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HDN
Intro, Disease Process, Classification & Pathogenesis
Question | Answer |
---|---|
Hemolytic disease of the newborn is? | destruction of RBCs of the fetus & neonate by AB produced by the mother |
Th mother is stimulated to produce ABs by? | curent or previous pregnancies or by transfusion |
HDN is most commonly caused by | anti-D and other Rh blood group ABs |
During pregnancy there is fetomaternal hemorrhage | which are RBCs from fetus enter the mothers circulation, 0.1ml |
Mother forms antibodies against | paternal antigens |
IgG antibodies cross placenta | and bind to fetal RBCs |
D hemolytic disease | caused by anti-D alone or in combo with anit-C or anti-E |
Other hemolytic disease | caused by other Rh ABs or blood group ABS, anti-K, anti-c |
ABO hemolytic disease | usually caused by anti-A,B in O women |
FHM occurs in # of pregnancy | 75%, usually immediately after delivery |
Other causes of FHM | amniocentesis, abortion, chorionic villus sampling, cordocentesis,etopic preg, blunt trauma to abdomen |
Since advent of Rh immune globulin | < 1% of D neg mothers exhibit immunization |
Incidence of 'D' HDN = | 18% in untreated D neg mothers of D pos infants |
Prevalance of non-anti-D HDN = | <0.3% |
Transfusion of D pos red cell products | to women of child bearing age should be avoided |
IF D pos transfusion necessary | then Rh IG prophylacic treatment |
Hemolysis & Erythropoiesis | Maternal IgG AB attaches on fetal RBCs; AB/AG complex removed by macrophages in spleen; fetal bone marrow & hempietic tissue in liver & spleen increase RBC production |
Anemia | moderate to severe depending on #RBCs destroyed; severe anemia may lead to hydrops fetalis from enlarged liver and spleen; |
Anemia cont | RBC destruction continues after birth as long as maternal AB in system |
Hydrops fetalis | severe edema, effusions, ascites |
Bilirubnemia | RBC lysis casuse release of HgB which is metabolized into indirect bikirubin; then may be transported across placenta & conjugated in maternal liver to direct bilirubin & then excreted |
Bilirubnemia cont | total bili elevated in fetal serum & amniotic fluid, but not harmful; after birth, accumulation of indirect bili to toxic levels & can cause brain damage |