Persistent lethargy, hypothermia, and failure to thrive in a neonate.

Case: A 7-day-old male presented to the emergency department of our hospital with a history of lethargy and poor feeding for 1 day. He had no fever, no vomiting, no diffi culty breathing, and no other complaints. He was born at 37 weeks’ gestation by normal spontaneous vaginal delivery, and his birth weight was 4 kg. The mother was colonized with group B streptococcus infection and received penicillin while in labor. She reported no medical history of herpes simplex virus (HSV) or any other infections. Rupture of membranes occurred 18 hours before delivery. In the newborn nursery, the mother reported that the infant had a low body temperature at 24 hours of life and required placement under an overhead warmer. His temperature stabilized and he was discharged to home at 48 hours of life. His total bilirubin level was 14 mg/dL on day of life 3, and he received home phototherapy on days 3 and 4. He did well on days 5 and 6, until day of life 7, when he presented to the emergency department.