Iron deficiency anemia
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Reticulocytes |
Blood cells |
Alternative names
Anemia - iron deficiency
Definition
Iron deficiency anemia is a
decrease in the red cells of the blood caused
by too little iron. (See also Iron-deficiency
anemia - children.)
Causes
and risks
Iron deficiency anemia is the most common form
of anemia. Approximately 20% of women, 50% of
pregnant women, and 3% of men are iron deficient.
Iron is an essential component of hemoglobin,
the oxygen carrying pigment in the blood. Iron
is normally obtained through the food in the
diet and by the recycling of iron from old red
blood cells.
The causes of iron deficiency are too little
iron in the diet, poor absorption of iron by
the body, and loss of blood (including from
heavy menstrual bleeding). It can also be related
to lead poisoning in children.
Anemia develops slowly after the normal stores
of iron have been depleted in the body and in
the bone marrow. Women, in general, have smaller
stores of iron than men and have increased loss
through menstruation, placing them at higher
risk for anemia than men.
In men and postmenopausal women, anemia is
usually due to gastrointestinal blood loss associated
with ulcers, the use of aspirin or nonsteroidal
anti-inflammatory medications (NSAIDS), or colon
cancer.
High-risk groups include: women of child-bearing
age who have blood loss through menstruation;
pregnant or lactating women who have an increased
requirement for iron; infants, children, and
adolescents in rapid growth phases; and people
with a poor dietary intake of iron through a
diet of little or no meat or eggs for several
years. Risk factors related to blood loss are
peptic ulcer disease, long term aspirin use,
or colon cancer.
Prevention
Dietary sources of iron are
red meat, liver, and egg yolks. Flour, bread,
and some cereals are fortified with iron. If the
diet is deficient in iron, iron should be taken
orally. During periods of increased requirements
such as pregnancy and lactation, increase dietary
intake or take iron supplements.
Symptoms
- Pale skin color (pallor)
- Fatigue
- Irritability
- Weakness
- Shortness of breath
- Sore tongue
- Brittle nails
- Unusual food cravings (called pica)
- Decreased appetite (especially in children)
- Headache - frontal
- Blue tinge to sclerae (whites of eyes)
Note: There may be no symptoms if anemia is mild.
Signs
and tests
- Low hematocrit and hemoglobin (red
blood cell measures)
- Small red blood cells
- Low serum ferritin (serum iron) level
- High iron binding capacity (TIBC) in the
blood
- Blood in stool (visible or microscopic)
Treatment
Identification of the cause of the deficiency
is essential, particularly in older patients
who are most susceptible to intestinal cancer.
Oral iron supplements are in the form of ferrous
sulfate. The best absorption of iron is on an
empty stomach, but many people are unable to
tolerate this and may need to take it with food.
Milk and antacids may interfere with 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.
Supplemental iron is needed during pregnancy
and lactation because normal dietary intake
rarely supply the required amount.
The hematocrit should return to normal after
2 months of iron therapy, but the iron should
be continued for another 6 to 12 months to replenish
the body’s iron stores, contained mostly in
the bone marrow.
Intravenous or intra-muscular iron is available
for patients when iron taken orally is not tolerated.
Iron-rich foods include raisins, meats (liver
is the highest source), fish, poultry, eggs
(yolk), legumes (peas and beans), and whole
grain bread.
Prognosis
With treatment, the outcome
is likely to be good. In most cases the blood
counts will return to normal in 2 months. |