Generality
Anisocytosis means a condition characterized by the presence of red blood cells (or erythrocytes) of various sizes in the peripheral blood.
This haematological alteration is frequently associated with some forms of anemia, but may also depend on numerous other pathologies or physiological situations. Among the causes that can induce anisocytosis are myelodysplastic syndromes, food-related problems (eg vitamin deficiencies or iron deficiency), chronic inflammatory diseases (such as celiac disease, infections and certain neoplasms) and pregnancy.
The presence of anisocytosis is found undergoing a blood test, which evaluates, in particular, the average corpuscular volume of red blood cells ( MCV ) and the amplitude of the erythrocyte distribution ( RDW ).
The treatment of anisocytosis depends on the underlying causes and may include, for example, taking supplements based on iron or vitamins, changing the diet and more or less recurrent blood transfusions.
What's this
What is meant by anisocytosis?
Anisocytosis is a medical term which indicates the simultaneous presence of red blood cells of various sizes in the bloodstream, often with different degrees of hemoglobinization .
Red blood cells: shape and size
- 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 constant shape and size . Normally, a red blood cell appears as a biconcave disk with a flattened core and has an average diameter of about 7-8 microns. In the presence of some pathologies, however, these parameters can vary and erythrocytes take on different shapes and sizes.
- 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) .
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.
For the correct clinical interpretation, then, the MCV must be compared with the other erythrocyte indices.
In the presence of anisocytosis, a patient's red blood cells are not of equal size. Consequently, the hemoglobin contained in them may also vary. Anisocytosis is generally found in various forms of anemia, but can also be seen in pathological conditions and other problems (eg vitamin deficiencies, pregnancy, etc.).
When the examination of the peripheral smear, the red blood cells are of different forms, sometimes bizarre, one speaks of poichilocytosis .
Causes and Risk Factors
Anisocytosis may depend on an insufficient or defective erythropoiesis (differentiation and maturation line of the red blood series), which entails the circulation of red blood cells of different sizes.
As anticipated, anisocytosis can be found in the clinical picture of numerous conditions. In most cases, this depends on the presence of microcytes (ie red blood cells smaller than normal) and macrocytes (larger erythrocytes) in the blood.
The pathologies in which anisocytosis is found are:
- Myelodysplastic syndromes : pathological conditions that are characterized by the presence of a defect in the bone marrow that makes it unable to produce some blood cell lines (erythrocytes, leukocytes and platelets) in adequate quantities;
- Sideroblastic anemia : disease related to inadequate use of available iron;
- Thalassemia : hereditary alterations to the blood, in which there is a deficient synthesis of one or more chains that make up hemoglobin
- Leukemias : tumoral pathologies involving hematopoietic stem cells, bone marrow and the lymphatic system.
Anisocytosis can also be observed in the clinical picture of:
- Iron deficiency anemias (or iron deficiency anemias);
- Hemolytic anemia of autoimmune or traumatic origin;
- Aplastic anemias;
- Medullary replacement (myelophysis);
- Chronic inflammatory diseases;
- Hepatopathies (diseases affecting the liver, such as cirrhosis);
- Some tumoral pathologies and metastases (eg colon cancer);
- Cytotoxic chemotherapy;
- Bleeding;
- Pregnancy.
Anisocytosis with microcytosis: most common causes
Anisocytosis with microcytosis is usually associated with:
- Chronic iron deficiency, secondary to:
- Low iron intake;
- Decreased iron absorption;
- Excessive iron loss;
- Sickle cell anemia;
- thalassemia;
- 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.
Anisocytosis with macrocytosis: main related disorders
Anisocytosis with macrocytosis may depend on:
- Folate deficiency anemia;
- Vitamin B12 deficiency anemia (or pernicious anemia);
- Megaloblastic anemia;
- Hemolytic anemias;
- Myeloproliferative disorders (eg myelofibrosis, thrombocythemia and polycythemia vera);
- Chronic hepatopathies;
- Hypothyroidism;
- Gastroenteritis, malabsorption syndromes and other pathologies of the gastrointestinal tract (eg Crohn's disease or celiac disease);
- Chronic obstructive disorders of the respiratory system (eg COPD);
- splenectomy;
- Chronic alcoholism;
- Chronic exposure to benzene;
- Severe hyperglycemia.
Symptoms and Complications
Depending on the cause that caused it, anisocytosis involves variable clinical pictures.
In addition to the manifestations related to specific causal diseases, there are often signs and symptoms determined by the fact that the size of the red blood cells present in the blood are different from each other.
This leads to a reduction in the activity of transporting oxygen, which involves more frequently:
- Skin pallor (accentuated especially at face level);
- Fatigue and weakness;
- Palpitations;
- Low body temperature;
- Loss of appetite;
- Headache;
- Dizziness;
- Fragility of nails and hair;
- Shortness of breath.
Diagnosis
Anisocytosis: how is the diagnosis established?
Anisocytosis is found in routine blood tests and can be suspected in the presence of symptoms indicative of anemia, including continuous pallor and fatigue. Sometimes, however, the diagnosis can be made entirely by chance, as the patient is asymptomatic.
After collecting the medical history, the family doctor prescribes a series of laboratory investigations to determine the causes of anisocytosis.
Anisocytosis: blood tests
For a better characterization of anisocytosis, it is useful to perform the following blood tests :
- Complete blood count:
- Red blood cell count (RBC) : erythrocyte count is generally, but not necessarily decreased in macrocytic anemia;
- 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, used to establish the average size of red blood cells), Medium Corpuscular Hemoglobin ( MCH, coincides with the average hemoglobin content for each red blood cell) and Medium Corpuscular Hemoglobin Concentration ( MCHC, given 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);
- Reticulocyte count : quantifies the number of young (immature) red blood cells present in peripheral blood;
- Platelets, leukocytes and leukocyte formula ;
- Hematocrit (Hct) : percentage of the total volume of blood made up of red blood cells;
- Amount of hemoglobin (Hb) in the blood;
- Red cell size variability (amplitude of red blood cell distribution or RDW, from the English " 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.
Any anomalies found during the definition of these parameters can alert laboratory personnel to the presence of anomalies in the red blood cells; the blood sample could be subjected to further analysis to identify the cause of anisocytosis. Rarely, examination of a sample from the bone marrow may be necessary.
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.
When it is necessary to establish with greater precision the pathological significance of aniscocytosis or other alteration of the MCV, it is useful to cross this value with other parameters, such as RBC, MCH and MCHC. The value of MCV is of clinical importance even when interpreted in the light of another blood parameter: the 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
The treatment of anisocytosis varies according to the cause: the correct management of the pathologies responsible for this haematological condition improves the symptoms and usually determines the resolution of the clinical picture. It should be noted, however, that some forms of anisocytosis depend on congenital pathologies, therefore they are not curable.
In any case, the doctor will be able to advise the patient on the best interventions for their condition.
Possible interventions: some examples
In the presence of mild and transient forms, anisocytosis does not compromise quality of life and no special measures are required. However, some forethought may be useful.
For example, your doctor may recommend that you take vitamin B12 and folic acid supplements orally to increase normocyte production. If the anisocytosis is maintained by an iron deficiency anemia, the use of oral iron (or intravenous, when the patient is symptomatic and the clinical picture is severe) and vitamin C (helps to increase capacity body to absorb iron).
In more serious cases, on the other hand, the management of anisocytosis may include:
- Blood transfusions to make up for the lack of normal red blood cells and to avoid complications such as heart failure;
- 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 in the treatment of anisocytosis covers regularly practiced physical activity and the adoption of a healthy and balanced diet .
