Differential Diagnosis for Elevated Bilirubin in a 2-Day-Old Newborn
- Single Most Likely Diagnosis
- Breastfeeding jaundice: This condition is the most likely cause due to the newborn being exclusively breastfed since birth and presenting with elevated bilirubin levels at 2 days of age. The weight loss of 120g (about 4% of birth weight) also supports this diagnosis, as it is common in breastfeeding jaundice due to inadequate milk intake.
- Other Likely Diagnoses
- ABO incompatibility: Although less likely given the baby's blood type is A- and the mother's is O+, ABO incompatibility can still occur and cause elevated bilirubin levels. However, it is less common than breastfeeding issues in this context.
- Breast milk jaundice: This typically presents later than 2-3 days of age, but it could be considered if the bilirubin levels continue to rise after ensuring adequate breastfeeding.
- Do Not Miss Diagnoses
- Hemoglobinopathy: Although rare, conditions like hemoglobinopathies can cause significant jaundice and anemia. It's crucial to rule out these conditions due to their potential severity and the need for specific management.
- Other hemolytic diseases: Conditions such as Rh incompatibility (less likely given the blood types provided but still possible with other antibodies) or other red blood cell alloimmunizations could lead to significant hemolysis and jaundice.
- Rare Diagnoses
- Congenital infections: Certain infections can cause jaundice in the newborn period, though they are less common and typically associated with other symptoms.
- Metabolic disorders: Disorders affecting bilirubin metabolism, such as Gilbert syndrome, or other metabolic conditions can cause jaundice but are less likely to present this early and severely.
- Biliary atresia or other obstructive jaundice causes: These conditions are rare and usually present with conjugated hyperbilirubinemia, but they are critical to diagnose early for effective treatment.