| ID | 359 |
|---|---|
| Name | ABO INCOMPATIBILITY |
| Cause | |
| Signs Symptoms | |
| Diagnosis | Diagnosis: Diagnosis is usually postnatal- 1. Blood grouping of molher & infant. 2. Hb- usually normal but may be = 10-12 gm%. 3. Bilirubin- increased. In 10-20% cases indirect (unconjugated) bilirubin may reach 20mg/dl or more unless phototherapy is employed. 4. Reticulocyte- = 10-15% - important criterion. 5. Direct coomb’s tesl (infant)- weakly to modera-tely positive (but may also be negative). 6. Blood film- spherocytosis (may be excluded hereditary spherocytosis). |
| Investigations | |
| Management | Management: Rh- Incompatibility A. Intra-uterine measure- 1. Early induction of labour (between 33-34 wks) in a Rh negative mother- if repeated amniocentesis shows optical density in higher zone i.e zone 2 or 3. 2. An intrauterine intraperitoneal or intraumbilical venous transfusion of erythrocytes compatible with mothers blood, (i.e Rh-ve blood)- first transfusion at 28-29 wks. then every 2-3 wks. interval but nol after 35 wks. Indications- Si. When risk of death from erythroblastosis or from premature delivery is greater than the tranfusion procedure, b. Several optical density readings in zone 3. c. Family history of still birth or hydrops foetalis. B. Postnatal measure (life birth)- 1. General mangement- a. Proper resuscitation by experienced obste-tricians or pediatricians. b. Temperature stabilization- room heater or incubator may be used if available. c. Arrangement for E.T- blood for exchange transfusion (E.T) should be as fresh as possible (should not be more than 4 days old). Acid citrale-dextrrose (ACD) or heparin may be used as anticoagulants. If the blood is obtained before delivery, il should be taken from a type ‘O’ Rh negative donor & should be compatible with the mother’s serum by indirect coomb’s test. After delivery, blood should be oblained from an Rh negative donor compatible with both the mother’s & the infant’s serum; when possible type ‘O’ donor blood are usually employed, but blood of the infant’s ABO type may be used when the mother has the same type. d. Monitoring of the infant for exchange transfusion. e. Correction of acidosis (if any)- by 1 -2meq/kg of NaHCO3 f. Correction of anemia- a small transfusion of compatible packed red cells if necessary. g. Volume expansion for hypotension with 1 .v fluid if indicated. h. Provision of assisted ventilation if resp. failure, including O2 inhalation. i. Airway clearence- by oropharyngeal suction. 2. Exchange transfusion (E.T)- for detail proce-dure, see below. 3. Phototherapy to lower the unconjugated bilirubin from the blood & body. 4. Preventive measure (for Ihe subsequent pregnancies): Mother should be given, Inj. Human anti-D globulin 300ngm (1ml) i.m within 72 hours of delivery or abortion. This quantity is sufficient to eleminate approximately 10ml of potentially antigenic fetal cells from the maternal circulation. If there is more fetomaternal transfusion, may require proportionately more Rho Gam, which when administered at 28-32 weeks of gestation & again at birth (i.e at 40th weeks) may be more effective. This may reduce the risk of hemolytic disease in subsequent pregnancies from between 10-20% to less than 1%. ABO Incompatibility 1. General measure- the baby usually does not require any resuscitation of respiratory support, if otherwise preterm or small for date. Normal breast feeding & maintenance of room temp. 2. Phototherapy- may be effective in lowering the unconjugated S. bilirubin in case of mild to moderate hyperbilirubinemia. 3. Exchange transfusion- For detail procedure see below. Blood to be trasnfused: In case of ABO incompatibility exchange transfusion is done with blood of the same ABO group as that of the mother (i.e usually ‘O’ group) Rh group should match the infants (if baby is Rh-ve) that is blood should be cross matched with maternal blood (& also with baby’s blood). |
| Introduction | In majority cases of hemolylic disease of newborn, il is due lo ABO incompatibility and is ususally milder than Rh incompatibility. In ABO incompatibility maternal antibody may be formed against B cells if the mother is type A or againsl A cells if the mother is type B. However, usually the mother is type O & the infant is A or B. Another important thing is that, although the infant is type A or B & antibodies against A & B antigens occur without prior immunization (natural antibodies), Ihese are ordinarily presenl in I the 195 fraction of gamma globulin (IgM), which can not cross the placenta. But in some cases antibodies againsl A antigen may be present in the 7s fraction (of IgG), which crosses the placenta; so that ABO isoimmune hemolytic disease usually occurs in A group infants & B type infants are practically free from hemolytic diseases of newborn from ABO incompatibility. ABO incompatibility usually occurs in 20-25% of pregnancies & hemolytic disease develops only in 10% of such infants, usually with Al antigen (which is more antigenic than A2). The low incidence of severe ABO hemolytic disease relative to the incidence of incompatibility between the blood groups of mother & child is due lo low antigenicity of the ABO features in the fetus & newborn infanl. |
| History | |
| Etiology | |
| Clinical Features | Clinical features: 1. Mosl cases are mild with jaundice as the only manifestation. 2. Infant is nol generally affected al birth; pallor is not present & ‘hydrops foetalis’ is extremely rare. 3. Jaundice usually appears during the first 24 hours of birth. 4. Rarely it may become severe with symptoms & signs of kemicterus. 5. Liver & spleen-are not greatly enlarged, if at all. |
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