Anemia, One of the More Common Blood Disorders, Occurs When the Level of Healthy Red Blood

About Anemia

Anemia, one of the more common blood disorders, occurs when the level of healthy red blood cells (RBCs) in the body becomes too low. This can lead to health problems because RBCs contain hemoglobin, which carries oxygen to the body's tissues. Anemia can cause a variety of complications, including fatigue and stress on bodily organs.

Anemia can be caused by many things, but the three main bodily mechanisms that produce it are:

1. excessive destruction of RBCs
2. blood loss
3. inadequate production of RBCs

Among many other causes, anemia can result from inherited disorders, nutritional problems (such as an iron or vitamin deficiency), infections, some kinds of cancer, or exposure to a drug or toxin.

Anemia Caused by Destruction of RBCs

Hemolytic anemia occurs when red blood cells are being destroyed prematurely. (The normal lifespan of RBCs is 120 days; in hemolytic anemia, it's much shorter.) And the bone marrow (the soft, spongy tissue inside bones that makes new blood cells) simply can't keep up with the body's 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 autoimmune hemolytic anemia, the immune system mistakes RBCs for foreign invaders and begins destroying them. Other kids inherit defects in the red blood cells that lead to anemia; common forms of inherited hemolytic anemia include sickle cell anemia, thalassemia, glucose-6-phosphate dehydrogenase (G6PD) deficiency, and hereditary spherocytosis.

• Sickle cell anemia is a severe form of anemia found most commonly in people of African heritage, although it can 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 leads to premature destruction of RBCs, chronically low levels of hemoglobin, and recurring episodes of pain, as well as problems that can affect virtually every other organ system in the body. About 1 out of every 625 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 RBCs. Thalassemia major, also called Cooley's anemia, is a severe form of anemia in which RBCs 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.
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency most commonly affects males of African heritage, although it has been found in many other groups of people. With this condition the RBCs either do not make enough of the enzyme G6PD or the enzyme that is produced is abnormal and doesn't work well. When someone born with this deficiency has an infection, takes certain medicines, or is exposed to specific substances, the body's RBCs suffer extra stress. Without adequate G6PD to protect them, many red blood cells are destroyed prematurely.
• Hereditary spherocytosis is a genetic disorder of the RBC's membrane that can cause anemia, jaundice (yellow-tinged skin), and enlargement of the spleen. The RBCs have a smaller surface area than normal red blood cells, which can cause them to break open easily. A family history increases the risk for this disorder, which is most common in people of northern European descent but can affect all races.

Anemia Caused by Inadequate Production of RBCs

Aplastic anemia occurs when the bone marrow can't make enough RBCs. This can be due to a viral infection, or exposure to certain toxic chemicals, radiation, or medications (such as antibiotics, antiseizure drugs, or cancer treatments). Some childhood cancers can also cause aplastic anemia, as can certain chronic diseases that affect the ability of the bone marrow to make blood cells.

High levels of hemoglobin and RBCs help fetal blood carry enough oxygen to developing babies in the relatively oxygen-poor environment in utero. After the child is born, more oxygen is available and the baby's hemoglobin level normally drops to a low point at about 2 months of age, a condition known as physiologic anemia of infancy. This temporary and expected drop in the blood count is considered normal and no treatment is required because the infant's body soon starts making RBCs on its own.

Anemia also occurs when the body isn't able to produce enough healthy RBCs because of an iron deficiency. Iron is essential to hemoglobin production. Poor dietary iron intake (or excessive loss of iron from the body) can lead to iron deficiency anemia, the most common cause of anemia in kids. Iron deficiency anemia can affect kids at any age, but is most common in those younger than 2 years old. Young children who drink excessive amounts of milk are at increased risk for iron deficiency.

Girls going through puberty also have a particularly high risk for iron deficiency anemia because of the onset of menstruation; the monthly blood loss increases the amount of iron they need to consume in their diets.

Signs and Symptoms

If your child has anemia, the first symptoms might be mild skin paleness and decreased pinkness of the lips and nailbeds. These changes may happen gradually, though, so they can be difficult to notice. Other common signs include:

• irritability
• fatigue
• dizziness, lightheadedness, and a rapid heartbeat

If the anemia is caused by excessive destruction of RBCs, symptoms also may include jaundice, a yellowing of the whites of the eyes, an enlarged spleen, and dark tea-colored urine.

In infants and preschoolers, 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. Research indicates that developmental problems may last into and beyond school age if the iron deficiency is not properly treated.

Diagnosing Anemia

In many cases, doctors don't diagnose anemia until they run blood tests as part of a routine physical examination. A complete blood count (CBC) may indicate that there are fewer RBCs than normal. Other diagnostic tests may include:

• Blood smear examination: Blood is smeared on a glass slide for microscopic examination of RBCs, which can sometimes indicate the cause of the anemia.
• Iron tests: These include total serum iron and ferritin tests, which can help to determine whether anemia is due to iron deficiency.
• Hemoglobin electrophoresis: Used to identify various abnormal hemoglobins in the blood and to diagnose sickle cell anemia, the thalassemias, and other inherited forms of anemia.
• 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 and is also used if a disease affecting the bone marrow (such as leukemia) could be causing of the anemia.
• Reticulocyte count: A measure of young RBCs, this helps to determine if RBC production is at normal levels.

In addition to running these tests, your doctor may ask about a family history of anemia and your child's symptoms and medications. This may lead the doctor to perform other tests to look for specific diseases that might be causing the anemia.

Treatment

Treatment for anemia depends on its cause. It's important not to assume that any symptoms your child may be having are due to iron deficiency. Be sure to have your child checked by a doctor.

If your child has iron deficiency anemia, the doctor may prescribe medication as drops (for infants) or as a liquid or tablet (for older kids), which usually must be taken for as long as 3 months to rebuild the body's store of iron. The doctor also may recommend adding certain iron-rich foods to your child's diet or reducing milk intake.

If your teenage daughter is anemic and has heavy or irregular menstrual periods, her doctor may prescribe hormonal treatment to help regulate the bleeding.

Folic acid and vitamin B12 supplements may be prescribed if the anemia is traced to a deficiency of these nutrients, although this is rare in children.

Anemia caused by an infection will usually improve when the infection passes or is treated. If a certain medication appears to be the cause, your doctor may discontinue it or replace it with something else — unless the benefit of the drug outweighs this side effect.

Depending on the cause, treatment for more severe or chronic forms of anemia may include:

• transfusions of normal red blood cells taken from a donor
• removal of the spleen or treatment with medications to prevent blood cells from being removed from circulation or destroyed too rapidly
• medications to fight infection or stimulate the bone marrow to make more blood cells

In some cases of sickle cell anemia, thalassemia, and aplastic anemia, bone marrow transplantation may be used. In this procedure, bone marrow cells taken from a donor are injected into the child's vein; they then travel through the bloodstream to the bone marrow and begin producing new blood cells.

Caring for a Child With Anemia

The type, cause, and severity of your child's anemia will determine what kind of care is needed. Rest assured, though, that kids often tolerate anemia much better than adults.

In general, a child with significant anemia may tire more easily than other kids and therefore need to limit activity levels. Make sure that your child's teachers and other caregivers are aware of the condition. If iron deficiency is the cause, follow the doctor's directions about dietary changes and taking any iron supplements.

If the spleen is enlarged, your child may be prohibited from playing contact sports because of the risk that the spleen could rupture or hemorrhage if your child is hurt. Certain forms of anemia, such as sickle cell anemia, require other more specific kinds of care and treatment.

Preventing Anemia

Whether anemia can be prevented depends on its cause. Currently, there is no way to prevent anemia due to genetic defects affecting the production of RBCs or hemoglobin.

However, you can help prevent iron deficiency, the most common form of anemia. Before following any of these suggestions, be sure to talk them over with your doctor:

• Cow's milk consumption. During the first 6 months of life, babies are usually protected against developing iron deficiency by the stores of iron built up in their bodies before birth. But after month 6, they often don't get enough iron through breast milk alone or regular cow's milk (which contains less iron than fortified infant formula). Regular cow's milk can cause some infants to lose iron from their intestines, and drinking lots of it can make a baby less interested in eating other foods that are better sources of iron. For these reasons, regular cow's milk is not recommended for children until they reach 1 year of age and are eating an iron-rich diet. In addition, they should not drink more than 24-32 ounces (709-946 ml) of milk each day. If you can't get your child to eat more iron-rich foods, speak with your doctor about giving your child an iron supplement.
• Iron-fortified cereal and formula. These products can help ensure that your baby is getting enough iron, especially during the transition from breast milk or formula to solid foods.
• Well-balanced diet. Make sure that your kids regularly eat foods that contain iron. Good choices include iron-fortified grains and cereals, red meat, egg yolks, leafy green vegetables, yellow vegetables and fruits, potato skins, tomatoes, molasses, and raisins. If your child is a vegetarian, you'll need to make an extra effort to ensure sufficient iron sources 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.

If you have any questions about anemia or you think your child might have it, speak with your doctor.

Reviewed by: Robin E. Miller, MD
Date reviewed: April 2009