Significant bruising or cephalohematoma (increases RBC turnover). c
Maternal gestational DM.
Pathophysiology
Physiological neonatal jaundice
↑ Bilirubin production: ↑ RBC mass/hematocrit at birth with a shorter RBC lifespan (~90 days vs. 120 days).
↓ Bilirubin clearance: Transiently ↓ activity of hepatic UDP-glucuronosyltransferase (UGT1A1) (takes ~2 weeks to reach adult levels). c
↑ Enterohepatic circulation: Sterile newborn gut lacks bacteria to convert bilirubin to urobilinogen; high intestinal β-glucuronidase deconjugates bilirubin, allowing reabsorption.
Definition: a type of neonatal jaundice caused by insufficient breastfeeding
Pathophysiology: insufficient breast milk intake → lack of calories and inadequate quantities of bowel movements to remove bilirubin from the body → ↑ enterohepatic circulation → increased reabsorption of bilirubin from the intestines → unconjugated hyperbilirubinemia
Clinical features: onset within 1 week
Breast milk jaundice
Definition: a type of neonatal jaundice caused by increased levels of β-glucuronidase in maternal breast milk
Pathophysiology: increased concentration of β-glucuronidase in breast milk → ↑ deconjugation and reabsorption of bilirubin → persistence of physiologic jaundice with unconjugated hyperbilirubinemiac
β-Glucuronidase is found in breast milk and the intestinal brush border.
Deconjugation of bilirubin by bacterial β-glucuronidase can lead to pigment stone formation.
Clinical features: onset within 2 weeks after birth; lasts for 4–13 weeks
Healthy, thriving infant with appropriate weight gain.
Normal hydration status (wet diapers, moist mucous membranes).
Progressive jaundice (cephalocaudal progression).
Normal-colored stools (not pale/acholic) and light-colored urine.
Diagnostics: Unconjugated (indirect) hyperbilirubinemia with normal direct bilirubin (< 1.0 mg/dL or < 10% of total).
Treatment
Reassurance & Continue Breastfeeding: First-line.
Encourage maternal hydration and frequent feeding (8-12 times/day) to promote GI motility and stooling. c
Phototherapy:
Initiated if TSB levels exceed the age-specific phototherapy threshold based on the AAP nomogram.
Temporary cessation of breastfeeding:
Only indicated if TSB approaches exchange transfusion thresholds. Substitute with formula for 24-48 hours to abruptly lower bilirubin, then resume breastfeeding.
Clinical features
Diagnostics
Treatment
Complications
Kernicterus (chronic bilirubin encephalopathy)
Develops over first years of life
Pathophysiology: deposition of unconjugated bilirubin (liposoluble) in the basal ganglia and/or brain stem nuclei