L’anemia is a relatively common health problem characterized by a lack of red blood cells. Red blood cells are cells found in the blood. They are used, among other things, to supply oxygen to tissues and organs.

People with anemia may feel weary et run out of steam more easily than usual, because their hearts have to work harder to supply their bodies with oxygen.

According to the World Health Organization, 25% of the world’s population suffers from anemia¹. Half of these cases are thought to be attributable to deficiency nutritional in fer. women who have heavy periods, children and preschoolers and pregnant women are most at risk of anemia.

Causes

Several situations can give rise to anemia.

• A iron deficiency.
• A vitamin deficiency.
• A chronic disease or bone marrow disease.
• A genetic disease, which leads for example to a too rapid destruction of red blood cells.
• A hemorrhage, that is, a flow of blood outside the blood vessels.

Main types of anemia

• Iron deficiency anemia. It is the most common form of anemia. Heavy periods and a diet low in iron are the most common causes. Iron deficiency anemia changes the size of red blood cells, which become smaller than normal (microcytic anemia). For more information, see our Iron Deficiency Anemia fact sheet.
• Anemia caused by vitamin deficiency. This type of anemia produces very large, deformed red blood cells (macrocytic anemia). The most common are those caused by a deficiency of vitamin B12 or vitamin B9 (folic acid). The first can occur due to insufficient food intake of this vitamin, poor absorption in the gut, or a condition called pernicious anemia. For more details, see our B12 deficiency anemia fact sheet.
• Anemia caused by chronic disease. Many chronic diseases (and sometimes their treatments) can reduce the amount of red blood cells circulating in the blood. This is the case with cancer, Crohn’s disease and inflammatory diseases such as rheumatoid arthritis. Kidney failure can also cause anemia because the kidneys secrete erythropoietin, the hormone that stimulates the production of red blood cells. However, these retain their normal size and appearance (normocytic anemia).
• Haemorrhagic anemia. Heavy blood loss after a serious accident, surgery or childbirth, for example, can quickly cause anemia. Certain gastrointestinal problems (a peptic ulcer, intestinal polyps or colorectal cancer) can also lead to it, but this time causing a slight and constant loss of blood in the stool (sometimes invisible), over a long period of time.
• Hemolytic anemia. This type of anemia is characterized by too rapid destruction of red blood cells. It can be due to an immune system reaction (autoimmune or allergic), to the presence of toxins in the blood, to infections (for example, malaria), or even be congenital (sickle cell anemia, thalassemia, etc.). The congenital form mainly affects individuals of African origin.
• Sideroblastic anemia. This term covers a group of very rare anemias in which the red blood cells cannot fix the iron in the hemoglobin. This is an enzymatic problem of hereditary or acquired origin. The red blood cells are then smaller than normal.
• Aplastic anemia (or aplastic). This rare disease occurs when the bone marrow no longer produces enough blood stem cells. Thus, there is not only a lack of red blood cells, but also of white blood cells and blood platelets. In 50% of cases, aplastic anemia is caused by toxic agents, certain drugs or exposure to radiation. It can also be explained by serious illnesses, such as cancer of the bone marrow (for example, leukemia).

Diagnostic

Since one cannot rely on symptoms alone to establish a diagnostic, it is necessary to undertake a laboratory examination of a blood sample. A complete blood count (complete blood count) is normally prescribed by the doctor.

Here are 3 main parameters :

• Hemoglobin level : the concentration of hemoglobin (the respiratory pigment contained in red blood cells) in the blood, expressed in grams of hemoglobin per liter of blood (g / l) or per 100 ml of blood (g / 100 ml or g / dl ).
• Hematocrit level : the ratio, expressed as a percentage, of the volume occupied by the red blood cells of a blood sample (passed through the centrifuge) in relation to the volume of whole blood contained in this sample.
• Red blood cell count : the number of red blood cells contained in a given volume of blood, normally expressed in millions of red blood cells per microliter of blood (millions / µl).

Normal values

Remark. These values ​​for hemoglobin and hematocrit are the norm for 95% of people. This means that 5% of individuals have “non-standard” values ​​while being in good health. In addition, results that are at the lower limits of normal may indicate the onset of anemia if they were usually higher.

other blood tests may be required in order to clarify a diagnosis and to discover the cause of the anemia. Depending on the case, the examination of the decals red blood cells, the dosage of fer or different vitamins in the blood, etc.