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Diagnosis of acute posthemorrhagic anemia in children
Last reviewed: 04.07.2025

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The diagnosis of acute posthemorrhagic anemia and hemorrhagic shock is established based on a combination of anamnestic, clinical and laboratory data. Of primary importance are clinical data, pulse rate, arterial pressure, and diuresis.
The hematological picture of acute posthemorrhagic anemia depends on the period of blood loss. In the early period of blood loss (reflex vascular phase of compensation), due to the entry of deposited blood into the vascular bed and a decrease in its volume as a result of reflex narrowing of a significant portion of the capillaries, the quantitative indicators of erythrocytes and hemoglobin in a unit of blood volume are at a relatively normal level and do not reflect true anemia. This is also due to the fact that there is a parallel loss of both formed elements and blood plasma. Early signs of blood loss are leukocytosis with neutrophilia and a left shift and thrombocytosis, which are noted already in the first hours after blood loss. Severe anemia after blood loss is not detected immediately, but after 1-3 days, when the so-called hydremic phase of compensation occurs, characterized by the entry of tissue fluid into the circulatory system. In this phase, the number of erythrocytes and hemoglobin progressively decreases, the true degree of anemia is revealed without a decrease in the color index, i.e. the anemia is normochromic and normocytic. The bone marrow compensation phase begins 4-5 days after blood loss. It is characterized by the presence of a large number of reticulocytes in the peripheral blood, and normocytes may appear in young children. It has been established that with acute posthemorrhagic anemia, the proliferative activity of the bone marrow increases significantly - effective erythropoiesis increases approximately 2 times compared to the norm. These changes are explained by increased production of erythropoietins in response to hypoxia. Simultaneously with high reticulocytosis, young cells of the granulocytic series are found in the peripheral blood, a shift to the left is noted, sometimes to metamyelocytes and myelocytes against the background of leukocytosis. Restoration of the mass of erythrocytes occurs within 1-2 months, depending on the volume of blood loss. In this case, the body's reserve iron fund is used up, which is restored after several months. This can lead to the development of latent or obvious iron deficiency, in which microcytosis and hypochromia of erythrocytes can be observed in the peripheral blood.
In newborns, a comprehensive clinical and laboratory assessment of the severity of anemia is important. In newborns in the first week of life, the criteria for anemia are: Hb level below 145 g / l, red blood cell count less than 4.5 x 10 12 / l, Ht less than 40%. The same indicators are used to diagnose anemia in the second week of life, in the 3rd week and later, anemia is diagnosed with a hemoglobin level < 120 g / l, red blood cell count less than 4 x 10 ' 2 / l. If the newborn's history includes risk factors for the development of posthemorrhagic anemia, a complete clinical blood test is necessary at birth and then the hemoglobin and hematocrit levels should be determined in the first day of life every 3 hours after. In the peripheral blood test, the hemoglobin level and red blood cell count may initially even be normal, but after a few hours they decrease as a result of hemodynamics. Anemia is normochromic, thrombocytosis and leukocytosis with a left shift may be present. In posthemorrhagic shock, the BCC is always below 50 ml/kg of body weight, and the central venous pressure (CVP) is below 4 cm H2O (0.392 kPa) up to negative values.