You are called by the nursery nurse to evaluate a 3-day-old infant, who is feeding poorly. Delivery was by repeat Cesarean section with intact membranes at 39 weeks gestation. The prenatal course was unremarkable. All maternal labs including Group B strep status were negative. Birthweight was 3.2 kg. The Apgar scores were 6 and 9 at 1 and 5 minutes, respectively. No delivery room resuscitation was required.

The vital signs include Temperature: 99.9 rectal, heart rate 160 bpm, respiratory rate 60, weight 2.9 kg. Physical exam reveals a lethargic infant who has no dysmorphic features. The skin is yellow. The sclera are icteric. The remainder of the physical exam is unremarkable.

1) List 3-5 possible diagnoses based on the history and physical exam.

2) What additional history would be helpful?

3) What additional physical exam findings would be helpful?

4 ) What laboratory or radiology data would assist with the diagnosis?

5) Cite a current pediatric reference used to answer these questions.