Iron deficiency anemia

Causes

Iron deficiency anemia is the most common form of anemia.

Red blood cells bring oxygen to the body's tissues. Healthy red blood cells are made in your bone marrow. Red blood cells move through your body for 3 to 4 months. Parts of your body then remove old blood cells.

Iron is a key part of red blood cells. Without iron, the blood cannot carry oxygen effectively. Your body normally gets iron through your diet and by re-using iron from old red blood cells.

You get iron deficiency anemia when your body's iron stores run low. You can get iron deficiency if:

• You lose more blood cells and iron than your body can replace
• Your body does not do a good job of absorbing iron
• Your body is able to absorb iron, but you are not eating enough foods with iron in them
• Your body needs more iron than normal (such as if you are pregnant or breastfeeding)

Iron loss can be due to bleeding. Common causes of bleeding are:

• Heavy, long, or frequent menstrual periods
• Cancer in the esophagus, stomach, or colon
• Esophageal varices
• The use of aspirin, ibuprofen, or arthritis medicines for a long time, which can cause gastrointestinal bleeding
• Peptic ulcer disease

The body may not absorb enough iron in the diet due to:

• Celiac disease
• Crohn's disease
• Gastric bypass surgery
• Taking too many antacids that contain calcium

You may not get enough iron in the diet if:

• You are a strict vegetarian
• You are an older adult and do not eat a full diet

Symptoms

You may have no symptoms if the anemia is mild.

Most of the time, symptoms are mild at first and develop slowly. Symptoms may include:

• Feeling grumpy
• Feeling weak or tired more often than usual, or with exercise
• Headaches
• Problems concentrating or thinking

As the anemia gets worse, symptoms may include:

• Blue color to the whites of the eyes
• Brittle nails
• Light-headedness when you stand up
• Pale skin color
• Shortness of breath
• Sore tongue

Symptoms of the conditions that cause iron deficiency anemia include:

• Dark, tar-colored stools or blood
• Heavy menstrual bleeding (women)
• Pain in the upper belly (from ulcers)
• Weight loss (in people with cancer)

Exams and Tests

To diagnose anemia, your doctor may order these blood tests:

• Hematocrit and hemoglobin (red blood cell measures)
• RBC indices

Tests to check iron levels in your blood include:

• Bone marrow exam (rare)
• Iron binding capacity (TIBC) in the blood
• Serum ferritin
• Serum iron level

Tests that may be done to look for the cause of iron deficiency:

• Colonoscopy
• Fecal occult blood test
• Upper endoscopy

Treatment

Taking iron supplementsand eating iron-rich foods are important parts of treating iron deficiency anemia. However, you and your health care provider must first search for the cause of your anemia.

Iron supplements (most often ferrous sulfate) are needed to build up the iron stores in your body. Most of the time, your doctor or nurse will measure your iron levels before starting supplements.

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

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

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

Iron-rich foods include:

• Chicken and turkey
• Dried lentils, peas, and beans
• Eggs (yolk)
• Fish
• Meats (liver is the highest source)
• Peanut butter
• Soybeans
• Whole-grain bread

Other sources include:

• Oatmeal
• Raisins, prunes, and apricots
• Spinach, kale, and other greens

Outlook (Prognosis)

With treatment, the outcome is likely to be good. However, it does depend on the cause. Usually, blood counts will return to normal in 2 months.

When to Contact a Medical Professional

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.

Alternative Names

Anemia - iron deficiency

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..

Update Date: 2/7/2012

Updated by: Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.