Objective Define Erythroblastosis fetalis Explore Pathogenesis & pathophysiology of hemolysis due to RH & ABO incompatibility Distinguish the clinical finding of cases of Erythroblastosis fetalis Judge and be able for diagnosis all type of blood group incompatibility

Hemolytic dis. Of newborn ( Erythroblastosis fetalis ) The most serious cause of indirect hyperbilirubinemia with anemia in newborn because blood group incompatibility between the mother & infant which may be due to passage of maternal Ab against fetal RBC leading to hemolysis . it include Rh incompatibility . ABO incompatibility . subgroup incompatibility as Kell ( K ) , M , Duffy , C

Hemolytic disease of Rh incomp Pathogenesis & pathophysiology : Rh+ve having Rh Ag in the RBC either ( C, c , D , E , e ) the most common is D Ag , or Rh-ve which is not having the Ag , when Rh –ve expose to Rh+ve blood it will start to develop Ab which is called Anti D .

Rh-Isoimmunization

Hemolytic disease of Rh incomp Pathogenesis & pathophysiology : Rh-ve mother get pregnant with Rh+ve baby & blood may go from fetus to the mother by feto-maternal tansfusion (usually > 1ml )during pregnancy, abortion , or labour, so Rh Ag D pass from baby to mother lead to sensitization of the mother & formation Anti Rh Ab initially IgM which not cross the placenta then there will be formation of IgG Ab which can cross the placenta reaching fetal blood & causing agglutination & destruction of fetal RBC causing haemolysis , anemia & erythroblastosis fetalis .

Hemolytic disease of Rh incomp Pathogenesis & pathophysiology : Haemolytic disease of Rh incomp. usually occur in 2nd baby & Rarely occur in 1st baby . because transfusion of Rh +ve fetal blood to Rh –ve mother tend to occur near delivery that is too late for mother to become sensitized & transmit Ab to her infant which usually need time to occur but when she get pregnant with 2nd Rh +ve baby he will get the disease .

Hemolytic disease of Rh incomp Pathogenesis & pathophysiology : It will occur in 1st baby when mother previously sensitized by receiving Rh +ve blood for some reason or when she is previously abort Rh +ve baby with no treatment by Anti D . Once sensitization occur & development of the disease , the severity tend to be more with successive pregnancy .

Pathogenesis & pathophysiology : When IgG Ab cross the placenta to fetal blood & causing agglutination & destruction of fetal RBC causing haemolysis , anemia & erythroblastosis fetalis in which anemia with compensatory hyperplasia of erythropoietic tissue leading to massive enlargement of the liver and spleen. also, profound anemia results in pallor, signs of cardiac decompensation (cardiomegaly, respiratory distress), circulatory collapse.

Pathogenesis & pathophysiology : edema , ascites and massive anasarca develop in sever cases , that is due to anemia , reduction in serum albumin (oncotic pressure), and heart failure . This clinical picture of excessive abnormal fluid in two or more fetal compartments (skin, pleura, pericardium, placenta, peritoneum, amniotic fluid), termed hydrops fetalis

Hemolytic disease of Rh incomp Incidence is low because : - May get Rh –ve baby . 50 % of pregnancies develop feto maternal transfusion . capacity of Rh –ve mother to form Ab is variable ( good or weak ) . if ABO incomp. present may partially protect against sesitization by removal of Rh +ve cells from circulation by Anti-A or Anti-B which is IgM that not cross the placenta

Hemolytic disease of Rh incomp Clinicle manifestation It is various from mild to severe so either develop only lab evidence of mild hemolysis ( 15 % ) that is jaundice or anemia or severe when the patient develop hepato-splenomegally in addition to anemia & jaundice which may be present at birth or may be absent at birth & rapidly rise within 1st 24 hr. & may lead to kernicterus some times appear after 1st 24 hr

Hemolytic disease of Rh incomp Clinicle manifestation more severe cases ( hydrops fetalis ) there is oedema , massive anasarca pleural effusion , pericardial effusion , in addition to hepato-splenomegally , pallor , jaundice . heart failure , circulatory collapse . The patient with hydrops fetalis may be present with IUD or died shortly after birth because of respiratory distress & birth asphyxia .

hydrops fetalis

Hemolytic disease of Rh incomp Clinicle manifestation Some patients may have hepatic dysfunction & hypo-albuminemia in others hypoglycemia may occur because of hyperinsulinemia or pancreatic islet hypertrophy . In severe cases there may be petechae & purpura because of thrombocytopenia due to decrease BM production or DIC .

Hemolytic disease of Rh incomp Post Natal Dx In Rh –ve pregnant women with Hx of sensitization (abortion , pregnancy , previous blood transfusion ) , we should suspect the case & should aspirate cord blood at delivery room or blood from infant if present to you later & Send for

Hemolytic disease of Rh incomp Post Natal Dx blood group & Rh, TSB that is usually 3-5 mg/dL at birth but may rapidly increase within 1st 6 hour or very high since birth or it rise in 1st day or later on . CBC , retic count , blood smear . usually show anaemia increase retic with polychromasia increase NRBC, WBC usually normal, platelet may decrease in sever cases . coomb's test (usually strongly +ve & may stay for few days to several month )

Hemolytic disease of Rh incomp Post Natal Dx when there is sign of hemolysis with -ve coomb,s test we should think of ABO incomp. or non immune cause of hemolysis as:- enzyme deficiency ( G6PD,PK deficiency ) . cell membrane disease spherocytosis , alpha Thalasaemia .

Antinatal Dx When we have pregnant Rh-ve women with possible sensitization by previouse blood transfusion , abortion or pregnancy . we should do parents blood group & Rh tested for potential incompatibility also we can do fetal blood group & Rh from fetal DNA , fetal cell from maternal circulation . then measure maternal Anti-D Ab (IgG ) of the pregnant women in 12-16 wk ,28-32 wk & 36wk of gestation . The severity of fetal disease monitored by amniocentesis , percutaneous UBS & U/S.

Ultrasound For Dx of IU Hydrops , early findings are organomegally ( liver , spleen , heart ) , double bowel sign ( bowel oedema ) & placental thickening , polyhydramnios , ascites , pleural , pericardial effusion & then skin , scalp oedema fetal well being (biophysical profile ) , doppler U/S for fetal distress( increase vascular resistance ) . PUBS if Doppler and ultrasonography suggest erythroblastosis fetalis. PUBS is performed to determine fetal hemoglobin levels and to transfuse packed RBCs in fetal anemia (Hct < 30%).

Amniocentesis so there is 3 relative declining zones , It is done if there is evidence of maternal sensitisation with maternal titre of Ab >1/16 or by U/S sign of hydrops or hemolysis, fetal distress . It is done for measurment of increase bilirubin in the amniotic fluid by spectrophotometry done at 18-20 week , it reflects the degree of haemolysis & risk of IUD so there is 3 relative declining zones , 1st zone when fetus is unaffected or mildly affected 2nd zone the fetus moderately affected 3rd zone the fetus is severely affected .

Treatment of an Unborn Infant. If the fetus in zone 3 or if hydrops with anaemia & haematocrit of < 30 % with pulmonary immaturity or fetus less than 35 –37 week gestation so we have to give him IU transfusion with packed O –ve RBC ,the transfusion is either into peritoneal cavity or more likely into umbilical vein Transfusions should achieve a post-transfusion Hct of 45–55% . Indications for delivery include pulmonary maturity, fetal distress, complications of PUBS, or 35–37 wk of gestation.

Birth of live born infant Should be attained by paediatrician ,resuscitation must be ready , also fresh O-ve blood croosed matched with mother serum should be prepared befor delivery. If clinical sign of sever hemolytic anemia or hydrops ( pallor , HSmegally , petieche or ascites ) evident at birth & may have sever respiratory distress or birth asphyxia so we may need to do resuscitation by endotracheal intubation & suction ,oxygen , ambu bag with supportive measure , temperature stabilization , correction of acidosis , may need exchange transfusion or blood transfusion (small shoot of packed RBC ) according to the state of the infant , also patient some time may need volume expander during resuscitation .

Prevention of Rh isoimmunization It is done by prevent sensitization of pregnant Rh –ve woman by giving her human Anti D globuline which combine with & eliminate RH +ve fetal RBC that passed to maternal circulation thus prevent sensitization. It is given at 28 - 32 week of gestation & within 72 hr. of the delivery (should given after each pregnancy of RH +ve baby ) . also given within 72 hr. of abortion , delivery of ectopic pregnancy , amniocentesis , abdominal trauma in pregnancy , chorionic villous biopsy & trans-placental hemorrhage . also we have to prevent exposure of Rh –ve mother to Rh +ve Ag ( Rh +ve blood transfusion

ABO INCOMPATABILITY It is more common & usually result in milder haemolytic disease than Rh incomp. The cause is reaction of maternal Anti A or Anti B Ab to A or B Ag in fetal RBC or newborn .Usually seen in infant of type A or B blood group born to mother type O blood group . although Anti- A & Anti - B Ab are naturally present with out previous immunization that is usually in form of IgM that can not cross the placenta , but when mother expose to A or B Ag (during first ABO incomp. pregnancy or abortion ) leading to maternal sensitization & formation of IgG which cross placenta & leading to fetal hemolysis during 2nd or next ABO incomp. pregnancy .

ABO INCOMPATABILITY however some mother (usually type O blood group ) has naturally present Anti A or Anti B Ab of IgG ( 7S ) type which cross the placenta easily , that is why ABO Incomp.can occur in the 1st pregnancy . Although ABO Incomp. occur in 20 – 25 % of pregnancies haemolytic disease develop in only 10 % of such offspring .

Clinical Manifestation Infant generally not affected at birth , most cases are mild with jaundice as the only manifestation . Jaundice may appear in the 1st 24 hr. or later 2nd , 3rd day & rarely develop severe jaundice & kernicterus . 10 – 20 % of patients having TSB reaching 20 or more unless phototherapy . anemia usually is not present , some time may occur in sever cases The liver and spleen may be normal or enlarged in sever hemolysis hydrops fetalis extremly rare .

Diagnosis Blood group of the mother (usually group O) & baby ( usually A or B ) Increase TSB ( often the only abnormality ) Hb. Usually normal but may be as low as 10 – 12 gm /dL . Coomb's test either weak to moderately +ve or –ve , with increase retic. Count . Polychromasia , NRBC , spherocyte ,

Subgroup incomp. As Kell , C , e , Duffy these subgroup incomp. Also may associated with anemia & hyperbilirubinemia ,some time Hepato-spleenomegally , coombs test is invariably +ve Also some time may present with hydrops fetalis , exchange transfusion also may be needed some time .