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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 1-month-old girl presents to her pediatrician with her mother. The patient was born at 38 weeks gestation via Caesarian section for cervical incompetence. The patient’s mother has no complaints, although she notes that the child had a runny nose and cough for a few days last week. The patient’s mother endorses decreased appetite during the aforementioned illness which has now returned to baseline. The patient’s family history is significant for an older brother with glucose-6-phosphate dehydrogenase (G6PD) deficiency and a maternal uncle with cirrhosis secondary to chronic hepatitis B. On physical exam, the patient has scleral icterus and dark urine staining her diaper. Laboratory testing reveals the following:

Serum:
Na+: 137 mEq/L
Cl-: 102 mEq/L
K+: 4.2 mEq/L
HCO3-: 24 mEq/L
Urea nitrogen: 12 mg/dL
Glucose: 96 mg/dL
Creatinine: 0.36 mg/dL
Alkaline phosphatase: 146 U/L
Aspartate aminotransferase (AST): 86 U/L
Alanine aminotransferase (ALT): 76 U/L
Total bilirubin: 4.6 mg/dL
Direct bilirubin: 3.8 mg/dL

Which of the following is the most likely diagnosis?
assistant
Obstruction of the extrahepatic biliary tree