Anemia of Chronic Disease
What is anemia of chronic disease?
Anemia of chronic disease refers to having low levels of red blood cells as a result of autoimmune diseases (diseases in which the body’s immune system attacks joints and/or body organs) or other chronic illnesses. Chronic diseases are those that last longer than 3 months. This condition is also called anemia of inflammation or anemia of inflammation and chronic disease (AI/ACD).
How common is anemia of chronic disease?
It is the second most common type of anemia, after anemia caused by a deficiency of iron.
Who is at risk for developing this condition?
The most common diseases that can cause anemia are:
- Any type of infection
- Chronic kidney disease (Nearly every patient with this type of disease will be get anemia because kidneys make erythropoietin (EPO), a hormone that controls the production of red blood cells in the bone marrow.)
- Autoimmune diseases
- Rheumatoid arthritis, a chronic inflammation of joints
- Systemic lupus erythematosus (or lupus), tissue damage from an immune system attack on the body
- Vasculitis, an inflammation of blood vessels
- Sarcoidosis, an inflammatory disease that commonly affects the lung and lymph glands, most likely caused by an abnormal immune response
- Inflammatory bowel disease (Crohn’s disease and ulcerative colitis), which affects the intestines
- Chronic rejection of a transplanted organ
- Heart failure
Symptoms and Causes
What causes anemia of chronic disease?
Chronic diseases may cause changes in red blood cells, the oxygen-carrying blood cells made by bone marrow. These changes can cause red blood cells to die sooner and slow down their production.
In anemia of chronic disease, the iron that is normally recycled from old red blood cells to help make new red blood cells is retained within a system of cells called macrophages. This limits the amount of iron available to help create new red blood cells.
In addition, the way that iron is metabolized within cells is impaired. (Metabolism is a series of organized chemical reactions needed by the body to survive.)
What are the symptoms of anemia of chronic disease?
The symptoms are similar to those caused by iron-deficiency anemia and include:
- Feeling tired or weak
- Having pale skin
- Having shortness of breath
- Being dizzy or feeling faint
- Rapid heartbeat
- Having headaches
Some people have no symptoms. Some people have symptoms only when they are exercising.
Diagnosis and Tests
How is anemia of chronic disease diagnosed?
The symptoms of the disease causing the anemia may mask the symptoms of the anemia itself, so doctors will want to perform a blood test.
The test looks for a low level of hemoglobin. This substance is the red pigment in the blood that carries oxygen. A normal hemoglobin level is 12.3-15.3 g/dL for adult women and 14-17.5 g/dL for adult men. A fingerstick test can be used to measure hemoglobin.
Most important, the blood test will reveal a low serum iron in a person with anemia. Serum is a liquid part of blood.
The blood test may also reveal:
- A reticulocyte count that is low (reticulocytes are immature red blood cells)
- A low total iron binding capacity
- A high serum ferritin level
- An increase in sedimentation rate from inflammatory proteins released into the blood
Erythropoietin (EPO) levels may be measured if your hemoglobin level is less than 10 g/dL.
A bone marrow biopsy may also be performed. The bone marrow biopsy is performed in an outpatient setting under either local anesthesia or light sedation and involves collecting a sample of bone marrow by inserting a needle into the pelvis. Increased iron stores in the bone marrow, in addition to a low serum iron level, indicate anemia of chronic disease.
Management and Treatment
How is anemia of chronic disease treated?
The anemia associated with anemia of chronic disease is usually mild. Treating the underlying disease that is causing the anemia is the first step to treating most forms of anemia of chronic disease. In many cases, treating these diseases will resolve the anemia and its symptoms. This strategy may not work for anemia caused by cancer and chronic kidney disease, however. Other treatment options may be necessary.
Blood transfusions may be used when the anemia is especially severe (hemoglobin < 8.0 g/dL). Transfusions are not used as a long-term therapy because of risks—such as iron overload and potential immune system side effects—that may increase the risk of getting an infection.
A synthetic form of EPO may be given by subcutaneous (under the skin) shots if EPO levels are reduced. You may also receive supplemental iron therapy if EPO is used as a treatment. If you are receiving EPO therapy, your hemoglobin levels will be checked every few weeks to see if it is helping. Usually, therapy is adjusted so that your hemoglobin levels fall in the 11-12 g/dL range.
There are also experimental treatments being studied.
Can anemia of chronic disease be prevented?
It may not be possible to prevent the anemia of chronic disease, but you might be able to help yourself by making some changes to your diet. You should make sure to get enough iron, folate, and vitamin B-12 (also called cobalamin). Some foods you could choose include chicken or turkey, beans, spinach, fortified breakfast cereals, and enriched bread.
Outlook / Prognosis
What is the prognosis for someone with anemia of chronic disease?
Treating the disease that causes the anemia usually means that the anemia will be resolved. You should always let your provider know if symptoms, like fatigue, return.