diet easily provides enough iron. In general, most people need just 1 mg, and menstruating women need 2 mg of extra iron each day. This means that lack of iron in the diet is not a common cause of iron deficiency anemia, except in infants. In fact, most American adults may be consuming too much iron in their diet. Most of the iron in red blood cells is recycled and reused. Iron-poor diets are a cause of anemia only in people with existing risks for iron deficiency. Peptic Ulcers and Their Causes. The bacteria H. pylori are known to be primary causes of peptic ulcers, and many older people with ulcers have anemia. Anemia in such cases, however, may not result from bleeding ulcers. Instead, anemia is more likely due to the presence of bacteria impairing the ability of these people to absorb iron or vitamin B12. The bacteria, in fact, may also bind to iron and reduce its availability in the intestine, causing iron deficiency anemia. Medications (NSAIDs). Aspirin and drugs such as ibuprofen and naproxen are called nonsteroidal anti-inflammatory drugs (NSAIDs). About 70% of long-term users of these medications have some sign of gastrointestinal bleeding, although it is rarely significant enough to cause anemia. Bleeding Due to Other Medical Conditions. Iron deficiencies most commonly occur from internal blood loss due to other conditions that range in severity from hemorrhoids toheavy menstruation to benign colon polyps to colon cancer. Very heavy periods (menorrhagia) are the most common causes of anemia in premenopausal women. Cancers of the gastrointestinal tract account for 2% of cases of iron deficiency (the rate is higher when menorrhagia is excluded). Pica. Pica is the craving for non-food substances such as ice, starch, or clay. It is a possible cause of iron deficiency, particularly in those who eat clay or starch, which interferes with iron absorption in the stomach. To complicate matters, pica (particularly ice cravings) may also be a symptom, rather than a cause, of anemia. Hookworm. Hookworm infects about 1 billion people worldwide and is a major cause of anemia in infested areas. Impaired Absorption of Iron. Certain intestinal diseases (inflammatory bowel disease, celiac disease) or surgical procedures that affect the gastrointestinal tract can impair the ability of the intestine to absorb iron. (Such conditions also often impair folic acid absorption as well.) Genetic Causes. Some people are born with iron deficiency. Certain cases may be due to a mutation of the Nramp2 gene, which regulates a protein responsible for delivering iron to the cells. Anemia of Chronic Disease (ACD)Anemia of chronic disease (ACD), also called anemia of chronic inflammation (ACI), is a common condition associated with a wide variety of persistent inflammatory diseases. It can be very severe and require transfusions. The Inflammatory Process and ACD. ACD is not completely understood. In ACD, iron is not efficiently recycled from blood cells, and red blood cell survival is reduced. In addition, there is impaired response to erythropoietin, the hormone that acts in the bone marrow to increase the production of red blood cells. (Abnormal function and low levels of erythropoietin, in fact, may be the most important factor in ACD, with iron insufficiencies being a consequence.) The process leading to ACD may occur in the following way:
Diseases Associated with ACD and Inflammation. The chronic diseases that are associated with this process include:
Not all chronic diseases involve the inflammatory process and anemia. For example, high blood pressure is a chronic disease, but it does not affect red blood cells. Treatment-Related Anemia. Anemia can also result from the therapies used to treat conditions. For example, anemia is a common side effect of cancer treatments. Chemotherapy and radiation can impair the bone marrow's production of red blood cells and contribute to the extreme fatigue that many patients experience during cancer therapy. Patients with hepatitis C frequently receive combination therapy of ribavirin and interferon; ribavirin can induce anemia. Hepatitis C also affects many patients with HIV or AIDS. In addition to ribavirin, patients with HIV or AIDS can develop anemia as a result of highly active anti-retroviral therapy (HAART) and, in particular, from the drug AZT. Other medications that increase the risk for anemia are certain antibiotics, some antiseizure medications (phenytoin), immunosuppressive drugs (methotrexate, azathioprine), antiarrhythmic drugs (procainamide, quinidine), and anti-clotting drugs (aspirin, warfarin, heparin). Megaloblastic AnemiaMegaloblastic anemia is the end-product of deficiencies in the B vitamins folate or vitamin B12 (also called cobalamin), or both. Such deficiencies produce abnormally large red blood cells (megaloblastic ) that have a shortened life span. Neurologic problems are also associated with these deficiencies. Several conditions can cause these deficiencies. Causes of Vitamin B12 Deficiency. Conditions that cause vitamin B12 deficiencies include:
Vitamin B12 deficiency from diet is very rare, since the liver stores over a 3-year supply. It usually does not occur even in alcoholism, vegetarianism, or in malnourished people with kidney failure or cancer. Since animal products are the chief source, however, true vegan vegetarians may need a supplement, fortified food, or appropriate food selection known to contain adequate amounts of this vitamin. Causes of Folate Deficiency. The body stores only about 100 times its daily requirements for folate and can exhaust this supply within about 3 months if the diet is deficient in folate.
Any condition that disturbs the small intestine and impairs its absorption ability can cause a deficiency. Such disorders include:
Deficiencies can also arise due to high demand for folic acid caused by conditions such as cancer, pregnancy, severe psoriasis, severe hyperthyroidism, and hemolytic anemia. Some drugs, including Dilantin, methotrexate, trimethoprim, and triamterene, may also hinder folate absorption.
Risk FactorsAlthough nutritional iron-deficiency anemia has declined in industrialized nations, it affects an estimated 2 billion people worldwide. Even in the U.S., iron deficiency is the most prevalent nutritional deficiency. It is highly associated with poverty. People in lower socioeconomic groups have double the risk of those who are middle or upper class. Among Americans with iron deficiency anemia, young children have the highest risk followed by premenopausal women. Adolescent and adult men and postmenopausal women have the lowest risk. Men, in fact, are at risk for iron overload, probably because of their higher meat intake. General Risk Factors for Anemia in Infants and Children. Up to 20% of American children and 80% of children in developing countries become anemic at some point during their childhood and adolescence. Iron deficiency is the most common cause in children, but other forms of anemia, including hereditary blood disorders, can also cause anemia in this population. African-American children have the highest rates of anemia (about 25%) while other ethnic groups have an incidence under 20%. Iron deficiency affects about 9% of children younger than 2 years. About 3% of children in this age group are anemic as a result. Children in lower-income homes are at higher risk than those in higher income homes. In a study of low-income children, ages 6 months to 5 years, the prevalence of anemia was over 10%, and was nearly 18% in children younger than 2 years. However, children in any income group can develop iron deficiency. Young children 9 - 18 months have the highest risk for iron deficiency anemia in the U.S. Such children also are at great risk for problems in mental development from anemia. Infant boys may have 10 times more risk than baby girls. In general, full-term infants who are breastfed by their mothers have sufficient iron stores for their first 6 months of life. After that, they must rely on other sources for iron. Iron-deficiency anemia in infants and small children can be due to one or more of the following factors:
Better social services and more accurate ways of diagnosing and monitoring anemia are needed in these high-risk groups. There is still considerable debate on how to define iron deficiency and anemia in infants. New research suggests that a reticulocyte hemoglobin content (CHr) test may be better than a standard hemoglobin test for detecting iron deficiency in babies. Reticulocytes are immature red blood cells. The CHr test measures the amount of hemoglobin in these cells. Risk Factors for Anemia in Premenopausal Women. In a major government study, 9 - 16% of adolescent and adult women under 49 years were iron deficient. Hispanic American and African-American women had double the prevalence of Caucasian women. The risk for anemia in adolescent girls is about 3%. Anemia is generally mild in young women, however, and is more likely to occur with one or more of the following conditions:
Risk Factors for Anemia in Older Adults. Although studies have reported various estimates on the prevalence of anemia in older adults, one recent survey suggested that anemia affects approximately 10% of adults aged 65 years and older, and more than 20% aged 85 years and older. The causes of anemia in older adults were equally distributed among nutritional deficiencies, chronic inflammatory disease, chronic renal disease, and unexplained anemia. Most cases were mild. People with AlcoholismPeople with alcoholism are at risk for anemia both from internal bleeding and vitamin B deficiencies. People with Iron-Poor DietsAlthough most Americans probably consume too much iron in their diets, some people may be at risk for diet-related iron deficiencies:
Chronic or Critical IllnessesAnyone with a chronic disease that causes inflammation or bleeding is at risk for anemia. Critical illness in the intensive care unit is also highly associated with anemia. AthletesWorking out regularly may cause some iron loss, which is comparable to that from menstruation and rarely worrisome. One 2000 study suggests that dietary choices may account for most cases of sports anemia. Intense, sustained exercise, such as that performed by marathon runners, may cause a condition called sports anemia, which may be due to slight gastrointestinal bleeding, damaged red blood cells, low iron intake, or poor intestinal absorption of iron.
ComplicationsMost 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 AnemiaBecause 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 WomenPregnant 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 AdolescentsOne 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 ElderlyAnemia 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:
Effects of Vitamin B12 Deficiencies and Pernicious AnemiaIn 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 CancerAnemia 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 DiseaseAnemia is associated with higher mortality rates and possibly heart disease in patients with kidney disease. Anemia in Patients with Heart FailureThe 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.
SymptomsSymptoms of anemia vary depending on the severity of the condition. Anemia may occur without symptoms and be detected only during a medical examination that includes a blood test. When they occur, symptoms may include:
Unusual SymptomsPica. One odd symptom, (which in some cases is a cause of iron deficiency), is pica. This is the habit of eating unusual substances, such as ice (called pagophagia), clay, cardboard, foods that crunch, or raw starch. For example, in one study, half of people whose pica took the form of pagophagia (eating at least one tray of ice every day for 2 months) or eating foods that crunch (such as raw potatoes, carrots, or celery) were iron deficient. The pica often stops, particularly in children, when iron supplements are given. Pica is difficult to detect because patients are often ashamed to admit to such cravings. Frequent Breath Holding. Studies have also indicated that children who hold their breath frequently when angry or upset, even to the point of fainting, may be iron-deficient. In one study, taking iron supplements reduced this phenomenon in 88% of treated children. Symptoms of Megaloblastic Anemia and its CausesSymptoms of Megaloblastic Anemia. The symptoms of megaloblastic anemia from vitamin B12 or folic acid deficiencies include not only standard anemic symptoms but also:
Over time, psychiatric and neurologic problems develop. Vitamin B12 deficiencies cause neurologic symptoms (numbness and tingling, depression, memory loss, and irritability), and folate deficiency may result in depression and dementia (in severe cases). Symptoms of Pernicious Anemia. Early neurologic symptoms of pernicious anemia are due to B12 deficiency. They include numbness and tingling, depression, memory loss, and irritability. Advanced nerve damage can cause loss of balance and staggering, confusion, dementia, spasticity, loss of bladder control, and erectile dysfunction. Folic acid deficiency does not cause neurologic damage, although people with this deficiency can be irritable, forgetful, and experience personality changes. Of concern for patients with pernicious anemia and B12 deficiency anemia is that folic acid supplements can mask the presence of this disease in its early stages but not cure it. The only cure is vitamin B12 supplementation. DiagnosisThe first step in any diagnosis is a physical examination to determine if the patient has symptoms of anemia and any complications. Because anemia may be the first symptom of a serious illness, determining its cause is very important. This may be difficult, particularly in the elderly, malnourished, or people with chronic diseases, whose anemia may be caused by one or more factors. A detailed medical, personal, and dietary history should report:
The doctor should examine the patient carefully, especially checking for swollen lymph nodes, an enlarged spleen, and pale skin and nail color. Blood Tests to Determine the Presence of Any AnemiaFor anemia from any cause, specific blood tests are given to determine anemia from any cause. Blood and Hemoglobin Counts. A complete blood count (CBC) test is performed to determine the presence of anemia. The red blood cells, or erythrocytes, and their iron-bearing component, hemoglobin, are measured. For example, severe anemia in adults is defined by the World Health Organization as:
A low red blood cell (RBC) count could indicate a number of problems, including bleeding or a failure by bone marrow to manufacture red blood cells. Hematocrit. Calculating the percentage of red blood cells in blood plasma (a measurement called the hematocrit) is also important. Plasma is the liquid portion of blood. People with a high volume of plasma may be anemic even if their blood count is normal because the blood cells have become diluted. Normal percentages are highest in the very youngest individuals and decline as people age. They also vary by gender. The following are some examples of normal range:
Smokers, people at high altitudes, and those who are dehydrated tend to have higher than normal hematocrit levels. Those at greater risk for low hematocrit levels include pregnant women and patients with cirrhosis, heart failure, and splenomegaly. Reticulocyte Count. Reticulocytes are immature red blood cells, and their count reflects the rate of red blood cell production. The upper normal limit is about 100,000/mL. A low count, when bleeding isn't the cause, suggests problems in production in the bone marrow. An abnormally high count indicates that the red blood cells are being destroyed in high numbers and indicates hemolytic anemia. New research suggests that the reticulocyte hemoglobin content (CHr) test may be more accurate than a standard hemoglobin test for detecting iron deficiency in infants. This test may help identify babies who are at risk for becoming anemic and help them get treated earlier. Blood Morphology. A blood smear viewed under a microscope allows an expert to classify the blood by its color, size, and shape (its morphology ). Generally red blood cells are categorized as:
The shape of the red blood cells, which can be distorted in many blood disorders, is also important in determining a diagnosis. Diagnosing Iron Deficiency Anemia and its CausesThere are two steps in making a diagnosis in patients with symptoms of iron deficiency anemia:
Determining if Iron Stores are Low. The following findings are important in determining that a person is iron deficient:
Determining Causes of Iron Deficiency. When iron deficiency anemia is diagnosed, the next step is to determine what causes the iron deficiency itself.
If the patient's diet suggests low iron intake and other causes cannot be established using inexpensive or noninvasive techniques, then the patient may simply be given a monthly trial of iron supplements. If the patient fails to respond, further evaluation is needed. Diagnosing Anemia of Chronic Disease (ACD)Usually anemia of chronic disease is recognized during the management of the primary disease and, if the anemia is mild, additional diagnostic tests are rarely needed. The following are typical findings in ACD:
Diagnosing Vitamin B-Related AnemiasDoctors need a multi-step diagnostic procedure for determining vitamin B deficiencies and the anemias that cause or are caused by them. Doctors may arrive at a diagnosis of vitamin B12 or folic acid deficiencies from different routes:
Diagnosing Megaloblastic Anemia. Very large oval red blood cells indicate megaloblastic anemia. Abnormally shaped neutrophils (certain white blood cells) may also be present. Bone marrow aspiration may need to be performed if the disease is strongly suspected but the diagnosis is not clear. Determining Vitamin Deficiency. Once megaloblastic anemia has been diagnosed, the doctor will need to determine which vitamin deficiency is causing it. This is extremely important, because if a vitamin B12-deficient patient receives folate replacement only, then irreversible nerve injuries may develop. Even if blood tests for megaloblastic anemia are normal, patients with neurologic and psychiatric abnormalities that have no detectable cause should still be tested for vitamin B12 deficiency. Deficiencies may be suggested by the presence of other disorders:
Often, vitamin B deficiencies cannot be determined by a history or symptoms alone. Blood tests are the primary indicators of both vitamin B12 and folic acid deficiencies, but even blood tests for these vitamins are not always straightforward:
Measuring methylmalonic acid and homocysteine, substances in the blood that increase when levels of one or both vitamins are low, improves accuracy. Tests for Pernicious Anemia. Once a vitamin B12 deficiency has been established and the doctor has not found any intestinal abnormalities or other factors to account for the deficiency, the doctor presumes a diagnosis of pernicious anemia. Pernicious anemia may also be diagnosed through various blood (such as complete blood count) or urine tests. Pernicious anemia is treated with vitamin replacement, but the condition is easily missed, particularly in patients whose diets are rich in folic acid. Folic acid can mask the early symptoms of pernicious anemia but not cure it. Consequently the disease may persist until serious neurologic symptoms occur. With folic acid now a required additive in many commercial foods, some experts are concerned about an increased incidence in pernicious anemia. Dietary FactorsIron found in foods is either in the form of heme or non-heme iron:
The absorption of non-heme iron often depends on the food balances in meals. The following foods and cooking methods can enhance absorption of iron:
Certain nutrients interfere with the body's absorption of dietary iron. They include:
![]() Getting enough calcium to keep bones from thinning throughout a person's life may be made more difficult if that person has lactose intolerance or another reason, such as a tendency toward kidney stones, for avoiding calcium-rich food sources. Calcium deficiency also affects the heart and circulatory system, as well as the secretion of essential hormones. There are many ways to supplement calcium, including a growing number of fortified foods. Sources of Vitamins B12 and Folate. Vitamins B12 and folate are important for prevention of megaloblastic anemia and for good health in general.
Preventing Anemia in Infants and Small ChildrenThe main source of iron for an infant from birth to 1 year of age is in milk, either from breast milk, iron-fortified infant formula, or cereal. The best methods for preventing iron deficiency during infancy are: Breastfeeding and Iron-Supplemented Formulas. Mothers should be encouraged to breastfeed their babies for their first year. Up to half of the iron in breast milk is absorbed by the baby and is sufficient to prevent anemia for the first 4 - 6 months, assuming that the mother had adequate iron stores during pregnancy. Breast milk itself is low in iron, but if the mother's diet is healthy, vitamin C and lactose in the breast milk may enhance iron absorption. Breastfed babies should have iron supplements after 4 - 6 weeks, even if they are still nursing. Infants who are not breastfed should start with iron-fortified formulas. Most experts strongly discourage the use of low-iron formulas (less than 4.0 mg/L). However, a 2002 study suggested that formulas with iron levels as low as 1.6 mg Fe/L provide sufficient iron to infants and higher amounts do not add any benefit. Parents should discuss the best formula with their doctor. Children given iron supplements may have a slightly higher risk for diarrhea. Experts advise against cow's milk for the first year of life. Recommendations for Toddlers. Toddlers who did not have iron supplements during infancy should be checked for iron deficiency. After the first year, children should be given a varied diet that is rich in sources of iron, B vitamins, and vitamin C. Milk does not contain enough iron and can decrease children's appetite for iron-rich foods. Toddlers older than 1 year should not drink more than 2 cups of milk a day. A preference for apple juice over vitamin-C rich orange juice does not reduce iron absorption in children with any otherwise healthy diet. TreatmentOral iron supplements are the best way to restore iron levels for people who are iron deficient, but they should be used only when dietary measures have failed. However, iron supplements cannot correct anemias that are not due to iron deficiency. One study reported that doctors prescribed iron pills for 64% of patients with anemia without performing tests to confirm whether iron deficiency was actually the cause. The study suggested that iron replacement was appropriate in less than half of these patients. Iron replacement therapy can cause gastrointestinal problems, sometimes severe ones. Excess iron may also contribute to heart disease, diabetes, and certain cancers. Experts generally advice against iron supplements in anyone with a healthy diet and no indications of iron deficiency anemia. However, a 2003 study suggested that supplements help reduce fatigue in women with low iron stores but no signs of anemia. Treatment of Anemia of Chronic Disease. In general, the best treatment for anemia of chronic diseases is treating the disease itself. In some cases, iron deficiency accompanies the condition and requires iron replacement. Erythropoietin, most often administered with intravenous iron, is used for some patients. Treatment of Megaloblastic Anemia. The standard treatments for megaloblastic anemia are vitamin B12 injections and folic acid replacement. Iron SupplementsSupplement Forms. To replace iron, the preferred forms of iron tablets are ferrous salts, usually ferrous sulfate (Feosol, Fer-In-Sol, Mol-Iron). Other forms include ferrous fumarate (Femiron, FerroSequels, Feostat, Fumerin, Hemocyte, Ircon), ferrous gluconate (Fergon, Ferralet, Simron), polysaccharide-iron complex (Niferex, Nu-Iron), and carbonyl iron (Elemental Iron, Feosol Caplet, Ferra-Cap). Specific brands and forms may have certain advantages. The following are some examples:
Regimen. The general guidelines for iron replacement are as follows:
Other tips for taking iron are as follows:
Full recovery takes 6 - 8 weeks. Recovery will take longer in people with internal bleeding that is not under control. Iron replacement therapy must continue for about 6 months, even if anemia has been reversed. Treatment must be continued indefinitely for people with chronic bleeding; in such cases, iron levels should be closely monitored. Side Effects. Common side effects of iron supplements include the following:
Interactions with Other Drugs. Certain medications, including antacids, can reduce iron absorption. Iron tablets may also reduce the effectiveness of other drugs, including the antibiotics tetracycline, penicillamine, and ciprofloxacin and the Parkinson's disease drugs methyldopa, levodopa, and carbidopa. At least 2 hours should elapse between doses of these drugs and iron supplements. Supplements. The following vitamin and mineral supplements may improve iron absorption:
Intravenous or Injected IronIn some cases, iron is administered through muscular injections or intravenously. Intravenous iron has the advantage of causing less gastrointestinal discomfort and inconvenience. It may be in the form of iron dextran (Dexferrum, InFed), sodium ferric gluconate complex in sucrose (Ferrlecit), or iron sucrose (Venofer). Ferrlecit or Venofer are proving to be at least equally effective and safer than iron dextran. Candidates. The injected or intravenous forms should be limited to the following patients with iron deficiency:
Certain patients, even if they meet these qualifications, may not be appropriate candidates or should be monitored closely for complications. They include:
Side Effects. Some side effects differ depending on how the iron is administered and include the following:
For both methods, side effects and serious complications can include:
Oral and injected iron should never be given at the same time. Intravenous iron therapy may be appropriate for some pregnant women who meet these requirements, depending on the pregnancy term and other factors. Transfusions and Bloodless MedicineTransfusions are used to replace blood loss due to injuries and during certain surgeries. They are also commonly used to treat severely anemic patients who have thalassemia, sickle cell disease, myelodysplastic syndromes, or other types of anemia. Some patients require frequent blood transfusions. Iron overload can be a side effect of these frequent blood transfusions. If left untreated, iron overload can lead to liver and heart damage. Iron chelation therapy is used to remove the excess iron caused by blood transfusions. Patients take a drug that binds to the iron in the blood. The excess iron is then removed from the body by the kidneys. For many years, deferoxamine (Desferal) was the only drug used in chelation therapy. This drug is usually injected intravenously, using an infusion pump. The infusion can last 8 - 12 hours and may be needed 5 - 7 days a week until iron levels are normal. A new drug, deferasirox (Exjade), was approved in 2005 for children and adults as a once-daily treatment for iron overload due to blood transfusions. It does not require injections. Patients mix the deferasirox tablets in liquid and drink the medicine. Doctors hope that this new drug may make it easier for patients to tolerate chelation therapy. Studies have shown that deferasirox works as well as deferoxamine in ridding the body of excess iron. Bloodless Medicine. Bloodless medicine and surgery is a new field designed to reduce or minimize blood loss and transfusions. It also attempts to address the problems in treating certain religious groups, such as Jehovah's Witnesses, who refuse transfusions. Some techniques involved in this field include new surgical procedures or drugs that minimize blood loss, the use of erythropoietin, volume expanders (administration of fluids to dilute blood), using tiny blood samples for testing, and methods (Cell Saver) for recovering and recycling blood during surgery. Erythropoiesis-Stimulating DrugsErythropoietin is the hormone that acts in the bone marrow to increase the production of red blood cells. It has been genetically engineered as recombinant human erythropoietin (rHuEPO) and is available as epoetin alfa (Epogen, Procrit, and Eprex). Novel erythropoiesis stimulating protein (NESP), also called darbepoetin alfa (Aranesp), lasts longer in the blood than epoetin alfa and requires fewer injections. These medications are also called “erythropoiesis-stimulating drugs.” Levels of erythropoietin are reduced in anemia of chronic disease. Injections of synthetic erythropoietin can help reduce the need for blood transfusions and improve quality of life measures. Erythropoietin is currently used for treating patients with anemia related to the following conditions:
Although these drugs are used to treat anemia, they can sometimes cause severe anemia. If patients taking these drugs do develop severe anemia, the doctor will immediately stop drug treatment. The risk of drug-caused anemia is greatest for patients with chronic kidney failure who receive these drugs through under-the-skin injections. To reduce the risk of anemia, epoetin alfa and darbepoetin alfa should be given intravenously to patients on dialysis. Dosing target levels of erythropoiesis-stimulating drugs are controversial, especially for patients with chronic kidney disease. In 2006, two important New England Journal of Medicine (NEJM ) studies indicated that aggressive dosing to completely normalize hemoglobin levels does not work better than standard dosing that only partially corrects anemia. In addition, the higher dosing approach was associated with increased risk for serious cardiovascular events including heart failure, heart attack, and fatal stroke. In response to these NEJM studies, the FDA issued the following warnings to doctors and patients:
Epoetin may increase the risk for blood clots. Some experts are also concerned that certain patients may develop antibodies that react against epoetin. This may be more of a problem with some brands (Eprex) than others. Antibiotics for H. PyloriH. pylori, the bacteria that cause peptic ulcers, is associated with anemias from vitamin B12 deficiency and iron deficiency. People whose anemia is associated with H. pylori infection, however, do not respond to iron therapy. Studies indicate that the eradication of H. pylori infection with antibiotics can reverse anemia in such patients and may lead to long-lasting recovery. Vitamin Replacement for Megaloblastic AnemiaVitamin B12 Therapy. Injections of vitamin B12 (usually formulations called cyanocobalamin or hydroxocobalamin), oral folic acid therapy, or both, rapidly reverse the production of abnormally large red blood cells. (Treatments still may not reverse neurologic symptoms if they are extensive or have continued for too long.) A typical regimen for vitamin B12 replacement is as follows:
Other forms of vitamin B12 are also available and can be used to treat B12 deficiency. Vitamin B12 nasal spray offers the same advantage of avoiding the need for absorbing the vitamin in the GI tract without the inconvenience of the injections. Some experts feel that even oral B12 in high doses (2,000 mcg/day) can maintain B12 levels once the deficiency is treated. The injections are safe and have no adverse side effects, but they may mask an underlying medical or psychological condition. Some doctors give vitamin B12 injections for fatigue and other vague symptoms of general mild discomfort. In one study, 10% of patients in a rural clinic were given regular B12 shots, with 6% of patients having no medical need for them. Folic Acid Treatment. Folate deficiency is easily remedied in 4 - 5 weeks with daily oral doses of 1 - 2 milligrams of folic acid. Many doctors give vitamin B12 along with folic acid unless B12 deficiency is definitely ruled out. Resources
ReferencesCappellini MD, Cohen A, Piga A, Bejaoui M, Perrotta S, Agaoglu L, et al. A phase 3 study of deferasirox (ICL670), a once-daily oral iron chelator, in patients with beta-thalassemia. Blood. 2006 May 1;107(9):3455-62. Chaves PH, Carlson MC, Ferrucci L, Guralnik JM, Semba R, Fried LP. Association between mild anemia and executive function impairment in community-dwelling older women: The Women's Health and Aging Study II. J Am Geriatr Soc. 2006 Sep;54(9):1429-35. Drueke TB, Locatelli F, Clyne N, Eckardt KU, Macdougall IC, Tsakiris D, et al. Normalization of hemoglobin level in patients with chronic kidney disease and anemia. N Engl J Med. 2006 Nov 16;355(20):2071-84. Hillmen P, Young NS, Schubert J, Brodsky RA, Socie G, Muus P, Roth A, et al. The complement inhibitor eculizumab in paroxysmal nocturnal hemoglobinuria. N Engl J Med. 2006 Sep 21;355(12):1233-43. Oepkes D, Seaward PG, Vandenbussche FP, Windrim R, Kingdom J, Beyene J, et al. Doppler ultrasonography versus amniocentesis to predict fetal anemia. N Engl J Med. 2006 Jul 13;355(2):156-64. Singh AK, Szczech L, Tang KL, Barnhart H, Sapp S, Wolfson M, et al. Correction of anemia with epoetin alfa in chronic kidney disease. N Engl J Med. 2006 Nov 16;355(20):2085-98.
Review Date:
1/17/2007 Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997-
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