Text B. Iron Deficiency Anemia

Many nutrients are needed for red blood cell production. The most critical are iron, vitamin B12, and folic acid, but the body also needs trace quantities of vitamin C, riboflavin, and copper, as well as a proper balance of hormones, especially erythropoietin (a hormone that stimulates red blood cell production). Without these nutrients and hormones, red blood cell production is slow and inadequate, and the cells may be deformed and unable to carry oxygen adequately. Chronic disease also may lead to decreased red blood cell production.

The body recycles iron: when red blood cells die, the iron in them is returned to the bone mar­row to be used again in new red blood cells. The body loses large amounts of iron only when red blood cells are lost through bleeding, causing a deficiency of iron. Iron deficiency is one of the most common causes of anemia, and blood loss is virtually the only cause of iron deficiency in adults. A diet low in iron may cause a deficiency in infants and small children, who need more iron because they are growing. In men and postmenopausal women, iron deficiency usually indicates bleeding in the gastrointestinal tract. Monthly menstrual bleeding may cause iron deficiency in premenopausal women.

Normal dietary iron intake usually can't com­pensate for iron loss from chronic bleeding, and the body has a very small iron reserve. Conse­quently, lost iron must be replaced with supple­ments. Because a developing fetus uses iron, pregnant women also take iron supplements.

 

How Iron Deficiency Anemia Develops

Iron deficiency anemia usually develops gradually, in stages. Symptoms develop in the later stages. Stage 1 Iron loss exceeds intake, depleting iron reserves, primarily in bone marrow. Blood levels of ferritin (a protein that stores iron) progressively decrease. Stage 2 Because depleted iron reserves can't meet the needs of developing red blood cells, fewer red blood cells are produced. Stage 3 Anemia begins to develop. Early in this stage, the red blood cells appear normal, but there are fewer of them. Hemoglobin levels and hematocrit are reduced.

Stage 4 The bone marrow tries to compensate for the lack of iron by speeding up cell division and producing very small (microcytic) red blood cells, which are typical of iron deficiency anemia. Stage 5 As iron deficiency and anemia progress, the symptoms of iron deficiency may develop and symptoms of anemia worsen.

Symptoms

Anemia ultimately leads to fatigue, shortness of breath, an inability to exercise, and other symptoms. Iron deficiency may produce its own symptoms, such as pica (a craving for nonfoods such as ice, dirt, or pure starch), tongue irritation (glossitis), and cracks at the sides of the mouth (cheilosis) and in the fingernails, which have a spoonlike deformity (koilonychia).

Diagnosis

Blood tests are used to diagnose anemia. Usu­ally, a person who has anemia is tested for iron deficiency. Iron levels can be measured in the blood. Levels of iron and transferrin (the protein that carries iron when it isn't inside red blood cells) are measured and compared. If less than 10 percent of the transferrin is saturated with iron, iron deficiency is likely. However, the most sen­sitive test for iron deficiency is measuring the blood level of ferritin (a protein that stores iron). A low level of ferritin indicates iron deficiency. However, sometimes ferritin levels are normal or high despite iron deficiency because they can be artificially increased by liver damage, inflamma­tion, infection, or cancer.

Occasionally, more sophisticated tests are needed to make the diagnosis. The most specific test is a bone marrow examination in which a sample of cells is examined under a microscope to determine their iron content.

Treatment

Because excessive bleeding is the most com­mon cause of iron deficiency, the first step is to locate its source and stop the bleeding. Drugs or surgery may be needed to control excessive men­strual bleeding, repair a bleeding ulcer, remove a polyp in the colon, or treat bleeding from the kidneys.

Generally, treatment also includes replacing the lost iron. Most iron tablets contain ferrous iron sulfate, iron gluconate, or a polysaccharide. Iron tablets are absorbed best when taken 30 minutes before meals. In general, one iron tablet a day is sufficient, but occasionally two are needed. Because the intestine's ability to absorb iron is limited, larger doses are wasted and are likely to cause indigestion and constipation. Iron almost always turns stools black—a normal, harmless side effect.

Correcting iron deficiency anemia with iron supplements usually takes 3 to 6 weeks, even after the bleeding has stopped. Once the anemia is cor­rected, a person should continue to take iron sup­plements for 6 months to replenish the body's reserves. Blood tests are usually performed pe­riodically to ensure that the person's iron supply is sufficient and that the bleeding has stopped.

Rarely, iron must be given by injection. Iron injections are reserved for people who can't tolerate iron tablets or who continue to lose large amounts of blood from ongoing bleeding. Whether iron is given by injections or tablets, recovery time from anemia is the same.

 

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