RHESUS INCOMPATIBILITY Dr Afaf I Alnoury RHESUS INCOMPATIBILITY
ﺑﺴﻢ ﺍﻟﻠﻪ ﺍﻟﺮﺣﻤﻦ ﺍﻟﺮﺣـﻴـﻢ RHESUS INCOMPATIBILITY Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY MATERNAL BLOOD GROUP IMMUNIZATION Hemolytic Disease (Erythroblastosis Fetalis) The Rh Group system: èThe Rh blood group system is the most common & most important blood group system causes immunization & hemolytic disease. Fisher’s Theory èThe Rh antigen are grouped in three pairs Dd, Cc & Ee. èThe presence of D determined that the individual is Rh +ve. èThe absence of D that determine that a person is Rh D –ve. è 45% of Rh +ve individual are homozygous. è 55% of Rh +ve individual are heterozygous. Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY The Pathogenesis of Maternal Blood Group Immunization Blood transfusion Fetal Maternal Transplacental Hemorrhage (TPH) Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY The Pathogenesis of Maternal Blood Group Immunization Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY Incidence Of Rh immunization Amount of antigen necessary to produce Rh immunization: The incidence of Rh immunization is dose dependent. è 15% became immunized after 1 ml of Rh+ve red cell. è 33% became immunized after 40 ml of Rh+ve red cell. è 65% became immunized after 250 ml of Rh+ve red cell. èThe secondary immune response is provoked by very small amount of Rh+ve blood (0. 1 - 0. 5 ml of red cells) Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY Pathogenesis of Hemolytic Disease of fetus & newborn (HDN) The basic pathogenesis of HDN is the destruction of Rh+ve fetal red cells by maternal Rh antibody (Ig. G anti D). RBC destruction, fetal anemia production of fetal erythropoietin bone marrow produce RBC’s extramedullary organs (liver, spleen, kidney & adrenal) to produce RBC’s Hepatosplenomegaly Nucleated red cells elements appear in fetal circulation (normoblast, erythroblasts) erythroblastosis faetalis Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY Severity of Rh hemolytic disease Mild: n n n Indirect bilirubin does not exceed 16 -20 mg/100 ml No anemia 50% No treatment Moderate: n n n Fetal hydrops doesn't develop Moderate anemia 30% severe jaundice with risk of kernicterus unless treated Severe: n Fetal hydrops develop in utero Before 34 weeks After 34 weeks 10 – 12% Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY Prediction Severity of Rh hemolytic disease History of fetus or infant with Rh disease Maternal Rh antibody measurement Amniocentesis amniotic fluid optical density measurement Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY Management of the Rh hemolytic disease First visit: n ABO, antibody screening test Rh-ve Immunized antibodies Repeat antibodies@ 18 -20 weeks then monthly ultrasound Maternal antibody measurement Non immunized Prophylactic dose @ 28 – 32 weeks Prophylactic dose after delivery if fetus Rh +ve -ve Non immunized No antibodies immunized Rh Amniocentesis Extrauterine Fetal transfusion Follow up Intrauterine fetal transfusion Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY Management of the Rh hemolytic disease Husband Rh + ve Heterozygous 50% chance Rh –ve fetus Rh - ve Mother Blood gp O 66. 5% chance of ABO Incompatibility Decrease the risk of Rh immunization From 16% to 1. 5% Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY Amniocentesis Indications: Timing: Technique: Hazards: Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY Intrauterine fetal transfusion Indications: Technique: n n Intraperitoneal fetal transfusion (IPT) Direct intravascular transfusion (IVT) Hazards: n Maternal Infection Trauma n Fetal Over transfusion Cardiac tamponade Infection Precipitation of labour Umbilical vein compression Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY Prevention Every Rh –ve unimmunized women who deliveries on Rh +ve baby should be given a prophylactic dose of Rh IG as soon after delivery as possible. Every Rh –ve unimmunized women who aborts should have at least 50 μg of Rh IG. Every Rh –ve unimmunized women undergoing amniocentesis should be given one prophylactic dose of Rh IG. Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY Prevention cont. One prophylactic dose of Rh –ve unimmunized pregnant women at 28 weeks gestation. IF MASSIVE TRANSPLACENTAL HEMORRHAGE OF Rh +ve fetal red cells into an Rh –ve unimmunized women is diagnosed after delivery, one prophylactic dose of Rh IG should be given for every 25 ml of fetal blood and fraction. Dr. Afaf I. Alnoury
RHESUS INCOMPATIBILITY Dr. Afaf I. Alnoury
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