ANAEMIA OF PREMATURITY

Anaemia of prematurity

Anaemia of prematurity

Anemia in preterm infants. Anemia is one of the most frequent pathologies in infants. About 20% of full-term children suffer with this disease, and among preterm in the first year of life anemia develops in virtually all. The severity of anemia is higher, the lower the gestational age re6enka. In the first months of life in preterm infants with very low birth weight (less than 1500) and gestational age less than 30 weeks. Severe anemia requires transfusion of packed red blood cells, up to 90%. In the pathogenesis of early anemia of prematurity plays a role not only the formation of iron deficiency, which is characteristic of all young children, but also factors of incomplete ontogeny.

For premature infants is characterized by morphological changes of erythrocytes. Thus, abnormal erythrocyte forms account for 27%, whereas in term neonates of all - 14%. (Rodden and Hayes 2006 503)

This ensures that the period of life of erythrocytes in term of almost 2 times longer than in preterm infants, and 60-70 and 35-50 days respectively. Shortening the life of red blood cells may contribute to the structural features of their membranes. In studying the composition of lipids of erythrocyte membranes in children with early anemia of prematurity showed that from 2 nod week they have a decrease in phospholipids content and increased cholesterol. These changes progress to the 6th week of life and in the midst of anemia reaches a maximum, which correlates with clinical and laboratory symptoms.

In violation of the permeability of erythrocyte membranes in preterm infants also plays the role of low levels of vitamin E, which is localized in the membranes and is actively involved in peroxide phosphorylation. Deficiency of vitamin E observed in 86% of preterm infants. Embryonic red blood cells in the early stages of ontogeny produce germ (embryonic) form of hemoglobin. Between 7 to 12 weeks of intrauterine life fetal hemoglobin is replaced by fetal. Hemoglobin level is also dependent on gestational age, accounting for a 10-week average of 90 g / l, while the 38-week 170 ± 20 g / liter. (Salsbury 2001 19)

Fetal hemoglobin has a higher affinity for oxygen, and slower returns oxygen to tissues, compared with hemoglobin in adults. Switching the synthesis of fetal hemoglobin in adult hemoglobin is under the control of genes located at 11, and 16 chromosomes and begins a 30-32-week fetal development. The content of fetal hemoglobin in preterm infants at birth is on average 70-80% in term neonates - 60-70%. More than half of fetal hemoglobin is replaced by adult hemoglobin in the first days of life in the future, this process is somewhat slower, but by 4-5-th month of postnatal life in most children is about 1% of fetal hemoglobin. Premature babies, this process is slow, the bulk of the change of hemoglobin falls on the 40 Th week of gestation, and a complete change is stretched nearly the entire first year of ...