Unconjugated hyperbilirubinemia in the newborn
0. Metabolism process review-- Heme-->[heme oxygenase]-->biliverdin-->[biliverdin reductase]-->bilirubin-->[UGT1A1]-->conjugated bilirubin-->[beta-glucuronidase]-->unconjugated bilirubin
1. Total bilirubin:
-- usually > 1mg/dL
# hematocrit 50~60% (more RBC)
# shorter life span of RBC (85 days)
# deficient UGT1A1
# increased enterohepatic circulation
-- can reach 10~14 mg/dL @ 3~5 days old (East-Asians)
-- resolves within the first one to two weeks after birth
-- >25 mg/dL: bilirubin-induced neurologic dysfunction (BIND)--> kernicterus
2. Neonatal hyperbilirubinemia (>35 wks)
-- check hour-specific Bhutani nomogram: >95th percentile
-- severe if
# appear at first 24 hrs
# >95th percentile
# 0.2 mg/dL ↑ per hour
# after 2 weeks
# conjugated >1 mg/dL or >20 percent
3. Breast milk jaundice
-- >5 mg/dL for several weeks (max. 12 wks)
-- etiology: some unknown factor in milk promoting enterohepatic circulation
4. Breast feeding failure jaundice
-- combined with low output (urine+stool), hypovolemia, weight loss
