Pathophysiology & Risk Factors

Elevated unconjugated (indirect) bilirubin from rapid RBC breakdown plus an immature liver that conjugates slowly. Physiologic jaundice appears AFTER 24 hours, peaks days 3-5 (term) and 5-7 (preterm), and resolves by 2 weeks with total serum bilirubin (TSB) usually under 12 mg/dL in term infants. Pathologic jaundice appears within the first 24 hours, rises faster than 5 mg/dL per day, or exceeds hour-specific Bhutani nomogram thresholds.

Term physiologic ceiling (~12)

Physiologic range (term, after 24 h)

Rising/pathologic — phototherapy (risk-adjusted, Bhutani)

Critically high — exchange (risk-adjusted)

mg/dL total serum bilirubin (term)

Signs & Symptoms

EarlyProgresses →

scleral icterus

yellow sclera often first visible sign

facial yellowing

jaundice begins cephalad

Late / Severe

cephalocaudal progression

spreads face to chest to abdomen as TSB rises

Other findings

yellowing on blanched skin

press skin to reveal underlying color

Diagnostics & Labs

Diagnostic

total serum bilirubin Hallmark

objective quantification; plotted against hour-specific nomogram

transcutaneous bilirubin

noninvasive screening estimate

direct Coombs test

detects antibody-mediated hemolysis in ABO/Rh incompatibility

Monitor

serial bilirubin levels

track trajectory and rate of rise

follow-up TSB 4-6 h after phototherapy

confirms level is declining

Interventions & Priorities

Phototherapy setup sequence

Undress to diaper, apply eye shieldsmax skin exposure + retinal protection
Place under light at prescribed distancecorrect irradiance
Monitor temperature every 2-4 hwatch for hyperthermia
Feed every 2-3 hdrive bilirubin out via stool
Repeat TSB 4-6 h laterconfirm decline

Treatments & Medications

phototherapy Hallmark

first-line; blue-green light 460-490 nm converts unconjugated bilirubin to water-soluble isomers

exchange transfusion

reserved for critically elevated levels unresponsive to phototherapy

Patient Teaching

feed every 2-3 hours, not on restriction

frequent feeds increase stooling and clearance

do not use direct sunlight as treatment

uncontrolled, risks sunburn and temperature instability

remove eye shields during feeds

allow visual stimulation and bonding, reapply after

breastfeeding jaundice vs breast milk jaundice

insufficient intake days 2-5 vs benign milk-substance enterohepatic recirculation after day 5-7

expect resolution by 2 weeks

persistence beyond 2 weeks needs evaluation

Complications

kernicterus Hallmark

unconjugated bilirubin crosses blood-brain barrier, deposits in basal ganglia; irreversible neurologic damage

Report Nowescalate immediately

jaundice within first 24 hours of life Hallmark

always pathologic until proven otherwise

bilirubin rising faster than 5 mg/dL per dayrise > 5 mg/dL/day

rapid hemolytic trajectory

TSB above hour-specific nomogram threshold

confirms pathologic hyperbilirubinemia needing intervention

high-pitched cry

early kernicterus sign

opisthotonus

bilirubin neurotoxicity

hypotonia progressing to hypertonia

evolving acute bilirubin encephalopathy

seizures

advanced bilirubin neurotoxicity

jaundice persisting beyond 2 weeks

evaluate for pathologic or conjugated cause

Clinical Pearl

Yellow in 24 — never okay. Jaundice before 24 hours of life is pathologic until proven otherwise: first day, first alarm.

Newborn Jaundice