Hemolytic disease of the newborn (HDN) - a disease associated with the incompatibility of fetal blood to maternal blood.The reasons for this state, diagnosis and treatment of disease and will be discussed in this article. Content
incompatibility between maternal blood and fetal blood may be associated with the Rh factor and group incompatibility.It is known that there are four different blood group 0 (I), A (II), In (III) and AB (IV).85% of Europeans in the blood has Rh-factor, and 15% of Europe's population is Rh negative.
HDN in 3-6% of cases developed with Rh incompatibility, when Rh-negative mothers develop Rh-positive fetus: Rhesus conflict arises.Incompatibility group antigens (ABO conflict) develops in the presence of the fetus A (II) c.Blood (2/3 cases) or In (III) (approximately 1/3 of the time) and 0 (I) c.mother.When the group incompatibility HDN milder than in rhesus conflict.
In all these cases, the red blood cells in the fetus have different antigenic qualities.If these red blood cells overcome the placental barrier and get into the blood of the mother, the mother's body starts producing antibodies to these erythrocytes.
If you get these specific antibodies in the body of the fetus can begin the process of destruction of red blood cells (hemolysis), leading to the development not only of anemia but also dangerous to the fetus jaundice.
Sensitization mother (purchase of increased sensitivity to a particular antigen) occurs not only during pregnancy: a much greater degree of fetal red blood cells enter the mother's body during childbirth.Therefore, the risk of tension-type headache for the first child less than (antibodies have not had time to develop in the mother's body) than for subsequent children.
Please note that sensitization can occur when abortion (miscarriage or an artificial medical abortion) as the Rh factor is formed in the fetus is already 5 weeks of pregnancy.Sensitization can occur when a woman transfusion Rh incompatible blood (even if the transfusion was performed in early childhood).
is not always in the Rh blood incompatibility of the couple in a child developing HDN.The baby may inherit from a parent Rh factor, it may not inherit it.
Therefore HDN due to Rh incompatibility occurs in 0.5% of babies were born, while the Rh incompatibility of the couple celebrated in 20 times more often.In addition, the low birth rate is not every mother develops such a pronounced sensitization to the fetus occurred severe HDN.It is important for the development of the disease and the degree of permeability of the placenta.
When an ABO HDN number of previous pregnancies does not matter, since sensitization may contribute to a number of factors.
erythrocyte destruction not only leads to anemia fetus or infant, but also a significant increase in blood levels of bilirubin.Normally indirect bilirubin bound to albumin (a type of blood proteins) and is converted into direct bilirubin.But too many indirect bilirubin, released from the destroyed red blood cells, does not manage to bind to albumin and blood continues to circulate in the blood and increase.
indirect bilirubin is toxic to the nervous system.Upon reaching a level above 340 umol / L in term infants and above 200 umol / L of preterm it is able to penetrate the blood-brain barrier and to strike the brain (especially the cortex and subcortical nuclei).As a result of developing bilirubin encephalopathy or kernicterus.
indirect bilirubin is dangerous not only for the nervous system: it is a tissue poison that causes degenerative changes in many organs until necrosis cells.When liver damage in the blood rises as the level of direct bilirubin, develops concentration of bile stasis in her bile ducts and reactive hepatitis.
The destruction of red blood cells, the child develops anemia, in response to which there are atypical foci of hematopoiesis.In the internal organs are laid breakdown products of red blood cells.Deficiency develops trace elements (copper, iron, zinc, etc.).
distinguish between such clinical forms of HDN:
Fruit die in utero, or the baby is born in a very critical condition, with severe edema.
skin is pale, jaundiced.Child sluggish sharply reduced muscle tone, significantly increase the size of the liver and spleen, expressed phenomena of cardiopulmonary diseases.The hemoglobin level of less than 100 g / l.In this form of newborns die within 1-2 days after birth.
With an increase in bilirubin levels may increase drowsiness and lethargy of the child, there is a decrease in muscle tone, there is a monotonous cry.When the concentration of indirect bilirubin to critical parameters (usually 3-4 days) show signs of kernicterus: nagging cramps, large bulging fontanelle, muscle tension neck, monotonous cry, appears a symptom of "setting sun" (a small part of the iris is visible on the lower eyelid).
critical indicator of the level of bilirubin:
- 10% of full-term infants with tension-type headache is the excess of 340 mmol / l;
- 30% of babies - more than 430 mmol / l;
- for 70% of newborns - more than 520 mmol / l.
In rare cases, even a high level of indirect bilirubin is 650 mmol / l, does not lead to the development of kernicterus.
If untreated, the child may die 3-6 days of life.When kernicterus in surviving children may experience intellectual disabilities up to idiocy, impaired physical development.
7-8 days of life on the background of the therapy developed bile stasis: the child appears greenish tinge to the skin, dark urine and discolored feces, blood increased direct bilirubin.In the analysis of the blood was anemia, which can last up to 2-3 months.Long-held and yellowness of the skin.If there is no nervous system recovery, though long, yet complete.
general condition of the child suffers a little.On examination revealed an enlarged liver and spleen.The concentration of indirect bilirubin increases several times.Prognosis is generally favorable.
HDN, which arose as a result of the conflict on the ABO blood group, occurs most often mild, but late diagnosis can lead to bilirubin encephalopathy.
When combined Rh incompatibility and ABO incompatibility, that is, when a double incompatibility HDN milder than in an isolated Rh-conflict.
There antenatal (prenatal) and postnatal (postpartum), the probability of diagnosis of HDN.
Antenatal held with the Rh blood incompatibility of spouses and subject to obstetric and gynecological history of women (miscarriage, abortion, stillbirth, blood transfusion).It determines whether the immune conflict.
Antenatal diagnosis includes:
Postnatal diagnosis of HDN conducted taking into account:
the treatment of severe HDN shown exchange transfusion of fresh (no more than 3 days old) blood in order to prevent increasing levels of bilirubin to a life-threatening concentration (20 mg%).Blood transfusion is conducted under strict indications.
If there is the risk of HDN the analysis of umbilical cord blood.If the level of bilirubin in it above 3 mg% and the Coombs test is positive, the transfusion should be carried out immediately.
In the absence of analysis of umbilical cord blood and the existing suspicion of HDN conducted Coombs test and determine the level of bilirubin in the blood of the baby.
through the catheter into the umbilical vein is injected rhesus negative blood at the rate of 180-200 ml / kg body weight of the newborn (thereby replaced 95% of the blood of the baby).After the infusion of every 100 ml of blood is introduced 1-2 ml of calcium gluconate.In order to prevent infection of the umbilical vein baby appoint a 3-day course of antibiotics.
After 96 hours of a child's life blood transfusion is performed, depending on the general condition of the child.When the bilirubin level of 20 mg%, severe anemia and positive Coombs - transfusions performed.If the sample is negative, then controlled by the further content of bilirubin in the blood.
after blood transfusion bilirubin are monitored every 6 hours.Upon detection of an ongoing hemolysis transfusion may be repeated.
When incompatibility ABO blood donations entered about (I) the group does not contain the A and B antibodies.In the case of high (above 20 mg%) the level of bilirubin in the blood of newborn blood transfusions odnogruppnoy even in the absence of incompatible blood parents.
important role played by medical history, if previously born children have tension-type headache and in the blood of pregnant women increased antibody titer after 37 weeks of pregnancy termination performed by its rodostimulyatsii or caesarean section.
main method of prevention is intramuscular globulin containing specific Rh antibodies immediately after the first birth.This prevents sensitization of an Rh-negative mother's Rh-positive fetus in subsequent pregnancies.