6

• Jaundice


  Yellow colouration of the skin, usually resulting from accumulation of unconjugated, lipid-soluble bilirubin pigment
• Jaundice


  • Elevated levels of unconjugated bilirubin are potentially neurotoxic
  • May also be due to deposition of pigment from conjugated bilirubin
• Jaundice is seen in 60% of term infants and 80% of preterm infants during first week of life
• Bilirubin metabolism in fetal and neonatal life


  Schematic illustration provided
• Why neonates are at increased risk of jaundice

  • Bilirubin metabolism less efficient, particularly in preterm infants
  • Haemoglobin concentration falls rapidly in first few days due to haemolysis
  • 1g haemoglobin yields 640micromol (35mg) of bilirubin
  • Red cell life span 70 days in newborns compared to 120 days in adults
• Classification of neonatal jaundice

  • Timing: <24 hours, 24 hours - 2 weeks, >2 weeks
  • Site of problem: Pre-hepatic, Hepatic, Post-hepatic
• Jaundice <24 hours of life

  Always pathological, usually due to haemolysis or congenital infection
• Haemolysis


  • Erthyroblastosis fetalis caused by transplacental passage of maternal antibody active against paternal RBC antigen of the infant
  • Commonly associated with D antigen of Rhesus group or ABO incompatability
  • Glucose-6-phosphate dehydrogenase (G6PD) deficiency
  • Spherocytosis caused by abnormality in skeletal protein of RBC membrane
• Jaundice 24h - 2 weeks of life


  Physiological, breast milk jaundice, infection, bruising, polycythaemia, Crigler-Najjar syndrome
• Jaundice >2 weeks of life


  Prolonged in term infant (>3 weeks in preterm infant), need to distinguish unconjugated and conjugated fractions
• Clinical manifestations of jaundice

  • Cephalocaudal progression, unconjugated bright yellow/orange, conjugated greenish/muddy yellow
• Kernicterus


  Bilirubin neurotoxicity, occurs when unconjugated bilirubin level exceeds albumin-binding capacity, leads to lethargy, poor feeding, irritability, hypertonia, opisthotonus, later choreoathetoid cerebral palsy, learning difficulties and sensorineural deafness
• Management of neonatal jaundice

  1. Measure bilirubin level (conjugated and unconjugated fractions if >2 weeks), plot on chart, determine need for phototherapy and/or exchange transfusion, use serial bilirubin measurements to assess response

  2. Other blood tests: haemoglobin/haematocrit, CBC, maternal and infant blood group, Coombs test, reticulocyte count, peripheral blood film, serology
• Phototherapy and exchange transfusion thresholds

  • Day 1: Any visible jaundice
  • Day 2: 15/13 mg/dL (term/preterm)
  • Day 3: 18/16 mg/dL (term/preterm)
  • Day 4: 20/17 mg/dL (term/preterm)
• Phototherapy


  • Light (blue band, wavelength 450nm) converts unconjugated bilirubin to harmless water soluble pigment, eyes should be covered, may cause temperature instability, rash and dehydration
• Exchange transfusion


  • Used when high risk of rapid development of dangerous anaemia or jaundice, measure Hb, haematocrit and bilirubin four hourly, replace baby's blood with donor blood, usually via umbilical venous catheter or peripheral venous and arterial lines, total exchange 2 x 85ml/kg
• Need to ensure that the baby is adequately hydrated
• References provided