Polycythemia in newborn

polycythemia definition,c/f and management

1. POLYCYTHEMIA IN NEWBORN KANCHAN GAWADE

2. Definition Polycythemia  (  polyglobulia )  is increased total RBC mass Central venous hematocrit > 65 % the hemoglobin is greater than 22 mg/ dL Hct initially rises after birth due to placental transfer of blood and decrease to baseline at 24 hrs Hyperviscosity is increased viscosity of the blood more than 2 SD of mean resulting from increased numbers of RBCs

3. Blood viscosity is ratio of shear stress to shear rate and is dependent on pressure gradient along the vessel,radius,length of vessel and velocity of flow of blood. Viscosity is directly prop to Hct and plasma viscosity whereas inversely proportional to deformability of RBCs Relation between Hct and viscosity is linear till Hct is 60 % after that viscosity increases exponentially

4. Poiseuille's law: Resistace to blood flow is directly prop to viscosity                    R = 8hL /π r(4) Where R = resistance to blood flow, h = viscosity, L = length of the vessel, and r = radius of the vesse

5. Oxygen delivery vs. Hematocrit

6. Incidence 1-5% of term newborns It is increased in IUGR, SGA and post term Half of these are symptomatic Hyperviscosity occurs in 25% of infants with hematocrit 60-64% Hyperviscosity without polycythmia occurs in 1% ( nonpolycythemic hyperviscosity )

7. Pathophysiology Clinical signs result from regional effects of hyperviscosity and from the formation of microthrombi Tissue hypoxia Acidosis Hypoglycemia Organs affected – CNS , kidneys, adrenals, cardiopulmonary system, GI tract

8. Pathophysiology of Polycythemia

9. Causes Placental red cell transfusion -- -- Delayed cord clamping – at 1 min blood volume of baby is 80 ml / kg. -- At 2 min – blood vol of infant is 90 ml/kg -- In newborn with polycythemia blood volume is inversly proportional to birth weight. -- Cord stripping

10. Causes Placental red cell transfusion -- --Holding baby below the mother at delivery -- Maternal to fetal transfusion – diagnosed with K-B test --Twin to twin trasfusion --forceful uterine contraction before cord clamping

11. Causes Placental insufficiency --Increased fetal erytropoesis d/t chronic hypoxia --SGA and IUGR --Maternal hypertension like preeclampsia --Post term --Mothers with chronic hypoxia (heart dis ,pulmonary dis ) --Pregnancy at hihg altitude ,maternal smoking

12. Other conditions Diabetic mother – raised erythropoiesis LGA CAH , patau syndrome, edward syndrome , downs syndrome (PED) Maternal use of propranolol sepsis

13. Clinical features Mostly asymtomatic CNS – poor feeding , lethargy,hypotonia , apnea, tremers , jitteriness,seizures , cerebral venous thrombosis. CVS - cynosis , tachypnea , heart murmur, CHF, cardiomegaly , increased pulmonary vascular resisance,prominent vascular markings.

14. Clinical features RENAL- decreased GFR ,decrease sodium excretion, renal vein thrombosis, Hematuria , proteinurea OTHERS – thrombosis ,thrombocytopenia, poor feeding, decrease in calcium, NEC ,testicular infracts, priapism , DIC

15. Screening WHOME TO SCREEN IUGR babies LGA babies Infant of diabetic mother Lager of the twins

16. SCREENING Not routinly done in all term babies high-risk neonates screened at 2 hours of age If Hematocrit value >65% at 2 hours of age repeat screening at 12 and 24 hours.

17. Diagnosis Central venous hematocrit > 65% ALWAYS draw a central venous sample if the capillary hematocrit is > 65% Warmed capillary hematrocrit > 65% only suggestive of polycythemia BLOOD VISCOSITY – may be measured where facility available

18. Management Asymptomatic infants HCT 60 -70 % increase fluid intake and repeat HCT after 4 to 6 hr central venous hematocrit > 70% (consider partial exchange transfusion )

19. Management Symptomatic infants with peripheral HCT > 65% Partial exchange transfusion is advisable. For exchange can use normal saline, 5 % albumin, or FFP Volume exchanged = ( Weight (kg) x blood volume) x (observed hct - desired hct ) /observed hct Blood volume is 80-90 ml/kg in term and 90-100 ml/kg in pre term In exchange blood from umbilical vein and normal saline infused in peripheral vein

20. AIIMS PROTOCOL SYMTOMATIC – Partial exchange transfusion(PET) ASYMTOMATIC- Hct >75% - transfusion Hct 75 – 70 % - extra fluid alliquote @20 mkd Hct <70 % - monitor Hct The Cochrane review – with exchange transfusion there is no difference in morbidity of patient --PET causes NEC

21. Other labs to check Serum glucose Hypoglycemia is common with polycythemia Serum bilirubin Increased bili due to increased RBC turnover Serum sodium, BUN, urine specific gravity Usually high if baby is deyhdrated Blood gas to rule-out inadequate oxygenation as cause of symptoms Platelets , as thyrombocytopenia can be present Serum calcium b/c hypocalcemia can be seen

22. Prognosis Increased risk of GI disorders and NEC with partial exchange transfusion ( PET) PET is controversial ! Infants with asymptomatic polycythemia have an increased risk for neurologic sequelae .