Updated: 12/29/2021

Congenital Hyperbilirubinemia

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  • Snapshot
    • A 3-day old newborn girl is evaluated in the hospital for jaundice that was first visible only in her face as seen in the image, but has gradually progressed to the trunk and extremities. She was born at 35 weeks' gestation to a healthy mother with an uncomplicated pregnancy course. On physical examination, her muscle tone is weak in the upper extremities and she has an altered cry. A total serum bilirubin level is measured and is found to be elevated and in the 99th percentile.
  • Introduction
    • Overview
      • congenital hyperbilirubinemia may be due to either accumulation of conjugated or unconjugated bilirubin in newborns
    • Congenital Hyperbilirubinemia
      Unconjugated Hyperbilirubinemia
      SyndromePathophysiology
      Characteristics
      Gilbert syndrome
      • Defect in glucuronyl transferase
      • 5% of population
      • Increase in serum unconjugated bilirubin
      • Jaundice presents in stressful situations
      • Benign
        • no treatment necessary
      Crigler-Najjar syndrome
      • Deficiency of glucuronyl transferase
      • Markedly increased serum unconjugated bilirubin
      • Type 1
        • severe jaundice,death from kernicterus is common by 1 year of age; liver transplant is curative
      • Type 2
        • less severe; responds to treatment with phenobarbital
      Conjugated Hyperbilirubinemia
      Dubin-Johnson syndrome
      • Defective liver excretion of bilirubin
      • Increase in serum conjugated bilirubin
      • Benign
        • no treatment necessary
      • Liver turns black
      Rotor syndrome
      • Impaired hepatic uptake and defective excretion of bilirubin
      • Increase in serum conjugated bilirubin
      • Benign
        • no treatment necessary
        • milder than Dubin-Johnson syndrome
      • Liver does not turn black
  • Epidemiology
    • Incidence
      • Gilbert syndrome
        • 3-7% of individuals
      • Crigler-Najjar syndrome
        • 1 in 750,000-1,000,000 newborns
      • Dubin-Johnson and Rotor syndrome
        • rare, incidence unknown
  • ETIOLOGY
    • Pathophysiology
      • significant unconjugated congenital hyperbilirubinemia
        • ↑ bilirubin production due to pathological hemolysis
        • ↓ bilirubin clearance due to inherited genetic defects that impair bilirubin conjugation
          • i.e., Gilbert syndrome and Crigler-Najjar syndromes (see table below)
      • conjugated congenital hyperbilirubinemia
        • impaired liver excretion of bilirubin
          • i.e., Dubin-Johnson and Rotor syndromes (see table below)
    • Genetics
      • mutations
        • Gilbert syndrome and Crigler-Najjar syndrome
          • UGT1A1 gene
            • encodes for a protein that catalyzes the conjugation of bilirubin with glucuronic acid
  • Presentation

    • Symptoms
      • jaundice
      • signs of bilirubin encephalopathy (kernicterus)
        • decreased feeding
        • lethargy
        • abnormal muscle tone
        • high-pitched cry
        • fever
        • seizures
    • Physical exam
      • scleral icterus
      • jaundice that may have cephalocaudal progression
      • brown discoloration of the urine (conjugated hyperbilirubinemia)
      • abnormal muscle tone and seizures (bilirubin encephalopathy)
  • Studies
    • Serum bilirubin level
      • increased levels of total serum bilirubin
        • typically ranges from 1-5 mg/dL in Gilbert syndrome
      • direct bilirubin concentration of ≥ 10 μmol/L may indicate conjugated hyperbilirubinemia
      • direct bilirubin is < 15% of total serum bilirubin in Crigler-Najjar syndrome
    • Complete blood cell count
      • screen for hemolysis
  • Differential
    • Physiologic neonatal jaundice (benign congenital hyperbilirubinemia)
      • key distinguishing factor
        • resolves after 1-2 weeks after birth
        • caused by turnover of fetal erythrocytes and immature ability of infant's liver to metabolize bilirubin
  • Treatment
    • Medical
      • phenobarbital
        • treatment for Crigler-Najjar syndrome type 2 (detectable but low UGT1A1 activity)
          • ↑ liver enzyme synthesis
    • Surgical
      • liver transplant
        • curative for Crigler-Najjar syndrome type 1
  • Complications
    • Kernicterus
      • incidence
        • rare
        • may occur from bilirubin encephalopathy in Crigler-Najjar syndrome type I
      • treatment
        • plasma exchange transfusion
        • long-term phototherapy
  • Prognosis
    • Gilbert syndrome
      • benign
      • good prognosis
    • Crigler-Najjar syndrome
      • patients often die within a few years of life
    • Dubin-Johnson syndrome
      • benign
      • good prognosis
    • Rotor syndrome
      • benign
      • good prognosis with milder presentation compared to Dubin-Johnson syndrome

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