Bbilirubin-induced brain dysfunction.

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Aetiology

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

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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

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Diagnosis

Imaging

MRI