Differential Diagnosis for a 4-week-old Boy with Jaundice
- Single most likely diagnosis
- Biliary atresia: The high direct bilirubin level (10 mg/dL) in a 4-week-old infant is concerning for biliary atresia, a condition where the bile ducts are blocked or absent, leading to direct hyperbilirubinemia.
- Other Likely diagnoses
- Breast milk jaundice: Although breast milk jaundice typically presents with indirect hyperbilirubinemia, some cases can have a mixed pattern, and the fact that the infant is breast-feeding well makes this a consideration.
- ABO incompatibility: Although less likely given the direct bilirubin elevation, ABO incompatibility can cause jaundice in newborns, especially if the mother's immune system reacts against the baby's red blood cells.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Biliary atresia (also listed as the most likely diagnosis, but included here for emphasis): Prompt diagnosis and treatment of biliary atresia are crucial to prevent liver damage and the need for liver transplantation.
- Duodenal atresia: Although the infant is feeding well, which makes this less likely, duodenal atresia can cause obstructive jaundice and requires urgent surgical intervention.
- Rare diagnoses
- Rh incompatibility: Given the mother is Rh-positive and the baby is also Rh-positive, Rh incompatibility is unlikely to be the cause of jaundice in this case.
- Other rare causes of direct hyperbilirubinemia, such as congenital infections (e.g., CMV, toxoplasmosis), genetic disorders (e.g., progressive familial intrahepatic cholestasis), or metabolic disorders, are less likely but should be considered if initial evaluations do not lead to a diagnosis.