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Anemia, the most common form of blood disorder, limits the blood's ability to carry sufficient oxygen throughout the body. In a healthy person, disc-shaped red blood cells contain hemoglobin, a red pigment that carries oxygen to the tissues and carries away the waste material, carbon dioxide. Anemia occurs when the overall number of red blood cells decreases or when the amount of hemoglobin available in those cells decreases.
There are many different types of anemia, but generally the condition can be traced to one of three causes:
environmental factors, such as deficiency of a certain nutrient (most commonly iron) or the side effect of certain medications
external or internal blood loss or infection
inherited or acquired problems with the production and function of red blood cells or hemoglobin
Types of Anemia and Their Causes
Iron Deficiency Anemia
Inadequate dietary iron intake is the most common cause of anemia in children. That's because iron is essential for the production of hemoglobin in the red blood cells. Iron deficiency anemia can affect children at any age, but it is most commonly seen in children younger than age 2 - usually between 9 months and 18 months - and teens, particularly adolescent girls.
During the first 6 months of life, babies are usually protected against developing iron deficiency due to the stores of iron built up in their bodies while they are in the uterus. However, by the second half of the first year of life, as infants continue to undergo significant growth, often they do not take in adequate iron through breast milk or cow's milk to support their iron needs. In fact, if babies and toddlers drink large quantities of cow's milk, they may become less interested in other foods that are actually better sources of iron.
The adolescent growth spurt that occurs during puberty is also often associated with increased risk for iron deficiency anemia. Girls are at even higher risk because of the onset of menstruation; the monthly blood loss increases the need for dietary iron. In a recent report on iron deficiency in the United States, the Centers for Disease Control and Prevention
(CDC) noted that, according to a 1996 survey, less than half of 1- to 2-year-olds and just over one fourth of teen girls were meeting the recommended daily allowance for iron.
Blood loss can also be a factor in iron deficiency anemia - whether because of menstruation, excessive bleeding due to injury or a problem with the blood's clotting mechanism, or internal bleeding, such as intestinal bleeding due to inflammatory bowel disease. Presence of these factors can increase the body's need for iron.
Anemia can also be caused by deficiency in the nutrients folic acid and vitamin B12, both of which are necessary for normal blood production. Pernicious anemia is a type of anemia that occurs when a person lacks a substance that is necessary to absorb and process vitamin B12. However, these forms of nutritional anemia are rarely found in babies and young children.
Hemolytic Anemia
Hemolytic ("hemo" means blood, "lytic" means destroying) anemia occurs when red blood cells are being destroyed prematurely and the bone marrow (soft, spongy part of the bone that produces new blood cells) simply can't keep up with the demand for new cells. This can happen for a variety of reasons. Sometimes, infections or certain medications, such as antibiotics or antiseizure medicines, are to blame. In what's known as autoimmune hemolytic anemia, the immune system mistakes red blood cells for foreign invaders and begins destroying them. Other children either develop or inherit defects in the red blood cells, which may involve the cell membranes or the production of certain enzymes (proteins that speed up or cause chemical reactions) or hemoglobin. The most common forms of inherited hemolytic anemia are sickle cell anemia and thalassemia.
Sickle cell anemia is a severe form of anemia found almost exclusively in people of African heritage, although it may also affect those of Caucasian, Saudi Arabian, Indian, and Mediterranean descent. In this condition, the hemoglobin forms long rods when it gives up its oxygen, stretching red blood cells into abnormal "sickle" shapes. This results in premature destruction (hemolysis) of red blood cells, chronically low levels of hemoglobin (anemia), and recurring episodes of pain. About one out of every 500 African-American children is born with this form of anemia.
Thalassemia, which usually affects people of Mediterranean, African, and Southeast Asian descent, is marked by abnormal and short-lived red blood cells. Thalassemia major, also called Cooley's anemia, is a severe form of anemia in which red blood cells are rapidly destroyed and iron is deposited in the skin and vital organs. Thalassemia minor involves only mild anemia and minimal red blood cell changes.
Aplastic Anemia
Aplastic anemia occurs when the bone marrow is unable to produce sufficient numbers of blood cells. The problem may be caused by an inherited genetic defect, as in Fanconi anemia (which affects levels of all three blood cell types: red, white, and platelets) and Diamond-Blackfan anemia (which affects red blood cell levels). More commonly, aplastic anemia is caused by exposure to certain toxic chemicals, radiation, or medications, such as antibiotics, antiseizure medications, or cancer medications. For some reason, children who develop anemia after exposure to toxic chemicals seem to be unusually sensitive to the particular substance triggering the condition.
In about half of all cases, aplastic anemia has no apparent cause. The condition is rare, affecting only two to six out of every one million people in the United States and Europe.
Can Anemia Be Prevented?
Whether anemia can be prevented depends on the underlying cause. Presently, there is no way to prevent anemia that is caused by genetic defects of the red blood cell or hemoglobin.
However, there are steps you can take to help prevent iron deficiency - the most common form of anemia. Before following any of these suggestions, be sure to talk them over with your child's doctor. Each child's needs are different, and iron overdose can cause serious health problems. In fact, the American Academy of Pediatrics (AAP) points out that iron is actually a significant cause of poisoning in children younger than 5.
cow's milk consumption: Cow's milk given too early (before 6 months of age) or in too great quantities has been associated with cases of anemia. Infants under 6 months fed regular cow's milk may experience irritation of the bowel, which can lead to small amounts of blood loss. Furthermore, babies and toddlers who drink too much cow's milk may become less interested in foods with higher iron content. Parents also tend to associate milk with good nutrition and may not realize that the child needs better sources of iron. In general, your child should not drink more than 24 to 32 ounces of milk each day. If you still can't get her to eat more iron-rich foods, speak with your child's doctor about adding an iron supplement to her diet.
iron-fortified cereal and formula: These products can help ensure that your baby is getting enough iron, especially as she makes the transition from breast milk or formula to solid foods.
well-balanced diet: Make sure that your child or teen regularly eats foods that contain iron. Good choices include iron-fortified grains and cereals, red meat, egg yolks, leafy green and yellow vegetables, yellow fruits, potato skins, tomatoes, molasses, and raisins. If your child is a vegetarian, you'll need to make an extra effort to ensure that she gets sufficient iron. That's because iron found in meat, poultry, and fish is more easily absorbed than iron found in plant-based and iron-fortified foods. Also, be aware that certain food combinations can inhibit or promote absorption of iron. For example, drinking coffee or tea (including iced tea) with a meal can significantly lower the amount of iron absorbed. On the other hand, vitamin C helps the body absorb iron.
side effects of medications: Numerous medications can cause anemia. In most cases, the benefit of the drug your child's doctor prescribes outweighs the risk, but your child may need to be monitored for signs of anemia.
Signs and Symptoms of Anemia
The most common sign of iron deficiency and other types of nutritional anemia is mild paleness of the skin, which most apparent as a decreased pinkness of the lips, the lining of the eyelids, and the nail beds. A friend or relative who sees your child only occasionally may be more likely to notice this than you are because the changes usually happen so gradually.
Your child may also be irritable and easily fatigued.
Other symptoms can include dizziness, lightheadedness, and a rapid heart rate, all a result of the heart's effort to compensate for lower hemoglobin levels by pumping more blood throughout the body.
In addition to these symptoms, hemolytic anemia may cause jaundice (yellow-tinged skin), dark tea-colored urine, and enlargement of the spleen or liver. Normally, the spleen and liver remove old red cells from the blood at the end of their life cycles. As cells are destroyed prematurely, the organs become clogged with cells.
Sickle cell anemia often causes additional symptoms, including unexplained fever, swelling of the hands and feet, episodes of pain due to blockages in the blood vessels by sickled red blood cells, problems fighting infection, and eye problems.
Children and young adults who have aplastic anemia often experience easy bruising, nausea, tiny areas of bleeding in the skin, and abnormal bleeding from the gums, nose, vagina, or gastrointestinal tract.
Diagnosing Anemia
In many cases, doctors don't discover anemia until they run blood tests as part of a routine physical examination. A complete blood count
(CBC) may indicate that there are fewer red blood cells than normal. Other diagnostic tests may include:
blood smear examination: Microscopic examination of red blood cells can help to establish whether anemia is present and its cause. Normal growth and hemoglobin production are characterized by richly pigmented cells of uniform shape and size. Cells that are extremely large, abnormally pale or small, or misshapen may be indicators of specific types of anemia.
hemoglobin electrophoresis: This test identifies various abnormal hemoglobin in the blood.
bone marrow aspiration and biopsy: This test can help determine whether cell production is happening normally in the bone marrow. It's the only way to diagnose aplastic anemia definitively.
In addition to running these tests, your child's doctor may ask about a family history of anemia and anemia symptoms and signs such as jaundice and enlarged spleen, medications your child takes, and previous and current infections.
Treating Anemia
Treatment for anemia cannot begin until the underlying cause is identified. It's important not to assume that any symptoms your child may be having are due to iron deficiency ? be sure to have her checked by a doctor, and don't attempt to treat her yourself before doing so.
If your child does have iron deficiency anemia, the doctor may prescribe medication in the form of drops (for infants) or liquid or tablet form (for older children). The doctor also may recommend adding certain iron-rich foods to your child's diet. In infants and preschool children, iron deficiency anemia can result in developmental delays and behavioral disturbances, such as decreased motor activity, and problems with social interaction and attention to tasks. Recent research studies indicate that that behavioral problems may persist into and beyond school age (5 years) if the iron deficiency is not properly treated..
If your teenage daughter is anemic and has heavy menstrual periods, her doctor may prescribe a birth control pill to moderate the bleeding.
Folic acid and vitamin B12 supplements may be prescribed if the anemia is traced back to a deficiency of these nutrients.
If a certain medication appears to be the cause, your child's doctor may discontinue it or replace it with something else - unless the benefit of the drug outweighs this side effect.
If an infection is the cause, curing the infection will usually cure the anemia as well.
Treatment for more severe, chronic forms of anemia may include:
a transfusion of normal red blood cells to help replenish the supply of normal blood cells
a splenectomy, removal of the spleen, to allow more red blood cells to remain in circulation
corticosteroids (hormones that control key bodily processes) such as prednisone to counter the process of premature destruction of red blood cells by the immune system
other drugs to suppress the immune system and stimulate red blood cell production
infection-fighting drugs or vaccines
bone marrow transplantation to treat severe cases of sickle cell anemia, thalassemia, and aplastic anemia (This high-risk procedure involves taking marrow from a donor and injecting it into the child's vein; the donated marrow then travels through the bloodstream to the bone marrow, where it begins producing new blood cells. The chance of success is usually greatest when there is a histocompatible - someone with a closely genetically matching mix of body proteins - sibling donor.)
extra fluids and pain medication (especially for children with sickle cell anemia)
Caring for a Child With Anemia
If your child has anemia, she may tire more easily than other children and therefore need to limit her activity. Make sure that her teachers and other caregivers are aware of her condition. If an iron deficiency is the cause, follow her doctor's directions about dietary changes and iron supplementation.
If her spleen is enlarged, she probably will be prohibited from playing contact sports because of the risk of rupture and hemorrhage.
Children who have sickle cell anemia need to keep well hydrated, so make sure that your child drinks plenty of water and carries a water bottle during activities. Also, extremes in temperature can make the condition worse, so make sure she dresses appropriately for the environmental temperature.
These are general suggestions, however; the type, cause, and severity of your child's anemia will determine what kind of care she needs. Talk this over with her doctor.
Call your child's doctor if any of your child's symptoms reappear or worsen suddenly.
Reviewed by: Steve Dowshen, MD
Date reviewed: June 2000
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