VERIFIED CONTENTAuthor: Dominika Wilk

Anemia resulting from chronic diseases is the second most common cause of a decrease in the level of hemoglobin and iron in the body, which results in anemia due to inflammation. This is not necessarily the result of iron deficiency anemia. See how to properly diagnose this type of ailment and how to treat it.

Oanemia in chronic diseaseswe say when iron deficiency in the body is not due to its malabsorption in the digestive system or deficiencies resulting from the diet, but when there is an imbalance the process of recovering iron from the body as a result of disease. Anemia, which occurs as a result of a chronic disease, is the result of ongoing inflammation in the body, and although the body has adequate amounts of iron that can be obtained, for example, to create hemoglobin, the body cannot use them.

What is anemia in chronic disease?

To understand how anemia develops as a result of a chronic disease, you should first understand how your body obtains iron. Contrary to appearances, the amount of iron that we obtain with the diet is only a fraction of the amount of this element that the body needs to produce, among others hemoglobin that is part of the erythrocytes (red blood cells that transport oxygen), or iodization of thyroid hormones, the production of many enzymes and proteins.

Considering thathumans absorb 5-10% of the iron consumed in food(the average intake is 10-15 mg per day), it can be estimated that it is less more 1 mg, with the demand a thousand times greater ( for the production of erythrocytes alone, 2500 mg of this element is needed ).

So where does the body get the amount of iron it needs? It obtains them in the process of recovering it, e.g. from dying erythrocytes. These erythrocytes are absorbed by macrophages and broken down there, e.g. for heme and biliverdin.

Hem is converted to iron ions and in a long transport process in which a protein (transferrin) is involved, it reaches the bone marrow, where new erythrocytes are formed.

For their production and maturationiron is necessary, so with disrupted transport and recovery of this element, anemia can occur (this is what happens in anemia resulting from chronic diseases).

Causes of anemia due to chronic diseases

The main obstacle to getting iron from the body in chronic diseases is a protein called hepcidin, which blocks macrophages from extracting iron and inhibits iron absorption from the gut. As a result of the pro-inflammatory cytokines that appear in inflammation, the concentration of hepcidin increases.

This effectively blocks the possibility of obtaining iron from the diet, as well as prevents the acquisition of iron from the tissues. Hepcidin causes, for example, that macrophages cannot give up iron, which they obtained as a result of decomposing the erythrocyte.

Another cause of anemia due to chronic disease is decreased production of erythropoietin, a hormone produced in the kidneys that stimulates the bone marrow to produce red blood cells.

This is due to the action of inflammatory cytokines, which may inhibit the production of erythropoietin in the kidneys or make the body less sensitive to it. If there is less erythropoietin, the amount of red blood cells produced will automatically decrease. The same will happen as a result of your insensitivity to this hormone.

Inflammation can also cause the red blood cells produced in the bone marrow to live shorter. They will also be captured faster by macrophages, which, however, due to the action of the aforementioned hepcidin, will not be able to release the iron obtained from them.

Another cause of anemia, especially in cancer, is infiltration of bone marrow cells. This displaces normal bone marrow tissues and, at the same time, reduces the production of red blood cells. Also, infection of the marrow cavity by microorganisms can result in a deficit of he althy bone marrow cells.

Anemia of chronic diseases (especially if they are inflammatory bowel diseases such as Crohn's disease or ulcerative colitis) may also result from hidden bleeding from the gastrointestinal tract. Then, as a result of the loss of an increased amount of blood, anemia may occur.

Diseases causing anemia in chronic diseases

Anemia in chronic diseases accompanies those conditions which cause inflammation in the human body. So they can be:

  • viral diseases (in children, even an ordinary viral infection can lead to anemia),
  • bacterial diseases, e.g. tuberculosis,
  • parasitic diseases,
  • fungal diseases,
  • autoimmune diseases,
  • connective tissue diseases, e.g. RA,
  • chronic kidney disease,
  • cancer.

Symptoms of anemia as a result of chronic diseases

The symptoms of anemia as a result of chronic disease are the same as with any other type of anemia. They mainly manifest themselves in:

  • weakening,
  • pale skin and mucous membranes,
  • fatigue,
  • concentration disorders,
  • headaches.

In addition, of course, it is accompanied by symptoms related to the occurrence of the underlying disease.

How to diagnose anemia in chronic diseases?

To distinguish anemia in chronic diseases from the second most common form of anemia - iron deficiency anemia, a series of tests should be performed to determine what is the main reason for the patient's weakness and malaise. Recommended laboratory tests are:

  • morphology with smear,
  • iron,
  • ferritin,
  • transferryna,
  • hepcidin,
  • CRP,
  • OB,
  • sTfR

Iron deficiency anemia and anemia resulting from chronic disease have decreased iron levels. However, they differ in the level of ferritin - a store of iron: iron deficiency anemia is reduced, and increased in chronic diseases.

The high rate of ferritin in chronic disease is due to the fact that it is also an acute phase protein that increases when inflammation occurs. This is why in iron deficiency anemia, CRP is also tested, which is also an acute phase protein.

When this index or ESR is elevated, then we have confirmation that the body is struggling with inflammation. In turn, transferrin, which is a negative protein of inflammation and at the same time an iron transporter, will decrease in chronic diseases (similarly to anemia resulting from iron deficiency).

Soluble Transferrin Receptor (sTfR) levels in chronic disease anemia will be normal, while iron deficiency anemia will be reduced. A protein (hepcidin) that blocks the release of iron stores will rise above normal in chronic disease, while in iron deficiency anemia it will remain at normal levels.

Table 1. Comparison of blood count parameters and iron metabolism indices in anemia of chronic diseases and iron deficiency anemia

Rated parametersAnemia of diseasechronicIron Deficiency Anemia
Hemoglobin concentrationmost often>8g / dl could be<8g/dl
MCV (mean red blood cell volume) / MCH (mean blood hemoglobin mass)normal or slightly loweredreduced
Iron concentrationreducedreduced
Transferrin saturationreducedreduced
Ferritin concentrationnormal or elevatedreduced
Soluble Transferrin Receptor (sTfR) concentrationin normelevated
Hepcidin concentrationelevatedreduced
Hemoglobin content in reticulocytes (CHr)normal or reducedreduced

Source: T. Jackowska, J. Wójtowicz, Anemia of chronic diseases, "Advances in medical science" 2014, vol. 27, No. 10B, p. 34

Treatment of anemia in chronic diseases

Restoring the proper level of iron in the body and regaining the proper functioning of iron metabolism depends primarily on the cure of the disease that causes the disorders.

Usually, in inflammatory diseases, especially kidney diseases, erythropoiesis stimulating factors (the process of multiplication and maturation of red blood cells in the bone marrow) are used, and sometimes iron is administered intravenously.

Contraindication to the administration of erythropoietin are, however:

  • stroke history,
  • active neoplastic disease ( although it depends on the case),
  • severe hypertension,
  • drug hypersensitivity,
  • selective red cell aplasia.

In turn, oral administration of iron usually does not make sense, as the process of absorption of this element from the intestines is difficult. Therefore, the most sensible path of treating anemia in chronic diseases is the elimination of inflammation accompanying chronic diseases, e.g. rheumatic disease.

Then there is a chance that the process of healing and recovering the appropriate iron parameters will be possible.

  • Iron deficiency - causes, symptoms, diet
  • Aplastic anemia. Types and symptoms of aplastic anemia

Category:

Cardiology