Haemolytic Disease Of New Born

Question 1

Definition

Answer 1

Allo-immune disorder in which the lifespan of the fetal and or neonatal red cells is shortened due to binding of transplacentally transferred maternal IgG antibodies on fetal red cells anyigens foreign to the mother inherited by the fetus from the father

Question 2

Aetiology/ pathogenesis

Answer 2

Antibodies directed agaunst the D- antigen in Rhesus blood group system( Rhesus Haemolytic disease)

Antibodies directed against the A and B antigens ( ABO Haemolytic Disease)

Antibodies directed against other red cell antigens

Question 3

Rhesus Haemolytic Disease

Answer 3

Occurred as a result if acquired rhesus positive red cells by a rhesus negative mother through fetomaternal hemorrhage provoking a primary response of anti-D igG antibodies capable of crossing the placenta

Repeated exposure of Rh positive fetal blood cells to rh negative mother produces a secondary immune response marked by production of large quantity of anti-D igG antibody leading to extravascular phagocytosis and lysis occuring predominantly in the spleen

Question 4

ABO incompatibility protecting against primary Rh immunization

Answer 4

Fetomaternal ABO incompatibility offers protection against primary Rh immunization because incompatible fetal red cells are destroyed rapidly by maternal anti A and anti B antibodies reducing maternal exposure to Rh D antigens

Question 5

Timing of Rh immunoglobulin prophylaxis

Answer 5

In absence of Rh immunoglobulin prophylaxis sensitization occurs within 6 months after delivery of first Rh- positive baby

Question 6

ABO HAEMOLYTIC DISEASE

Answer 6

Commoner than Rh Haemolytic disease

Limited to mothers who’re blood group O and children are A or B

Confined to the 1%of such women with high titre IgG antibodies

Milder & rarely responsible for fetal death since anti A and anti B are of IgM type and dont cross the placenta

Occurs with same degree in first as in subsequent pregnancy

Question 7

Classes of antibodies to A and B antigens

Answer 7

IgM if environmentally stimulated e.g bacteria

IgG if stimulated by foreign erythrocytes e.g transfusion of ABO incompatible erythrocytes or maternal-fetal ABO incompatibility

Question 8

Haemolytic disease of other red cell antibodies

Answer 8

Kell, duffy, kidd and MNS systems

Question 9

Clinical features

Answer 9

Anemia symptoms 
Jaundice: bilirubin encephalopathy 
                  Kernicterus symptoms 
Hepatosplenomegaly
Hydrops fetalis

Question 10

Prevention

Answer 10

Rh neg mothers to have prophylactic anti D immunoglobulin

All rh neg mothers who deliver rh positive baby should have Rh Ig forget within (72) hours post partum

Antibody quantification in alloimmuned mother to determine number of fetal cells in mother (standard dose of 300ug dose of anti Rh Ig affords protection against 30ml of Rh-positive blood)

Question 11

Management

Answer 11

Intrauterine fetal transfusion: transfused with freshly packed O neg Rbc antigen neg for any other antibodies (unit of blood must be cytomegalovirus seronegative/ leukodepleted/ irradiated and crossmatched against mother blood)

Exchange blood transfusion ( 9-12 hrs of birth to remove sensitized red cells and bilirubin and maternal antibodies) also corrects anemia

Immunomodulation- use of IV IgG, plasmparesis, glucocorticoids in Rh sensitized pregnant mothers to suppress antibody response to antigens

Phototherapy