Newborn Jaundice

Metabolism:

• Product of heme metabolism
• 80-90% is formed from breakdown of Hb
• Two steps:
• Hb + HO (spleen / liver) => CO + Biliverdin
• Biliverdin + Bv reductase => Bilirubin

Clearance & Excretion:

• Hepatic uptake: BR + Alb
• Conjugation: UGT makes BR more H2O sol
• Excretion: Conj-BR secreted into bile
• Cannot be absorbed in intestine of infants since sterility
• Some enz that deconjugate and then reabsorbed

Neonatal Jaundice:

• Nonpathologic: caused by normal changes in BR metabolism
• Term NB: BR is 2-3x higher than adults
• NB's have more RBC's & increased RBC turnover
• Clearance is decreased in NB's
• Mainly due to deficiency of enz UGT1A1

Neonatal Jaundice:

• UGT in TNB is approx 1% of adult
• Reaches adult status at 14 wks
• Increased recirculation of BR

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Normals:

• Caucasians & AA: mean peak = 48-96 hrs
• Normal: 7-9 mg/dl; 95%: 13-18 mg/dl
• Asian: mean peak = 72-120 hrs
• Mean can = 10-14 mg/dl

Physiological jaundice:

• Resolves in 1-2 wks after birth
• Usually by 5th day in Cauc & AA, by 10th day Asians
• We see NB's at 5th day @ AHEC

Hyperbilirubinemia:

• >35wk: TB >95th% on the hour specific Buhtani nomogram
• TB >25-30 mg/dl = increased risk for BIND
• ABE = acute manifestations of BIND
• (Hypertonia, arching, retrocollis, fever, high pitched cry)
• Kernicterus = chronic and permenant sequelae of BIND

Severe Hyperbilirubinemia:

• Jaundice in first 24 hrs.
• TB > hour specific 95%
• Jaundice in TNB after 2 wks age
• DBIL >1.0 mg/dl if TBIL
• Rate of TB rise > 0.2 mg/dl per hour

Causes of Severe HyperBR:

• ABO or Rh(D) incompatibility
• Inherited RBC membrane defects (HS, Ellipto)
• RBC enz deficits (G6PD, PK, porphyria)
• Sepsis
• Dehydration (fluid concentration)

Causes of Severe HyperBR:

• Decreased clearance: defects in UGT:
• Crigler-Najar syndrome
• Gilbert's syndrome

Breast Milk Jaundice:

• Persistence of physiological jaundice beyond week 1
• Commonly with TB >5 mg/dl
• ? Component of milk that increases reabsorption of BR

Treatment:

• Phototherapy
• See Pedi handout:

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