Topic: Broncho – pneumonias, kernicterus
Question: Describe the pathophysiology, clinical presentation and management of Kernicterus in newborn.
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Unconjugated hyperbilirubinemia can result from increased production or decreased excretion of bilirubin.
The causes of increased production of unconjugated bilirubin are:
Kernicterus, or bilirubin encephalopathy, is bilirubin-induced neurological damage, which is most commonly seen in infants. It occurs when the unconjugated bilirubin (indirect bilirubin) levels cross 25 mg/dL in the blood from any event leading to decreased elimination and increased production of bilirubin. The unconjugated bilirubin can cross the blood-brain barrier as it is lipid-soluble, unlike the water-soluble conjugated bilirubin. It gets deposited in the brain tissue, mainly the basal ganglia. The neurotoxicity of unconjugated bilirubin leads to various neurologic sequelae.
Pathophysiology
– Kernicterus refers to neurologic impairment caused by bilirubin toxicity to the developing brain in neonatal jaundice.
– Neonatal jaundice occurs when bilirubin, a byproduct of red blood cell breakdown, accumulates faster than the newborn’s liver can clear it.
– Unconjugated bilirubin can cross the immature blood-brain barrier and cause toxic neuronal damage.
– Basal ganglia, brainstem, cerebellum, hippocampus and subcortical nuclei are most vulnerable.
Clinical Presentation
– Early signs: Lethargy, poor feeding, hypotonia
– Intermediate stage: High-pitched cry, fever, seizures
– Advanced stage: Opisthotonos, paralysis, impaired upward gaze, deafness
– Chronic: Choreoathetoid cerebral palsy, dental enamel defects, gaze abnormalities, sensorineural hearing loss
Management
– Prevention: Identify and monitor infants at risk, promote adequate feeding and hydration
– Phototherapy: Converts unconjugated bilirubin into water-soluble isomers
– Exchange transfusion: Removes bilirubin-laden blood and replaces with fresh donor blood
– IV immunoglobulin: Decreases bilirubin production in isoimmune hemolytic disease
– Supportive care: Control seizures, maintain airway and circulation
– Long-term: Physical, occupational and speech therapy for neurologic sequelae; hearing aids or cochlear implants for hearing loss
The key is to recognize and treat neonatal hyperbilirubinemia aggressively to prevent bilirubin neurotoxicity and permanent neurological damage known as Kernicterus
