Neonatal Bilirubin Toxicity (Kernicterus)
Neonatal Bilirubin Toxicity (Kernicterus)
Key Concepts
- Potentially devastating neurological condition caused by severe hyperbilirubinemia
- Unconjugated bilirubin crosses blood-brain barrier causing neuronal injury
- Prevention through early recognition and treatment is crucial
- Risk factors must be identified within first 24 hours of life
Epidemiology
- Incidence: 0.4-2.7 per 100,000 live births
- Higher risk in developing countries
- More common in East Asian and Mediterranean populations
- Males more affected than females
Molecular Mechanisms
- Unconjugated bilirubin accumulation in plasma
- Disruption of blood-brain barrier
- Neuronal membrane damage
- Mitochondrial dysfunction
- Apoptosis of neurons
Schematic overview of the proposed pathophysiological mechanisms underlying bilirubin-induced neuronal injury.(source)
Risk Factors
- Maternal Factors:
- Blood type incompatibility (ABO, Rh)
- Diabetes mellitus
- Race/ethnicity
- Drugs affecting bilirubin metabolism
- Neonatal Factors:
- Prematurity (<38 weeks)
- Low birth weight
- Sepsis
- Hemolysis
- G6PD deficiency
- Cephalohematoma
- Poor feeding
- Dehydration
Affected Brain Regions
- Basal ganglia (globus pallidus)
- Hippocampus
- Subthalamic nuclei
- Cerebellum
- Brainstem nuclei
- Cranial nerve nuclei III, IV, VIII
T2-weighted axial MRI at 6 months of age in a male born at 40 weeks of gestation with hyperbilirubinemia due to G6PD deficiency and a total bilirubin of 39 mg/dl (665 µM) at 125 hours of age, treated with two double-volume exchange transfusions, diagnosed at 27 months of age with moderate to severe, motor-predominant kernicterus.(source)
Clinical Evaluation
Acute Phase Signs
- Phase 1 (1-2 days):
- Poor feeding
- Lethargy
- Hypotonia
- Weak suck
- Phase 2 (intermediate):
- Hypertonia
- Retrocollis
- Opisthotonus
- High-pitched cry
- Phase 3 (advanced):
- Seizures
- Apnea
- Death
Laboratory Assessment
- Total serum bilirubin (TSB)
- Direct bilirubin
- Blood type and Rh factor
- Direct Coombs test
- Complete blood count
- Reticulocyte count
- G6PD screening
- Albumin levels
Risk Assessment Tools
- Hour-specific bilirubin nomogram
- Bilirubin/Albumin ratio
- Transcutaneous bilirubinometry
- Clinical risk factors assessment
Treatment Approaches
Phototherapy
- Primary intervention method
- Indications based on:
- Gestational age
- Postnatal age
- TSB levels
- Risk factors
- Types:
- Conventional (blue light)
- LED phototherapy
- Intensive (double surface)
- Fiber optic blankets
Exchange Transfusion
- Indications:
- Failed phototherapy
- Severe hyperbilirubinemia
- Signs of acute bilirubin encephalopathy
- Procedure details:
- Double volume exchange
- Careful monitoring required
- Complications management
Supportive Care
- Hydration maintenance
- Temperature regulation
- Feeding support
- Frequent monitoring
- Eye protection during phototherapy
Long-term Sequelae
Neurological
- Choreoathetoid cerebral palsy
- Hearing impairment/loss
- Dental enamel hypoplasia
- Gaze abnormalities
- Cognitive impairment
Developmental
- Speech and language delays
- Motor delays
- Learning disabilities
- Behavioral problems
Prevention Strategies
- Universal bilirubin screening
- Risk assessment before discharge
- Parent education
- Early follow-up after discharge
- Proper feeding establishment
Prognosis
- Dependent on:
- Severity of exposure
- Duration of exposure
- Timing of intervention
- Underlying conditions
- Regular developmental follow-up required
- Early intervention programs beneficial
Disclaimer
The notes provided on Pediatime are generated from online resources and AI sources and have been carefully checked for accuracy. However, these notes are not intended to replace standard textbooks. They are designed to serve as a quick review and revision tool for medical students and professionals, and to aid in theory exam preparation. For comprehensive learning, please refer to recommended textbooks and guidelines.
