Reticulocytosis is an increase in the concentration of reticulocytes (immature erythrocytes) in the peripheral blood by more than 1% of the number of all erythrocytes. The main cause is various anemia (posthemorrhagic, hemolytic), as well as pathological conditions that cause general hypoxia in the body. The leading place in the clinical picture is occupied by anemic syndrome - pallor of the skin and mucous membranes, dizziness, palpitations. The level of reticulocytes is examined in the general blood test (CBC). To correct reticulocytosis, it is necessary to treat the underlying disease.
Taking into account the regenerative ability of the bone marrow, the following reticulocytosis is distinguished:
There is also physiological reticulocytosis in newborns. Immediately after birth, the processes of hematopoiesis are activated as an adaptive reaction to extrauterine life. In addition, newborn red blood cells contain fetal hemoglobin, which is why they are destroyed very quickly. The level of reticulocytes on the first day of life ranges from 2 to 40%, then decreases sharply on the second day, and by the age of 10-12 reaches the norm for adults.
The most common non-pathological cause of reticulocytosis is a reaction to the treatment of iron deficiency, folic acid deficiency anemia. Its occurrence 3-5 days after the start of iron and folic acid preparations, vitamin B12 injections indicates a successful response to therapy. An increase in the concentration of reticulocytes in these cases indicates the normalization of hematopoiesis processes. Also, reticulocytosis can develop after successful chemotherapy or radiation therapy of oncohematological diseases (leukemia).
Bleeding is considered the most common cause of reticulocytosis. With blood loss (both acute and chronic), the level of hemoglobin decreases. In response, the kidneys secrete erythropoietin, the main physiological stimulator of erythropoiesis. Under its influence, the processes of mitosis and maturation begin to activate in the erythroblasts of the bone marrow. With intensive hematopoiesis, part of the immature erythrocytes enters the blood.
In acute external or internal bleeding (trauma, fracture, rupture of internal organs), reticulocytosis occurs on days 4-5, regresses after about 1 week, its degree depends on the amount of blood loss. The cause of minor but persistent long-term reticulocytosis is chronic bleeding, for example from hemorrhoidal veins. According to the persistent increase in the proportion of reticulocytes, one can also suspect hidden bleeding from the gastrointestinal tract (with gastric ulcer and 12 duodenal ulcer, malignant tumor of the colon).
Reticulocytosis - hematological syndrome
Another cause of reticulocytosis is recognized as diseases accompanied by the destruction of red blood cells (hemolysis). The scheme of the pathogenesis of reticulocytosis in these pathologies does not differ significantly from that in posthemorrhagic anemia (decreased hemoglobin, erythropoietin). With massive hemolysis, the rate can reach 60-70%. The following diseases are distinguished, accompanied by hemolysis (hemolytic anemia):
Diseases characterized by a decrease in the partial oxygen content in the blood or a deterioration in general circulation and causing circulatory hypoxia can also cause reticulocytosis. The mechanism of its development is similar to previous pathologies. However, since the level of hemoglobin and erythrocytes does not decrease in diseases of this group, increased hematopoiesis leads not only to reticulocytosis, but also to secondary erythrocytosis and hyperhemoglobinemia. The concentration of reticulocytes reflects the severity of the underlying disease, but does not reach such high numbers as with blood loss or hemolytic anemia.
In some cases, oncohematological pathologies become the cause of reticulocytosis, namely, polycythemia vera (Wakez's disease) and erythroblastic leukemia. The pathological mechanism is due to malignant (clonal, tumor) degeneration of a pluripotent (in polycythemia) or erythroblast (in leukemia) stem cell. Reticulocytosis is persistent, high (can reach up to 30-50%), Polycythemia is also characterized by an increase in the number of all formed elements (leukocytes, erythrocytes, platelets). With erythroblastic leukemia, a large number of blast cells are present in the blood.
The count of reticulocytes is carried out in a clinical blood test. The appearance of reticulocytosis requires an appointment with a doctor for examination in order to find out the cause. First of all, chronic blood loss should be excluded. To do this, the specialist examines the skin and mucous membranes for pallor, measures blood pressure and heart rate. Then an additional examination is assigned, including:
Complete blood count - a method for detecting reticulocytosis
There are no methods to directly reduce the number of reticulocytes. To correct reticulocytosis, it is necessary to eliminate its cause, which implies the treatment of the underlying pathology. Reticulocytosis that occurs a few days after the start of vitamin B12 or iron supplementation is normal and does not require intervention. In the case of a pathological increase in the indicator, depending on the cause, the following treatment is prescribed:
Massive incessant bleeding requires surgical intervention - ligation, clipping of blood vessels, endoscopic hemostasis (electro-, cryo- or laser coagulation). The main treatment for many hemolytic anemias (hereditary microspherocytosis, sickle cell anemia, thalassemia) involves the removal of the spleen (splenectomy). 2 weeks before the operation, it is necessary to vaccinate against pneumococcus, meningococcus, Haemophilus influenzae. If conservative treatment of erythroblastic leukemia is ineffective, hematopoietic stem cell transplantation is performed.
It is impossible to predict the prognosis by the level of reticulocytosis, the outcome is directly determined by the type and severity of the underlying pathology. Physiological reticulocytosis in neonates or after supplementation with folic acid, iron, and vitamin B12 is benign. Congenital heart defects, hemoglobinopathies or oncohematological diseases are characterized by a high percentage of deaths. If prolonged reticulocytosis is detected, it is necessary to consult a specialist to clarify the cause and select the treatment.