1 / 51

بسم الله الرحمن الرحيم

بسم الله الرحمن الرحيم. Management of Rh alloimmunization. CDE (Rhesus) System. Includes c, C, D, e, E D negativity defined as absence of D antigen. Antibodies Associated with . Anti-c, Anti-D, Anti-E, and Anti-Kell

vernados
Download Presentation

بسم الله الرحمن الرحيم

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. بسم الله الرحمن الرحيم

  2. Management of Rh alloimmunization

  3. CDE (Rhesus) System • Includes c, C, D, e, E • D negativity defined as absence of D antigen

  4. Antibodies Associated with • Anti-c, Anti-D, Anti-E, and Anti-Kell • Anti-D-immunoglobulin prophylaxis reduced the hemolytic disease caused by anti-D, but not the others

  5. Minor RBC Antigens causes hemolyisis • Kell is most common of minor • Responsible for 10% of cases of severe antibody-mediated anemia **Transfuse women with Kell(-) blood**

  6. Inert Antibodies • Antigens such as A, P, Le (a), M, I, IH, and Sd (a) are innocuous • Mostly are IgM • Lewis antibodies is the commonest one detected

  7. Sensitization rate • 16 percent without prophylaxis • 2 percent with routine postpartum administration • 0.1 percent with routine antenatal administration

  8. Causes of Rh isoimmunization • Delivery • Induced abortion • Spontaneous abortion • Ectopic pregnancy • Partial molar pregnancy • Chorionic villus sampling • Cordocentesis

  9. Amniocentesis • External cephalic version • Abruptio placenta • Antenatal hemorrhage • Maternal abdominal trauma • Spontaneous • Needles • Blood and blood product

  10. Clinical Management • Routine booking blood group &Antibodies screen • Rh –v Ab –v • Determine father’s RhBC status if • -v No risk

  11. If the father is +ve for-D-antigen, fetus is at RISK - Repeat Antibodies screen at 28 weeks for Rh-ve women prior to receiving Anti-D immunoglobulin -Determine father’s RBC antigen status and zygosity

  12. Clinical Management • If Antibody screen is +ve, identify antibody type • Identify the risk factors for alloimmunization(past pregnancies, transfusions, shared needles)

  13. Clinical Management • Obtain antibody titer from the mother if the past history is not significant for an affected pregnancy. **Titers less reliable after a sensitized pregnancy** Consider invasive testing at titer of 1:16 or greater by indirect Coombs

  14. Clinical Management • If Antibodies titer remains below critical titer- invasive testing is not indicated and the patient can be followed up by serial Antibodies titter • Serial titers before 18-20 weeks not necessary

  15. If Antibodies titer is above the critical level or the past history is positive regardless of the antibodies titer- invasive testing is indicated

  16. Clinical Management • Amniocentesis for amniocytes at 15 weeks by (PCR) to determine fetal blood type if father is heterozygous. • Free fetal DNA in maternal circulation.

  17. Fetal antigenic determination Amniocentesis, CVS, cordocentesis samples can be used to determine fetal antigen status by DNA typing 100% accuracy in 390 samples Bennett et al. 1993 Molecular analysis of maternal plasma: fetal DNA for RhD 100% accuracy in 45 fetuses second/third trimester Lo et al. N Engl J Med 1998;339:1734-8.

  18. PCR from cell free DNA in maternal serum 100% accuracy in 137 fetuses (including 21 female fetuses) Finning et al. Transfusion 2002;42:1079-85. Possible utility in embryo selection for sensitized mothers

  19. Clinical Management • Serial amnio to measure delta OD450 and plot values on Liley or Queenan graph

  20. Delta OD450 • Spectral analysis of amniotic fluid at 450 nm proposed in 1961 by Liley- measures change in OD • Measures the level of bilirubin and predicts severity of hemolytic disease after 27 weeks • Delivery or intrauterine transfusion if delta OD450 falls into zone III or upper zone II

  21. Queenan Curve • Proposed another method of using delta OD450 • Suggested four zones and extended the gestational age to 14 weeks

  22. Limitations of Amniocentesis • May give a falsely elevated bilirubin level in presence of mec or blood May be low after exposure to light or in Kell alloimmunization

  23. Cordocentesis • Gold standard for detection of fetal anemia • Complications! • 2.7% total risk of fetal loss • Reserved for patients with increased MCA-PSV or delta OD450

  24. MCA-PSV • Velocity of blood flow in brain increased with anemia 1. Increased cardiac output 2. Vasodilatation in the brain 3. Decreased blood viscosity

  25. MCA & FETAL ANEMIA • The MCA PSV correlated well with hematocrit and hemoglobin concentrations and is useful for predicting the severity of fetal anemia (Mari G. 1995) • The MCA PSV increases in fetuses with anemia (Roberts AB. 2001)

  26. FETAL ANEMIA Fetal anemia  blood viscosity Cardiac output peripheral vasodilatation Blood flow to the Brain, Heart and Adrenal gland Mari G. 1990 Many A. 1996 HecherK. 1995 Bahauddin Sallout

  27. Correct Technique for MCA Doppler • Fetus resting • Circle of Willis imaged in axial image using color Doppler • Entire length of MCA • Close to origin of internal carotid artery

  28. MCA LOCALIZATION • In a transverse axial view of the fetal head at a slightly more caudal plane than the one used for BPD • At this level, which include the cerebral peduncles, the MCA can be seen as a major lateral branch of the circle of Willis Bahauddin Sallout

  29. Transverse view of the fetal head with color Doppler showing the circle of Willis Flow velocity waveforms from the MCA at 32 wk MIDDLE CEREBRAL ARTERY

  30. MIDDLE CEREBRAL ARTERY • Normal flow in 1º trimester • Normal flow in 2º & 3º trimester

  31. MCA-PSV

  32. MCA & FETAL ANEMIA Fetal anemia due to maternal alloimmunization Bahauddin Sallout

  33. MCA ABSENT DIASTOLIC FLOW Severe hydrops (kell antibody) Bahauddin Sallout

  34. Rh Alloimmunization management • If using MCA-PSV, and initial is less than 1.5 MoM, weekly testing • Cordocentesis or delivery depends on the gestational age once the MCA-PSV reaches 1.5 MoM

  35. Mari et al. N Eng J Med 2000

  36. Advantages of MCA-PSV • Non-invasive • Mother not put at risk for worsening alloimmunization • Can be used with all antibodies other than RhD, including anti-Kell antibodies

  37. Disadvantages of MCA-PSV • Need skill • Done weekly • Accuracy decreases after 35 weeks • False +ve results 12 percent

  38. Current evidence supporting MCA-PSV Doppler velocimetry Initial prospective study of 16 fetuses: 14 anti-D, 2 anti-c Mari et al. Ultrasound Obstet Gynecol 1995;5:400-5. Since then several prospective and retrospective studies: over 200 additional cases Rbc alloimmunization and parvovirus B19 1-Scott et al. Prenat Diagn 1998;18:1143-8. 2-Teixeira et al. Ultrasound Obstet Gynecol 2000;15:205-8. 3-Delle Chiaie et al. Ultrasound Obstet Gynecol 2001;18:232-6. 4-Mari et al. N Eng J Med 2000;342:9-14. 5-Zimmermann et al. Br J Obstet Gynecol 2002;109:746-52. 6-Mari et al. Ultrasound Obstet Gynecol 2002;99:589-93.

  39. Current evidence supporting MCA-PSV Doppler velocimetry Sensitivity 87-90% Specificity 88-100% PPV 53-74% NPV 98-100% Data combined from 7 studies: rbc alloimmunization and parvovirus B19

  40. Prediction of fetal anemia by MCA-PSV Doppler compared to Amniocentesis 4 Comparative Studies N = 28 Nishie EN, et al. Am J Obstet Gynecol 2003;188:214-9 N = 28 Pereira L et al. Am J Obstet Gynecol 2003;189:1002-6 N = 38 Bullock ,et al. Ultrasound Obstet Gynecol 2005 N = 165 Oepkes D, et al. N Engl J Med 2006;355:156-64.

  41. Current evidence MCA-PSV Doppler Amniocentesis Sensitivity 53-86 64-100 Specificity 71-78 81-91 PPV 44-100 47-75 NPV 95-96 97-100 N =259 Cumulative ranges from 4 trials

  42. Conclusion MCA-PSV accurately predicted moderate to severe fetal anemia Compared to conventional management, MCA-PSV may have a better predictive accuracy for moderate or severe anemia in alloimmunization Management by MCA-PSV may eliminate the need for amniocentesis and reduce the number of PUBS performed in alloimmunized pregnancies

  43. Potential Benefits of Management by MCA-PSV • 14,000 cases of alloimmunization per year in the U.S. • Avoid 24,500 amniocenteses and 900 PUBS • Avoid 1 pregnancy loss/preterm delivery for every • 100 patients; 142 nationwide per year • Avoid worsening sensitization from procedure • related bleeding complications – TPH risk 2-10% following amniocentesis, 50% following PUBS

  44. Prevention of Alloimmunization Doses of ani-D-immuonoglubuline for Rh-ve) • 50 mcg dose protects against 2.5 ml of Rh (+) RBC’s • 300 mcg dose protects against 15 ml of RBC’s or 30 ml of Rh (+) blood • 20 mcg per ml RBC

  45. Preventionstandard recommendations • 300 mcg dose within 72 hrs of delivery to unsensitizedRh (-) women (Rh positive infant) 13 days , 28 days • 300 mcg at 28 weeks UNLESS father known to be Rh (-) • Repeat Antibody Screen before giving the prophylactic dose?

  46. Indications for administration of anti-(D) immune globulin

  47. Fetal death in the second or third trimester • Blunt trauma to the abdomen • Antepartum hemorrhage in the second or third trimester (eg, placenta previa or abruption) • External cephalic version

  48. Prevention • Test for excessive fetal-maternal hemorrhage after blunt trauma, abruption, cordocentesis, and bleeding assoc. with previa • Kleihauer Betke

More Related