Neonatal jaundice

(Redirected from Kernicterus)


  • Neonatal jaundice can affect up to 84% of term newborns and is often a benign process that is quickly corrected once identified. It is also the most common cause for hospital readmission for neonates post birth.[1]
  • The most important piece of the evaluation is distinguishing between unconjugated and conjugated hyperbilirubinemia since a conjugated (direct) hyperbilirubinemia is always pathologic and often more severe

Risk Factors

Clinical Features

General neonatal jaundice features

A neonate with jaundice on exam.

Differential Diagnosis

Indirect (Unconjugated) Hyperbilirubinemia

More common causes are listed first, followed by less common causes

  • Breast milk jaundice
    • Due to substances in milk that inhibits glucuronyl transferase. It may start as early as 3rd day and reaches peak by 3rd week of life. It is unlikely to cause kernicterus
  • Breast feeding jaundice
    • Patient does not receive adequate oral intake which then causes reduced bowel movement/bilirubin excretion. Best diagnosed by looking for signs of dehydration and comparing weight to birth weight.
  • Blood group incompatibility: ABO, Rh factor, minor antigens
  • Diabetic mother/gestational diabetes
  • Internal hemorrhage
  • Physiologic jaundice
  • Polycythemia
  • Sepsis
  • Hemoglobinopathies: thalassemia
  • Red blood cell enzyme defects: G6PD Deficiency, pyruvate kinase
  • Red blood cell membrane disorders: spherocytosis, ovalocytosis
  • Hypothyroidism
  • Immune thrombocytopenic purpura
  • Mutations of glucuronyl transferase (i.e., Crigler-Najjar syndrome, Gilbert syndrome)

Direct (Conjugated) Hyperbilirubinemia

Conjugated bilirubinemia implies a hepatic or post hepatic cause. More common causes are listed first.


Neonatal jaundice workup

The most important component of the workup is differention of direct vs indirect bilirubinemia

  • Total and direct bilirubin levels ("neonatal bilirubin")
  • CBC (for evaluation of hemolytic anemia or polycythemia vera)
  • Consider coombs or T&S (mom & baby)

Neonatal jaundice diagnosis

  1. Determine if there are red flags or obvious diagnosis based on history and exam
    • Mother's blood type (important if mother is RH negative or O blood type)
    • Assess for any signs of decreasing oral intake or signs of dehydration?
    • Baby's general appearance (well appearing? evidence of sepsis?)
  2. Determine bilirubinemia type: direct vs indirect
    • Direct
      • Admit
    • Indirect
      • Determine risk category
        • See table below
      • Determine if patient is above of below bilirubin cutoff by age and risk category


  • Breast Milk Jaundice
    • Do not need to routinely stop breast-feeding
    • If bilirubin elevated beyond 10 mg/dL:
      • Stop feeding for 1-2 days, substitute with bottle, and then resume breast milk
      • Recurrence of prior hyperbilirubinemia is uncommon upon resuming
    • Treat with phototherapy when levels exceed 20 mg/dL
  • Breast-Feeding Jaundice (Starvation Jaundice)
    • Supplement with expressed breast milk or formula
  • Exchange transfusion
    • Consider if signs of bilirubin encephalopathy, typically only occurs when the indirect bili level exceeds 25
      • Hypertonia, arching, retrocollis, opisthotonos

Phototherapy guidelines for neonatal jaundice

Total Bilirubin Cutoff by Risk Group
Age Low Risk Medium Risk High Risk
Birth 7.0 5.0 4.0
24h 11.5 9.0 8.0
48h 15 14 10
72h 17.5 15 14
96h 20 17.5


5+days 21 17.5 15
  • Low Risk: ≥38 weeks + no risk factors
  • Medium Risk: (≥38 weeks + risk factors) or (35-37 weeks and no risk factors)
  • High Risk: 35-37 weeks + risk factors
Phototherapy is only used for an indirect hyperbilirubinemia


  • Direct hyperbilirubinemia
    • If new diagnosis, always admit to the hospital for further evaluation
  • Indirect hyperbilirubinemia
    • Admit if septic or concerning disease process
    • Typically determined by need for phototherapy (see chart above)

See Also

External Links


  1. Sgro M, Campbell D, Shah V. Incidence and causes of severe neonatal hyperbilirubinemia in Canada. CMAJ. 2006;175(6):587–590.