The Facts
The blood that circulates throughout the body performs a number of critical functions. It delivers oxygen, removes carbon dioxide, and carries life-sustaining nutrients. By acting as the vehicle for long-distance messengers (such as hormones), blood helps the various parts of the body communicate with each other. This is carried out by blood cells, working in partnership with the liquid part of the blood (plasma). Most of the cells that make up your blood are red blood cells (erythrocytes). White blood cells (leukocytes), which defend the body against foreign matter, including bacteria, viruses, and fungi, are also present.
Anemia occurs when there aren't enough healthy red blood cells in the blood. Most anemias are more of a symptom than a disease, and can be the result of a variety of health conditions. With any form of anemia, it's important to find the cause before treatment begins.
Anemia of chronic disease develops as a result of a long-term infection or disease. Usually, it does not cause severe anemia. Anemia of chronic disease is thought to be the second most common type of anemia, next to iron deficiency anemia. Although anemia of chronic disease is most often seen in people who have a chronic disease, it can also appear in young children who only have a simple ear infection. Anemia of chronic disease may go unnoticed and untreated because the attention is centered on the disease that is causing it.
In the past, it was believed that anemia of chronic disease was associated only with infections such as syphilis and tuberculosis. Over the last 30 years, connections between the condition and diseases such as rheumatoid arthritis, connective tissue disorders, chronic infection, trauma, or cancer have also been established.
Causes
Although the exact cause of anemia of chronic disease is not known, it is related to the effects of chronic diseases on the red blood cells. These conditions cause a number of changes in the body's red blood cells. The lifespan of red blood cells becomes shorter, production of new red blood cells in the bone marrow slows down, and iron is "withheld" so that it cannot be used to make new red blood cells. Normally the body recycles iron from "old" red blood cells and uses it to make new ones. In anemia of chronic disease, the body does not recycle iron as easily, so it is "held up" in the old red blood cells.
The following are examples of conditions that can cause anemia of chronic disease:
- chronic infections (e.g., tuberculosis, lung abscess, and endocarditis)
- autoimmune diseases or diseases with inflammation (e.g., rheumatoid arthritis, lupus, ulcerative colitis, Crohn's disease, giant cell [temporal] arteritis)
- cancers (e.g., Hodgkin's disease, lung cancer, breast cancer)
