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Anemia and Arthritis

Distinguishing Anemia of Chronic Disease and Iron Deficiency Anemia

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Updated July 22, 2013

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Anemia is a condition that occurs when the blood has an abnormally low number of red blood cells or amount of hemoglobin. Hemoglobin is an iron-rich protein that attaches to oxygen in the lungs so it can be transported to tissues throughout the body.

Anemia is not uncommon in people with inflammatory types of arthritis, such as rheumatoid arthritis. For example, anemia of chronic disease is a specific type of anemia which develops in response to inflammation. Anemia of chronic disease must be distinguished from other types of anemia, though, because treatment depends on the type.

Symptoms of Anemia

Common symptoms associated with anemia include fatigue, shortness of breath, dizziness, rapid heartbeat, irregular heartbeat, headache, cold hands, cold feet, pale or yellowish skin, and chest pain. A person with anemia may experience one or more of these symptoms. If there are no obvious signs or symptoms of anemia, the condition may go undetected until a blood test is performed.

Types of Anemia

Iron-deficiency anemia is the most common type of anemia. As its name suggests, this type of anemia develops when you lack a sufficient amount of iron in your body. Typically, blood loss is the reason for iron-deficiency anemia, but poor absorption of iron may also cause the condition.

Vitamin-deficiency anemia can develop when there are low levels of vitamin B12 or folic acid in the body. With B12 deficiency, often the vitamin is not well-absorbed. Pernicious anemia is one of many causes of B12 deficiency.

Aplastic anemia is a rare type of anemia that develops when the body stops producing sufficient numbers of red blood cells. Viral infections, exposure to toxic chemicals, autoimmune diseases, and certain drugs are considered possible causes.

Hemolytic anemia occurs when there is abnormal rupture of red blood cells within the bloodstream or in the spleen. Possible causes include mechanical reasons (e.g., aneurysm), infection, autoimmune disease, or congenital or inherited abnormalities (e.g., sickle cell anemia).

Anemia of chronic disease is an anemic condition that develops secondary to another medical condition. It may be associated with cancer, kidney disease, liver disease, thyroid disease, rheumatoid arthritis, or any condition that interferes with production of red blood cells.

Distinguishing Anemia of Chronic Disease From Iron-Deficiency Anemia

For people with inflammatory types of arthritis, it is important to distinguish between the two most common types of anemia which affect them - iron-deficiency and anemia of chronic disease. Many arthritis patients take an NSAID (nonsteroidal anti-inflammatory drug) as part of their treatment regimen. NSAIDS have been tied to an increased risk of gastrointestinal bleeding. Patients and doctors must be aware of the risk, monitoring symptoms as well as periodic blood tests to check blood counts. As previously stated, blood loss can be the underlying reason for iron-deficiency anemia.

With anemia of chronic disease, iron metabolism is altered. When inflammation is triggered by the immune system, iron metabolism in the body goes into defense mode, so to speak. When this occurs, there is a mild drop in hemoglobin, less iron is absorbed by the body, free iron in the body is stored in liver cells, and the ferritin level in serum increases.

Anemia of chronic disease does not progress. Generally, hemoglobin levels hover in a slightly lower than normal range, not typically lover than 9.5 mg/dl. In both iron-deficiency anemia and anemia of chronic disease, serum iron is low. Small red cells may be observed microscopically in either condition, but they are more typical of iron-deficiency anemia. Transferrin, a protein that transports iron, is elevated in iron-deficiency anemia -- a sign that the body needs more iron. The total iron-binding capacity (TIBC), an indirect measurement of transferrin, is low in anemia of chronic disease -- a sign that there is enough iron but it is not readily available. TIBC is usually high when iron stores are decreased and low when iron stores are elevated. In iron-deficiency anemia, TIBC is typically in excess of 400 mcg/dl because iron stores are low.

Serum ferritin is often used to distinguish between the two types of anemia but it can be elevated in the presence of inflammation. With an inflammatory condition, serum ferritin may be raised to normal levels, even if iron-deficiency anemia exists. It can be confusing. The serum transferrin receptor test can help sort it out because it is less affected by inflammation. In iron-deficiency anemia, serum transferrin receptor will be high. In anemia of chronic disease, serum transferrin receptor is usually low or on the low side of normal.

Anemia of chronic disease is not treated with iron supplementation. Additional iron can actually be harmful, depending on the underlying chronic disease. Iron supplementation may be indicated in iron-deficiency anemia, however. Also, if there is bleeding, the source of bleeding should be identified.

Sources:

Anemia. American Society of Hematology. Accessed 7/13/13.
http://www.hematology.org/patients/blood-disorders/anemia/5225.aspx

Iron Disorders Institute. Anemia of Chronic Disease. Accessed 7/13/13.
http://www.irondisorders.org/anemia-of-chronic-disease

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