Internal Medicine


Bbilirubin-induced brain dysfunction.


Risk factors

  • Premature birth
  • Rh incompatibility
  • Polycythemia – often present in neonates
  • Sulfonamides (e.g. co-trimoxazole) – displaces bilirubin from serum albumin
  • Crigler-Najjar syndrome type I
  • Gilbert’s syndrome
  • G6PD deficiency
  • Bruising

Clinical features

I. Acute bilirubin encephalopathy (ABE)

Acute state of elevated bilirubin in the CNS.

  • Clinical features:
    • Lethargy, decreased feeding, hypotonia or hypertonia, a high-pitched cry, spasmodic torticollis, opisthotonus, setting-sun sign, fever, seizures, and even death
  • If the bilirubin is not rapidly reduced, ABE quickly progresses to chronic bilirubin encepalopathy.

II. Chronic bilirubin encephalopathy (CBE)

Chronic state of severe bilirubin-induced neurological lesions.

  • Reduction of bilirubin in this state will not reverse the sequelae.
  • Clinical features:
    • Movement disorders
      • Athetoid cerebral palsy and or dystonia, 60% have severe motor disability (unable to walk).
    • Auditory dysfunction
      • Auditory neuropathy (ANSD)
    • Oculomotor impairments
      • Nystagmus, strabismus, Impaired upward or downward gaze, and/or cortical visual impairment
    • Dental enamel hypoplasia/dysplasia of the deciduous teeth
    • Gastroesophageal reflux
    • Impaired digestive function

III. Subtle bilirubin encephalopathy (SBE)

SBE is a chronic state of mild bilirubin-induced neurological dysfunction.

  • Clinical features:
    • Neurological, learning and movement disorders
    • Isolated hearing loss and auditory dysfunction




Axial T1-weighted (TR/TE = 516/9) MR image shows abnormal hyperintensity in the globus pallidus (arrows) in an infant with kernicterus. | Oakden, W. K., Moore, A. M., Blaser, S., & Noseworthy, M. D. (2005). Spectroscopic Characteristics of Kernicterus: A Possible Metabolic Signature. American Journal of Neuroradiology, 26(6), 1571 LP-1574. Retrieved from

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