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Iron deficiency anemia

Definition

Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. There are many types of anemia. Iron deficiency anemia is a decrease in the number of red cells in the blood caused by too little iron.

See also: Iron deficiency anemia - children

Alternative Names

Anemia - iron deficiency

Causes, incidence, and risk factors

Iron deficiency anemia is the most common form of anemia. About 20% of women, 50% of pregnant women, and 3% of men do not have enough iron in their body.

Iron is a key part of hemoglobin, the oxygen-carrying protein in the blood. Your body normally gets iron through diet and by recycling iron from old red blood cells. Without iron, the blood cannot carry oxygen effectively. Oxygen is needed for every cell in the body to function normally.

The causes of iron deficiency are:

• Blood loss
• Poor absorption of iron by the body
• Too little iron in the diet

It can also be related to lead poisoning in children.

Anemia develops slowly after the normal iron stores in the body and bone marrow have run out. In general, women have smaller stores of iron than men because they lose more through menstruation. They are at higher risk for anemia than men.

In men and postmenopausal women, anemia is usually caused by gastrointestinal bleeding due to:

• Certain types of cancer (esophagus, stomach, colon)
• Esophageal varices
• Long-term use of aspirin or nonsteroidal anti-inflammatory medications (NSAIDS)
• Peptic ulcer disease

Iron deficiency anemia may also be caused by poor absorption of iron in the diet, due to:

• Celiac disease
• Crohn's disease
• Gastric bypass surgery
• Taking antacids

Other causes of iron deficiency anemia include:

• Heavy, long, or frequent menstrual bleeding
• Not receiving enough iron in the diet (for example, if you are a strict vegetarian)

Adults at high-risk for anemia include:

• Those who use aspirin, ibuprofen, or arthritis medicines for a long time
• Women who are pregnant or breastfeeding who have low iron levels
• Seniors
• Women of child-bearing age

Symptoms

• Blue color to whites of the eyes
• Brittle nails
• Decreased appetite (especially in children)
• Fatigue
• Headache
• Irritability
• Pale skin color
• Shortness of breath
• Sore tongue
• Unusual food cravings (called pica)
• Weakness

Note: There may be no symptoms if the anemia is mild.

Signs and tests

• Fecal occult blood test
• Hematocrit and hemoglobin (red blood cell measures)
• Iron binding capacity (TIBC) in the blood
• RBC indices
• Serum ferritin
• Serum iron level

Treatment

The cause of the iron deficiency must be found, especially in older patients who face the greatest risk for gastrointestinal cancers.

Iron supplements (ferrous sulfate) are available. For the best iron absorption, take these supplements with an empty stomach. However, many people cannot tolerate this and may need to take the supplements with food.

Patients who cannot tolerate iron by mouth can take it through a vein (intravenous) or by an injection into the muscle.

Milk and antacids may interfere with the absorption of iron and should not be taken at the same time as iron supplements. Vitamin C can increase absorption and is essential in the production of hemoglobin.

Pregnant and breastfeeding women will need to take extra iron because their normal diet usually will not provide the required amount.

The hematocrit should return to normal after 2 months of iron therapy. However, iron should be continued for another 6 - 12 months to replenish the body's iron stores in the bone marrow.

Iron-rich foods include:

• Eggs (yolk)
• Fish
• Legumes (peas and beans)
• Meats (liver is the highest source)
• Poultry
• Raisins
• Whole-grain bread

Support Groups

Expectations (prognosis)

With treatment, the outcome is likely to be good. Usually, blood counts will return to normal in 2 months.

Complications

There are usually no complications. However, iron deficiency anemia may come back. Get regular follow-ups with your health care provider.

Children with this disorder may be more likely to get infections.

Calling your health care provider

Call for an appointment with your health care provider if:

• You have symptoms of this disorder
• You notice blood in your stool

Prevention

Everyone's diet should include enough iron. Red meat, liver, and egg yolks are important sources of iron. Flour, bread, and some cereals are fortified with iron. If you aren't getting enough iron in your diet (uncommon in the United States), take iron supplements.

During periods when you need extra iron (such as pregnancy and breastfeeding), increase the amount of iron in your diet or take iron supplements.

References

Mabry-Hernandez IR. Screening for iron deficiency anemia--including iron supplementation for children and pregnant women. Am Fam Physician. 2009 May 15;79(10):897-8.

Alleyne M, Horne MK, Miller JL. Individualized treatment for iron-deficiency anemia in adults. Am J Med. 2008;121:943-948.

Brittenham G. Disorders of Iron Metabolism: Iron Deficiency and Iron Overload. In: Hoffman R, Benz EJ, Shattil SS, et al, eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 36.