Case 1: Rapidly Rising Bilirubin Level in a 3-day-old Term Infant.

A female infant is delivered at 38 weeks and 6 days’ gestation, after induction of labor for preeclampsia, to an otherwise healthy 37-year-old, gravida 1, para 0 woman via vacuum-assisted vaginal delivery with 4 pulls and no pop-offs. The vacuum was used secondary to fetal heart rate decelerations. The mother was colonized with group B Streptococcus and received adequate intrapartum antibiotic prophylaxis. The infant is floppy at birth with a weak cry and heart rate greater than 100 beats/min. Continuous positive airway pressure is administered at 5 minutes of age because of respiratory distress, which resolves by 20 minutes of age. The infant’s Apgar scores are 4 and 7 at 1 and 5 minutes, respectively. She has a birthweight of 3.15 kg (43rd percentile). The mother and infant both have O+ blood type and screen negative for antibodies. The infant’s total bilirubin (TB) levels at 25 and 31 hours after birth are 9.1 mg/dL (155.6 μmol/L) and 11.5 mg/dL (196.7 μmol/L), respectively (Fig 1); direct bilirubin is not measured. Triple bank phototherapy (bili blanket and 2 bank overhead bili light) is initiated at 31 hours of age, because of a rapid rise in TB at a rate of 0.4 mg/dL per hour (6.8 μmol/L per hour). (Fig 1) The infant continues to receive phototherapy for 18 hours, with a subsequent TB level of 10.4 mg/dL (177.8 μmol/L). Phototherapy is stopped, and the infant is discharged from the hospital. Figure 1. Total bilirubin by age. Results displayed in conventional units. At 78 hours of age, the infant is readmitted because of a TB level of 18.9 mg/dL (323.2 μmol/L), with a phototherapy TB threshold of 18.3 mg/dL (312.9 μmol/L) and 0.30 mg/dL per hour (5.1 μmol/L per hour) rate of rise (1); direct bilirubin level is 0.63 mg/dL (10.8 μmol/L; normal <6.8 μmol/L). …