Iron-deficiency anemia

Definition
Anemia is a condition marked by a decreased number of red blood cells or hemoglobin (a protein in red blood cells that contains iron). Your body needs iron to produce hemoglobin and carry oxygen throughout the body. With iron-deficiency anemia, the body has inadequate iron stores that, in turn, result in low hemoglobin levels.

Causes/associated factors
Iron deficiency is a symptom of various diseases and the most universal cause of anemia. Specifically, iron-deficiency anemia is usually the result of decreased iron absorption or a greater demand on your body's stored iron.
The condition may also be related to acute or chronic blood loss (especially gastrointestinal), parasitic infections, inadequate amounts of iron in the diet or malabsorption of iron. Pregnancy, breastfeeding or heavy menstrual bleeding may also play a role, as well as chronic aspirin use. For adolescents, rapid growth spurts may be to blame. Sometimes, a combination of factors is responsible.

For infants and children, iron-deficiency anemia is often related to poor nutrition. Healthy, full-term infants are born with enough iron stores to last three to six months after birth. However, premature infants often have low iron stores at birth and grow quickly. This creates a high demand for nutrients -- including iron. Children between ages 6 months and 2 years often consume large quantities of milk, which may lead to the exclusion of foods that contain iron.

Risk factors for developing iron-deficiency anemia include:

poverty
blood loss
poor nutrition
eating a vegetarian diet without adequate iron content
stomach ulcers (sores or lesions)
colitis (inflammation of the colon)
hemorrhoids (stretched and swollen veins in the anus or lower rectum)
tumors in the gastrointestinal tract
diverticulitis (inflammation of the diverticula, which are small, protruding pouches that can develop in the gastrointestinal tract, usually in the colon)
Premature or low birthweight infants, young children, adolescents, women of childbearing age and elderly adults are also at risk for iron-deficiency anemia.


Signs/symptoms
In most cases, symptoms are not apparent at first. As the condition progresses, the symptoms tend to become more noticeable. Symptoms of iron-deficiency anemia may include:
fatigue and weakness
tongue inflammation
paleness, especially in the hands and lining of the lower eyelids
fainting
breathlessness
rapid heartbeat or palpitations
appetite loss
abdominal discomfort
headaches
cravings for ice, paint or dirt
listlessness or irritability
for children, unusual quietness, withdrawal or developmental delays

Diagnosis
The doctor will ask questions about your medical history and do a physical exam. You may need a series of tests, including blood studies to measure hemoglobin, hematocrit (the percentage of total blood volume of red blood cells), iron levels, total iron-binding capacity and red blood cell counts.
Blood tests will also measure ferritin, an iron protein made of up to 23 percent iron that's found in the intestinal lining, spleen and liver. Ferritin controls the transportation of iron from the intestines to your bloodstream.

Sometimes, gastrointestinal X-rays are done. Additional tests may be needed to help the doctor rule out other possible causes for blood loss or malabsorption of iron. Bone marrow aspiration, for example, is a procedure that helps doctors estimate iron stores and rule out other abnormalities, such as abnormal tissue growths.

For men, postmenopausal women and any other adults with suspicious symptoms, the doctor may recommend a thorough gastrointestinal evaluation to rule out any type of gastrointestinal cancer. Endoscopy (examination of a body organ or cavity with an endoscope -- a thin, flexible tube equipped with a camera lens and light) can help the doctor identify sites of obscure bleeding. Other possible diagnostic procedures may include:

rectal exam
colonoscopy (a procedure used to examine the inside of the colon)
gastroscopy (a procedure used to examine the stomach and abdominal cavity)
sigmoidoscopy (a procedure used to examine the rectum, the end of the large intestine and lower part of the colon, another part of the intestine)

Treatment
Iron-deficiency anemia is treated by correcting the underlying cause. For example, if an ulcer is identified as the source of your blood loss, the ulcer will be treated. If no underlying cause is identified, the main remedy is often a balanced diet and several months of oral iron supplements, such as ferrous sulfate.
If the oral supplement you are taking causes gastrointestinal discomfort, discuss specific supplement options with your doctor. Side effects may be dosage-related, and your doctor may recommend slowly increasing the dosage or taking the supplement with food. Other iron preparations, such as ferrous gluconate, may be recommended instead. Your doctor will also advise you about medications you're currently taking that could potentially interact with iron supplements, such as vitamin E, antacids, tetracycline antibiotics, penicillamine, allopurinol and antiulcer medications.

Iron from an animal source is more easily absorbed by the body. This type of iron is called heme iron. Iron from a plant source is called nonheme iron. Nonheme iron is better absorbed by the body when taken in combination with heme iron or food rich in vitamin C.

Good sources of dietary heme iron include (from the highest iron content to the lowest):

meat, especially liver
poultry
salmon, canned with bone
Remember, the darker the meat color, the more heme iron present. Therefore, the dark meat of chicken has more iron than the white meat.

Good sources of dietary nonheme iron include (from highest to lowest):

pumpkin seeds
blackstrap molasses
beans (may vary depending on type, etc.)
dark green leafy vegetables such as spinach
raisins
dried fruits
enriched cereals and breads, especially whole-grain (read food labels since amount varies)
egg yolks
peanut butter
Taking iron supplements with anything high in vitamin C, such as orange juice, may help improve absorption. Iron supplements with added ingredients, such as vitamin C, are not necessary and often are more expensive, however. Tea, coffee, milk, antacids and fibrous foods may have the opposite effect and actually decrease iron absorption. Do not take enteric-coated supplements (those with a coating that will keep the supplement from dissolving until it reaches the small intestine). They don't dissolve in the stomach, where iron absorption occurs. On another note, iron supplements often create black bowel movements.

If you can't take iron supplements in pill form, your doctor may prescribe iron by injection. This is less common, and due to potential adverse reactions, you may first need an evaluation by a hematologist (a doctor who specializes in the study of blood).

Note: Excess supplemental iron intake can be fatal for children. Rarely, it can lead to hemochromatosis (excessive iron deposits that cause liver enlargement) for adults. Keep all iron supplements and medications out of reach of children to avoid accidental ingestion or poisoning, and always follow the recommended dosages.


Complications
Ongoing gastrointestinal blood loss may result in continued anemia, despite iron supplementation. In rare cases, intravenous or intramuscular injections of iron supplements may lead to serious reactions.

Pregnancy-specific information
Anemia is common during pregnancy because of the increased blood volume in your body. Iron deficiency and blood loss are the most common reasons pregnant and postpartum women develop anemia. Subsequent pregnancies may be affected if excessive blood loss exhausts your iron stores.
If you're pregnant, breastfeeding or planning pregnancy, discuss iron supplements with your health care provider. If you develop iron-deficiency anemia, oral iron supplements may be prescribed. You may need to continue taking the supplements for up to three months after the condition clears up. A mother's iron-deficiency anemia doesn't typically affect the infant's iron levels. Studies suggest that this type of anemia may lead to an increased risk for premature births and low birth weight babies, however.


Senior-specific information
Iron-deficiency anemia is common in adults over age 65, but it's not a normal consequence of aging. For older adults, iron-deficiency anemia is often related to blood loss from the gastrointestinal tract. At any age, the underlying cause needs to be identified and treated.

Prevention
To prevent iron-deficiency anemia, eat foods rich in iron. Only take iron supplements if ordered and as directed by your doctor. If you develop the condition, it's essential to correct any underlying causes.