Anemia - Introduction

Pica. Pica is the craving for non-food substances such as ice, starch, or clay. It is a possible cause of iron deficiency, particularly in those who eat clay or starch, which interferes with iron absorption in the stomach. To complicate matters, pica (particularly ice cravings) may also be a symptom, rather than a cause, of anemia.

Hookworm. Hookworm infects about one billion people worldwide. It is a major cause of anemia in areas where it occurs.

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Impaired Absorption of Iron. Certain intestinal diseases (e.g., inflammatory bowel disease, celiac disease) or surgical procedures that affect the gastrointestinal tract can impair the ability of the intestine to absorb iron. (Such conditions also often impair folic acid absorption as well.)

Click the icon to see an image of inflammatory bowel disease.

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Genetic Causes. Some people are born with iron deficiency. Certain cases may be due to a mutation of the Nramp2 gene, which regulates a protein responsible for delivering iron to the cells.

Anemia of Chronic Disease (ACD)

Anemia of chronic disease (ACD), also called anemia of chronic inflammation (ACI), is a common condition associated with a wide variety of diseases associated with a persistent inflammatory process. It can be very severe and require transfusions.

The Inflammatory Process and ACD. ACD is not completely understood. In ACD, iron is not efficiently recycled from blood cells, red blood cell survival is reduced, and there is impaired response to erythropoietin, the hormone that acts in the bone marrow to increase the production of red blood cells. (Abnormal function and low levels of erythropoietin, in fact, may be the most important factor in ACD, with iron insufficiencies being a consequence.)

The process leading to it may occur in the following way:

The immune system activates white blood cells and releases various compounds during times of infection that are intended to fight invaders and heal wounds. Such an event causes an inflammatory state in the areas of the attack.
White blood cells called macrophages release small put powerful proteins known as cytokines, which are critical in the development of ACD. Cytokines are indispensable for healing. However, often in chronic and inflammatory diseases cytokines are overproduced and cause serious tissue injury and in some cases, even organ damage. In the case of ACD, they prevent production of erythropoietin, the hormone that acts in the bone marrow to increase the production of red blood cells. Specific cytokines implicated in anemia are interleukin 1 (IL-1), tumor necrosis factor (TNF), and interferons.
As part of this process, mechanisms prevent the release of recycled iron needed in the bone marrow for the manufacturing of red blood cells. Iron absorption in the intestines is also blocked. Theoretically, this is a protective measure, since iron may help infectious organisms proliferate. In such cases, iron stores are high, but the usable iron in circulation is low.
Researchers have identified a peptide called hepcidin, which prevents iron absorption in the intestine as well as blocks the release of iron by immune factors for red blood cell production. Some experts believe high levels of the peptide may play a central role in preventing the release of iron during infection and inflammatory states and is critical in ACD.