USMLE® Step 1 style questions USMLE
USMLE® Step 2 style questions USMLE
A 1-month-old infant is brought to the emergency department because of failure to thrive and recurrent vomiting. The patient was born full-term at home via an uncomplicated vaginal delivery. Shortly after birth, the patient began experiencing nausea and vomiting after feedings. The patient was at the 50th percentile for weight at birth. At today’s visit, the patient is at the 25th percentile. Temperature is 36.9°C (98.4°F), pulse is 108/min, blood pressure is 77/40 mmHg, and respiratory rate is 56/min. Physical examination reveals jaundice and hepatomegaly. Fundoscopic examination reveals bilateral clouding of the lens. Urine dipstick is negative for glucose. Additional testing reveals the presence of reducing substances in the urine. Which of the following is the most likely diagnosis?