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Neonatal Hematology for the Primary Care Physician

Neonatal Hematology for the Primary Care Physician. Vlad C. Radulescu, M.D. University of Kentucky. Topics. Normal newborn hematologic parameters Common causes of anemia in the newborn Neonatal screening for abnormal hemoglobins Hemostatic abnormalities

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Neonatal Hematology for the Primary Care Physician

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  1. Neonatal Hematology for the Primary Care Physician Vlad C. Radulescu, M.D. University of Kentucky

  2. Topics • Normal newborn hematologic parameters • Common causes of anemia in the newborn • Neonatal screening for abnormal hemoglobins • Hemostatic abnormalities • Current use of umbilical cord blood stem cells

  3. Case #1 • 3 months old infant • 32 weeks gestation, birth weight : 2100 g • Spent two weeks in NICU for respiratory distress, feeding difficulties • Feeding well, thriving, appropriate growth • CBC: • WBC 10,500 / fl, • Hgb 9.5g /dl, MCV 95fl, • platelet count 245,000 / fl

  4. Normal Newborn CBC • Hemoglobin • Red blood cell indices : Mean Corpuscular Volume • Peripheral smear

  5. Neonatal changes that impact thered blood cell indices • Sudden increase in tissue oxygenation after birth • Decrease erythropoietin levels • Decreased hemoglobin production • Transition from fetal hemoglobin to adult hemoglobin • Rapid growth

  6. Hemoglobin Data extracted from: The Harriet Lane Handbook, 19th edition, table 14-1

  7. Hemoglobin Full term Premature 1200 -2350 g Premature <1200 g Adapted from: Nathan and Oski Hematology of Infancy and childhood, 7th ed.

  8. Mean Corpuscular Volume Data extracted from: The Harriet Lane Handbook, 19th edition, table 14-1

  9. Normal Adult Blood Smear

  10. Neonatal Blood Smear

  11. Hemoglobin, MCV are high at birth and decrease over the first few months of life, more dramatically for the pre-term infant • MCV < 94fl in newborn • 2/3 had Bart’s Hemoglobin • Suggestive of alpha thalassemia

  12. Case #1 : normal infant • 3 months old infant • 32 weeks gestation, birth weight : 2100 g • Spent two weeks in NICU for respiratory distress, feeding difficulties • Feeding well, thriving, appropriate growth • CBC: • WBC 10,500 / fl, • Hgb 9.5g /dl, MCV 95fl, • platelet count 245,000 / fl

  13. Anemia in the Newborn

  14. Anemia in the Newborn

  15. Anemia in the Newborn • Presentation • Life threatening event • Pallor, difficulty feeding, poor weight gain, tachycardia • Incidental finding • Does it require immediate intervention? • If a transfusion is indicated should any tests be done prior to transfusion • Does the newborn have to be referred to a hematologist?

  16. Evaluation of Anemia in the Newborn • CBC • RBC indices – MCV (Mean Corpuscular Volume) • Reticulocyte count • Elevated – RBC destruction ( hemolysis) or bleed • Decreased – decreased RBC production • Coombs ( direct anti-globulin test) • Positive in immune hemolysis • Maternal and fetal blood type • Identifies mismatched in the ABO and Rh blood types that may represent set-ups for allo-immunization

  17. Anemia through blood loss • Fetal- maternal transfusion • Rupture of the cord • Laceration of the placenta • Internal hemorrhage • Intracranial • Retroperitoneal • Intrathoracic • Intraabdominal

  18. Anemia due to hemolysis • Immune hemolysis • Maternal alloimmunization to fetal RBC antigens • Maternal auto-antibodies ( Lupus) • Non-Immune Hemolysis • Enzymes • G6PD • RBC membrane • spherocytosis • Hemoglobin • Thalassemia, Hgb. SS

  19. Hemolytic Disease of the Newborn • The mother becomes sensitized to antigens present on fetal red blood cells • Fetal- maternal hemorrhage • Prior maternal transfusion • Antigens • Rh • ABO • Kell, Duffy, Kidd • Maternal antibodies cross the placenta • IgG can cross, IgM, IgA can not cross • Transport increases in the 3rd trimester

  20. Hemolytic Disease of the Newborn • Maternal antibodies bind to fetal RBC and sometimes other tissues • AB, Duffy, Kidd, Kell antigens are expressed on erythroid and non erythroid tissues • Rh, MN, SS antigens expressed only on erythroid tissues • Antibodies bound to RBC induce hemolysisif • they can activate complement • promote cell mediated cytotoxicity

  21. Hemolytic Disease of the Newborn • RhD • Most commonly identified antigenic stimulus • Mother is Rh negative, fetus Rh positive • The incidence has dropped with the use of anti-D antibodies to decrease maternal sensitization • ABO • Mother is type O, fetus is type A, B • Kell, Duffy, Kidd • Maternal sensitization may be due to prior maternal blood transfusions mismatched in the minor blood types

  22. Hemolytic Disease of the Newborn • Diagnosis: • Mismatch between maternal and newborn blood types • History of prior maternal transfusions • Combs ( Direct Antiglobulin Test) positive • Neonatal Hyperbilirubinemia • Managemnt • Anemia • simple or exchange transfusion • Hyperbilirubinemia • Phototherapy • Exchange transfusions

  23. Anemia through decreased production • Physiologic anemia • Anemia of prematurity • Late anemia of the hemolytic disease of the newborn • Bone marrow failure syndromes • Diamond Blackfansdr. • Fanconisdr. • Nutritional deficiencies • Infections • Infiltrative processes • Leukemia • Neuroblastoma

  24. Anemia of prematurity • Causes • Low erythropoietin levels • Small circulating blood volumes • Blood loss • Hemolysis • Minimize blood loss • PRBC transfusions • Hgb < 7 g/dl • Apnea & bradycardia • Tachycardia • Tachypnea • Poor weight gain • Respiratory distress • Erythropoietin • Iron supplements

  25. Hemoglobin Screening in Newborns

  26. Hemoglobin Screening in Newborns • Goal: early diagnosis of sickle cell disease • The first manifestations of sickle cell disease in infants may be life-threatening complications: • Pneumococcal sepsis • Splenic sequestration

  27. Methodology • High performance liquid chromatography • Identifies different types of hemoglobin • Relevant for sickle cell disease: Hgb S , Hgb C • Incidental findings: Hgb H, Hgb Bart’s, Hgb E, D, etc.

  28. Normal variants Embrionic Fetal a2 g2 Adult 1 a2 b2 Adult 2 a2 d2 Abnormal variants S, D, C, E : abn. bchain Barts: g4 H: b4 Hemoglobin

  29. Hemoglobin Switching during development

  30. Normal newborn • Screening test: FA • Hemoglobin electrophoresis: • Hgb F 60-90% • Hgb A1 10-40% • Hgb A2 < 1 %

  31. Sickle Cell Syndromes

  32. Sickle Cell Syndromes: Interventions • Refer to Pediatric Hematology/ repeat testing • Evaluate infant for splenomegaly. • Educate parents/caregivers regarding • risk of sepsis , aggressive management of fevers • splenic sequestration in Sickle Cell disease • Pen V K 125 mg po bid until repeat testing confirms or rules out a sickle cell syndrome

  33. Thalassemia Syndromes

  34. Globin Genes

  35. Alpha Thalassemia

  36. Alpha Thalassemia • Follow-up tests: • CBC, Hemoglobin electrophoresis • Consider alpha globin gene mutation analysis • Family history • Ethnic origin: common in SE Asia • History of anemia or microcytosis • Genetic counseling • Consider Pediatric Hematology referral

  37. Non- Sickle Hemoglobinopathies

  38. Carriers of Hemoglobin Variants

  39. Carriers of Hemoglobin Variants • In general, no medical intervention is needed for the patient • Genetic counseling : asses the risk of having a child with sickle cell disease or thalassemia major • For the patient future children • For the patient’s parents • Evaluation of the carrier state : CBC, Hgb electrophoresis

  40. Hemostatic abnormalities in the newborn

  41. Case # 2 • FT newborn • Covered in petechiae at birth • Birthweight : 3.4kg • Apgar scores: 9, 9 • Case # 3 • FT male newborn • Birthweight: 3.5kg • Apgar scores: 8, 9 • Oozing for 4 hrs. at the site of the heel-stick • Develops unexpected bleeding after circumcision

  42. Hemostatic abnormalities:presentation • Petechial rash • Ecchymoses • Cephalohematoma • Small but prolonged bleeding at the heel-stick site • Hematoma at the IM injection site • Oozing form the umbilicus • Bleeding with circumcision • Intracranial bleeding

  43. Laboratory evaluation • CBC • PT • PTT • Fibrinogen • Platelet Function Analysis • Normal values*

  44. Neonatal Thrombocytopenia

  45. Neonatal Thrombocytopenia • Prevalence • Common in the sick newborn • 20-40% of NICU admissions • 70-80% of very low birth weight premature newborns • Uncommon in the healthy newborn (1-2%) • Timing • <72 hrs – due to prenatal or perinatal factors • >72 hrs - due to postnatal factors • Sepsis • Necrotizing enterocolitis

  46. Thrombocytopenia in the sick newborn • Frequently associated with: • Infection • Asphyxia • Meconium aspiration • Respiratory distress syndrome • Necrotizing enterocolitis • Presence of indwelling catheters • Predictor of poor prognosis • Mortality • Intestinal gangrene in NEC • Frequently leads to bleeding complications

  47. Thrombocytopenia in the well -looking newborn • Maternal history • Drug ingestion • Sulphonamides, valproic acid, carbamazepine, quinindine • Hypertension / Pre-eclampsia • Infections during pregnancy • Maternal ITP/ low maternal platelet count • Previous newborn with thrombocytopenia • Neonatal Allo-immune Thrombocytopenia (NAIT)

  48. Thrombocytopenia in the well -looking newborn • Newborn exam • Normal • NAIT • Maternal ITP • Maternal drug exposure • Congenital abnormalities • Thrombocytopenia absent radii syndrome (TAR) • Fanconi anemia • Hepatosplenomegaly • Infection • Leukemia

  49. Neonatal Allo-Immune Thrombocytopenia ( NAIT) • Mechanism • The mother is exposed to a Platelet antigen they do not posses • The mother produces an IgG. antibody that • crosses the placenta • Induces thrombocytopenia in the newborn • Incidence 1:5000- 10,000 birth • May occur with the first pregnancy, more severe with subsequent pregnancies • Manifestations • Thrombocytopenia • Purpura • Internal hemorrhage including intracranial hemorrhage

  50. Neonatal Allo-Immune Thrombocytopenia ( NAIT) • Diagnosis • Identification of maternal and paternal platelet antigens • Maternal and paternal genotyping • Management • Platelet transfusions • IV Immunoglobulins • Subsequent pregnancies • Close monitoring • IV Ig. • Steroids • Cord blood sampling and in utero platelet transfusions

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