A 4-day-old, full-term boy is brought to the office for his first visit after an uncomplicated vaginal delivery and unremarkable newborn nursery course. The patient's mother, gravida 1 para 1, has blood type A positive, and prenatal laboratory results and ultrasound were normal. Birth weight was 3.4 kg (7 lb 8 oz) and length was 48.5 cm (18 in). He has been exclusively breastfed since birth and nurses for 10 minutes on each breast every 4 hours. The mother's milk began to come in this morning. The infant passed several dark brown, sticky, meconium stools during the first 2 days of life, but his last stool was yesterday and dark green. He has 2 wet diapers each day but has not voided today. The neonate's current weight is 3 kg (6 lb 10 oz). He has scleral icterus and jaundice of the face, chest, and abdomen. The rest of his physical examination is normal. Laboratory results are as follows:

Which of the following is the most likely cause of this infant's hyperbilirubinemia?

Question

A 4-day-old, full-term boy is brought to the office for his first visit after an uncomplicated vaginal delivery and unremarkable newborn nursery course.  The patient's mother, gravida 1 para 1, has blood type A positive, and prenatal laboratory results and ultrasound were normal.  Birth weight was 3.4 kg (7 lb 8 oz) and length was 48.5 cm (18 in).  He has been exclusively breastfed since birth and nurses for 10 minutes on each breast every 4 hours.  The mother's milk began to come in this morning.  The infant passed several dark brown, sticky, meconium stools during the first 2 days of life, but his last stool was yesterday and dark green.  He has 2 wet diapers each day but has not voided today.  The neonate's current weight is 3 kg (6 lb 10 oz).  He has scleral icterus and jaundice of the face, chest, and abdomen.  The rest of his physical examination is normal.  Laboratory results are as follows:
 
Which of the following is the most likely cause of this infant's hyperbilirubinemia?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d688_0cf5_bc81_b7bc807cdca8_MD0003_00 Breastfeeding jaundice, also known as breastfeeding failure jaundice, refers to exaggerated unconjugated (indirect > direct) hyperbilirubinemia in the first week of life that is caused by insufficient intake of breast milk. The decreased enteral intake leads to delayed stooling (ie, decreased bilirubin elimination) and increased enterohepatic circulation. Poor intake also causes dehydration (eg, decreased urinary output, excessive weight loss), which in turn leads to decreased bilirubin delivery to the liver and decreased conjugation, thereby exacerbating the unconjugated hyperbilirubinemia and jaundice. Breastfeeding challenges leading to insufficient breast milk intake can result from: Maternal factors: Delayed milk production or inadequate milk supply; infrequent feeding; cracked/clogged nipples Infant factors: Poor latch (eg, due to breast engorgement); ineffective suck; falling asleep In the first few days of life, exclusively breastfed infants actually consume colostrum (stage I lactogenesis/secretory initiation); maternal milk production (stage II lactogenesis/secretory activation) should increase significantly during the first 48-72 hours of life when infants are frequently brought to the breast for suckling. On average, exclusively breastfed newborns should feed for ≥10-20 minutes per breast every 2-3 hours. During the first week of life, the number of wet diapers a day should equal at least the infant's age in days (eg, a 4-day-old infant should have ≥4 wet diapers a day). Healthy neonates normally lose up to 7% of their birth weight in the first 5 days of life due to excretion of excess fluid acquired in utero and during labor. This 4-day-old infant with jaundice has unconjugated hyperbilirubinemia, with an indirect (= total − direct) bilirubin of 13.1 mg/dL and a direct bilirubin of 0.9 mg/dL. In addition, he has excessive weight loss (~12%) and decreased urine output (<4 wet diapers a day), both of which are signs of dehydration. Given his relatively short, infrequent feeds (10 minutes every 4 hours) and his mother's delayed milk production (>3 days), this presentation is most consistent with breastfeeding jaundice. (Choice A) Common causes of alloimmune hemolytic disease include ABO or Rh incompatibility. ABO hemolytic disease almost exclusively affects infants with blood types A or B who are born to mothers with type O blood, and Rh incompatibility does not occur in Rh+ mothers. (Choice B) Biliary atresia presents with conjugated hyperbilirubinemia (direct bilirubin >20% of total bilirubin) in the first 2 months of life. Other findings include clay-colored stools, dark urine, and an enlarged liver, none of which are present in this infant. (Choice C) Breast milk jaundice occurs in breastfed infants whose physiologic jaundice (due to normal changes in neonatal bilirubin metabolism) persists beyond the first week of life. Breast milk jaundice may be due to high levels of β-glucuronidase in breast milk, which deconjugate intestinal bilirubin and increase enterohepatic circulation. Unlike infants with breastfeeding jaundice, those with breast milk jaundice do not have signs of dehydration or feeding difficulty. (Choice E) Dubin-Johnson syndrome is a rare autosomal recessive condition characterized by conjugated hyperbilirubinemia, which this infant does not have. Affected individuals are usually asymptomatic except for mild scleral icterus. (Choice F) Galactosemia is a rare cause of conjugated hyperbilirubinemia due to galactose-1-phosphate uridyl transferase deficiency. In addition to jaundice, neonates develop vomiting and growth failure due to inability to digest galactose in breast milk or cow's milk-based formulas. Educational objective: Breastfeeding jaundice manifests as unconjugated hyperbilirubinemia and dehydration in the first week of life. Affected infants may also have decreased urine output and delayed stooling, which leads to suboptimal bilirubin elimination and increased enterohepatic circulation of bilirubin. References: Evaluation and treatment of neonatal hyperbilirubinemia. (http://www.ncbi.nlm.nih.gov/pubmed/25077393) Neonatal jaundice and human milk. (http://www.ncbi.nlm.nih.gov/pubmed/21942599)

A 4-Day-Old, Full-Term Boy Is Brought to the Office for His