Neonatal jaundice refers to the yellow discoloration of a newborn’s skin and sclera due to elevated levels of bilirubin in the blood (hyperbilirubinemia). Bilirubin is a yellowish pigment produced from the breakdown of red blood cells.
- Clinical jaundice manifests in neonates when bilirubin > 85 µmol/L (5 mg/dL).
- In adults, visible jaundice appears at lower bilirubin levels (~34 µmol/L or 2 mg/dL).
Pathophysiology & Basic Concepts
- Hemoglobin Breakdown:
Red blood cells (RBCs) contain hemoglobin (Hb), which carries oxygen. When RBCs age (~120 days lifespan), they are removed by the reticuloendothelial system (liver and spleen).
Hb breaks down into:- Globin (reused by the body as protein)
- Heme (iron compound broken down into bilirubin)
- Bilirubin is produced from heme and normally processed by the liver to be excreted. Accumulation causes yellow staining (jaundice).
- Newborns have high Hb (18-19 g/dL) to meet fetal oxygen needs. After birth, Hb drops to ~11 g/dL in the first week, causing increased RBC breakdown and bilirubin production, often exceeding the newborn liver's processing capacity — leading to physiological jaundice.
Types of Neonatal Jaundice
1. Physiological Jaundice
- Occurs typically after the first 24 hours of life.
- Peaks by day 3-5 and resolves by day 10.
- Due to immature liver enzymes and high RBC turnover.
- Commonly seen in normal newborns; usually harmless.
- Risk factors: prematurity, bruising, polycythemia, breastfeeding.
2. Pathological Jaundice
- Appears within the first 24 hours or persists beyond 2 weeks.
- Caused by factors disrupting bilirubin metabolism or causing excessive RBC destruction.
- May cause muddy or generalized jaundice.
- Causes include:
- Hemolytic diseases (Rhesus or ABO incompatibility)
- Hypoxemia
- Sepsis
- Endocrine/metabolic disorders
- Bile duct obstruction
- Hypoglycemia
Clinical Significance and Risks
- Bilirubin toxicity: High unconjugated bilirubin crosses the blood-brain barrier → deposits in brain nuclei (basal ganglia, hippocampus, etc.) causing kernicterus (permanent brain damage).
- High serum bilirubin is an emergency to prevent neurological injury.
Diagnosis and Investigations
- Serum Bilirubin (SBR) measurement is key.
- Assess mother’s and baby’s blood group and Rh factor.
- Coombs test to detect immune hemolysis.
- Check Hb for anemia and signs of hemolysis.
- Screen for infection if suspected.
Indications to investigate further:
- Jaundice within 24 hours of life.
- Jaundice persisting beyond 10 days.
- SBR above treatment thresholds (e.g., >250 µmol/L in term infants).
- Jaundice in a sick newborn.
Management
Goals:
- Prevent bilirubin encephalopathy.
- Treat underlying cause.
- Maintain hydration and nutrition.
Phototherapy
- Converts unconjugated bilirubin into water-soluble forms (biliverdin) that can be excreted.
- Uses blue light wavelength (400-500 nm).
- Indicated for:
- Jaundice in first 24 hours
- Deep jaundice (palms and soles)
- Premature infants with jaundice
- Hemolytic jaundice
Adverse effects:
- Dehydration and increased water loss
- Loose stools
- Irritability or lethargy
- Skin rash
- Overheating
- Retinal injury (protect eyes)
- Tanning/bronze baby syndrome
- Potential nutritional deficiencies (vitamins, calcium)
Exchange Transfusion
- Considered if phototherapy fails or bilirubin rises rapidly.
- Removes bilirubin and antibody-coated RBCs.
- Thresholds vary but often around 400-430 µmol/L bilirubin.
Adjunctive Treatments
- Phenobarbital: Accelerates bilirubin clearance.
- Tin-mesoporphyrin: Inhibits heme oxygenase enzyme (bilirubin production).
- IV immunoglobulin (IVIG): Reduces hemolysis in immune-mediated jaundice.
- Activated charcoal: Binds bilirubin in the gut (experimental).
Nursing and Supportive Care
- Ensure adequate feeding and hydration.
- Monitor bilirubin levels regularly during treatment.
- Educate parents on signs of worsening jaundice.
- Protect baby’s eyes during phototherapy.
- Monitor for adverse effects of treatment.
Summary
| Aspect | Physiological Jaundice | Pathological Jaundice |
|---|---|---|
| Onset | After 24 hours | Within 24 hours or prolonged jaundice |
| Duration | Resolves by day 10 | >2 weeks, may be persistent |
| Cause | Immature liver, high RBC turnover | Hemolysis, infection, metabolic disorders |
| Severity | Mild | Often severe, may cause kernicterus |
| Treatment | Usually none or phototherapy | Phototherapy, exchange transfusion, treat cause |
