Isoimmunization

BPKIHS CN 3rd year, 2011 batch

1. BPKIHS CN 3 rd Year, 2011 Batch

2. Group Member Kalpana Kawan Bibechana Gautam Bhagishori Singh Buddhisara Sunar Gunjan Rawal Khushi Hirachan Lalita Devi Kumai

3. Presentation on Isoimmunization

4. GENERAL OBJECTIVES At the end of this teaching learning session the participants will be able to explain about ISOIMMUNIZATION.

5. SPECIFIC OBJECTIVES At the end of this teaching learning session the participants will be able to Define some important terms. Define isoimmunization . D efine Rhesus factor. Explain about ABO incompatibility & Rh incompatibility. State the Incidence. of isoimmunization . Enlist the causes of isoimmunization .

6. Explain the pathophysiology of isoimmunization . List out the diagnostic measures. Explain about the preventive measures of isoimmunization . Explain about neonatal & fetal effects due to isoimmunization . Describe the management of isoimmunization .

7. ISOIMMUNIZATION

8. SOME TERMINOLOGIES ANTIGEN: is any substance that causes your immune system to produce antibodies against it. ANTIBODY: is a protein produced by the body’s immune system when it detects harmful substances called, antigens. HAEMOLYSIS: destruction of RBCs within the body, it may result from poisoning, infection or the action of antibodies. ALLELE: in (x, y) gene x is an allele, i.e , is one of a number of alternative forms of same gene.

9. HYDROPS FETALIS: Is a severe, life threatening problem in which abnormal amounts of fluid build up in two or more body areas of a fetus or a newborn. SALINE AGGLUTININ[ IgM ]: This type of antibody is 1 st to appear in the maternal circulation . They are large molecules cannot pass through the placental barrier & is not harmful to fetus.

10. ALBUMIN AGGLUTININ[ IgG ]: It is also called incomplete or blocking antibody . Because of its small molecule it can cross the placenta barrier & cause damage to the fetus. TITRE: is a laboratory test that measures the level of antibodies in a blood sample. COOMBS’ TEST: Is used to detect antibodies that are stuck to the surface of red blood cells.

11. KERNICTERUS: is staining and subsequent damage of the brain by bile pigment(bilirubin), which may occur in severe cases of hemolytic disease of the newborn. AMNIOCENTESIS: Is a the process of withdrawl of a sample of amniotic fluid surrounding a fetus in the uterus, by means of a syringe inserted through the abdominal wall under direct ultrasound guidance.

12. DEFINITION Isoimmunization is defined as a production of immune antibodies in an individual in response to an antigen derived from another individual of same species.

13. It occurs in two stages. Sensitization Immunization

14. SENSITIZATION Is defined as alteration of the responsiveness of the body to the presence of foreign substance. In the development of an allergy, an individual becomes sensitized to a particular allergen. The phenomena of sensitization are due to the production of antibodies . It occurs in the women having Rh factor negative blood with fetus having Rh positive in utero, sensitization may occur at first pregnancy and is more likely in subsequent one.

15. IMMUNIZATION A n individual who is Rh negative doesn’t naturally carry antibodies to the Rhesus factor. If by some means Rh positive RBCs enter her circulation, they alert the immune system & antibodies may be produced in order to destroy the foreign protein. This is most likely to occur if blood from an Rh positive fetus leaks across the placental barrier and enters the next blood stream. It may also occur as a result of a mismatched blood transfusion.

16. THE RHESUS FACTOR A group of antigens that may or may not be present on the surface of the red blood cells. It forms the basis of the rhesus blood group system. Most people have the rhesus factor that is they are rh positive. People who lack the factor are termed rh negative.

17. Contd…… h eterozygous positive father: Dd Homozygous positive father: DD Rh negative mother: dd Therefore a heterozygous father may transmit either a positive or negative gene to his children. But a homozygous father will always transmit a positive gene therefore the child could be affected.

18. ABO INCOMPATIBILITY ABO incompatibility describes an immune reaction that occurs in the body if two blood samples of different, incompatible ABO types are mixed together, when these RBC act as antigen & an immune response is triggered. It afflicts newborns whose mothers are blood type O, and who have a baby with type A, B or AB.

19. Rh INCOMPATIBILITY is a condition which develops when a pregnant women has an Rh negative blood type and the fetus she carries has Rh positive blood type.

20. INCIDENCE Incidence varies in different racial and geographical groups. It is lowest amongst the mongoloid races, intermediate amongst the Asian and Africans and higher amongst the Caucasians. India got 5%.

21. CAUSES Transfusion of Rh positive blood to a Rh negative women. Sizable feto -maternal leak from an Rh positive fetus to an Rh negative mother. Such a leakage may occur during: Early pregnancy loss Miscarriage Missed abortion Elective abortion

22. Contd … Ectopic abortion Procedures Chorionic villus sampling Amniocentesis Fetal blood sampling Caesarean section Others idiopathic

23. Contd …. Maternal trauma Manual removal of placenta Internal and External version Leakage during normal delivery

24. PATHOPHYSIOLOGY There is normally no mixing of fetal & maternal blood during pregnancy & labour . When the placenta begins to separate & the chorionic villi tear, the risk of feto -maternal transfusion is increased. Rhesus antigens of the fetal red cell stimulate the production of maternal antibodies.

25. Contd … The first encounter may not result in actual antibody formation but the women will be sensitized: on a second encounter antibodies are produced in abundance. Once formed there antibodies are permanent. The antibody formed in the maternal system [ IgG ] crosses the placenta barrier & enters into fetal circulation.

26. Contd … The antibody will not have any effect on Rh negative fetus. If the fetus is Rh positive, the antibody becomes attached to the antigen sites on the surface of the erythrocytes.

27. The affected cells are rapidly removed from the circulation by the reticulo -endothelial system. Depending upon the degree of destruction of the fetal red cells, various types of fetal hemolytic disease appear.

28. Fetal RBC are broken down, there is decreased level of RBCs then anemia is seen. Bilirubin, the end product of RBC breakdown accumulates in the body cause jaundice.

29. Due to anemia, the fetal growth is retarded. Due to jaundice, kernicterus is seen which cause FETAL DEATH.

30. DIAGNOSIS The essential diagnosis are: The mother must be Rh negative. P resence of maternal Rh antibodies as shown by a positive indirect coombs’ test on mother’s blood. Maternal antibody titre posing risk to fetus. History of birth of previous affected baby. Fetal cord blood shows low level of Hb % at birth & raised bilirubins .

31. 6. Recently amniotic fluid bilirubin concentration evaluate Rh disease which shows bright yellow color .

32. DIRECT COOMBS’ TEST The direct coombs’ is used to detect these antibodies or complement proteins that are bound to the surface of RBC. A blood sample is taken & the RBCs are washed & then incubated with antihuman globulin[also known as coombs’ reagent]. If this produces agglutination [clumping together] of RBCs, THE DIRECT COOMBS’ TEST IS POSITIVE.

33. INDIRECT COOMBS’ TEST INDIRECT COOMBS’ TEST: The indirect coomb’s test is used in prenatal testing of pregnant women , & in testing blood prior to a blood transfusion. It detects antibodies against RBCs that are present unbound in the patient’s serum. In this case serum is extracted from the blood sample taken from the patient. Then the serum is incubated with the RBC of known reference values from other patient blood samples. If this produces agglutination of RBCs, THE INDIRECT COOMBS’ TEST IS POSITIVE.

34. PREVENTION OF MATERNAL ISOIMMUNIZATION There are three ways of preventing a women from producing rhesus antibodies . Avoiding transfusion of Rh positive blood. Even a small amount of Rh positive blood introduced into the circulation of Rh negative person will result in SENSITIZATION. Rh positive blood should never be administered if the individual’s blood group is unknown & whenever possible cross matching should be undertaken prior

35. Contd…… blood transfusion. Prevention of avoidable feto-maternal transfusion. Precautions during caesarean section; to prevent blood spilling into the peritoneal cavity. Prophylactic ergometrine; with the delivery of the anterior should preferably be witheld, as it may facilitate fetomaternal bleed.

36. Contd…… Amniocentesis;should be done after sonographic localisation of the placenta to prevent it’s injury. Forcible attempt; to perform external verson under anaesthesia should be avoided. Manual removal of placenta should be done gently. To refrain from abdominal palpation as far as possible in abruptio placenta.

37. Contd……. Administration of ANTI D immunoglobulin When to administer? It should be administered within 72 hours or preferably earlier following delivery or abortion. It should be given provided the baby born is Rh positive and the direct coombs test is negative. In case,where the specified time limit is over (>72hour)

38. Contd…….. She may be given up to 14-28 days after delivery to avoid sensitization. DOSE ; ANTI ‘D’gamma glubulin is administered intramuscularly to the mother 300 microgram followig delivery.

39. Contd….. All Rh negative unsensitized women should receive 50 microgram of Rh-immune globulin im within 72 hours of induced abortion, spontaneous abortion, ectopic pregnancy or chronic villus biopsy in the first trimester. Women with pregnancy beyond 12 weeks should have full dose of 300 microgram.

40. Fetal effects The effect of R h isoimmunization on the fetus include Destruction of fetal RBC’s cause anaemia with continious during intrauterine life. Erythroblastosis fetalis . Hydrops fetalis : tissue hypoxia and acidosis eventually lead to intra uterine fetal death.

41. NEONATAL EFFECTS Congenital hemolytic anaemia . Hyperbilirubinemia , if timely actions are not taken the hyperbilirubinemia results in deposition of bilirubin in the basal cerebral ganglia leading to kernicterus. Progressive anemia can lead to congestive cardiac failure. Icterus gravid neonatrum.

42. MEDICAL MANAGEMENT OF ISOIMMUNIZATION ANTENATAL MANAGEMENT Detection of maternal sensitization. Detection of maternal sensitization is confirmed by the detection of Rh antibodies in maternal circulation, it is done by titre technique. Titre below 4IU/ml are unlikely to produce severe fetal disease. All Rh negative pregnant women should have their blood tested for Rh antibodies at the 1 st antenatal visit and again at 28 th & 34 th weeks of gestation. .[ acc. To DC Dutta , textbook of obstetrics, 16 th edition]

43. Contd ……. Management of affected fetus by intrauterine intravascular transfusion. Blood may be given to the baby by a needle introduced through mothers abdomen. Blood is given either intravascularly [into the umbilical vein] or intraperitoneally . The first method is preferable, as blood enters the fetal circulation directly and severely anemic fetuses may be saved.

44. Contd…. POSTNATAL MANAGEMENT Evaluation & management at birth requires close coordination between obstetrician & neonatologist. The neonates may be born with anemia, hepato-spleenomegaly & ascites and rapidly develops hyperbilirubinemia. These infants are hypo-coagulable & have a tendency of developing hypogly cemia. The presence of positive DCT is sufficient to confirm the diagnosis in an Rh positive neonate born to a sensitized Rh negative women.

45. Contd… Treatment of neonatal anemia In those infants who exhibit only anemia, fresh packed red cells are to correct this defect. The management of hydrops fetalis which is the several form of the disorder is usually done by the rapid correction of anemia by small exchange transfusion 20 to 40 ml/kg body wt raises the hematocrit sufficiently.

46. Contd … TREATMENT OF NEONATAL JAUNDICE . Phototherapy exposure of neonates to light with wave length of 420-470mm results in addition of bilirubin & convertion to products that are water soluble, are not neurotoxic and which can be excreted via stool and urine. It takes 12-24 hrs to be effective.

47. Contd … Exchange transfusion: helps by removing unconjugated bilirubin & Rh positive cells coated with antibodies. Traditionally double volume exchange transfusion done via umbilical vein using group specific negative blood cross matched with mothers serum effectively.

48. NURSING MANAGEMENT 1 . All pregnant women should be screened for blood ABO & Rh groups at the first antenatal visit. 2 . If negative, she is advised to obtain her husband’s ABO & Rh group. 3 . At 35wks, repeat maternal blood for Rh antibodies. If negative, observe her until delivery. If positive, treat her like any Rh sensitized patient. 4 . Collect previous history.

49. Contd ….. 5 . The prevention of maternal sensitization due to Rh positive fetal RBCs that leak into the maternal circulation, when the placenta separation at delivery, is achieved by the administration of HUMAN Rh ANTI-D within 72 hrs of the event. 6. send grouping & Rh typing of baby after delivery as well as serum bilirubin to detect neonatal jaundice. 7. observe for anemia, jaundice, sucking reflex, irritability,etc .

50. Contd …… 8. Observe the child for change in color of urine & stool. 9. counsel the patient party before phototherapy & exchange blood transfusion. 10. phototherapy care should be provided. 11. Prevent from complications of phototherapy

51. REFERENCES Cunningham F, M acdonald P, & Leveno k, William’s obstetrics, 19 th edition,1993 page no:1004-1006. Bennett V, Brown L, Myles textbook for midwives, 12 th edition,1996, page no: 543-545. Daffary N, Shirish , Manual of obstetrics, 2 nd edition, 2007, Read elsevier I ndia P vt. Ltd.page no:167-171. Mudaliar & Menons , Clinical obstetrics, 9 th edition, 1995, Orientlongman , 397-399, 202 Thomas R, Moore, Robert R, Gynaecology & obstetrics, 7 th edition, 1993, page no; 444.

52. Chamberlian G, Turnbull’s obstetrics, 3 r d edition, 2004, Library of congress cataloging in publication data, page no: 247-261. Tuitui R, Suwal SN, Mannual of Midwifery-I, 8 th edition, 2012, page no: 321-324. Tuitui R, Suwal SN, Mannual of Midwifery-III, 8 th edition, 2012, page no: 234-235. Shrestha U, Tuladhar K, Integrated science, 4 th edition, 2009, Makalu publication, page no: 83-85.