Anaemia caused by chronic diseases
Chronic (long-term) illnesses can cause anaemia. Often, anaemia caused by chronic diseases goes undetected until a routine test such as a full blood count reveals abnormal results. Several follow-up tests may be used to determine the underlying cause. There are many chronic conditions and diseases that can result in anaemia. Some examples of these include:
- Kidney disease — red blood cells are produced by the bone marrow in response to a hormone called erythropoietin, made primarily by the kidneys. Chronic kidney disease can cause anaemia resulting from too little production of this hormone; the anaemia can be treated by giving erythropoietin injections.
- Inflammatory conditions — whenever there are chronic diseases that stimulate the body’s inflammatory system, the ability of the bone marrow to respond to erythropoietin is decreased. For example, rheumatoid arthritis (a severe form of joint disease caused by the body attacking its own joints, termed an autoimmune disease) can cause anaemia by this mechanism.
- Other diseases that can produce anaemia in the same way as inflammatory conditions include chronic infections (such as with HIV or tuberculosis (TB), cancer and cirrhosis.
A number of tests may be used as follow up to abnormal results of initial tests such as a full blood count and film to determine the underlying cause of chronic anaemia. Some of these may include:
- Reticulocyte count
- Serum transferrin receptor can assist with the differentiation between iron deficiency anaemia and anaemia of chronic disease. (Serum ferritin may be elevated due to acute phase reactants even when the patient is iron deficient).
- Tests for inflammation such as CRP
- Tests for infections such as HIV and TB.
Treatment of anaemia due to chronic conditions usually involves determining and/or resolving the underlying disease. Blood transfusions may be used to treat the condition in the short term.