It is also known as anemia of inflammation.
It is a condition that can be associated with many different underlying disorders, including chronic diseases such as cancer, certain infections, and autoimmune and inflammatory diseases, such as rheumatoid arthritis or lupus.
Anemia is characterized by low circulating red blood cells or hemoglobin (the part of red blood cells that carries oxygen). It is generally a mild or moderate condition.
In mild cases, anemia may not be associated with any symptoms, or it may cause fatigue, pale skin, and lightheadedness. The underlying mechanisms that cause chronic anemia are complex and not fully understood.
Signs and symptoms of chronic anemia
Chronic anemia varies in severity from one person to another. Affected individuals can develop various symptoms such as fatigue, pale skin, lightheadedness, shortness of breath, fast heartbeat, irritability, chest pain, and additional findings.
These symptoms can occur in anyone with a comparable degree of anemia. In most cases, the symptoms associated with the underlying disease generally precede the symptoms of mild or moderate anemia.
Chronic anemia can be severe and cause more severe complications in rare cases.
The exact cause of chronic anemia can vary. Generally, several processes occur at the same time. Anemia can be caused by a slight shortening of the average survival of red blood cells.
Also, red blood cells ( erythropoiesis ) or erythropoietin (a hormone that stimulates the production of red blood cells) can be affected. Red blood cells carry oxygen to the body. The exact cause of chronic anemia may depend on the underlying condition.
For example, cancer cells can secrete certain substances that damage or destroy immature red blood cells.
In some cases, cancer cells or infectious diseases can infiltrate the bone marrow and the soft, spongy material found in long bones where blood cells form.
Researchers have found that people with chronic anemia also have an imbalance in the distribution of iron in the body and cannot use iron to create new blood cells despite having sufficient or high levels of iron stored in their tissues.
Iron is a critical mineral found in every cell in the body and is essential for the body to function and grow properly. This mineral is found in many foods, such as red meat, poultry, eggs, and vegetables.
Iron levels must stay in a specific range within the body. Otherwise, they can cause anemia (low functional iron levels) or damage to affected organs (abnormally high iron levels in particular tissues).
Iron is needed to make hemoglobin, the part of a red blood cell that carries oxygen.
A key finding in chronic anemia is increased iron uptake and retention within specific cells, leading to reduced amounts of available iron for hemoglobin production.
Lack of functional iron hinders the development of hemoglobin, which in turn reduces the amount of oxygen delivered throughout the body (anemia).
Researchers believe that the immune system, which constantly remains active in people with chronic diseases, produces substances that influence the development, storage, and transport of iron within the body.
Cells in the immune system produce cytokines, specialized proteins that stimulate or inhibit the function of other immune system cells.
Hepcidin, a hormone produced in the liver that helps regulate the metabolism and transport of iron within the body, plays a vital role in developing chronic anemia.
Researchers believe that a specific cytokine known as interleukin 6 (IL-6) stimulates hepcidin production in most cases. However, hepcidin can also be produced in response to inflammation by pathways that do not involve IL-6.
Too much hepcidin causes too much iron to be trapped within cells, reducing the amount of iron available to produce hemoglobin, resulting in anemia.
Most researchers believe that hepcidin is a crucial factor influencing the development of chronic anemia.
Populations are affected by chronic anemia.
Chronic anemia affects men and women in equal proportions. People of any age who have a chronic inflammatory condition can develop the disease.
The exact incidence of chronic anemia is unknown, and some researchers believe it is underreported or often unrecognized. Iron deficiency anemia is the second most common cause of anemia in the United States.
Iron deficiency anemia is a common condition in which individuals have insufficient iron levels in the body and cannot produce enough red blood cells to carry oxygen throughout the body.
Iron deficiency anemia can cause various symptoms, including fatigue, weakness, pale skin, shortness of breath, headaches, and lightheadedness.
Additional symptoms in people with iron deficiency anemia include cold hands or feet, irritability, irregular heartbeat, and increased susceptibility to developing infections.
Iron deficiency anemia is caused by insufficient iron levels in the body, resulting from blood loss. This diet supplies little iron or the inability to absorb sufficient amounts of iron from the gastrointestinal tract.
Chronic anemia and iron deficiency anemia can be confused because both are associated with decreased circulating iron.
The anemia seen in chronic kidney disease is usually caused by erythropoietin deficiency due to kidney cell damage.
However, some patients with kidney disease also have inflammation or infections, and chronic anemia can be part of their anemia.
The diagnosis of chronic anemia is based on identifying characteristic symptoms, a detailed history of the patient, a thorough clinical evaluation, and a variety of specialized tests.
Such tests can measure levels of certain substances in the body, including hemoglobin levels, serum iron levels, total iron-binding capacity, global red blood cell count, or regular or increased levels of ferritin in the blood.
Ferritin is a protein that binds to iron and is used as an indicator of the body’s iron stores in blood plasma. Another test that can be performed measures transferrin saturation.
Transferrin is a protein that participates in iron transport from the intestines to the bloodstream.
Methods have been developed to allow reliable measurement of hepcidin in plasma but are not currently available or approved for use in diagnosing anemia of chronic disease.
Standard therapies for chronic anemia
Treatment of chronic anemia is directed at the underlying disease. If the underlying condition is flourishing, the anemia usually improves or resolves entirely without immediate treatment.
Efforts to treat anemia by correcting the iron imbalance in the body with therapies such as oral iron supplements or vitamins have generally proven ineffective.
Such efforts can hurt overall health. For example, iron supplementation is controversial because certain diseases, such as cancer, use iron to grow and spread, and certain infections use iron for food.
More research is needed to understand the complex mechanisms that ultimately result in chronic anemia and what role traditional therapies for anemia and iron imbalance have in treating affected people.
In rare cases associated with severe anemia, blood transfusions or treatment with medications that stimulate the production of erythropoietin (a hormone that stimulates the production of red blood cells) may be necessary.