Background Information

Classification

Physiological neonatal jaundice:

• >24 hours after birth
• Always unconjugated (indirect) hyperbilirubinaemia
• Typical duration
  • <14 days in term babies (born ≥37 weeks)
  • <21 days in preterm babies (born <37 weeks)

Pathological neonatal jaundice:

• Onset <24 hours after birth
• Can be either unconjugated (indirect) or conjugated (direct) hyperbilirubinaemia
• Typically causes prolonged neonatal jaundice

Prolonged neonatal jaundice:

• Duration
  • >14 days in term babies (born ≥37 weeks)
  • >21 days in preterm babies (born <37 weeks)

Causes (to be added)

Complications

Note that only unconjugated bilirubin can cross the blood-brain barrier:

• Severe unconjugated hyperbilirubinaemia can result in:
  • Acute bilirubin encephalopathy and/or
  • Chronic bilirubin encephalopathy (aka kernicterus)

Conjugated bilirubin cannot cross the blood-brain barrier:

• Negligible neurotoxicity
• Main complications result from the underlying cause

Diagnosis Guidelines

Bilirubin Measurement

Timing

Method of Measurement

There are 2 ways to measure bilirubin levels:

Approach	Description	Indications
Serum bilirubin	Gold standard method (most accurate): Bilirubin measured directly from a blood sample	<24 hours old <35 weeks gestation Transcutaneous bilirubin indicates a bilirubin >250 micromol/litre (or above treatment threshold) to confirm results Babies receiving phototherapy (to monitor response)
Transcutaneous bilirubin	Screening method: A non-invasive skin probe that gives an estimation of bilirubin level using light reflection spectroscopy through the skin	≥35 weeks gestation, and >24 hours old, and No other indications for serum bilirubin measurement (see above)

Investigating Underlying Cause (to be added)

Management Guidelines

Management

Reassure that breastfeeding, nappy‑changing and cuddles can usually continue

If on/above treatment line → offer corresponding treatment accordingly (i.e. phototherapy or exchange transfusion)

• If the bilirubin level is within 50 mmol/L below the phototherapy threshold → repeat bilirubin measurement
• Otherwise, no routine repeat measurement is required

Example of a treatment threshold graph (exam questions always provide this table, and the thresholds depend on gestational age):

Phototherapy

Phototherapy should be given using an artificial light source (not natural sunlight)

 

Monitoring

Monitoring during phototherapy:

• Repeat 4-6 hours after initiating phototherapy
• Repeat every 6-12 hours when the serum bilirubin level is stable / falling

Monitoring after phototherapy:

• Repeat 12-18 hours after stopping phototherapy (to detect potential rebound)

Stopping Phototherapy

Only stop phototherapy when:

• Serum bilirubin level is at least 50 mmol/L below the phototherapy threshold

Intensified Phototherapy

Phototherapy can be intensified by adding another light source or increasing the irradiance of the initial light source

Consider if:

• Serum bilirubin level is rising rapidly (>8.5 mmol/L per hour), or
• Poor response (bilirubin continues to rise/does not fall within 6 hours of initiating), or
• Serum bilirubin is within 50 mmol/L below the threshold for exchange transfusion after 72 hours since birth

Exchange Transfusion

Exchange transfusion should be performed in an intensive care bed

• Use a double volume exchange transfusion
• Do not stop any ongoing phototherapy

References