A 4-day-old term neonate has total serum bilirubin of 22 mg/dL (indirect 21 mg/dL). He is exclusively breastfed and has lost 8% of birth weight. Blood group mother O+, baby A+, DAT positive. The mechanism of hyperbilirubinemia is:
- A Physiological jaundice with dehydration
- B Crigler-Najjar syndrome type I
- C ABO hemolytic disease of the newborn ✓
- D Breast milk jaundice
Explanation
ABO incompatibility occurs when a type O mother carries antibodies (anti-A, anti-B, which are IgG and can cross the placenta) against fetal A or B antigens. It predominantly affects O+ mothers with A+, B+ or AB+ babies. A positive direct antiglobulin test (DAT/Coombs) confirms antibody coating of neonatal red cells. Hemolysis with elevated indirect bilirubin results. Physiological jaundice at day 4 with this level (22 mg/dL) and positive DAT points specifically to hemolytic disease. Breast milk jaundice peaks at weeks 2–3 and is not associated with positive DAT. Crigler-Najjar presents with extreme bilirubin (>20 mg/dL) persisting beyond neonatal period.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.