Differential Diagnosis for a 3-week-old Boy with Worsening Jaundice
Single Most Likely Diagnosis
- Biliary Atresia: This condition is characterized by a blockage or absence of the bile ducts, leading to direct hyperbilirubinemia, which is consistent with the patient's laboratory results (elevated direct bilirubin). The pale stools also support this diagnosis, as bile salts are not reaching the intestines to give stools their normal color. Biliary atresia is a common cause of conjugated hyperbilirubinemia in infants and requires prompt surgical intervention.
Other Likely Diagnoses
- Neonatal Hepatitis: This condition can cause direct hyperbilirubinemia and hepatomegaly, similar to what is seen in this patient. It can be due to various causes, including infections and metabolic disorders. The normal liver enzymes (ALT and AST) do not rule out this diagnosis, as they can be elevated in some cases of neonatal hepatitis but are not universally present.
- Choledochal Cyst: A congenital anomaly of the bile duct that can cause obstruction and lead to direct hyperbilirubinemia. While less common than biliary atresia, it is another structural issue that could explain the patient's symptoms and lab results.
Do Not Miss Diagnoses
- Galactosemia: A metabolic disorder that can cause direct hyperbilirubinemia, hepatomegaly, and failure to thrive. It is crucial to diagnose early, as it requires a strict dietary change to avoid long-term complications. Although the patient is breastfed, which contains lactose (a disaccharide of glucose and galactose), galactosemia could still present with these symptoms.
- Tyrosinemia Type I: A rare genetic disorder affecting the metabolism of the amino acid tyrosine. It can lead to liver dysfunction, direct hyperbilirubinemia, and hepatomegaly. Early diagnosis is critical for management and preventing severe outcomes.
Rare Diagnoses
- Alagille Syndrome: A genetic disorder that affects the liver, heart, and other parts of the body. It can cause direct hyperbilirubinemia due to bile duct paucity. While it is a rare condition, it should be considered in the differential diagnosis of conjugated hyperbilirubinemia in infants.
- Progressive Familial Intrahepatic Cholestasis (PFIC): A group of rare genetic disorders that cause cholestasis, leading to direct hyperbilirubinemia. These conditions are important to diagnose due to their implications for liver function and the potential need for liver transplantation.