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Neonatal Jaundice

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Overview

Neonatal jaundice can be physiological or pathological. Physiological neonatal jaundice occurs due to the breakdown of foetal haemoglobin and replacement with adult haemoglobin which releases bilirubin and immaturity of the liver and its ability to conjugate bilirubin for excretion. This bilirubin is normally excreted by the placenta, however, once no longer present, this can lead to a transient rise in bilirubin in the neonate.

Jaundice in the first 24 hours is always pathological and requires urgent investigations and treatment.

High bilirubin levels can lead to kernicterus, which describes bilirubin-induced permanent brain damage.

Epidemiology

  • Around 6/10 of babies develop jaundice and this increases to 8/10 in premature babies

Causes

Jaundice within the first 24 hours

Jaundice in the first 24 hours is always pathological and requires urgent investigations and treatment. Its causes include:

Jaundice from days 2-14

Around 6/10 babies have jaundice from days 2-14 of life and this is usually physiological. At around 14 days, the liver is mature enough to conjugate bilirubin and jaundice resolves.

Babies that are breastfed are more likely to have neonatal jaundice (breast milk jaundice). Its exact reason is unknown, but this is thought to be due to components of breastmilk inhibiting the liver’s ability to process bilirubin. This generally resolves after a month and breastfeeding should still be encouraged as its benefits outweigh the risks of breast milk jaundice.

Jaundice after 14 days (prolonged)

Jaundice that is longer than 14 days is considered prolonged. Causes include:

Presentation

Overview

Yellowing of the skin is the primary feature, which usually first becomes visible in the face and forehead. In most cases, this is the only feature. Visual inspection alone is not sufficient to estimate bilirubin levels.

More severe jaundice and hyperbilirubinaemia can lead to or be associated with:

  • Neurological signs – these suggest kernicterus and can include:
    • High-pitched crying, seizures, hypertonia, fluctuating consciousness
  • Hepatosplenomegaly – suggesting haemolytic anaemia, sepsis, and infection

Investigations

Overview

Visual inspection alone is not reliable for estimating bilirubin levels. A total serum bilirubin level can be used as screening and is often the only test needed for moderately jaundiced babies who are well without pathological (within 24 hours) or prolonged jaundice.

Investigations for pathological or prolonged jaundice include:

  • Conjugated and unconjugated bilirubin – the most essential test:
    • Elevated conjugated bilirubin can suggest a hepatobiliary cause such as biliary atresia which requires urgent surgery
  • Full blood count (FBC), blood film, and reticulocyte count:
    • May identify haemolytic anaemia and show low haemoglobin, increased reticulocytes, and abnormal red blood cell shapes (e.g. spherocytes)
  • Coomb’s test:
    • Identifies ABO or rhesus incompatibility
  • Blood group:
    • Identifies the neonate’s ABO and rhesus status
  • Thyroid function tests (TFTs):
    • May identify hypothyroidism
  • Blood and urine cultures:
    • To screen for and identify infection

Management

Referral

Refer urgently for immediate assessment and management if any of the following apply:

  • Jaundice within the first 24 hours of life
  • The baby is jaundiced and unwell
  • Prolonged jaundice

Treatment

Treatment threshold tables are used which are based on total bilirubin measurements. If the treatment threshold is met, treatment involves:

  • Phototherapy – a specific frequency of light is shone on the skin which facilitates the breakdown and removal of bilirubin
  • Exchange transfusion if jaundice is severe

Complications

  • Kernicterus
  • Phototherapy may cause:
    • Dehydration
    • Loose stools
    • A benign skin rash which resolves after phototherapy is stopped
    • Potential retinal damage, which is avoided by putting on eye shields

Prognosis

  • Early diagnosis and effective treatment have now made kernicterus very rare in the UK

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