Iron-deficiency anemia

Iron-deficiency anemia is anemia caused by a lack of iron. Anemia is defined as a decrease in the number of red blood cells or the amount of hemoglobin in the blood. When onset is slow, symptoms are often vague, such as feeling tired, weak, short of breath, or having decreased ability to exercise. Anemia that comes on quickly often has more severe symptoms, including confusion, feeling like one is going to pass out or increased thirst. Anemia is typically significant before a person becomes noticeably pale. Children with iron deficiency anemia may have problems with growth and development. There may be additional symptoms depending on the underlying cause. Iron-deficiency anemia is caused by blood loss, insufficient dietary intake, or poor absorption of iron from food. Sources of blood loss can include heavy periods, childbirth, uterine fibroids, stomach ulcers, colon cancer, and urinary tract bleeding. Poor absorption of iron from food may occur as a result of an intestinal disorder such as inflammatory bowel disease or celiac disease, or surgery such as a gastric bypass. In the developing world, parasitic worms, malaria, and HIV/AIDS increase the risk of iron deficiency anemia. Diagnosis is confirmed by blood tests. Iron deficiency anemia can be prevented by eating a diet containing sufficient amounts of iron or by iron supplementation. Foods high in iron include meat, nuts, and foods made with iron-fortified flour. Treatment may include dietary changes, iron supplements, and dealing with underlying causes, for example, medical treatment for parasites or surgery for ulcers. Supplementation with vitamin C may be recommended due to its potential to aid iron absorption. Severe cases may be treated with blood transfusions or iron infusions. Iron-deficiency anemia affected about 1.48 billion people in 2015. A lack of dietary iron is estimated to cause approximately half of all anemia cases globally. Women and young children are most commonly affected. In 2015, anemia due to iron deficiency resulted in about 54,000 deaths – down from 213,000 deaths in 1990.

Signs and symptoms

Iron-deficiency anemia may be present without a person experiencing symptoms. It tends to develop slowly; therefore, the body has time to adapt, and the disease often goes unrecognized for some time. If symptoms present, patients may present with the sign of pallor (reduced oxyhemoglobin in skin or mucous membranes), and the symptoms of feeling tired, weak, dizziness, lightheadedness, poor physical exertion, headaches, decreased ability to concentrate, cold hands and feet, cold sensitivity, increased thirst and confusion. None of these symptoms (or any of the others below) are sensitive or specific. In severe cases, shortness of breath can occur. Pica may also develop; of which consumption of ice, known as pagophagia, has been suggested to be the most specific for iron deficiency anemia. Other possible symptoms and signs of iron-deficiency anemia include:

Child development Iron-deficiency anemia is associated with poor neurological development, including decreased learning ability and altered motor functions. This is because iron deficiency impacts the development of the cells of the brain called neurons. When the body is low on iron, the red blood cells get priority on iron, and it is shifted away from the neurons of the brain. Exact causation has not been established, but there is a possible long-term impact from these neurological issues.

Cause A diagnosis of iron-deficiency anemia requires further investigation into its cause. It can be caused by increased iron demand, increased iron loss, or decreased iron intake. Increased iron demand often occurs during periods of growth, such as in children and pregnant women. For example, during stages of rapid growth, babies and adolescents may outpace their dietary intake of iron, which can result in deficiency in the absence of disease or a grossly abnormal diet. Iron loss is typically from blood loss. One example of blood loss is by chronic gastrointestinal blood loss, which could be linked to a possible cancer. In women of childbearing age, heavy menstrual periods can be a source of blood loss, causing iron-deficiency anemia. People who do not consume much iron in their diet, such as vegans or vegetarians, are also at increased risk of developing iron deficiency anemia.

Parasitic disease The leading cause of iron-deficiency anemia worldwide is a parasitic disease known as a helminthiasis caused by infestation with parasitic worms (helminths); specifically, hookworms. The hookworms most commonly responsible for causing iron-deficiency anemia include Ancylostoma duodenale, Ancylostoma ceylanicum, and Necator americanus. The World Health Organization estimates that approximately two billion people are infected with soil-transmitted helminths worldwide. Parasitic worms cause both inflammation and chronic blood loss by binding to a human's small-intestinal mucosa, and through their means of feeding and degradation, they can ultimately cause iron-deficiency anemia.

Blood loss Red blood cells contain iron, so blood loss also leads to iron loss. There are several causes of blood loss, including menstrual bleeding, gastrointestinal bleeding, stomach ulcers, and bleeding disorders. The bleeding may occur quickly or slowly. Slow, chronic blood loss within the body – such as from a peptic ulcer, angiodysplasia, inflammatory bowel disease, a colon polyp or gastrointestinal cancer (e.g., colon cancer) – can cause iron-deficiency anemia.

Menstrual bleeding Menstrual bleeding is a common cause of iron deficiency anemia in women of childbearing age. Women with menorrhagia (heavy menstrual periods) are at risk of iron deficiency anemia because they are at a higher than normal risk of losing more iron during menstruation than is replaced in their diet. Most women lose about 40 mL of blood per cycle. Some birth control methods, such as pills and IUDs, may decrease the amount of blood and therefore iron lost during a menstrual cycle. Intermittent iron supplementation may be as effective a treatment in these cases as daily supplements and reduce some of the adverse effects of long-term daily supplements.

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