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Microcytosis of G.Bertelli

Generality

Microcytosis is a condition characterized by the presence, in peripheral blood, of red blood cells (or erythrocytes) of lesser magnitude than the norm.

The presence of microcytes is frequently related to hypochromic anemia . In this case, in addition to the microcytosis, the average concentration of hemoglobin (Hb) contained within the red blood cells is lower than the norm; the result is a reduced ability of the blood to carry oxygen.

However, the causes that can induce the increase in microcytes in the bloodstream are varied and also include iron deficiencies, thalassemia syndromes and chronic inflammatory diseases (such as celiac disease, infections and certain neoplasms).

The presence of microcytes is found undergoing a blood test, which assesses, in particular, the average corpuscular volume of red blood cells ( MCV ) and other erythrocyte indices .

The management of microcytosis may include the intake of iron and vitamin C supplements, diet modification and more or less recurrent blood transfusions. Sometimes, the disorder is transient and does not require any specific therapeutic intervention.

Did you know that…

In medicine, the term " microcitemia " is used with two meanings, ie as a synonym for:

  • Microcytosis (a condition in which red blood cells are smaller than the norm);
  • β-thalassemia or Mediterranean anemia (group of inherited haematological diseases in which the synthesis of beta hemoglobin chains is reduced or absent).

What's this

Red blood cells are blood cells that carry oxygen from the lungs to the tissues. In order for them to perform their function best, erythrocytes must have a biconcave disk shape with a flattened core and adequate dimensions.

When they are smaller than the norm, erythrocytes are called microcytes .

In the laboratory analysis, the most useful blood chemistry parameter to determine if red blood cells are normal, too large or too small, is the mean corpuscular volume (MCV) .

macrocytosis

Based on the size of the erythrocytes it is possible to distinguish:

  • Microcytosis : it is characterized by microcytic erythrocytes, ie smaller than the norm;
  • Macrocytosis : is the condition opposite to the microcytosis, in which the erythrocytes have a greater volume than normal.

Microcytic anemia

Microcytic anemia is a blood disorder characterized by an abnormal reduction in the average corpuscular volume of red blood cells (MCV).

Note

  • The various forms of anemia can be classified on the basis of the size of the red blood cells (microcytic, macrocytic and normocytic) and of the average concentration of hemoglobin (Hb) contained within them (hypochromic and hyperchromic).
  • Microcytic anemias are usually also hypochromic, ie they are associated with a lower hemoglobin concentration than normal, for age and sex.

Causes

Microcytosis can be caused by various conditions and is found in association with various hematological and non-hematological diseases.

Usually, the appearance of a population of microcytic erythrocytes is indicative of a defective or insufficient synthesis of hemoglobin . This involves the release of smaller elements into the circle, but the initial alterations may be minimal.

Microcytosis is often related to iron deficiency anemias (or iron deficiency anemias) and is frequent in the presence of: thalassemia, chronic inflammatory diseases, renal pathologies and some forms of cancer (the presence of blood in the faeces and microcytic anemia is typical, for example, of colon cancer).

In some cases, then, erythrocytes can be smaller due to the presence of genetic mutations that interfere with erythropoiesis, that is in the formation of blood cells; in this case, one speaks of hereditary microcytosis .

Microcytosis: main causes

Microcytosis is found mainly in the case of:

  • Chronic iron deficiency, secondary to:
    • Low iron intake;
    • Decreased iron absorption;
    • Excessive iron loss;
  • Thalassemias (hereditary alterations to the blood, in which there is a deficient synthesis of one or more chains that make up hemoglobin);
  • Inflammation or chronic diseases :
    • Chronic inflammatory diseases (eg rheumatoid arthritis, Crohn's disease etc.);
    • Various types of neoplasms and lymphomas;
    • Chronic infections (tuberculosis, malaria, etc.);
    • Diabetes, heart failure and COPD.
  • Lead poisoning (substance that causes inhibition of heme synthesis);
  • Vitamin B6 (pyridoxine) deficiency.

Symptoms and Complications

The microcytosis involves very variable clinical pictures: in some cases, the disorder is almost asymptomatic; at other times, the condition is debilitating and puts the life of the sufferer at risk.

Depending on the cause that determined it, the microcytosis takes on particular characteristics both in symptoms and in the values ​​found with laboratory analyzes.

In most cases, they manifest themselves:

  • Skin pallor (accentuated especially at face level);
  • Fatigue and weakness;
  • Fragility of nails and hair;
  • Loss of appetite;
  • Headache;
  • Shortness of breath;
  • Dizziness.

If they last for a few weeks, without ever regressing, these symptoms are indicative of the presence of anemia.

In the most severe cases, the microcytosis can be associated with:

  • Palpitations;
  • Stunning;
  • Chest pains;
  • Jaundice;
  • Blood loss and bleeding tendency;
  • Recurrent fever attacks;
  • Irritability;
  • Progressive distension of the abdomen (secondary to splenomegaly and hepatomegaly).

The complications of microcytosis occur when severe anemia is not treated and include:

  • Hypoxia;
  • Hypotension;
  • Heart and lung problems.

Diagnosis

Microcytosis is found in routine blood tests and can be suspected in the presence of symptoms indicative of anemia (eg, pallor and continuous fatigue). Sometimes, however, the response can occur in a completely random way, as the patient is asymptomatic. In this case it is advisable to consult a doctor to assess whether the microcytosis is transient or not and what is the cause.

After collecting the anamnestic information, the general practitioner prescribes a series of laboratory investigations, with the aim of evaluating:

  • Number and volume of red blood cells;
  • Quantity and type of hemoglobin;
  • State of body iron.

For a better characterization of microcytic anemia, therefore, the following blood tests are useful:

  • Complete blood count:
    • Number of red blood cells (RBC): generally, but not necessarily decreased in the case of microcytosis;
    • Erythrocyte indices: they provide useful information regarding the size of red blood cells (normocytic, microcytic or macrocytic anemias) and the quantity of Hb contained within them (normochromic or hypochromic anemias). The main erythrocyte indices are: Medium Corpuscular Volume (MCV), Medium Corpuscular Hemoglobin (MCH) and Medium Corpuscular Hemoglobin Concentration (MCHC);
    • Reticulocyte count: quantifies the number of young (immature) red blood cells present in peripheral blood;
    • Platelets, leukocytes and leukocyte formula;
    • Hematocrit (Hct);
    • Amount of hemoglobin (Hb);
    • Amplitude of erythrocyte distribution curve (RDW, from "Red Cell Distribution Width").
  • Microscopic examination of the erythrocytic morphology and, more generally, of the peripheral blood smear;
  • Serum iron, TIBC and serum ferritin;
  • Bilirubin and LDH;
  • Indices of inflammation, including C-reactive protein.

MCV: Normal values

As part of a complete blood count, the analysis of the MCV allows to know the "quality" of the red blood cells.

MCV is the abbreviation of " Mean Cell Volume " or " Mean Corpuscular Volume ". This acronym is used to indicate the average corpuscular volume, ie the average volume of red blood cells . In essence, the MCV lets you know if the erythrocytes are too small, too large or simply normal.

The MCV is, therefore, the most useful index to highlight a microcytosis and is obtained by dividing the hematocrit by the number of red blood cells.

This parameter also allows to classify the type of anemia according to the morphology of the red blood cells:

  • Microcytic anemias : MCV <80 fl *.
  • Normocytic anemias : MCV = 80-95 fl; any normocytic anemias may be due to acute bleeding or hemolysis (destruction of red blood cells).
  • Macrocytic anemias : MCV> 95 fl; the presence of macrocytes may be due to myelodysplasia, reticulocytosis, hypothyroidism, liver disease (liver disease, such as cirrhosis) and alcoholism.

* fl (femtolitri) is the unit of measurement of the average cell volume and is equivalent to 0.000001 billionths of a liter (0.000000000000001 liters); the MCV can also be expressed in cubic micrometers or µm3. It should be remembered, in fact, that a liter is equivalent to a cubic decimeter, a milliliter to a cubic centimeter, a microliter to a cubic millimeter and so on.

It should be noted that the MCV reference value may vary slightly from laboratory to laboratory. Therefore, when it is necessary to establish with greater precision the pathological significance of the microcytosis or another alteration of the MCV, it is useful to cross this value with other parameters, such as the number of red blood cells (RBC), the average content of hemoglobin for each red blood cell (MCH) and the average concentration of hemoglobin within a red blood cell (MCHC, apparently similar to the previous one, but very important, since it gives an indication of the relationship between the volume of red blood cells and their hemoglobin content ).

The value of MCV is of clinical importance even when interpreted in the light of another blood parameter: RDW. The latter provides information on the distribution of red blood cells and allows, among other things, the distinction between hypoproliferative anemia (characterized by the presence of reticulocytes, ie immature erythrocytes) and haemolytic anemia (due to an increase in the destruction of the corpuscles red).

Treatment

Microcytosis management is different depending on the type of cause.

The treatment of diseases responsible for microcytosis usually determines the resolution of the clinical condition. It should be noted, however, that some forms, such as those caused by thalassemia and some types of sideroblastic anemia, are congenital, and therefore cannot be cured.

What to do

In the presence of mild forms, the microcytosis does not compromise the quality of life and no particular measures are required. However, some forethought may be useful.

Generally speaking, your doctor may recommend you take iron supplements orally (or intravenously, when the patient is symptomatic and the clinical picture is severe) and vitamin C (it helps to increase the body's ability to absorb iron).

In the case of more severe forms, on the other hand, the management of microcytosis consists in the treatment of the underlying clinical condition, to improve the symptoms of the anemia produced, and may include:

  • Blood transfusions to make up for the lack of red blood cells and to avoid complications such as heart failure, possibly associated with a chelation therapy to avoid iron accumulation;
  • Splenectomy (if the disease causes severe anemia or excessive pathological enlargement of the spleen);
  • Bone marrow or stem cell transplant from compatible donors.

In addition to specific therapies, great importance is given to regularly practicing physical activity and changing eating habits.

In particular, patients with microcytosis can be recommended to:

  • Adopt a healthy and balanced diet, including the consumption of foods rich in iron (red meat, poultry, dark leafy vegetables, beans and raisins) and vitamin C (citrus fruits, grapes, peppers, broccoli, Brussels sprouts);
  • Consume foods rich in calcium and vitamin D, to limit the risk of osteoporosis (a disease often related to microcytic anemia);
  • Take folic acid supplements (to increase red blood cell production).

In any case, the doctor will be able to advise the patient on the best interventions for their condition.

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