USMLE® Step 1 style questions USMLE
A 3-week-old infant comes to the emergency department with persistent jaundice for the past 2 weeks. He was born full-term via vaginal delivery with no complications. The patient’s family history is significant for liver disease, with his mother saying, “I haven’t had any problems, but my mother did.” His temperature is 36.6°C (98.0°F), pulse is 125/min, respirations are 30/min, and blood pressure is 80/50 mm Hg. Physical examination shows patient is resting comfortably with mild jaundice and no rashes. A liver panel shows:
(Normal lab values for an infant this age: total bilirubin serum concentration of <5.0 mg/dL; direct bilirubin concentration of <20%, not exceeding 0.3 mg/dL). A cholecystogram shows a normal gallbladder. Which of the following is the most likely diagnosis?