Neonatal Jaundice (NNJ) - Complete Guide

Overview

1. Increased bilirubin production (neonatal RBCs have a shorter lifespan ~70-90 days)
2. Decreased clearance and excretion (immature hepatic glucuronyl transferase activity)
3. Increased enterohepatic resorption (reduced intestinal bacterial colonization, more deconjugation)

Types of Neonatal Jaundice

History Taking

• Blood type and Rh status (ABO/Rh incompatibility risk) - was RhoGAM given?
• Maternal antibody screen (direct antiglobulin test, DAT)
• Infections during pregnancy (TORCHS - toxoplasmosis, rubella, CMV, herpes, syphilis)
• Medications (drugs inhibiting UGT1A1: pregnanediol, novobiocin, chloramphenicol, gentamicin, atazanavir)
• Family history of hemolytic anemia, G6PD deficiency, hereditary spherocytosis, or prior neonatal jaundice requiring phototherapy/exchange transfusion

• Gestational age (term vs. preterm - prematurity is a major risk factor)
• Mode of delivery - were there birth injuries (cephalhematoma, intramuscular hematoma)?
• Any perinatal asphyxia?
• APGAR scores

• Formula or breast milk?
• Feeding frequency and duration
• Is the maternal milk supply adequate? Is latching successful?
• Signs of adequate intake (weight loss <10% of birth weight, adequate wet diapers)

• Timing of first meconium passage (delayed = obstructive cause)
• Stool color: yellow = normal; acholic (white/clay) stools = conjugated pathology (biliary atresia, neonatal hepatitis)
• Dark urine = conjugated hyperbilirubinemia
• Stool frequency

• Documented fever (sepsis)
• Vomiting or regurgitation
• Urine output (assess hydration)
• Lethargy, poor feeding, high-pitched cry (signs of bilirubin-induced neurologic dysfunction, BIND)

Physical Examination

• Yellow discoloration progresses cephalocaudally (head → face → trunk → limbs → palms/soles)
• Kramer's zones help estimate bilirubin visually, though this does NOT reliably correlate with serum levels - always confirm with lab measurement

• Cephalhematoma - collection of blood under the periosteum (subperiosteal); doesn't cross suture lines - increases bilirubin load
• Caput succedaneum - edema crossing suture lines; resolves faster
• Fontanelle: Bulging = raised ICP (meningitis, kernicterus); Sunken = dehydration

• Hepatomegaly or splenomegaly - suggests congenital infection, hemolytic disease, storage disorder, liver disease
• Masses

Differential Diagnosis

Unconjugated Hyperbilirubinemia

Conjugated Hyperbilirubinemia (always pathologic)

Investigations

• Total and direct (conjugated) serum bilirubin - mandatory to classify
• Transcutaneous bilirubin (TcB): Correlates well with TSB but does NOT differentiate conjugated vs. unconjugated; suitable only for very low-risk neonates with normal exam

• CBC + peripheral blood smear - anemia, reticulocytosis (hemolysis), polycythemia, spherocytes
• Reticulocyte count
• Blood type and Rh of mother and infant
• Direct antiglobulin test (DAT / Coombs test) - isoimmune hemolytic disease (ABO, Rh)
• G6PD level - particularly in male infants, African/Mediterranean/SE Asian ancestry
• Liver function tests - if conjugated jaundice or hepatic disease suspected
• Thyroid function (TSH/T4) - hypothyroidism
• Galactose-1-phosphate uridyl transferase - galactosemia (sick neonate with jaundice + cataracts)
• Serum albumin - at escalation of care threshold (albumin <3.0 g/dL = neurotoxicity risk factor)
• Cultures (blood, urine, CSF) - if sepsis suspected
• Abdominal ultrasound - biliary atresia, choledochal cyst
• Hepatobiliary scintigraphy (HIDA scan) - biliary atresia (absent excretion into bowel)

Management

2022 AAP Updated Guidelines (valid through 2027)

Step 1: Identify Risk Factors

• Gestational age <40 weeks
• Jaundice in first 24 hours
• Exclusive breastfeeding with suboptimal intake
• TSB/TcB close to phototherapy threshold at discharge
• Rapid rate of TSB rise (>0.3 mg/dL/hr in first 24 hrs; >0.2 mg/dL/hr thereafter)
• Family history of phototherapy or exchange transfusion
• Scalp hematoma, significant bruising
• Down syndrome
• Macrosomic infant of a diabetic mother

• Isoimmune hemolytic disease (ABO, Rh)
• G6PD deficiency or other hemolytic disorders
• Significant clinical instability in prior 24 hrs (sepsis, acidosis, asphyxia, significant lethargy, temperature instability)
• Serum albumin <3.0 g/dL

Step 2: Phototherapy

• Conventional: Banks of halogen or LED lights placed above the neonate
• Fiberoptic "bili-blanket": Placed under the neonate (useful in home phototherapy)
• Intensive phototherapy: Maximizes skin surface area exposure - multiple light sources above and below

• TSB should be measured within 12 hours of initiating phototherapy
• No benefit to adding IV fluids to phototherapy - continue enteral feeding
• Dehydrated infants may require fluid resuscitation
• Eye protection is required during phototherapy
• Monitor for bronze baby syndrome (in conjugated jaundice - don't use phototherapy)

• Permissible for infants meeting specific low-risk criteria
• Daily TSB monitoring
• Admit if TSB ≥1 mg/dL above phototherapy threshold

Step 3: Escalation of Care

• Rising TSB despite phototherapy
• Any recognized BNRF present

• Monitor TSB at least every 2 hours
• Intensive phototherapy immediately
• Prepare for possible exchange transfusion

Step 4: Exchange Transfusion (ET)

• TSB at or above the exchange transfusion threshold (approximately 25 mg/dL in low-risk term neonates, lower in high-risk and preterm)
• BIND/acute bilirubin encephalopathy signs regardless of TSB
• TSB rising despite intensive phototherapy approaching ET threshold

• Volume = 2 × blood volume = 2 × 80 mL/kg = ~160 mL/kg
• Uses umbilical venous catheter
• Replaces ~85% of the neonate's red cells
• Removes bilirubin-laden red cells, antibody-coated cells (in HDFN), and free antibodies

• Previously recommended at 0.5-1 g/kg when TSB approaches 2-3 mg/dL below ET threshold
• Two recent RCTs failed to show benefit; a meta-analysis showed a 4-fold increase in necrotizing enterocolitis
• Current stance: IVIG use in HDFN-related NNJ is discouraged (per updated evidence) - Creasy & Resnik's Maternal-Fetal Medicine

Step 5: Cause-Specific Management

Step 6: Post-Discharge Follow-Up

• Neonates discharged before 72 hours of age should be seen within 1-2 days
• Timing based on TSB risk zone at discharge, gestational age, and presence of risk factors

Kernicterus (Chronic Bilirubin Encephalopathy)

1. Athetoid/dyskinetic cerebral palsy
2. Sensorineural hearing loss
3. Upward gaze palsy (limitation of upward gaze)
4. Dental enamel hypoplasia (in deciduous teeth)

• Phase 1: Lethargy, hypotonia, poor sucking
• Phase 2: Irritability, hypertonia, high-pitched cry, fever, opisthotonus
• Phase 3: Apnea, seizures, deep stupor, coma, death

TSB >20-25 mg/dL in term neonates carries increased risk of BIND. Prevention hinges on timely screening and treatment before encephalopathy develops.

Summary Algorithm

Jaundice noted in neonate
        ↓
History + Physical Examination
Identify onset timing + risk factors
        ↓
Measure TSB (+ direct bilirubin)
        ↓
Plot on hour-specific nomogram (Bhutani)
        ↓
Below phototherapy threshold → Observe, feeding support, follow-up
At phototherapy threshold → Phototherapy (inpatient or home if low-risk)
At escalation threshold (2 mg/dL below ET) → Intensive phototherapy + STAT workup + prepare for ET
At exchange transfusion threshold → Double-volume exchange transfusion
        ↓
Treat underlying cause

Sources

• Tintinalli's Emergency Medicine: A Comprehensive Study, p. 780 (Tables 116-6, 116-7)
• Rosen's Emergency Medicine: Concepts and Clinical Practice (Tables 166.1, 166.2)
• Creasy & Resnik's Maternal-Fetal Medicine: Principles and Practice, p. 816
• Tietz Textbook of Laboratory Medicine, 7th Ed. (Box 51.2)
• Harrison's Principles of Internal Medicine, 22nd Ed.
• Quick Compendium of Clinical Pathology, 5th Ed.
• 2022 AAP Clinical Practice Guideline - Pediatrics 2022;150(3):e2022058859
• CHOP Clinical Pathway, 2022 AAP Guidance summary